Proceedings Scholar Metrics: H Index of proceedings on Computer Science, Electrical & Electronic Engineering, and Communications according to Google Scholar Metrics (2009-2013)

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Los autores españoles de Biblioteconomía y Documentación según Google Scholar Citations

Lista de los autores españoles que publican en
 Biblioteconomía y Documentación según Google Scholar Citations 
15-12-2014

Autor	Institución	Citas
Félix de Moya Anegón	CSIC	4401
Ismael Rafols	UPV	2351
Victor Herrero-Solana	UGR	2252
Rafael Aleixandre-Benavent	UV	1974
Emilio Delgado López-Cózar	UGR	1822
Isidro F. Aguillo	CSIC	1795
Lluís Codina	UPF	1458
Zaida Chinchilla-Rodríguez	CSIC	1408
Evaristo Jimenez-Contreras	UGR	1379
Benjamín Vargas-Quesada	UGR	1345
Yusef Hassan Montero	nosolousabilidad	1154
María Pinto Molina	UGR	1097
José Luis Ortega	CSIC	989
José Antonio Cordón García	USAL	972
Daniel Torres-Salinas	UNAV/UGR	962
José Antonio Merlo Vega	USAL	937
José-Antonio Gómez-Hernández	UM	935
Elias Sanz-Casado	UC3M	911
Ernest Abadal	UB	825
José A. Moreiro	UC3M	823
Elena Corera-Álvarez	CSIC	789
Rodrigo Costas	CWTS	782
Francisco Javier García Marco	UNIZAR	742
Rafael Ruiz-Perez	UGR	731
Lluis Anglada	CSUC	654
Julio Alonso Arevalo	USAL	632
Elea Giménez-Toledo	CSIC	591
Jesús Tramullas	UNIZAR	590
Mari-Carmen Marcos	UPF	567
Adolfo Alonso-Arroyo	UV	550
Ángel Borrego	UB	530
Antonio González Molina	UGR	452
J. Carlos Fernández-Molina	UGR	438
Imma Subirats-Coll	FAO	433
Eduardo Peis	UGR	425
Eva Méndez	UC3M	421
Núria Ferran Ferrer	UOC	418
Cristóbal Urbano	UB	414
Raquel Gómez-Díaz	USAL	410
Jorge Morato	UC3M	407
Remedios Melero	CSIC	389
Jose Manuel Barrueco	UV	383
José Manuel Estrada Lorenzo	Portal Salud Com. Madrid	378
Virginia Ortiz-Repiso	UC3M	374
Pedro López López	UCM	367
Josep-Manuel Rodríguez-Gairín	UB	365
Antonio Pulgarin	UNEX	364
Álvaro Cabezas-Clavijo	UGR	351
Isidoro Gil-Leiva	UM	343
Cristòfol Rovira	UPF	340
Carmen Galvez	UGR	327
Miguel Villamon	UV	327
Jose R. Pérez Agüera	UCM	325
Pablo Lara-Navarra	UOC	325
Javier Guallar	UB	324
Miguel Angel Marzal Garcia-Quismondo	UC3M	315
Ana M. Muñoz-Muñoz	UGR	313
Francisco Jesus Martin Fernandez	UGR	310
Pedro Hipola	UGR	309
Tomas Saorin	UM	288
J. Carlos García-Zorita	UC3M	282
María-Luisa Alvite Díez	UNILEON	278
Daniela De Filippo	UC3M	272
Carlos Olmeda-Gomez	UC3M	263
Maria Francisca Abad	UV	263
Luis Rodríguez-Yunta	CSIC	260
Antonia Ferrer-Sapena	UPV	251
Jose G. Moreno-Torres	UGR	251
Antonio Perianes-Rodríguez	UC3M	248
Rafael Pedraza-Jimenez	UPF	248
Pablo Dorta-González	ULPGC	247
María-Dolores Olvera-Lobo	UGR	244
Jose A. Senso	UGR	243
Inmaculada José Martínez Martínez	UM	239
Natalia Arroyo	Fund. GSR	239
Tomàs Baiget	EPI	234
Aurora González-Teruel	UV	218
Sonia Sanchez-Cuadrado	UC3M	205
Felipe Zapico-Alonso	UNEX	203
Fernanda Peset	UPV	200
Nicolás Robinson-García	UGR	194
Carolina Navarro Molina	UV	193
Juan Antonio Pastor Sánchez	UM	191
José Vicente Rodríguez Muñoz	UM	189
Jose M. Morales-del-Castillo	UGR	188
Miquel Termens	UB	186
Francisco-Javier Martinez-Mendez	UM	185
Maria Luisa Lascurain	UC3M	184
Mario Pérez-Montoro	UB	183
Máxima Bolaños-Pizarro	UV	183
Javier Lopez-Gijon	UGR	181
Aurora Cuevas-Cerveró	UCM	177
José Antonio Frías	USAL	176
Carlos Benito Amat	UPV	175
David Rodríguez Mateos	UC3M	175
Jorge Caldera-Serrano	UNEX	170
Felix del Valle	UCM	148
Nieves González Fernández-Villavicencio	UPO	148
Alfons González Quesada	UAB	141
Xavier Agenjo	Fund. Ignacio Larramendi	141
Mª Antonia Ovalle Perandones	UC3M	139
Carlos González Guitián	Sergas	137
Ana Pérez López	UGR	134
Helena Martín-Rodero	USAL	134
Juan Carlos Marcos Recio	UCM	129
Francisco Javier García Gómez	UM	128
Andreu Sulé	UB	124
Enrique Orduna-Malea	UPV	121
Michela Montesi	UCM	121
Gema Bueno de la Fuente	UC3M	120
David Carabantes Alarcón	UCM	119
Izaskun Lacunza	FECYT	118
Antonio Muñoz-Cañavate	UNEX	117
Jorge Franganillo	UB	116
Jorge Serrano Cobos	UPV	116
Jordi Ardanuy	UB	115
Mireia Ribera	UB	115
María Marsá	UNILEON	114
Natalia Papí Gálvez	UA	113
Nancy Diana Gomez	UC3M	112
Elisa Garcia-Morales	INFOAREA	106
Ciro Llueca	UB	103
Joaquín Rodríguez López	futurosdellibro	102
Jose María Gómez-Sancho	UNIZAR	101
Alexandre Lopez-Borrull	UOC	100
Josep Vives-Gràcia	GENCAT	98
Marina Losada	UPF	98
Francisca Hernández Carrascal	DIGIBIS	97
Tony Hernández-Pérez	UC3M	96
Ana Ríos Hilario	USAL	95
Rodrigo Sánchez Jiménez	UCM	87
Pilar Gutiérrez Arenas	UCO	82
Teresa Agirreazaldegi-Berriozabal	EHU	81
Angeles Maldonado	CSIC	78
Antonio Malalana Ureña	CEU	78
Elena Primo-Peña	ISCII	77
Rosana López Carreño	UM	77
Lluís Rius Alcaraz	UOC	74
Vicent Gimenez Chornet	UPV	70
Marta Somoza-Fernández	UB	68
Rafael Repiso	UNIR	68
Fernando Juárez Urquijo	Muskiz	67
Pedro Rueda-Ramírez	UB	67
Amadeu Pons i Serra	UB	64
Amalia Mas Bleda	CSIC	62
Javier Leiva-Aguilera	Catorze	62
Antonio Sánchez González	UHU	60
Pilar Cid-Leal	UAB	60
Mercedes Fernández Valladares	UCM	58
Maribel Dominguez	UAH	56
Miquel Codina	UPC	55
Isabel Escalona	UNEX	54
Llorenç Arguimbau	IEC	53
Blanca San Jose Montano	Portal Salud Com. Madrid	52
Lourdes Castillo	UV	49
Fatima Pastor-Ruiz	EHU	48
Vicent Falomir Delcampo	UJI	48
Valeria Molteni	SJSU	45
Paco López Hernández	UC3M	40
Alfonso Ibáñez	Línea Directa	39
Antonio Calderón-Rehecho	UCM	39
Jorge Mañana Rodríguez	CSIC	39
Yusnelkis Milanes-Guisado	Junta de Andalucía	39
Gonzalo Mochon Bezares	UC3M	38
María Jesús Colmenero Ruiz	UC3M	38
Tránsito Ferreras Fernández	USAL	36
Jose Morillo-Velarde Serrano	CEU	35
Leticia Barrionuevo	UNILEON	35
Marta Vázquez Vázquez	USAL	35
Martinez Pestaña	UC3M	32
Ana María González García	UC3M	31
Ángeles López Hernández	US	31
Ricard Monistrol	DIFUCOM	29
Agustin Torreblanca López	MINHAP	28
Diego Marcos Cartagena	UGR	27
Antonio Eleazar Serrano López	UC3M	26
María Belén Jaén Casquero	ISCII	26
Javier Perez Iglesias	UCM	24
Milagros Ronco	EHU	24
Ricard de la Vega	CSUC	24
Silvia Sunyer-Lázaro	UPC	24
Sonia González Molina	UJI	24
David Gomez Dominguez	Junta de Andalucía	23
Josefa Gallego Lorenzo	UNILEON	23
Rafael Olivares	UGR	23
Alvaro Roldán López	ISCII	22
Araceli García	USAL	22
Irene López Navarro	CSIC	20
Ricardo González Castrillo	URJC	20
Julián Marquina	baratz	19
Victor Manuel Moya Ruiz	Telefónica	19
Juan José Generelo Lanaspa	Gobierno de Aragón	18
Miguel Ángel Sánchez Herrador	Junta de Andalucía	18
Elisa Legerén	UGR	16
Inmaculada Ribes-Llopes	UPV	16
J. Tomás Nogales	UC3M	15
Rocio Serrano-Vicente	UNAV	15
Alexis Moreno-Pulido	UNED	14
María Olaran	Olarán	14
María Victoria Játiva Miralles	UA	14
Natalia Sastre-Miralles	UPV	14
Oscar Lilao-Franca	USAL	14
Anna Nicolau Payàs	Biblioteca Nacional de Catalunya	13
Juan-Antonio Barrera-Gómez	US	13
Kebi Jimenez Rodríguez	EHU	13
Ramon J. Pujades i Bataller	MECD	13
Antonio-Paulo Ubieto	UNIZAR	12
Francisca Pulgar Vernalte	EJ-GV	12
Joan-Isidre Badell	UPF	12
Gerardo Marraud	UVIGO	11
Juan Manuel Ayllón Millán	UGR	11
Marta Abarca Villoldo	UPV	11
Miguel Ángel del Prado Martínez	CEPYME Aragón	11
Paloma Alfaro Torres	UCLM	11
Ramon Voces-Merayo	UOC	11
Raquel Vallés-Navarro	UPV	11
Francisco Rubio	UPV	10
María del Carmen Rodríguez López	UNILEON	10
Raquel Martínez Sanz	UVA	10
Víctor Cámara Bados	UCM	10
Alberto Martín-Martín	UGR	9
JA Martínez-Morilla	ULPGC	9
José Antonio Sánchez Suárez	ULPGC	9
Antonio J. Gómez-Núñez	innovatec	8
Antonio Sanchez de Mora	MECD	8
Fernando Martín Rodríguez	UBU	8
Juan José Prieto Gutiérrez	UCM	8
Sofía Arguis Molina	Gobierno de Aragón	8
Sonia Martin-Castilla	USAL	8
Consuelo Martín Vega	UGR	7
Javier Gómez Castaño	UA	7
Andres Felipe Echavarría Ramírez	N/D	6
Anna Casaldaliga	UPF	6
Carmen Aldehuela Serra	UAL	6
Enrique Muriel-Torrado	CETIEX	6
José Ángel Maestro Cano	UPV	6
Josefina Servan Corchero	UNEX	6
Susana Corullón	UCM	6
Braulio Vázquez Campos	MECD	5
Cecilia Jaques	UPF	5
Enrique de la Fuente-Gutiérrez	UGR	5
Fernando Sánchez Pita	USAL	5
Florencio Nunez	FECYT	5
Jesús Bustamante-Díaz	HEYZEUS	5
María Ángeles Morales Cáceres	UMA	5
Pilar Grande González	UVA	5
Pilar Toro Sánchez-Blanco	Junta de Andalucía	5
Rafael Ibáñez Hernández	Ayto. de Burgos	5
Isabel Sempere	USC	4
Juan Medino Muñoz	Portal Salud Com. Madrid	4
Margarita Becedas	USAL	4
Nieves Lorenzo-Escolar	EHU	4
Soledad Vicente Rosillo	URJC	4
Toni Prieto	UPC	4
Adrián A. Díaz-Faes	CSIC	3
Boton-Muñoz MPM	UCO	3
Carmen Rodriguez Otero	Sergas	3
David Aznar-Lafont	UNAV	3
Diego Martín-Campo	USAL	3
Elvira Ordoñez Cocovi	US	3
Félix Pintado Pico	ULPGC	3
MA Codina Canet	MECD	3
Maria R. Osuna Alarcón	USAL	3
Arantxa Iturbide	UNAV	2
Belen Garcia-Delgado	UEM	2
Blanca Salom Carrasco	UV	2
Carlos Martín López	snoticias	2
Elena Osorio	UNILEON	2
Eva Calatrava Barrio	UPV	2
María Teresa García Ballesteros	Junta de Andalucía	2
Ana Doñate Cifuentes	CEU	1
Ana Jiménez Royo	CSIC	1
Carlos Calvo Muñoz	UEM	1
Catalina Guzmán-Pérez	UCO	1
Ester Badia	UPC	1
Fernando Rodríguez Junco	ULL	1
Javier Alonso	MECD	1
Jon Zabala Vázquez	UCM	1
José Carlos Morillo Moreno	UHU	1
Luis-María Fernandez-Martínez	EHU	1
Maribel Manzano García	UPSA	1
Rosario Guiard-Abascal	UM	1
Ana Baíllo Almuzara	CSIC	0
Ana Carrillo-Pozas	Biblioteca Nacional de España	0
Ángel Delgado	UPO	0
Angelica-Sara Zapatero-Lourinho	UCM	0
Antonia María Fernández Luque	Junta de Andalucía	0
Antonio Casado Poyales	UCLM	0
Beatriz Tejada Carrasco	UNED	0
Begoña Gimeno Arlanzón	UNIZAR	0
Belén Novoa-García	UPCOMILLAS	0
C Ruiz de Villegas	UCO	0
Carme Julià-Gil	UJI	0
Consuelo Gallardo Izquierdo	COP	0
Dolores Marset-López	UA	0
Elvira Curiel-Marín	UGR	0
Elvira Sanchis	GVA	0
Fernanda Garzón-Farinós	UCV	0
Gemma Armengol Roca	FPHAG	0
Gloria Lence	CSIC	0
Jordi García Gozálvez	UJI	0
José Antonio Moral-Muñoz	UGR	0
Josefa Romero Martinez	UM	0
Laura Donadeo Navalón	CSIC	0
Lidia París Folch	UJI	0
Luis Díaz del Río Romero	UC3M	0
Mª Begoña Gomez Rivero	UBU	0
Manuel Jose Villegas Lirola	Níjar	0
Manuel Ruiz de Luzuriaga	UNAVARRA	0
María del Carmen Martín-Marichal	ULPGC	0
María Luisa González Ayala	ULL	0
Maria Luz de andres	Portal Salud Castilla y León	0
Maria-Ángeles Sánchez-Beato-Espiau	UCLM	0
Marta Abad López	USC	0
Miguel-Ángel Vera-Baceta	UM	0
Pablo García Hernández	UC3M	0
Paz Ganan	UCM	0
Reyes Rojas García	US	0
Rosa Gómez-Albiñana	UJI	0
Salomé Eslava Ochoa	UNAV	0
Víctor Macías-Alemán	ULPGC	0

The most cited documents in Google Scholar & Web of Science: two sides of the same coin

As one more example of those unlikely but still curiously recurrent cases of two different teams simultaneously studying the same research problem, two studies on highly cited documents have been released this week with barely a few hours of difference between them. One of them was published by Van Noorden, Maher & Nuzzo in Nature. The other one was submitted by Martín, Ayllón, Orduña & Delgado López-Cózar to the arXiv repository.

The first one studies the top 100 most cited articles in Web of Science on the ocassion of the 50^th anniversary of the Science Citation Index (SCI), although it also offers an alternative list containing the top 100 most cited documents in Google Scholar. Additionally, the authors comment many of these articles individually and their contribution to the advancement of science.

Conversely, the second study, carried out in the ocassion of Google Scholar's 10^th anniversary,  takes a different approach to the same issue, analysing the highly cited documents in Google Scholar (a sample of 64,000 documents published between 1950 and 2013). Among other things, we compare the ranking obtained from Google Scholar data to the most cited documents in Web of Science.

This unique event has an interesting side effect, since it allows us to compare and verify the validity of the methodologies used and the results reached in both studies.

Our conclusion is that Google Scholar presents a different view to the one we were used to after many years using the Web of Science (50% of the highly cited documents in GS are not indexed in WoS). 

However, if we analyse only those documents that are indexed both in Google Scholar and the Web of Science (32,680 documents in our sample), Google Scholar presents a very similar portrait of the world of research to the one offered in Web of Science, with a significant difference: 91.6% of the documents have received more citations in GS than in WoS. Only 3,079 documents (9.4%) have more citations according to WoS than in GS. Furthermore, the average number of citations per document in GS is 1.79, and 1.08 in WoS, which means that on average, GS has 70% more citations per document than WoS.

Our recommendation: read, and compare

Academic Search Engines: A quantitative outlook, by José Luis Ortega

The recently published book entitled “Academic Search Engines: a quantitative outlook“ (Chandos Publishing) is the first monograph that deals in a joint, general, and exhaustive manner, with the topic of Academic Search Engines. And this makes itself immensely valuable. With this book we’ll have a complete view of the past, present and even the future of the tools whose aim is to improve the search and discovery of scientific information on the Web. The novelty of this work dwells both in the originality of the subject, and in the perspective from which it is approached: in a quantitative manner, instead of mere qualitative.

Reading this book we’ll learn the details of not only all the features, search functionalities, and the specifics of the information retrieval techniques used by these academic search engines, but also their coverage (the sources from which they feed, the number of documents that they cover and their typologies). In short, all the essential and necessary information to assess the quality of all these information systems, namely:

• the thoroughness and accuracy of their contents,
• the effectiveness of the tools used to retrieve and extract content
• the quantity, variety and quality of the results that they display.

The products that the book analyses are the following:

CiteSeerx, Scirus, AMiner, Microsoft Academic Search, Google Scholar, BASE, Q-Sensei Scholar, WorldWideScience

Each one of these academic search engines is subjected to a detailed analysis in its own chapter of the book, except the last three (BASE, Q-Sensei Scholar, WorlWideScience), which are examined together. The analysis is not merely descriptive, for the commentary is both incisive and critical, which allows the reader to quickly discern the strengths and weaknesses of each search engine.

After reading each one of these chapters, the conclusion is clear: academic search engines are so different in concept, purpose, and design, and deliver very different features and results, to the point that they cannot be easily compared.

Nonetheless, without any doubt, the most suggestive chapter is paradoxically the last one, where the author executes a comparative analysis of all search engines whose goal - in the author’s own words - is none other than “to analyze together these systems from different perspectives which contribute to have a multilayer view on the performance of each search service. In this way, this comparative approach would explain in a different form the advantages and shortcomings of each search engine in relation with the other ones, which would stress the significance of these facets. With that, it is not intended to do a competitive process to select the best search engine for scientific information, but to contextualize the performance of these search tools in relation with the other ones as a way to describe its advantages or to mark their weakness.”

Summarizing, these are the results of the comparative analysis:

• Google Scholar is the most exhaustive and complete academic search engine since it presents a deep crawling of the academic Web with a wide range of sources. And the duplicate management is rather satisfactory as well.
• According to the source types, Google Scholar is the search engine that feeds from a wider range of sources.
• From a qualitative point of view, Microsoft Academic Search has proved to be the best profiling tool, because the structure of the entire site is built around profiles at different aggregated levels.
• If the search interfaces are observed, BASE and Scirus are the services that produce better performance, whereas AMiner could be considered the worst engine in this aspect.
• According to their exporting features, BASE is still the best solution according to the number of different formats, although WorldWideScience and CiteSeerx are the tools allowing a larger number of records to download.

As it occurs in all endeavours of life, “nobody is perfect”, and that’s why it is not surprising this comparative analysis hasn’t been able to discover the ideal and perfect search engine: all of them stand out at least in one aspect, and at the same time, all of them are outperformed by the rest in many other aspects. As the author appropriately concluded, “As it has been seen throughout this benchmarking exercise, it has not been possible to appreciate what is the best system because it depends of each user’s needs.”

The principal problem of this book is that problem which affects all books that deal with technological topics, especially those discussing individual software or hardware products: obsolescence. Since technology is constantly changing and products are updated incessantly, it may happen that a product accessible at the time the book is being written (or a version of the product analysed) greatly differs from the time when the book is published, even to the point of being unrecognisable each other. Therefore, it may happen that a product analysed in a book is already dead by the time the book is released (such as Scirus), or that it is about to (Microsoft Academic Search). This, however, doesn’t diminish the interest of the book in the slightest, since from a scientific point of view, it is essential to know the contributions and solutions that every product has implemented to solve the problem of the search, retrieval and evaluation of scientific information on the Web.

Portrait of Google Scholar and its derivative products Scholar Metrics & Scholar Citations

Of special interest to our blog is the empirical analysis the author carried out on Google Scholar and its derivative products Google Scholar Metrics and Google Scholar Citations. Apart from describing in detail how the search engine works, the most relevant information, from our point of view, is the empirical data about its coverage:

• Google Scholar contains 109.3 millions of document, from which 94.74 millions (86.7%) would correspond to scientific documents and a 14.5 (13.2%) millions of Courts opinions, or Case laws.
• The distribution of publications over time is quite irregular, marked by peaks and valleys. These results suggest a slow increase rate with important freshness problems.
• Apart from legal documents, the dominant document type in GS is the “academic paper” (although the text doesn’t clarify it, we assume it is referring to journal papers), which represents 46.8% (44.4 million documents), followed by patents (19.6%; 18.55 million), and books (12.1%; 11.46 million). Moreover, the 21.1% of documents are included in a category that is not really a document type (citations), but just a bibliographic reference to a document that GS hasn’t been able to locate on the Web, only in the reference lists of other documents. It could be a book, a book chapter, a report, a journal paper, conference proceedings… Therefore, there is an elevated fraction of documents whose typology we still ignore.
• Regarding the sources from which GS extracts information, it is should be noted that 58.8% of the documents in GS come from publishers such as SpringerLink or ScienceDirect, 8.2% from Google Patents and Google Books, 28.1% corresponds to open access repositories (thematic repositories 16.9%; institutional repositories 11.8%) and finally the 4.7% from bibliographic services. However, it is worth remembering that these data have been obtained through queries that used the “site:” query command, which is not entirely reliable since it only offers approximate hit counts and not an exact number of documents. Also, it is only taking into account the primary versions of the documents, and not the rest of the versions, which may be stored in a great variety of hosts.
• Google Scholar’s search system shows serious inconsistencies that put the reliability of the search engine into question, especially about the estimated number of results displayed in the queries, and the limitation of 1,000 results per query.
• Google Scholar has significantly improved over time the management of duplicates, and corrected document parsing and erroneous citation counting and assignation.
• In December 2013, it is estimated that Google Scholar Citations contained 350,000 author profiles, with 18.3 millions of papers assigned to these profiles.
• The countries with a higher presence of author pages are the United States (24.8%), the United Kingdom (6.4%) and Brazil (5.3%).
• Three of the organizations with more profiles are from Brazil: Universidade de São Paulo (1.3%), Universidade Estadual Paulista (0.6%) and Universidade Estadual de Campinas (0.4%). After these, the author finds the most usual organizations in research rankings, such as the University of Michigan (0.5%), Harvard University (0.4%) and the University of Washington (0.4%).
• As regards the thematic coverage inside Google Scholar Citations, an overwhelming majority of the author profiles belong to researchers in the area of Computer Science. It is surprising the absence of profiles with labels related to relevant scientific areas such as Medicine, Chemistry and Physics.
• It is estimated that Google Scholar Metrics contained nearly 30,000 journals at the end of 2012.

After this exhaustive quantitative overview of Google Scholar and its derivative products, we want to point out some discrepancies and contradictory data with the results previously presented by our research group (EC3 Bibliography). These differences, from a technical and methodological point of view, open a fascinating scientific debate, and they demonstrate one more time the difficulty of making size estimations for tools with such an opaque and dynamic nature as these search engines.

There is only one thing to question ourselves: What is the future that awaits to these search engines? A search engine, regardless of all its sophisticated tools for searching scientific information, is designed to be used. Do we have data about the past and present use of these search engines? Trying to zero in on this issue, we have tried to determine which are the most popular academic search engines according to users’ queries, as measured by Google Trends. We have generated the charts both including Google Scholar and leaving it out, to be able to observe the differences. The results speak for themselves: there is ONE search engine above all the rest, which in practice becomes irrelevant today.

To sum up, and going back to the study that is the object of this review, we must conclude as we started: we are facing an essential reference work in the history of the search for scientific information on the Web in general, and specifically on the academic search engines.

You can buy this book here.