Scientific search engines


Web search engines are essential tools in the quest to locate online information. Most people use general search engines like Google or Bing for finding general information. For finding scientific information, however, it is recommended to use a more specialised search engine. The scientific search engines, restrict their search to sites which hold scientific content, like sites of universities, scientific publishers, repositories etc. In many cases, these search engines have also access to titles from restricted e-journal portals and digital bibliographies.

Journal articles that are found with these search engines are often full-text available, sometimes for free, but other times the access is restricted to students and staff members form organisations that are subscribed to these journals. In many cases, Leiden students and staffome cases it is possible through a link on the webpage (sfx) to get access directly to the full-text of these articles.

Google Scholar

What is Google Scholar?
Google Scholar (in Dutch: Google Wetenschap) is the best known scientific search engine. In its appearance, it resembles the regular Google page. A large difference, however, is that Scholar limits its search to scientific literature.

The titles that are found by Scholar are actually also found by the regular Google, but there you would have to locate them among ‘thousands’ of other search results. Amongst others, Google Scholar can find: scientific journal articles, books, conference proceedings, open access publications, dissertations and citations.

Searches in:
It is not exactly clear which databases are searched by Scholar (Google does not share this information). However, it is evident, that, apart form all the freely available information on the internet, Scholar has access to data from many (restricted) databases, under which Elseviers’ Science Direct, Pubmed, JSTOR, SpringerLink, Wiley Interscience and Informaworld.

Search options for Google Scholar
By default, Scholar searches full text of websites and articles. With ‘Advanced Scholar Search’ it is possible to limit a search query to, for instance, title words or time period. Compared to the regular Google, Scholar offers the following extra search fields:

  • Author

  • Publication (articles from a certain journal)

  • Date

  • Subject Areas (currently only available in the English Scholar)

The use of ‘wildcards’ (? *) is not possible.


  • At the top of the screen is the title (in blue).

  • Underneath it are the author(s), data of the journal in which the article has been published, the year of publication and  the Internet source in which Scholar has found the title (in green).

  • Underneath that there is an abstract (in black).

  • At the bottom the link "Cited by .." shows a list of articles or websites that refer to the original document.

  • ‘Related articles’ shows a list with articles on the same subject.

  • ‘All x versions’ shows all websites where this article was found.

  • The ‘[PDF]' sign at the right indicates that the article is freely available in full-text.

  • The Leiden-Fulltext SFX-link will be considered below.

From title to full-text
If there is no HTML or PDF in front of an article’s title, usually this article is not freely accessible. However, many of these articles are indeed accessible for students and staff members from universities and other organisations that are subscribed to the electronic version of these journals. Using Scholar inside Leiden University’s network, you can click on the sfx-link and immediately see whether a book or article is available in digital form or otherwise where you may find the paper version.
Outside the Leiden University network it is also possible to make use of the sfx-link; to do this, go to ‘Scholar Preferences’ and select ‘Universiteit Leiden’ as library link. After creating this library link, the Leiden sfx-button will appear as default option with every article in Scholar.

Saving results
It is not possible in Scholar to save a complete list of titles simultaneously, but it is possible to download one title at a time. To do so: move the cursor to ‘Scholar Preferences’ and select one of the Bibliography Managers (Endnote, Reference Manager, et cetera).

Tips / other

  • Preferrably use the English Google Scholar, as the Dutch and other language versions lag behind. Besides, there are differences in the search results between the Dutch and English Scholar.

  • The language settings may also have an effect on the search results!

  • There is an option to receive alerts! Left top above the little envelope.

Compared to other scientific search engines

  • Easy to use.

  • In general for search queries and queries in the field of the social sciences and humanities, Scholar produces the best qualitative and quantitative results in comparison to other general scientific search engines.

  • Unlike many other search engines, Scholar also shows book titles and citations.

  • Option for E-mail alerts. 


  • It  is not clear which sources are searched by Scholar.

  • It is not possible to search by subject, for example with keywords or words from an abstract.

  • It is not possible to save or mail a list of titles.

  • Searching with ‘wildcards’ (*, ? etc.) is not possible either.

  • In the list of results, you will find the title on top (in blue), then the Leiden SFX-link (this will appear only after you have changed the preferences; see paragraph below).
  • Then follows the author(s), data from the journal in which the article was published and the year of publication.
  • Underneath that, you will find an abstract (in black).
  • At the bottom the internet source in which the title was found is shown (in black).

A mouse-click on the title will lead you to an extended version of the title in the database where Scirus found the title (for instance the publisher’s webpage or a database). If there is a link to a full text-version, you will find it here.

Because Scirus searches a very large amount of web pages, a search in Scirus will often provide (too) many results. Fortunately, it is possible to narrow down the results to a specific source: journal sources, preferred web (material from scientific repositories) or other web (all other searched web pages). Searches can also be limited by other criteria.

From title to full-text
Many of the titles you will find with Scirus are only available to students or staff members from organisations that are subscribed to the relevant (e-)journals. As in Google Scholar it is possible to register Leiden University as ‘Library Partner Link’ under ‘Preferences’. After creating this library link, by default the Leiden sfx-button will appear with every article in Scirus.

Saving results
It is possible to mail, save or export (to Endnote, Reference Manager, etc.).an individual title or a complete list of titles.

Compared with other scientific search engines

  • Scirus indicates exactly in what sources it conducts its searches.

  • The search options are more advanced than in Scholar. One can, for instance,  search by subject and limit searches to source.

  • It is possible to use ‘wildcards’ (*, ? et cetera).

  • Search results (individual titles and lists of titles) can be saved or e-mailed.


  • No citations.

  • Results contain a lot less relevant articles than Google Scholar results. 


What is OAIster
OAIster gives access to scientific publications that are accessible worldwide through the internet. Most of these publications originate from repositories of individual universities and from a growing amount of Open Archive-journals. A comprehensive list of sources (over 11.000) can be found at the OAIster website.

OAIster records are fully accessible through WorldCat, and will be included in WorldCat search results along with records from thousands of libraries around the world. OAIster can however, also be searched as a separate database.

Search options
OAIster’s basic search screen searches in several fields simultaneously, but not in the full text. Neither is full text search supported in the advanced search screen. The latter, does however offer several options to specify the search query and combine search terms. Searches on subject can be performed by choosing the field keyword or subject.


In the short title presentation (see illustration above) one can only click the title as a link. This link leads to the full title-presentation which offers, amongst others, a link to the full text version (if available), sometimes an abstract and sometimes keywords.

From title to full-text
In the full title-presentation you will find a heading ‘Links to this item’. In most cases, this link will lead you to the full-text of an article or to an audio-(video) fragment. In some cases, however, a publication may not (yet) be available.

Saving results
It is possible to mail or save a list of titles in WorldCat, for the latter you would need a WorldCat account (free).
It is not possible to download one or more titles in txt-format or to export your titles to a bibliographic program.

Compared with other scientific search engines

  • OAIster indicates exactly in what sources it conducts its searches.

  • The search results in OAIster also contain audio-(visual) material which is not found by Google Scholar.

  • It has more advanced search options than Scholar. One can, for instance,  search by subject and limit searches to source.

  • It is possible to use ‘wildcards’ (*, ? et cetera).

  • All records have a link to the full-text version.

  • Title lists can be mailed.


  • OIAster gives far less results then Google Scholar or Scirus, because its searches are limited to scientific repositories and open access publications.

  • The full-text is not always available.

  • There is no possibility to export titles to a bibliographic program.

Last Modified: 26-05-2014