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Systematic reviews: Search the literature

Search the literature

Having defined your research question(s) and written a protocol, the next stage in the systematic review process will be conducting a comprehensive literature search. You will be running the search in all the databases that you specified in your protocol. You will need to adapt the search for each database, to allow for important differences between them, such as the proprietary thesaurus. This page provides information about some of the databases available at the University of Bath and how to search them.

Introduction to library databases

Library databases provide an index to journal literature. They may also index sources such as conference papers, patents and theses. Although there is some overlapping coverage, different databases index different ranges of journals. For a comprehensive search, you need to use more than one database. Some databases, such as PubMed, are free to access, but the majority are paid for through Library subscriptions.  

The same database may be available through more than one platform, or web interface. For example, Medline is available via PubMed and Web of Science (at University of Bath), and Ovid (at other Institutions). The underlying data is the same, but because each platform uses a different search engine, you will not get exactly the same results in each one. It is important in your systematic review to specify both the database and platform that you use.

Databases for health, medicine and psychology

PubMed includes almost exactly the same records found in the MEDLINE database. MEDLINE is available on a number of platforms and your search results may vary depending on which platform you use. Therefore, when writing up your review, you must state which one you have used (so your search results can be reproduced by anyone with access to the same platform).

PubMed is a reputable and extensive health and medicine database that uses a carefully controlled MeSH thesaurus to enrich its records and it also provides sophisticated filtering options.  To make the most systematic use of this database, please refer to:

The University of Bath Library subscription to Embase is on a platform called It includes access to:

  • Embase 'classic' 1947-1973
  • Embase 1974-
  • MEDLINE 1966-

We recommend that you exclude the MEDLINE records from your search results, so that you can report results from Embase alone.

PsycINFO indexes journals, books and theses.  The University of Bath Library subscription to PsycINFO is on a platform called APA PsycNET.

If you intend to develop a previously-published systematic review, you may need to adapt their PsycINFO search strategy for the APA PsycNET platform, e.g. if Ovid-hosted PsycINFO was used by the researchers.  It follows that when writing your own review, you must state which platform used to ensure that your search can be reproduced by anyone with access to the same platform or translated for a different platform.

BIOSIS Citation Index (available on the Web of Science database platform) indexes the biology literature, including biochemistry, microbiology and immunology, from 1926 to date.

General subject databases

Web of Science Core Collection consists of the following databases.  To select those you wish to include in your search, click 'More settings'. Note: different institutions subscribe to different years. You must report the years and databases that you searched.

  • Science Citation Index Expanded:1945-present
  • Social Sciences Citation Index:1970-present
  • Arts & Humanities Citation Index (A&HCI): 1975-present
  • Conference Proceedings Citation Index - Science: 1990-present
  • Conference Proceedings Citation Index - Social Science & Humanities: 1990-present
  • Book Citation Index - Science: 2005-present
  • Book Citation Index - Social Sciences & Humanities: 2005-present
  • Emerging Sources Citation Index: 2005-present
  • Current Chemical Reactions: 1985-present 
  • Index Chemicus: 1993-present

Further databases

If we haven't listed the database you want, please check the full list of our databases to see if we provide access:

You can also browse databases and other resources for your subject.  To do this, go to the Library homepage and click one or more subjects listed in the right-hand column. This will take you to subject-specific resource sections.

Searching grey literature

For a fully comprehensive literature search, you need to consider searching for 'grey literature', a category which covers documents that have either not been formally published or are not academic sources. Not all research outputs are found in journals and the inclusion of grey literature may reduce the risk of reproducing publication bias.  

Grey literature can include, for example; conference material (papers, posters, abstracts), working papers, postgraduate dissertations, theses, clinical trial information, patents, datasets, statistics, government papers and organisational documents (reports, statements, guidelines, procedures, policies).

Find evaluated sources of grey literature in social sciences and health: go to the Library homepage and click the relevant subject(s) listed in the right-hand column. Then explore the various links presented for that subject.  You can also find grey literature via Google Scholar searches. Be extra careful when evaluating Google results (note URL domains; education sites may include or .edu; research sites may include .org).

How to do a literature search

This is a generic guide introducing the basic techniques of literature searching including choosing and using keywords. You will need to build a unique strategy for each database because each one is different. For example, neoplasm has <10 subterms in the APA Thesaurus compared to >10 in MeSH and Embase's Emtree. You will also find some database-specific advice in the guide for Pubmed, Embase and PsycINFO.

Developing a search strategy for each database

As well as being an essential source of information about completed and ongoing studies, the Cochrane Database of Systematic Reviews (CDSR) provides ideas about how to structure a search: in the appendices of their review or protocol, the authors will describe their search methods for the identification of studies in their databases of choice.

Get access to the full text

It is normally easy to discover whether or not the Library provides an item you want to read.  If you are unable to access an item via a library database, here are a few tips:

  • First try searching the Library Catalogue for the article title. If that fails, search for the journal title and check which years (if any) we subscribe to.
  • Some articles are available on open access on the web. The best way to find these is using Google or Google Scholar.  We recommend searching for the article title in double quotes " ...". so that Google searches for the exact title only.
  • You could consider emailing the author to ask them to send you a copy.
  • Consider requesting the item using the Library's Inter-Library Loans service