Suarez-Almazor and colleagues demonstrated that, in a search for controlled clinical trials (CCTs) for rheumatoid arthritis, osteoporosis and lower back pain, only 67% of available citations were found by both Embase and MEDLINE. In the same way, date filters can be used to update a literature search since the last time it was conducted. The Cochrane Collaboration recommends PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) at a minimum. -. • OR – this operator is used to broaden a search, finding articles that contain at least one of the search terms within a concept. • variants in spelling (e.g.



The Literature Search. To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. Library staff are still ready to assist you with your information needs. For a comprehensive search of the literature it has been suggested that two or more electronic databases should be used (Suarez-Almazor Reference Suarez-Almazor, Belseck and Homik2000).

To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account.

The strategy follows the PICO framework and includes MeSH terms, free-text keywords and a number of other techniques, such as truncation, that have been outlined in this article.

NOTE: Discontinued as of Jan 2017, but resources are still accessible.

It is also important to search unpublished literature to reduce publication bias, which occurs from a tendency for authors and journals to preferentially publish statistically significant studies. Then enter the ‘name’ part of your Kindle email address below.


• The Allied and Complementary Medicine Database (AMED) is a database specifically for alternative treatments in medicine. • AND – this can be used to join sets of concepts together, narrowing the retrieved literature to articles that contain all concepts, for example the population or condition of interest and the intervention to be evaluated: (bipolar disorder OR bipolar depression) AND calcium channel blockers. It should identify sources to be searched (list of databases and trial registries) and keywords used in the literature (list of keywords).

Example of Boolean operator concepts (the resulting search is the light red shaded area).

However, with a vast and growing volume of published research available, searching the literature can be challenging.

Numbers in bold give the number of citations retrieved by each search. These two databases, however, are only available to either individual subscribers or through institutional access such as universities and hospitals.

Privacy The review question will guide not only the search strategy, but also the conclusions that can be drawn from the review, as these will depend on which studies or other forms of evidence are included and excluded from the literature review.
Andrea Cipriani is supported by the NIHR Oxford cognitive health Clinical Research Facility.

-, Understand the costs and funding options