Systematic Reviews: The Literature Search

CINAHL is a comprehensive database that indexes journals from the fields of nursing and allied health. Although CINAHL is not limited to evidence-based information, it is a useful source for finding evidence-based research. The Publication Type box on the Limits page contains limiters for "Clinical Trial," "Randomized Controlled Trial," "Case Study," “Systematic Review,” “Meta Analysis,” and “Meta Synthesis. There are CINAHL Headings entitled "Clinical Trial," "Randomized Controlled Trials," "Case Studies," and "Systematic Review."

PubMed provides access to MEDLINE, one of the world’s leading comprehensive databases for biomedical research, developed by the U.S. National Library of Medicine (NLM). PubMed is an excellent source to find evidence based scholarship, with both limiters and MESH headings for "Clinical Trial," "Randomized Controlled Trial," "Case Report, "Practice Guidelines, “Systematic Reviews,” and “Meta-Analysis.” The limiters are accessed under "Article Types" in the left-hand sidebar on the search results page.
-PubMed Clinical Queries, which is linked to the main search page of PubMed, has a preset filter to restrict searching to "clinical study categories" and "systematic reviews," with related research designs, including meta-analyses.
-PubMedHealth, which is also linked to the main PubMed search page, specializes in clinical effectiveness research, based on systematic reviews of clinical trials.

MEDLINE is searchable via Ovid MEDLINE. It contains the following limiters in the Subject buffer (in the left-hand sidebar of the search results page): "Case Reports," "Clinical Trial," "Practice Guidelines," "Randomized Controlled Trials," and "Meta-analysis,".

The Cochrane Library is a collection of databases. The primary output of the Cochrane Collaboration, the Cochrane Database of Systematic Reviews (“CDSR”), is a preeminent and authoritative resource for systematic reviews in the healthcare field. Reviews included in the CDSR answer a particular research question and are developed using methods found in the Cochrane Handbook for Systematic Reviews of Interventions. Because it is limited to systematic reviews, the CDSR does not have the large number of citations as databases such as MEDLINE or Scopus and as a result is easier to search.

Another Cochrane database, DARE, the Database of Abstracts of Reviews of Effects, summarizes systematic reviews that evaluate the effects of healthcare interventions. It is accessible via the “More Resources” tab on the main search page of the Cochrane Library.

The Joanna Briggs Institute (JBI) is a major resource in the field of evidence-based healthcare. JBI has developed a rigorous, standardized framework to appraise and synthesize evidence, in a manner similar to the Cochrane Database of Systematic Reviews. JBI includes seven publication types, including the JBI Library of Systematic Reviews and Systematic Review Protocols.

PsycInfo is an excellent resource for finding scientific studies in the behavioral and social sciences. There are limiters for "Clinical Trial," "Clinical Case Study," “Meta Analysis” and “Metasynthesis” in the Methodology box on the limiters page. While there is not a limiter for “systematic review,” a free text search using the string “systematic review” (with quotes) resulted in over 15,000 results.

Academic Search Complete is a multidisciplinary database.

Scopus, a large, comprehensive multi-disciplinary database of peer-reviewed research literature, is another useful resource to locate evidence-based literature, whether searching by keyword or by “indexterms,” a special search feature available in Scopus Advanced Search. Indexterms are derived from thesauri (e.g., Medical Subject Headings [“MESH”] of MEDLINE, or EMTREE of Embase) and then assigned to each record in Scopus. In particular, there are indexterms for “meta-analysis” and “systematic review.” It is also possible to limit search terms, i.e., "clinical trial," "randomized controlled trial," “systematic review” or “meta-analysis” to title, abstract, or keywords, for a more focused search, without using indexterms.

A sociology research database. Although there is no limiter for "systematic review," typing the string "randomized controlled trial" or "systematic review" with quotes will return relevant results.