Remember to document your searches. PRISMA Item 6 requires you to "Specify all databases, registers, websites, organizations, reference lists and other sources searched or consulted to identify studies. Specify the date when each source was last searched or consulted." And PRISMA Item 7 requires you to "Present the full search strategies for all databases, registers and websites, including any filters and limits used."
At a minimum you should search MEDLINE, EMBASE, and the Cochrane CENTRAL trials register. This is the recommendation of three medical and public health research organizations: the U.S. Agency for Healthcare Research and Quality (AHRQ), the U.K. Centre for Reviews and Dissemination (CRD), and the International Cochrane Collaboration (Source: Institute of Medicine (2011) Finding What Works in Healthcare: Standards for Systematic Reviews Table E-1, page 267). Some databases have an alternate version that search the same records: the content of MEDLINE is in PubMed, while the content of EMBASE is in Scopus. You should reformat your search for each database as appropriate, contact your librarian if you want help on how to search each database.
Begin by searching:
Some sources for pre-existing database search filters or "hedges" include:
You can also try searching PubMed for another validated search filter using some variation of a search like this, possibly adding your discipline or search topic keywords: ("Databases, Bibliographic"[Mesh] OR "Search Engine"[Mesh]) AND ("Reproducibility of Results"[Mesh] OR "Sensitivity and Specificity"[Mesh] OR validat*) AND (filter OR hedge)
Searching the databases, websites, and journals listed here is not required to perform a systematic review, but may be beneficial. Note that you may need to reformat your search. You can also check our subject research guides for suggestions.
You may wish to search one or more of the following resources.
Databases:
Clinical Trial Registers. The Cochrane Collaboration recommends for a systematic review to search both clinicaltrials.gov and the WHO ICTRP (See The Cochrane Handbook, section 4.3 for more information):
Guidelines:
Grey Literature / Datasets:
Dissertations and Theses:
Other: