No database covers 100% of published biomedical research. To avoid missing important publications, your best bet is to search multiple databases. MEDLINE (via either the PubMed or Ovid interfaces), Embase, the Cochrane Database of Systematic Reviews, and the Cochrane Register of Controlled Trials are four core databases to include in biomedical systematic reviews. You may also wish to include specialty nursing, psychology, or social science databases depending on the scope of your review.
Biomedical research and pharmacology citations and abstracts. Added functionality available with personal account.
Resource providing access to a collection of protocols and systematic reviews. Added functionality available with personal account. Good for foreground questions.
Database of controlled trials created as part of an international effort to create an unbiased, quality controlled source of data for systematic reviews. Added functionality available with personal account.
Nursing and allied health journal citations and full-text articles. Added functionality available with personal account. Good for background and foreground questions.
International psychiatry and mental health articles, reports, books and dissertations. Added functionality available with personal account.
To avoid publication bias, it is important to search for unpublished literature on your topic. Useful data may be available in meeting abstracts, white papers, and clinical trial registries. Links to several major grey literature sources are below.