You should consult with your medical librarian about which databases should be used for the literature search, but best practices suggests a minimum of 4 databases.
From the Canadian Agency for Drugs and Technologies in Health (CADTH).
InterTASC Information Specialists' Sub-Group Search Filter Resource
Easy access to published and unpublished search filters.
MeSH on Demand identifies MeSH® terms (Medical Subject Headings) in your submitted text (abstract or manuscript). MeSH on Demand also lists PubMed similar articles relevant to your submitted text.
Conducts a statistical analysis by querying PubMed, and generates tables that list citation frequencies by journal title, authors, MeSH, substances and country, among other things. This alternate overview of the literature helps identify text terms, most common authors, journals, countries and substances.
Advanced search queries for searching drug names or diseases. Includes MeSH headings and optimal keywords.
Enter the PMIDs of the articles you found in PubMed most related to your topic. The analyzer automatically pulls the MeSH heading and keywords assigned to those articles and lists them together in a handy chart.