PubMed® contains more than 38 million citations for biomedical literature from
PubMed is a free online search interface. Citations may include links to full text content from PubMed Central and publisher web sites
If you're used to using RamSearch or other Ebsco databases, the general layout of MEDLINE's simple search page will look very familiar - one search box, and a few buttons allowing the searcher to limit their search results after they run their first search.
Access the Advanced Search Page by clicking the "Advanced Search" link just above the Basic search box to the right.