Internet Search Engines for Primary Literature

• PUBMED

  http://www.ncbi.nlm.nih.gov/sites/entrez
  One of the most well known, public search engines for (primary) publications

• OVID

  http://www.ovid.com/site/catalog/DataBase/904.jsp
  Access usually through medical center libraries; similar to PUBMED, but offers enhanced search strategies

• TRIP

  http://www.tripdatabase.com/
  Meta-search engine