Science direct: www.sciencedirect.com
Ovidmedline: www.ovid.com
Pubmed: www.ncib.nlm.nhi.gov/pubmed
MDConsult: www.mdconsult.com
Cochrane Library: www.cochrane.org
Essentialevidence: www.essentialevidenceplus.com
Controllled trials: www.comtrolledtrials.com
Up to date: www.uptodate.com