AIDSinfo: Clinical Trials
http://aidsinfo.nih.gov/ClinicalTrials/Default.aspx?MenuItem=ClinicalTrials
Alzheimer's Disease Clinical Trials Database
http://www.nia.nih.gov/Alzheimers/ResearchInformation/ClinicalTrials
Centerwatch: Clinical Trials Listing Service
ClinicalTrials.gov
Good Clinical Practice in FDA-Regulated Clinical Trials
http://www.fda.gov/oc/gcp/default.htm
National Cancer Institute: Clinical Trials
http://www.cancer.gov/clinicaltrials
National Center for Complementary and Alternative Medicine: Clinical Trials