| MEDLINE (from 1966 through 03/25/2009) | University hospital Medical Information Network (UMIN) Clinical Trials Registry (for Japan) – UMIN CTR |
| Cochrane CENTRAL1 (from 1948 through 03/25/2009) | |
| Cochrane Database of Systematic Reviews (CDSR) (through 03/25/2009) | AstraZeneca Clinical Trials web site |
| Database of Abstracts of Reviews of Effects (DARE) (through 03/25/2009) | Bristol-Myers Squibb Clinical Trial Registry |
| Eli Lilly and Company Clinical Trial Registry | |
| Health Technology Assessment (HTA) (through 03/25/2009) | GlaxoSmithKline clinical trial register |
| African Index Medicus | |
| LILACS | Australasian Medical Index |
| Index Medicus for the South-East Asia Region (IMSEAR) | World Health Organization, Regional Office for the Eastern Mediterranean |
| Ukraine and the Russian Federation Panteleimon | The Institute for Scientific and Technical Information (Institut de l’Information Scientifique et Technique) of the French National Center for Scientific Research |
| Western Pacific Western Pacific Region Index Medicus (WPRIM) | |
| Turning Research into Practice (TRIP) database | IndMED |
| ProQuest Dissertation & Theses Database | KoreaMed |
| National Technical Information Service (NTIS) | OpenSIGLE |
| Conference abstracts Biosis.org | NHS Evidence - National Library of Guidelines |
| Australian National Health and Medical Research Council Clinical Practice Guidelines | New Zealand Guidelines Group |
| Canadian Medical Association – Infobase Clinical Practice Guidelines | NICE; National Institute for Health and Clinical Excellence (UK) |
| National Guideline Clearinghouse (US) | Pharmaceutical Industry Clinical Trials Database (ABPI/CMR) |
| Hong Kong clinical trials register - HKClinicalTrials.com | The Australian New Zealand Clinical Trials Registry |
| CenterWatch | |
| Indian clinical trials registry - Clinical Trials Registry-India (CTRI) | CenterWatch |
| ClinicalTrials.gov | |
| International Clinical Trials Registry Platform Search Portal | CORDIS: Community Research and Development Information Service |
| International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) Clinical Trials Portal | Current Controlled Trials |
| Platform Search Portal | |
| International Standard Randomised Controlled Trial Number Register | European Medicines Agency |
| Netherlands trial register | World Health Organization (WHO) International Clinical Trials Registry |
| South African National Clinical Trial Register | GlaxoSmithKline (GSK) Clinical Study Register |
| UK Clinical Research Network Portfolio Database | Novartis Clinical Trials |
| UK Clinical Trials Gateway | Roche trials database |
| UK National Research Register (NRR) | Wyeth (formerly Pfizer) clinical trials registry |
| Clinical study results for U.S.-marketed pharmaceuticals | |
| Bristol-Myers Squibb clinical trials database |
1
CENTRAL includes results of systematic searches of clinical trials from several databases such as Medline and EMBASE, as well as from handsearching journals and conference proceedings.