Grey Literature: Research Protocols

First launched in 1994, the Clinical Trials Listings Service assists patients in finding and volunteering for clinical trials. Today, "CenterWatch has the largest online database of industry-sponsored global clinical trials actively seeking volunteers."

"ClinicalTrials.gov is a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world." NIH database.

"The European Union Clinical Trials Register allows you to search for protocol and results information on:
interventional clinical trials that are conducted in the European Union (EU) and the European Economic Area (EEA)
clinical trials conducted outside the EU / EEA that are linked to European paediatric-medicine development."

"The ISRCTN registry is a primary clinical trial registry recognised by WHO and ICMJE that accepts all clinical research studies (whether proposed, ongoing or completed), providing content validation and curation and the unique identification number necessary for publication. All study records in the database are freely accessible and searchable."