1809-present. Produced by the National Library of Medicine. The major database for the medical literature. The database is freely available but using this link enables access to subscription-based journal content.
Cochrane Reviews are systematic reviews of primary research in human health care and health policy, and are internationally recognised as the highest standard in evidence-based health care. They investigate the effects of interventions for prevention, treatment and rehabilitation. They also assess the accuracy of a diagnostic test for a given condition in a specific patient group and setting."
Open access journal, under editorial control of the Campbell Collaboration, "an international research network that produces systematic reviews of the effects of social interventions." Read more about preparing systematic reviews and the Campbell Collaboration's requirements on their authors page.
The Cochrane Library is a collection of six databases that contain different types of high-quality, independent evidence to inform healthcare decision-making, and a seventh database that provides information about groups in The Cochrane Collaboration.