PubMed is a database created by the National Library of Medicine to facilitate searching the biomedical literature. The MEDLINE databases found within PubMed contains journals that have been reviewed by a panel of experts for quality. PubMed also contains PMC, which contains publicly accessible literature that have not necessarily gone through the same review process.
The Cochrane Library consists of a collection of regularly updated evidence-based health care databases. The collection is designed to provide information and evidence to support health care decision-making. It includes the Cochrane database of systematic reviews, and databases of clinical trials, and non-Cochrane systematic reviews.