Introduction: OAIster is a union catalog of millions of records that represent open access resources. This catalog was built through harvesting from open access collections worldwide using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). Today, OAIster includes more than 50 million records that represent digital resources from more than 2,000 contributors.
Available period: till Dec. 31, 2019
Link: OAIster