CORE (COnnecting REpositories)
 A service provided by the Knowledge Media Institute based at The Open University, United Kingdom. The goal of the project is to aggregate all open access content distributed across different systems, such as repositories and open access journals, enrich this content using text mining and data mining, and provide free access to it through a set of services.
 
OPEN ACCESS THESES AND DISSERTATIONS
OATD.org aims to be the best possible resource for finding open access graduate theses and dissertations published around the world. Metadata (information about the theses) comes from over 1100 colleges, universities, and research institutions. OATD currently indexes 5,900,730 theses and dissertations. 

OpenThesis
OpenThesis is a free repository of theses, dissertations, and other academic documents, coupled with powerful search, organization, and collaboration tools.