ProQuest Dissertations & Theses Global
Comprehensive collection of full text dissertations and theses since 1997 and strong retrospective full text coverage for earlier periods. Includes MSU dissertations and theses. Default search is for all fields except full text; go to Advanced Search and choose "Anywhere" from dropdown menu to search within full text.
Cómo buscar tesis doctorales… y encontrarlas (en el Blog de la BNE)
A discussion of other open access options.
Networked Digital Library of Theses and Dissertations
More than one million records of electronic theses and dissertations. Some full-text available, usually on institutional websites.