Dissertations & Theses Global
Full text documents range back to the early-to-mid-90s, depending on the granting university. Just search for the author or title of the document you're looking for.
If you are topic-searching with keywords in this database, it is almost always necessary to use the drop-down menu to the right to limit your search terms to "All Fields (not full text) -- ALL" and to just search the citation and abstract -- not search the full text.
If the PDF of the dissertation you want to view is not available in the database, you may request the dissertation through Interlibrary Loan.