Some UST dissertations have been submitted to ProQuest's database. You may download any of them. To find St. Thomas dissertations, under Search Options, for School Name, type in University of St. Thomas (Minnesota).
Dissertations and Theses from universities around the world. Almost all dissertations after 1996 are in full-text, as well as many written before. Excellent source for methodologies. Reference lists area gold-mine! Use to find seminal articles on your topic.
The website states "The Networked Digital Library of Theses and Dissertations (NDLTD) is an international organization dedicated to promoting the adoption, creation, use, dissemination and preservation of electronic analogues to the traditional paper-based theses and dissertations." Find openly accessible dissertations from many countries here.
Listing of Open Access Repositories containing dissertations and theses. You can search for individual theses here, but it's best if you know where the dissertation is located or which institutions are centers for research in your field.