Many universities make dissertations and theses available electronically. For older theses that are not electronic, the Library can often borrow a copy. Consider also looking for articles and books the author has created from dissertation and thesis research.
We do not access to the ProQuest Dissertations and Theses database. About half of US theses are locked up there. Fortunately, the other half are fairly open and accessible.
Best Bets -- WorldCat and OpenDissertations
WorldCat covers all subjects and includes records for over 95 million items held in thousands of libraries throughout the United States and Europe. Search by keyword, author, or title.
Look for ☐ Thesis/dissertation on the left column of results.
Click on that box to get a (usually) much smaller number of results. (Of course, for some searches, there might not be any theses or dissertations. In that case, you will not see a box for Thesis/dissertation.)
Some authors publish their dissertations as articles or books. The titles may be different from the original title. Consider searching for those too, using the author's name.
Starting in 2010, all Appalachian State University masters theses and doctoral dissertations are available electronically through NC DOCKS. Google crawls NC DOCKS, so they are available through Google Web searches also. You can also still find them through the Library Catalog.
Click on the ASU tab, unless you also want UNCG, UNCW, and other theses.
This repository also includes faculty publications, not just theses and dissertations.
NC DOCKS is a cooperative effort to make the scholarly output of the University of North Carolina System more available to the world. Current institutional participants include Appalachian State University, East Carolina University, UNC Greensboro, UNC Pembroke, and UNC Wilmington. NC DOCKS includes many full text articles, audio recordings, dissertations, and other formats. All materials are indexed by Google and are freely available to scholars and researchers world-wide.