In Library resources, the words "theses" or "thesis" used alone includes both doctoral dissertations and master's theses.
The primary database for searching and identifying theses and dissertations is ProQuest Dissertations & Theses Global. It includes millions of full-text dissertations, the majority of which were published after 1997, but hundreds of thousands of titles published before 1997 are also available. In addition to the full-text content, citations for over 5 million dissertations and theses are included.
If you know the exact title of the thesis, put quotes around the title.
CRL holds more than 800,000 doctoral dissertations from almost 100 universities outside of the U.S. and Canada. The bulk of the collection are dissertations written in the late 19th century and the early 20th century, but dates range from 1800 to the present. The University of Delaware Library is a member of CRL and can borrow dissertations requested by UD faculty, students, and staff.