Note that although these three resources can be exceedingly useful, they do not comprise all the scholarly publications you will want to explore for your independent work.
Whenever you identify a Ph.D. dissertation you would like to see (for instance, as a result of searching MLA International Bibliography), you should copy the title of it into the following database. This will usually provide the abstract and, for fairly recent ones, a link to the pdf of the entire work. If you can't get to the full text, either e-mail me or confer with another librarian, in person or via the chat service.
You can search by academic department, advisor, words in the thesis title, class year, or student name. If you find a senior thesis you would like to read, take the information from this database to the Mudd Manuscript Library. It is located across Olden Street from the E-Quad and between the Computer Science Building and the Carl Fields Center.