Dissertations
If it was published after 1997, the Get Text button should link you directly to it.
If it was published before 1997, you may still wish to search for the title or author in Dissertations and Theses, since complete copies of a few older dissertations are available.
If it is not, you can try requesting via Document Delivery Services ILLiad system, but they may have trouble getting it - many dissertations have not been published, and if the only copy available is the original copy, the library that owns it may be reluctant to lend it out.