On the left side of the library's home page, click on "OSCAR - Library Catalog" to go to the OSCAR search page, and then click on "Advanced Search." In the first box, type the department--such as computer engineering, etc., and then in the box labeled "Optional Search Limits/Sorts," look for the drop-down menu under "Location," and select "University Library Graduate Theses." (You may also search by author or title if you know which thesis you are looking for). Click "Submit" to do the search.
Theses are part of special collections, and print copies can only be viewed in the library (ie. not checked out) IF there is only one copy archival copy (ARS SCU Theses). To retrieve a print copy, copy the catalog record (or e-mail the record to yourself) and send your request to one of the Archives & Special Collections contacts: Archives Request
If there are additional copies available--those that indicate "Main Stacks" as part of the location can be checked out.
Electronic copies of graduate theses are searchable in Scholar Commons.