Search IUCAT for (but note that more recent IU dissertations may not yet be available there, in which case try the resources listed below). In IUCAT enter: thesis AND "Indiana University". Then enter your topic as another keyword.
We also have digital thesis and dissertations in our institutional repository, IUPUI ScholarWorks.
Theses and Dissertations Database
ProQuest Theses & Dissertations Global includes dissertations and dissertation abstracts for most US academic institutions. If the full text of an item is unavailable, request it through Interlibrary Loan.