The Theological Research Exchange Network (TREN) is a library of over 19,000 theological thesis/dissertation titles representing research from as many as 131 different institutions. TREN also makes available conference papers presented at annual meetings of several academic societies, including:
Evangelical Theological Society
American Society of Church History
North American Patristic Society
American Catholic Historical Association
Access TREN through the alphabetical list of databases, or directly here.