PQDT Global provides searchable citations and abstracts to dissertations and theses.
Database offers full text for most of the dissertations added since 1997. Dissertations are archived as submitted by the degree-granting institution. Some will be native PDF, some PDF image.
Each dissertation published since July 1980 includes a 350-word abstract written by the author. Master's theses published since 1988 include 150-word abstracts.