Dissertation Abstracts provides abstracts of U.S., Canadian, British, and other European dissertations and theses from 1861 to the present. The amount of additonal material varies, but may include the first several pages of the dissertation (including the table of contents), references, and in a few instances, the full text of the dissertation.
Getting Started: Other Databases
Many specialized article databases index dissertations and theses and may provide abstracts; not fulltext. These include (not an exhaustive list):
WorldCat is universal in subject scope and includes records for over 95 million items held in thousands of libraries throughout the United States and Europe. Search by keyword, author or title. Hint: Some authors publish their dissertations as books, potentially changing the original title.