EThOS : This Web site indexes UK dissertations and provides links to full text where available and provide assistance to institutions digitizing dissertations. Many of these are available electronically, at no charge, directly from the publishing institution.
Worldwide Theses held in digital repositories worldwide are usually available to read online.
The following repositories aggregate thesis records from universities and other research institutions: Networked Digital Library of Theses and Dissertations NDLTD - A large thesis index with links to many fulltext records.
Dissertations range from approximately to the present. No full text is available online, but items can be ordered through inter-library loan by students, faculty, and staff.
Note that these are online theses only.