A dissertation is a thesis submitted as a requirement for a doctoral degree. Library catalogs often use the technical term thesis: e.g. "Thesis (Ph.D.)."
There are different types of doctoral programs in music. The most frequently encountered are
D.M.A. (Doctor of Musical Arts): a performance degree
Ed. D. (Doctor of Education)
Ph.D. (Doctor of Philosophy): musicology, ethnomusicology, theory, composition.
While D.M.A. dissertations may be particularly useful to performers, Ph.D. dissertations tend to examine the topic in greater depth and to offer more extensive bibliographies.
Dissertations and Theses Full Text (ProQuest)
This is the primary bibliographic tool for dissertations in all disciplines, but coverage of titles from outside the U.S. is spotty. Master's theses are included selectively. PDFs of many dissertations are available for download, but note that others are unavailable due authors' restrictions. Also, some titles have no abstract: for these, references to the print editions of Dissertation Abstracts International, American Doctoral Dissertations, and Masters Abstracts indicate where the abstract may be found. (Dissertation Express is ProQuest's free site for searching and ordering dissertations. It contains no abstracts.)
NDLTD: Networked Digital Library of Theses and Dissertations
In recent years numerous universities, including Emory, have switched to electronic dissertations and theses (EDTs). This site provides access to EDTs from the various schools. (To search, choose the "VTLS Visualizer" option.) Many can be downloaded free.
RILM Abstracts of Music Literature
Coverage starts with 1967 and is international in scope. To limit your results to dissertations, use the Advanced Search and specify "doctoral dissertation" as the Publication Type.
There are two ways to obtain dissertations that Emory doesn't own or provide via online access.
About foreign dissertations at the Center for Research Libraries