As you are researching topics you will discover a variety of literature, including articles, books, dissertations, conference reports, government documents, and more. 

If your goal is to limit your search to the dissertation literature, see the options below. 
Note:  There is not a single resource in which all dissertations are indexed and freely available.
 

ASU and other UNC school dissertations (online):

~  From ~ 2010 - present, search NC Docks.
~ To find ASU dissertations:  Limit to ASU, Type, and Doctoral Dissertations.
 

Older ASU Dissertations
~  If you locate a dissertation in the library online catalog, check the availability.
~  View Online will lead you to the electronic version on NC DOCKS.
~  ASU Spec UArchives - LD 175 .D6 no. 137 is the specific call number for this dissertation in paper copy.  Make an appointment to view the item in the Special Collections Research Center.  
 

Proquest's Dissertation and Thesis Open (PQDT Open) database provides the full text of open access dissertations and theses -- free of charge. (It is a subset of a larger ProQuest subscription product.)

~  Search by topic or see the other search options.
~  Open Access full-text dissertations display in the search results.
 

ERIC database -  There is a option to Limit by Publication Type and the search results will then display only dissertations.

~  Enter your topic search.
~  Select Dissertations/Theses - Doctoral Dissertations OR one of the other choices from the Pub Type listing.
~  Consider if you want to also select Full Text. If you do not need full text immediately, you can use ILLiad to request a dissertation via interlibrary loan.
~  The results page provides citations & abstracts.  Full-text availability will have links, Full Text from ERIC.
 

WorldCat (First Search) - contains worldwide library records.  You can Limit to Internet Resources and by Publication Type.

~  Search for:  Enter a topic search
~  Limit type to:   Internet Resources
~  Subtype limits:   Any Content  >>  select  Thesis/dissertation  from the drop down menu
~  The results page will provide dissertation citations & abstracts.  Some of the Access links will be to full-text dissertations, abstracts only, or commercial pay sites.

Purchasing a dissertation is an option via ProQuest Order a Dissertation