Many theses and dissertations are available in full text online through an online database or Institutional Repository. For those that are not, you can try to request the item in one of two ways:
If you find an abstract of the dissertation in a database Mount Holyoke subscribes to but no full text, try clicking on the red "MHLinks" button to see if it is available in full text somewhere else.
You can also request theses and dissertations through ILLiad. (If this is your first time using ILLiad, you will need to sign up by clicking the link at the bottom of the page.) For a dissertation, make sure that you request the item in ILLiad as a book, not an article. Note that some theses and dissertations do not circulate to other libraries, and may not be available.