There are many potentially helpful journal databases; see the link on the Articles/Databases tab for a list appropriate for Theatre. Additionally, the following are useful for music theatre. These can be accessed either from the links provided here, or from the Research Gateway linked from the Library Homepage.
IIMP Full Text
“IIMP” stands for “International Index to Music Periodicals." It provides indexing and abstracts for more than 420 international music periodicals, plus full text for around 80 journals. Articles examine a wide spectrum of musical subjects, including music education, performance, ethnomusicology, musical theatre, theory, popular music forms and composition. Because many journals includes reviews, unless you particularly need review material you should check the “Exclude reviews” box on the search page.
RILM contains bibliographic information about books, periodical articles, dissertations and reviews published between 1967 and the present day. You can limit your search by language (for example, you might only want material in English, or in French); by year of publication; and by publication type, such as “monograph”, or “dissertation”. One big advantage of RILM over most other music databases is that in many cases the database provides you with an abstract – that is, a summary of what a particular article or book is about. This is particularly helpful in cases where you have found a lot of references and want to work out which are going to be the most relevant.