ASE is a good general-purpose database that includes both scholarly and popular material covering virtually all subject areas. Some items are available in full text and others are indexed only. Utilize the Subject Terms button in the top bar for more precise results.
"The definitive research tool for the study of theatre and the performing arts...[contains] over 60,000 journal articles, books, book chapters and dissertation abstracts on all aspects of theatre and performance in 126 countries."
MLA International Bibliography offers a detailed bibliography of journal articles, books, scholarly websites, and dissertations. Produced by the Modern Language Association, the electronic version of the bibliography dates back to the 1920's and contains over 2.3 million citations from more than 4,400 journals & series and 1,000 book publishers, including over 100,000 citations for works on film, television, and radio.