Scholarly articles -- critical analyses of particular plays, directors, actors, etc. -- can be found in journals and in books (such as collections and conference proceedings). Most databases will find articles in newspapers and magazines, others include books.
You can often retrieve articles from a database. However, the print version of the article may be the best one for your needs. If there are any photos, their quality will be much better than in the online version, and sometimes the online version doesn't include the photos at all. Also, in general it's easier to read print than screens.
Another type of criticism are the performance and book reviews written in the popular literature. Reviews and criticism often overlap. For more information, see Reviews.
You may also be interested in Artslynx's list of Theatre Journals, Magazines and Publications.
IBTD comprises the most comprehensive index of publications on all aspects of theatre and performance in 126 countries, from 1982 to the present. Many articles are available in full text online, as are several dozen complete books.
IIPA covers a broad spectrum of the arts and entertainment industry, including drama, theater, stagecraft, musical theater, dance, film, television, broadcast arts, circus performance, comedy, storytelling, opera, pantomime, puppetry, magic and more.
The MLA Bibliography indexes critical materials on literature and language. Its orientation is literary but it does list some articles focusing on performance. Note that it covers only modern languages -- for resources on classical theater and drama, see the Classics subject guide.
Arts & Humanities Citation Index (via Web of Science)
An international index to literature on the arts and humanities, indexing the contents of about 6,100 journals, covering about 1,000 fully and about 5,100 selectively.
The Dramatic Index. Boston: Boston Book, 1909-1949.
LSF AI3 M343 (LC)
Also known as Annual Magazine Subject-Index. Indexes articles and illustrations in American and English periodicals, and includes books, printed plays, government publications, and pamphlets.
Humanities Full Text (via WilsonWeb)
Humanities Abstracts indexes and abstracts articles from 400 English-language periodicals in all major scholarly fields. Coverage includes some of the best-known scholarly journals and numerous lesser-known but important periodicals.
Additional periodical indexes can be located in Orbis by using the following subject headings:
NOTE: When you search subject headings, use the spelling THEATER, not THEATRE.
TIME SAVER: You can often save yourself work by looking at existing bibliographies, which often include both books and articles. You can then locate more recent research by using article indexes and Orbis.
You can speed up your research process by searching several databases simultaneously. To do this, you can click on the link above. Or from the library's home page go to the Databases and Article Searching page. Then click on the link for Multi-Database Search (near the top of the page). Along the left there's a column with some options. Under Category, choose Arts. Then choose "Drama, Theater, Dance" from the list. If you need more articles on plays, you should also try the multi-database search for particular languages/literatures.
The Multi-Database Search feature covers the following databases: Arts & Humanities Citation Index, Humanities Full Text, International Bibliography of Theatre and Dance, International Index to the Performing Arts Full Text, MLA Bibliography, and Orbis. You can exclude databases if you like. However, there are several caveats:
In short, this is a quick-and-dirty search tool.
There are a few databases that are especially useful for media and popular culture, but the subject is covered to a greater or lesser extent by a large number of databases. For many purposes one can get by using a general database, but specialized databases go into more depth.
Use Academic Search Premier to search for articles in thousands of different scholarly journals and general interest magazines. Coverage extends back to the mid-1980s.
Humanities Full Text indexes and abstracts articles from 400 English-language periodicals in all major scholarly fields. The full text is available for many articles. Coverage includes some of the best-known scholarly journals and numerous lesser-known but important periodicals.
CMMC offers cover-to-cover indexing and abstracts for more than 570 journals on communication, mass media and related fields, selected coverage of nearly 200 more, and has the full text online for over 450 journals.
Indexes over 330 international periodicals. Use the Film Index for articles on TV shows. In addition to the usual types of searches, one can search for articles on a particular television series or show.
By going into Advanced Search, one can search search for articles on a TV series or show (choose the REVIEWS & PRODUCTS field).
IIMP indexes more than 400 music journals, and includes coverage of popular music. Use the Narrow Subject field for topical searches; I recommend using the "select from a list" link to find out how IIMP describes a genre. For instance, it uses "Rock 'n' Roll" and "Hip-Hop," which a lot of people would write as "Rock and Roll" and "Hiphop." It also alphabetizes in a way that ignores spaces (e.g., "Rap Music" follows "Ralph").
IIPA draws its current content from more than 200 international periodicals and also indexes articles and obituaries appearing in the New York Times and the Washington Post. IIPA covers nearly all aspects of the world of performing arts, including film, music, television, theater, and opera.
Although the MLA Bibliography mainly indexes critical materials on literature and language it does list some articles focusing on media, graphic novels, and various other topics.