The Modern Language Association (MLA) Bibliography on line: a good source for articles published in the last two decades or so.
Project Muse , an online collection of flagship journals in the humanities
The Johns Hopkins Guide to Literary Theory & Criticism , online
The Oxford English Dictionary online
Special dictionaries pertinent to the period, language and places you are interested in. These might include but not be limited to: The Oxford Dictionary of Modern Slang, ed. John Simpson; Black Talk: Words and Phrases from the Hood to Amen Corner , ed. Geneva Smitherman; The Dictionary of American Regional English; or Shakespeare's Bawdy (sexy double entendres through the Renaissance)
Periodicals in your fields of inquiry: ask your teachers what the most useful ones are
The Cambridge Histories of different periods and genres of literature in English
LEXIS-NEXIS academic universe : an on-line database good for finding recent interviews with living authors, reviews, etc.
TRIPOD caveat: when using subject searches on TRIPOD, don't just use what comes into your head, as it may or may not approximate the subjects headings actually keyed and may often result in falsely negative responses. Go directly to the source employed by the higher powers of the database and use it to select your search terms; that is, the Library of Congress Subject Catalogue, located in Canaday.