These two databases focus specifically on history, and are the best place to begin searching for articles:

Historical Abstracts
(via EBSCOhost)

Citations and abstracts for publications covering world history (excluding the U.S. and Canada).

These general databases cover all subjects, including history:

ProQuest

Full-text articles, citations and abstracts covering all subjects.

Wilson OmniFile Fulltext

Full-text articles, citations and abstracts covering all subjects.

JSTOR

Historical full-text coverage of arts and sciences journals, many back to the 1800s. Does not contain recent issues of journals (last 3-5 years), only older issues. Includes 20 history journals such as American Historical Review 1895-1999; Journal of Modern History 1929-1999; Journal of Negro History 1916-1999.

These three databases have full text newspaper articles:

LexisNexis Academic

Hundreds of regional, national, and international newspapers; business publications, and much more.

New York Times
(1851-2001)

Full page and article images of the historical New York Times.

ProQuest Newspapers

Nine national newspapers including the Los Angeles Times and Wall Street Journal.

These next databases cover history, but from a variety of disciplinary perspectives:

Annotated Bibliography of Antisemitism

A collection of databases covering publications on antisemitism.

ATLA Religion Index
(via EBSCOhost)

Citations and abstracts for publications covering all areas of religion.

Bibliography of Asian Studies

Citations to worldwide publications on East, Southeast, and South Asia.

Electronic Research Collections

Archived U.S. State Department documents; infomation on foreign policy, etc.

HLAS Online
Handbook of Latin American Studies

Citations to publications related to Latin American topics in the social sciences and humanities, compiled by the Library of Congress.

Iter
Gateway to the Middle Ages and Renaissance

Citations to publications covering European Medieval and Renaissance history and culture.