The following two databases cover all business topics and are the best place to begin searching for articles:

ABI / Inform
(via ProQuest)

Full-text articles, abstracts and citations to publications covering business, management, and economics. Includes full-text of the Wall Street Journal from 1984.

These next databases focus on specific business areas:

Business & Industry

Company, industry, market and product information from trade and industry publications.

Emerald Fulltext

Current full-text articles on management topics.

Literature of the Nonprofit Sector
(via The Foundation Center)

Citations and abstracts to publications on philanthropy, foundations, the nonprofit sector, and charitable giving.

These two databases have full text newspaper articles:

LexisNexis Academic

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

ProQuest Newspapers

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

These general databases cover all topics, including Business and Management:

ProQuest

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

Wilson OmniFile Fulltext

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

These two databases have a substantial number of articles relating to business and / or management, but from other disciplinary perspectives.

EconLit
(via Cambridge Scientific Abstracts)

Citations to publications covering all topics in the field of economics.

PsycINFO
(via EBSCOhost)

Citations and abstracts from nearly 2000 publications in the field of psychology and the psychological aspects of related disciplines.

These next two indexes are useful for locating older articles back several decades.

Business Periodicals Index
1958-1998; 46 volumes

Covers over 500 business-related periodicals. Many of these are already covered in ABI/Inform and Business and Company Resource Center, but indexing here goes back in time much farther than those databases and does cover some unique periodicals.

Location:
Gleeson Reference Annex, Lower Level

Wall Street Journal Index
1961-1983; 24 volumes.

Online indexing is available in ABI/Inform starting from 1982, and full-text from 1984. This print index covers earlier years, back to 1961.

Location:
Gleeson Reference Annex, Lower Level