Articles are excellent for finding:
Articles can either be scholarly or non-scholarly in nature.
Articles in scholarly journals generally have been reviewed by an editorial board, have gone through some type of peer-review process, and are the in-depth, primary account of original findings written by the researcher(s) in their field of academic interest. Many but not all professional journals are peer-reviewed.
Articles in popular magazines, newspapers and trade publications on the other hand are written from a non-scholarly perspective. They are generally not peer-reviewed, favor a much more informal writing style, and often have no, or only very brief, bibliographies. Non-Scholarly articles can be helpful but it just depends on what your research needs are.
Scholarly articles can generally be identified by several features:
(This list was inspired by the various lists available on library websites, particularly that of Judith Downie at California State University San Marcos)