If you're using OneSearch, use the gray left column to filter your results to Peer Reviewed Articles only. Under Show Only, choose Peer-reviewed Journals, and under Resource Type, choose Articles.

If you found your article elsewhere, you can use Ulrichsweb to determine if a journal
(where the article is published) is peer reviewed: http://library.calstate.edu/northridge/databases/proxy/209
(Other words for peer reviewed are scholarly, academic, or refereed.)
In general, try to remember the following about scholarly journals:
- Authors are authorities in their fields.
- Authors cite their sources in endnotes, footnotes, or bibliographies.
- Individual issues have little or no advertising.
- Articles must go through a peer-review or refereed process.
- Articles are usually reports on scholarly research.
- Illustrations usually take the form of charts and graphs.
- Articles use jargon of the discipline.