Research articles, or primary articles, are based on original research. Other kinds of articles appear in scholarly journals as well, including commentary and review articles. If you need to limit your sources to research articles, you must be able to tell the difference. Most research articles will contain the following:
ABSTRACT
A summary of the article. (Note: Abstracts appear in secondary articles as well.)
METHODS
Sometimes called "methodology" or "materials and methods," this section describes the author's research methods and tools: experiment, survey, data sources, etc.
RESULTS
Also called "findings," this is the section of the article in which raw data are presented.
DISCUSSION
Sometimes called "analysis," this is the section in which the author analyzes the data.
CONCLUSION
The author's conclusions based on the analysis.
REFERENCES
List of references to works cited in the article.
These standard parts of a research article may not always be labeled, and sometimes they are combined (for example, "Data and Methods"). Still, every research article indicates what methods and tools were used to conduct the research, what the results were, and how the author interprets those results.
From http://steelylibrary.nku.edu/researchhelp/tutorials/startingyourresearch/scholarlyjournalsandresearcharticles.html