Each database's interface looks a little different. But there are similar search techniques you can use:
If the index you're using doesn't seem to have a link to full text, try these steps:
Provides full text for more than 8,500 full-text periodicals, including more than 7,300 peer-reviewed journals, covering academic areas of study including social sciences, humanities, education, computer sciences, engineering, language and linguistics, arts & literature, medical sciences, and ethnic studies.
Full text is available for recent journal issues in Academic Search Complete