Finding full text of journal articles is usually fairly simple, but sometimes the library database you are using will not have the the full text of the article, only an abstract or a citation. Then you will see some text or a link like the following.
When you see any of these icons, you have a few options to find the full text of the article:
follow the full text link,
use Journals Search (on the library's homepage) to find the library's holdings of the article's journal, or