You can find most articles using the Omni search. Enter some keywords, a citation, a DOI, an author - whatever you need.
The link to full text is in the full description when you click the title.
Indexes (databases) offer more controlled and subject-specific searching. Search the index, find items you like, then follow the links to the full article. See the "Finding Articles" tutorial for details.
Successful searching requires two things: search in the right place, and select the best search terms.
For the right place, select a database that covers your topic appropriately.
For search terms, select a few key terms that you expect to find in a description of your topic.
These databases might also be useful, depending on your topic and your research needs. They're in alphabetical order.