Sometimes, when scanning your search results, you find that the 'perfect article' is not available in full-text. You can simply use the library ILL service and request the book or article you want here. Or, if you want to try to find it yourself, follow the steps below:
Note: Occasionally, especially with very recent / pre-publication articles, authors will post open access article copies on their web site. You may want to search the web to see if what you are looking for hasn't been made available on an author's personal web page. If you are a member of 'Research Gate' that would provide you another option for getting full-text articles online. The description on the popular website describes Research Gate as. "a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators." Membership is free.