Zotero provides the ability to save references from most library catalogs and databases, including WorldCat, PubMed, CINAHL or Cochrane. Zotero maintains a list of compatible sites, although many sites that do not appear on this list also work. When Zotero detects that you are looking at a book or article in a catalog, database, or recognizes websites such as Google Scholar, Library Thing or National Library of Medicine, you'll see a book, page, or folder icon appear in the address bar of your browser.
If you are on a page with a single search result, you will see the book or page icon. Click on the icon and Zotero will automatically save the citation.
If you are on a page of search results with many items, you will see a folder icon. Click on that folder icon to get a list of the items on the page and save the ones you want.