Many databases "tag" or add terms to the articles -- similar to tagging pictures in Facebook.
The agreed-upon, standard terms used in library catalogs and databases are called subject headings or descriptors.
The subject headings in a catalog or database record will often help you locate more books/articles that are similar. It works much as "find more like this" or "find similar" links do elsewhere.
Searching in full text databases often retrieves many things that seem unrelated. The search engine is finding the words, but they are far apart in the document. Proximity operators help solve this problem! These tell the search engine to return results when two words are within x number of words of each other. So Wilmington n5 riot, retrieves newspaper articles with these words within 5 words of each other: race riot in Wilmington, Wilmington North Carolina rocked by riot, etc.
The abbreviation used as a proximity operator varies from one database to another. When you are in the database, look for the "help" button to find specific search tips.
Your searches will work best in most databases if you break your topic apart and then combine the concepts with AND/OR. This is called Boolean logic and is named after a mathematician
AND - narrows your searches
Ex. Obesity AND Sugared drinks
OR - broadens your searches
Ex. sugared drinks OR sweetened beverages OR soft drink*
Most databases will have pull down boxes where you can select AND or OR.
You can also use these together by using parenthesis.
(obesity OR overweight) AND (sugared drinks OR sweetened beverage* OR soft drink* OR juice OR sports drinks)
The above in pictures
OR - gets all the info from both circles
AND - gets only the info where the circles overlap