The search engine operates by seeking matches with search terms from two distinct types of data pulled from the contents of AccessScience: a layer of semantic metadata associated with each article or other feature, and the exact matches of words or phrases in the text. Semantic matches are those based on the meaning of the search terms and the concepts they describe, allowing the user to find pertinent articles without having to search for all synonyms of a given search term. To supplement these semantic results, the search engine provides all articles and other types of content that contain exact matches to the search terms.