(PLS, WAIS, Fulcrum, Architext)
Documents are retrieved and displayed, with relevance scores, based on their likely relevance to your request. This is a proven, powerful technique that gives you leverage for dealing with large, complex information resources. All results from a distributed search are merged and displayed in a single relevance-ranked list. The relevance may be based on simple word density (how many times a word from your query is found in a document), but may include words weights in your query and/or in the text, proximity relationships between words and more complex relations).
See also ``query expansion''.