1. A computer-based searching method comprising: receiving, at a computer, a search concept that includes a plurality of principal words; determining a set of semantically similar words for at least one of the principal words; calculating a degree of membership for each word in each set that reflects a semantic similarity in meaning to the principal word of the set; performing the search; computing a score based at least on the degrees of membership for the words in the word set; and sorting the results using the computed scores.