1. A search method, comprising: receiving a query word string; retrieving a plurality of product information entries related to the query word string; extracting, from a memory, a first core product word from the query word string, the first core product word being the smallest semantic unit; extracting, from the memory, a plurality of second core product words from the product information entries, the plurality of second core product words being the smallest semantic units; for each second core product word, checking a list of candidate product words relating to a key product word for a presence of the each second core product word, the first core product word being matched to the key product word; in the event that the each second core product word is present in a list of candidate product words, reducing a weighting of the product information entry corresponding to the each second core product word, wherein the list of candidate product words contains a candidate is product word, wherein synthesized product word obtained by combining the candidate product word with the key product word and the key product word do not belong to the same category; and sorting and outputting the product information entries according to the adjusted weightings of the product information entries.