1. A method comprising: performing a matching of an input keyword to one or more inquiry words in a search click log; rewriting the input keyword in response to determining that the input keyword does not match any inquiry word in the search click log; obtaining one or more categories corresponding to at least one inquiry word in the search click log based at least in part on correlation information in response to determining that the rewritten keyword matches the at least one inquiry word in the search click log, wherein the correlation information is calculated between a plurality of inquiry words and a plurality of categories in the search click log by calculating confidence degrees of each category corresponding to a respective inquiry word, and wherein a confidence degree of a respective category corresponding to the respective inquiry word comprises a weighted combination of a first conditional probability between the respective inquiry word and the respective category when the respective category is clicked after the respective inquiry word is received, and a second conditional probability between the respective inquiry word and the respective category when one or more products under the respective category are clicked after the respective inquiry word is received; and publishing product information under the one or more obtained categories.