9. The apparatus as recited in claim 8 , wherein the determining of the primary keyword of the multiple words comprises determining the primary keyword using an Apriori algorithm.
8. An apparatus comprising: one or more processors; memory storing instructions that, when executed by the one or more processors, cause the one or more processors to perform acts comprising: obtaining multiple words searched by one or more users within a predetermined period; determining a primary keyword of the multiple words and a primary frequency that the primary keyword is searched; determining one or more relevant keywords associated with the primary keyword and a related frequency that each of the one or more relevant keywords and the primary keyword are searched together; computing one or more feature values for corresponding ones of the one or more relevant keywords based on the primary frequency and the related frequency; storing the one or more relevant keywords, a feature value corresponding to each of the one or more relevant keywords, and the primary keyword to generate keyword information; and updating the keyword information in a predetermined time period by: removing a relevant keyword having a feature value less than a predetermined value; and adding a relevant keyword having a feature value greater than the predetermined value; receiving a query generated by a user, the query including the primary keyword; and recommending a relevant keyword of the keyword based on the primary frequency of the primary keyword and the related frequency of the relevant keyword, wherein the recommending the relevant keyword comprises recommending the relevant keyword of the keyword when a feature value corresponding to the relevant keyword is greater than or equal to a predetermined threshold, the feature value being determined based on the primary frequency of the primary keyword and the related frequency of the relevant keyword.