13. A method comprising: determining a category to which a first wiki article is assigned, the first wiki article including a first title associated with a designated query intent and a first body, wherein the first wiki article is included in an initial key term set; retrieving a plurality of second wiki articles that are assigned to the category; extracting a plurality of second titles of the plurality of respective second wiki articles, wherein each of the second wiki articles includes a different title and a different body, and wherein the initial key term set includes the first title and the plurality of second titles; correlating each of the first title and the plurality of second titles with at least one respective clicked uniform resource identifier based on a search click log, wherein the search click log comprises a record of historical search queries provided by users and documents clicked by the users from search results retrieved in response to the search queries, and wherein each of the documents has a respective uniform resource identifier; generating an expanded key term set to include the initial key term set expanded to further include search terms correlated to the at least one respective clicked uniform resource identifier; training a search query intent classifier to classify search queries with respect to the designated query intent based on the expanded key term set; obtaining the designated query intent from a subsequent search query; and in response to obtaining the subsequent search query corresponding to the designated query intent, controlling the trained search query intent classifier to select advertisement data based on the expanded key term set.
15. The method of claim 13 , wherein correlating each of the first title and the plurality of second titles with at least one respective clicked uniform resource identifier using a search click log comprises: generating a bipartite graph that correlates each of the first title and the plurality of second titles to the at least one respective clicked uniform resource identifier based on the search click log.