17. The method of claim 11 , wherein the second ranking model is determined by training.
11. A method, comprising: obtaining a first set of ranked results by using a first ranking model to determine first rank scores corresponding to respective ones of at least some of a plurality of matching information items, wherein the first ranking model comprises a linear model; selecting a portion of the first set of ranked results based at least in part on one or more selection criteria, wherein the one or more selection criteria comprises: a number of search results to display at a page and a ratio of a selected number of the first set of ranked results to a total number of the first set of ranked results; obtaining a second set of ranked results by using a second ranking model to determine second rank scores corresponding to respective ones of at least some of the selected portion of the first set of ranked results, wherein the second ranking model comprises a nonlinear ranking model; and generating a search response based at least in part on the second set of ranked results.