12. The system of claim 11 , wherein assign a ranking score further comprises: determine, for each result in the subset of search results, an interest-similarity score indicating a degree of correspondence between the each result in the subset of search results and at least one user interest vector in the user interest profile, the user interest vector comprising at least one keyword and an importance score indicating a degree of interest between the user and the at least one keyword.
12. The system of claim 11 , wherein assign a ranking score further comprises: determine, for each result in the subset of search results, an interest-similarity score indicating a degree of correspondence between the each result in the subset of search results and at least one user interest vector in the user interest profile, the user interest vector comprising at least one keyword and an importance score indicating a degree of interest between the user and the at least one keyword. 13. The system of claim 12 , wherein assign a ranking score further comprises: assign a final score to each result in the subset of search results by combining the interest-similarity score and a relevancy score associated with the each result, the relevancy score indicating a degree of relevancy between the each result and the search query, wherein combining the interest-similarity score and the relevance score is weighted by a personalization degree in the user interest profile.