1. A computer-implemented method to re-rank a plurality of search results, the method comprising: receiving a search query; identifying one or more dominant concepts from the search query; expanding the one or more dominant concepts with a plurality of expanded concepts having a relationship with the one or more dominant concepts in a metabase; receiving a plurality of ranked search results; analyzing the search results using the expanded concepts; re-ranking the search results based on the expanded concepts; and providing the re-ranked search results for presentation to an end user.