1. A method, comprising: submitting, to a search engine, a first query comprising a first query term; receiving, in response to the first query, a first list comprising first results, each of the first results having a respective first ranking; deriving multiple keywords from the first query term; submitting, for each given derived keyword, a respective second query to the search engine, the respective second query comprising the first query term and the given derived keyword; receiving, in response to each of the respective second queries, a respective second list comprising respective second results, each of the respective second results having a second ranking and a corresponding first result; computing, for each given second result, one or more stability scores based on the second ranking of the given second result and the first ranking of the corresponding first result; and ranking the second results based on their respective one or more stability scores.