21. A system comprising: a computer program product stored on a tangible computer readable medium and comprising instructions that when executed cause a computer system to: decompose a search query that includes three or more words into a plurality of candidate phrasifications, including different groupings of words of the search query, each candidate phrasification comprising a disjoint union of component phrases, and each component phrase including at least one word or related word of the search query; score at least two of the candidate phrasifications, wherein the candidate phrasifications include one or more component phrases, and wherein the scoring is based on a probability of occurrence of each of the candidate phrasification's component phrases, and is based on the number of component phrases constituting the candidate phrasification, wherein candidate phrasifications having relatively fewer component phrases are weighted higher than candidate phrasifications having relatively more component phrases; select, based on the scores of the candidate phrasifications, at least one candidate phrasification, select, based on the scores of the candidate phrasifications, a subset of the candidate phrasifications; and execute a query of a document indexing using the selected subset of candidate phrasifications, wherein the query comprises the component phrases of each selected phrasification; and one or more processors configured for executing the instructions.
21. A system comprising: a computer program product stored on a tangible computer readable medium and comprising instructions that when executed cause a computer system to: decompose a search query that includes three or more words into a plurality of candidate phrasifications, including different groupings of words of the search query, each candidate phrasification comprising a disjoint union of component phrases, and each component phrase including at least one word or related word of the search query; score at least two of the candidate phrasifications, wherein the candidate phrasifications include one or more component phrases, and wherein the scoring is based on a probability of occurrence of each of the candidate phrasification's component phrases, and is based on the number of component phrases constituting the candidate phrasification, wherein candidate phrasifications having relatively fewer component phrases are weighted higher than candidate phrasifications having relatively more component phrases; select, based on the scores of the candidate phrasifications, at least one candidate phrasification, select, based on the scores of the candidate phrasifications, a subset of the candidate phrasifications; and execute a query of a document indexing using the selected subset of candidate phrasifications, wherein the query comprises the component phrases of each selected phrasification; and one or more processors configured for executing the instructions. 37. The system of claim 21 , wherein selecting at least one candidate phrasification includes selecting a number of candidate phrasifications, wherein the number is based on a source of the query.