10. A method for identifying relevant search results via an index, comprising steps of: receiving a search query and generating a semantic representation for the query comprising a plurality of substructures as a semantic analysis of the search query and a list of key terms, wherein the key terms each comprise a term in the search query or a term related to one of the terms in the search query; accessing an inverted index comprising a set of key terms each associated with a semantic representation for each of a plurality of passages comprising a plurality of substructures and further associated with a link to a reference document for the passage; identifying one or more of the passages as retrieval candidates by comparing the semantic representations associated with the passages with the semantic representation of the search query, comprising: selecting a subset of the key terms from the search query and querying the inverted index with the key terms in the subset; identifying within the inverted index a result set for each of the key terms in the subset; and scoring each of the results in the set based on a distance of relationships of the substructures in the semantic representation of the search query and the semantic representation of the passages and identifying a subset of the result sets as the retrieval candidates based on the scoring; and selecting one or more of the retrieval candidates based on a comparison of the semantic representation of the search query with the semantic representations for each of the retrieval candidates.
10. A method for identifying relevant search results via an index, comprising steps of: receiving a search query and generating a semantic representation for the query comprising a plurality of substructures as a semantic analysis of the search query and a list of key terms, wherein the key terms each comprise a term in the search query or a term related to one of the terms in the search query; accessing an inverted index comprising a set of key terms each associated with a semantic representation for each of a plurality of passages comprising a plurality of substructures and further associated with a link to a reference document for the passage; identifying one or more of the passages as retrieval candidates by comparing the semantic representations associated with the passages with the semantic representation of the search query, comprising: selecting a subset of the key terms from the search query and querying the inverted index with the key terms in the subset; identifying within the inverted index a result set for each of the key terms in the subset; and scoring each of the results in the set based on a distance of relationships of the substructures in the semantic representation of the search query and the semantic representation of the passages and identifying a subset of the result sets as the retrieval candidates based on the scoring; and selecting one or more of the retrieval candidates based on a comparison of the semantic representation of the search query with the semantic representations for each of the retrieval candidates. 12. A method according to claim 10 , comprising: refining the identification of the retrieval candidates based upon one or more heuristically tuned thresholds.