1. A computer-based system for processing a user query related to patent claim terms to generate a set of patent documents responsive to the query, the computer-based system comprising: a search engine executed by a computer and being adapted to receive a query and, based on the query, to search claims of patent documents contained in at least one database and adapted to yield a first set of candidate patent documents, wherein the query comprises a plurality of query permutations derived from the original query language and comprising either or both of a claim text-based query permutation and a key concept-based query permutation, and wherein the search engine is adapted to execute a plurality of query search permutations in arriving at the first set of candidate patent documents; and a re-ranking module comprising code executable by the computer and adapted to re-rank the entire first set of candidate patent documents based at least in part on a set of patent features without reducing the number of candidate patent documents in the set and generate a second set of ranked patent documents, the re-ranking module being adapted to weight the set of patent features based on a previously executed learning process; wherein the set of patent features comprises one or more from a group consisting of: fields of a patent; patent title; patent abstract; patent IPC code; patent references; patent claims; rank-c, representing a lowest rank of any claim of a patent in the first set of candidate patent documents; sim(c,c), representing a highest similarity score between the query and claims in a patent in the first set of candidate patent documents; sim(c,cs), representing a similarity score between the query and all the claims of a patent in the first set of candidate patent documents; sim(c,title), representing a similarity score between the query and the title of a patent in the first set of candidate patent documents; sim(c,abstract), representing a similarity score between the query and the abstract of a patent in the first set of candidate patent documents; sim(key,key), representing a similarity score between key concepts of the query and a patent in the first set of candidate patent documents; sim(key,title), representing a similarity score between the key concept of the query and the title of a patent in the first set of candidate patent documents; sim(key,abstract), representing a similarity score between the key concept of the query and the abstract of a patent in the first set of candidate patent documents; IPC-overlap, representing a number of overlapping IPC codes between IPC codes of a patent in the first set of candidate patent documents and the IPC codes of an initial high-ranking set of patents in the first set of candidate patent documents; and direct-Cite, representing the number of patents in the initial high-ranking set of patent documents that cite or are cited by a patent in the first set of candidate patent documents.