Document retrieval

Document retrieval is defined as the matching of some stated user query against useful parts of free-text records. These records could be any type of mainly unstructured text, such as bibliographic records, newspaper articles, or paragraphs in a manual. User queries could range from multi-sentence full descriptions of an information need to a few words and the vast majority of retrieval systems currently in use range from simple Boolean systems through to systems using statistical or natural language processing techniques.