US Patent 11640432 Document retrieval apparatus and document retrieval method

A document retrieval apparatus includes: a storage unit that stores documents and dictionaries applied to a model, a correspondence between a model and documents applied to the model, and a correspondence between a document and dictionaries applied to the dictionary; a model selecting unit that selects a model; a search target document specifying unit that specifies documents applied to the model selected by the model selecting unit as search target documents; a dictionary specifying unit that specifies dictionaries applied to the search target document; a query receiving unit that inputs a query; a search keyword extraction unit that extracts a search keyword group by applying the dictionary specified by the dictionary specifying unit to the query; a retrieving unit that retrieves the search target document using the search keyword group; and a retrieval result presenting unit that displays search results retrieved by the retrieving unit.