Patent ID: 7987184

Claim:
An information retrieval apparatus comprising: a first database which stores a plurality of keywords and a plurality of meaning items associated with each of said plurality of keywords; a second database which stores said plurality of meaning items and a plurality of retrieval target items respectively corresponding to said plurality of meaning items; a control unit which accepts a keyword designated by a user; a first estimation unit which estimates a plurality of meaning items of the designated keyword by searching the first database with the designated keyword; a search unit which searches the second database for a plurality of retrieval target items respectively corresponding to said plurality of estimated meaning items; a display unit which displays a first display menu showing said plurality of estimated meaning items and a second display menu showing at least one of the searched retrieval target items, the at least one of the searched retrieval target items corresponding to a meaning item selected on the first display menu; a log storage unit which stores a selection log including meaning items selected on the first display menu and retrieval target items selected on the second display menu; a second estimation unit which estimates, from the selection log, a selection tendency toward a retrieval target item on the second display menu which corresponds to the meaning item selected on the first display menu, wherein the selection tendency includes one of short-term selection tendency, long-term selection tendency, and co-occurrence selection tendency; and a ranking unit which performs ranking of said plurality of retrieval target items with respect to each of said plurality of meaning items on the basis of the selection tendency, wherein said ranking unit performs said ranking based on said long-term tendency in the event of a first retrieval operation executed when the user activates the apparatus and performs said ranking based on said short-term tendency in a second retrieval operation to an n th retrieval operation after the activation of the apparatus, wherein the display unit displays the at least one of the retrieval target items on the second display menu in accordance with the ranking.