7. The search apparatus according to claim 6 , wherein the threshold generation unit generates the threshold smaller than a minimum value of the scores of all the documents including the search term.
7. The search apparatus according to claim 6 , wherein the threshold generation unit generates the threshold smaller than a minimum value of the scores of all the documents including the search term. 8. The search apparatus according to claim 7 , wherein the threshold generation unit generates the threshold using a function which includes a linear expression of the length of the search term as a denominator and gradually increases toward the minimum value as the length of the search term becomes longer.