3. The bio-item searching apparatus according to claim 2 , wherein the processor includes: a co-occurrence correlation score calculating unit that calculates, for each of the two arbitrary bio-items, the co-occurrence correlation score based on the statistical calculation by using a number-of-co-occurrence-literatures table constituted by at least one of i) a number-of-literatures each including the one bio-item name and including an other bio-item name, j) a number-of-literatures each not including the one bio-item name and including the other bio-item name, k) a number-of-literatures each including the one bio-item name and including the other bio-item name, and m) a number-of-literatures each not including the one bio-item name and not including the other bio-item name, which are acquired by searching the bio-item literature set of the one bio-item with the other bio-item name, and a bio-item relation database creating unit that stores the co-occurrence correlation score calculated by the co-occurrence correlation score calculating unit in the bio-item relation database in association with the two bio-items.
3. The bio-item searching apparatus according to claim 2 , wherein the processor includes: a co-occurrence correlation score calculating unit that calculates, for each of the two arbitrary bio-items, the co-occurrence correlation score based on the statistical calculation by using a number-of-co-occurrence-literatures table constituted by at least one of i) a number-of-literatures each including the one bio-item name and including an other bio-item name, j) a number-of-literatures each not including the one bio-item name and including the other bio-item name, k) a number-of-literatures each including the one bio-item name and including the other bio-item name, and m) a number-of-literatures each not including the one bio-item name and not including the other bio-item name, which are acquired by searching the bio-item literature set of the one bio-item with the other bio-item name, and a bio-item relation database creating unit that stores the co-occurrence correlation score calculated by the co-occurrence correlation score calculating unit in the bio-item relation database in association with the two bio-items. 7. The bio-item searching apparatus according to claim 3 , wherein the number-of-literatures acquiring unit searches, for two of the candidate bio-items arbitrarily, the bio-item literature set of the one candidate bio-item to acquire a number Ns of literatures each including the other bio-item name and including the keyword, the table creating unit creates a three-dimensional number-of-literatures table based on the number-of-literatures Ns, the number-of-literatures table related to the two candidate bio-items, and the number-of-co-occurrence-literatures table related to the two candidate bio-items, the correlation score calculating unit includes a co-occurrence keyword correlation score calculating unit that calculates a co-occurrence keyword correlation score among the two candidate bio-items and the keyword based on the statistical calculation by using the three-dimensional number-of-literatures table, and the output unit outputs the co-occurrence keyword correlation score calculated by the co-occurrence keyword correlation score calculating unit to the output device in association with the two candidate bio-items.