5. The method as claimed in claim 4 , wherein said prospective index is attained by the following formula: P = Pr t × We t × ∑ j = 0 n ⁢ TF - IDF j , in which P represents a foreseeing index, Pr t represents a reference source gravity, We t represents a reference source weight, and n represents a year range and meets a condition of 0<n<4.
5. The method as claimed in claim 4 , wherein said prospective index is attained by the following formula: P = Pr t × We t × ∑ j = 0 n ⁢ TF - IDF j , in which P represents a foreseeing index, Pr t represents a reference source gravity, We t represents a reference source weight, and n represents a year range and meets a condition of 0<n<4. 11. The method as claimed in claim 5 , further comprising the steps of: factor estimating, comprising the step of: providing at least one questionnaire to adjust said reference source weight according to a result of said questionnaire, and verifying, comprising the steps of: providing a usefulness evaluation questionnaire to evaluate a usefulness of the step of recommending research information, and providing a usability evaluation questionnaire to evaluate a user acceptance of the step of recommending research information.