Abstract: The method of issue difference was adopted to compare the time-effects of sixty-nine high level Chinese Sci-tech periodicals by retrieval through OA publishing and three full text periodical databases.The author called for rapidly increase on the quality of OA periodicals,promoted the original OA periodicals,reduce the issue differences of OA publishing and databases such as CNKI,Weipu and Wanfang,It is also expected to heighten the OA consciousness of database companies and to track or integrate the OA per...