15 to 30 days. By consulting the information of official website of Northeast Normal University, in order to strengthen the guidance and inspection of the research process of doctoral dissertations and ensure the quality of doctoral dissertations, the papers need to be externally audited for 15 to 30 days. Northeast Normal University has a strong faculty, first-class teaching team and teaching level, good teaching quality and strict management. Deeply trusted and favored by students and parents.