1. Department of Clinical Medicine, Ningxia Medical University, Yinchuan, Ningxia, China
2. Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu, China
3. Institution of Clinical Research and Evidence-Based Medicine, The Gansu Provincial Hospital, Lanzhou, Gansu, China
4. Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
5. Department of Clinical Medicine, Lanzhou University, Lanzhou, Gansu, China
6. Department of Clinical Medicine, Gansu University of Chinese Medicine, Lanzhou, Chengguan, China
7. Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, Gansu, China