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