Department of Gastroenterology;
No. 463 Hospital of Chinese PLA;
Post-doctoral Research Station;
Shenyang General Hospital of Chinese PLA;
Xijing Hospital of Digestive Diseases;
Fourth Military Medical University;
Department of Gastroenterology;
Shenyang General Hospital of Chinese PLA;
Upper; gastrointestinal; bleeding; Blood; transfusion; Meta-analysis; Randomized; controlled; trial;