title: The optimal timing for urgent endoscopy in nonvariceal upper           gastrointestinal bleeding.
authors: C H
authors: CH
authors: Lim
authors: M M
authors: MM
authors: Ahmed
mesh_terms: D016099:Endoscopy, Gastrointestinal; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000401:mortality*; D016558:Hemostasis, Endoscopic; D017052:Hospital Mortality; D006801:Humans; D008297:Male