title: Rational role of upper gastrointestinal endoscopy.
mesh_terms: D004381:Duodenal Ulcer / Q000175:diagnosis; D004724:Endoscopy; D005767:Gastrointestinal Diseases / Q000175:diagnosis*; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis; D005773:Gastroscopy; D006801:Humans