The value of upper gastrointestinal endoscopy.
D004381:Duodenal Ulcer / Q000175:diagnosis / Q000000981:diagnostic imaging; D004724:Endoscopy; D005753:Gastric Mucosa; D005767:Gastrointestinal Diseases / Q000175:diagnosis*; D005773:Gastroscopy; D006801:Humans; D011859:Radiography; D013276:Stomach Ulcer / Q000175:diagnosis / Q000000981:diagnostic imaging