[Cytologically positive but plain X-ray negative lung cancer: an analysis of 34 cases].
D000328:Adult; D001999:Bronchoscopy; D003581:Cytodiagnosis; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008403:Mass Screening; D008875:Middle Aged; D011859:Radiography; D013183:Sputum / Q000166:cytology