title: Research on causes of lung cancer: case--control study of 523 cases of lung cancer.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002681:China; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology*; D008875:Middle Aged; D012306:Risk; D012907:Smoking