title: Cigarette smoking divided by professional groups in Beijing.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009790:Occupations; D012494:Sampling Studies; D012737:Sex Factors; D012907:Smoking