[Studies of the current prevalence of chronic bronchitis].
D000397:Air Pollution; D001991:Bronchitis / Q000453:epidemiology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012383:Romania; D012907:Smoking; D014505:Urban Population
Cercetări asupra prevanenţei actuale a bronşitei cronice.