Early therapy in chronic obstructive pulmonary disease: selection bias by exclusion?
Suissa
Samy
S
D006801:Humans; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000628:therapy*; D020127:Recovery of Function; D012017:Referral and Consultation; D015983:Selection Bias; D013997:Time Factors