Early intervention with tiotropium in Chinese patients with GOLD stages I–II chronic obstructive pulmonary disease (Tie-COPD): study protocol for a multicentre, double-blinded, randomised, controlled trial
Early intervention with tiotropium in Chinese patients with GOLD stages I–II chronic obstructive pulmonary disease (Tie-COPD): study protocol for a multicentre, double-blinded, randomised, controlled trial