Sputum Bacteriology in Acute Exacerbation of COPD in Taiwan---Emphasis on the Role of K. pneumoniae and P. Aeruginosa and the Effect of Inhaled Corticosteroid on the Incidence of Pneumonia (I) = 台灣地區慢性阻塞性肺疾急性惡化痰液細菌學之追蹤研究---著重於克雷白氏肺炎桿菌與綠膿桿菌之角色與吸入類固醇對肺炎之影響 (I)