Clinical study of Chinese herbs for reinforcing SHEN and supplementing QI in the cure of chronic obstructive pulmonary disease

INTERVENTION: Group A:Inhaled short‐acting bronchodilators + Chinese drugs for reinforcing shen and supplementing qi placebo + Bushen Fangchuan Pian placebo ;Group B:Inhaled short‐acting bronchodilators + Bushen Fangchuan Pian (5 tablets, tid, orally taken for 6 months)+Chinese drugs for reinforcing shen and supplementing qi placebo. ;Group C:Inhaled short‐acting bronchodilators + Chinese drugs for reinforcing shen and supplementing qi (125ml, bid, orally taken for 6 months) + Bushen Fangchuan Pian placebo. ; CONDITION: Chronic obstructive pulmonary disease PRIMARY OUTCOME: Frequency of COPD acute exacerbation;ST. George's respiratory questionnairy; SECONDARY OUTCOME: Lung function;Blood neutrophil counts;6‐minute walking test;BODE index; INCLUSION CRITERIA: 1.Aged 40 to 75 years old, male or female; 2.Able and willing to provide signed informed consent; 3.Patients with chronic obstructive pulmonary disease, and the severity of COPD is Grade II –III levels according to GOLD; 4.Qi deficiency syndrome, shen qi deficiency syndrome and deficiency of Shenyang syndrome according to Traditional Chinese medical Differentiation; 5.Without Respiratory tract infection and acute exacerbation of COPD over the past four weeks.