目的：了解男男性行为者（men who have sex with men,MSM）在参加暴露前预防用药（pre-exposure prophylaxis,Pr EP）临床试验中是否存在性......

目的:了解男男性行为者(men who have sex with men,MSM)在参加暴露前预防用药(pre-exposure prophylaxis,Pr EP)临床试验中是否存......