1 .李玉琴,李付广,刘广梅,等.郑州地区668例婴幼儿下呼吸道病毒感染的流行病学研究.中华传染病杂志,1997,15 ∶ 6.Acute otitismediainpatientswithbronchi Pediatrics,1998,101 ∶ 617‐619.2)vaccineinse ropositivechildrenwithbronchopul dysplasia . ......