Objective To explore the prevalence,diagnosis and management of childhood asthma in Lanzhou urban area. Methods Multi-stage,stratified and random cluster sampling was used to recruit children born during July 1st,1996 to July 1st,2010 from Lanzhou or other provinces but resided in Lanzhou for over half a year.The same screening questionnaires for the Third National Epidemiological Survey of Children's Asthma were distributed to parents of children at schools,kindergartens and communities.Asthmatic children ...