Influenza surveillance in Shanghai.
D000956:Antigens, Viral / Q000276:immunology; D002681:China; D004196:Disease Outbreaks / Q000453:epidemiology*; D006801:Humans; D009980:Influenza A virus / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology*
D000956:Antigens, Viral