短語詞組短語very virulent virus strain 超強毒株high virulent mutant strain 高毒力菌株very virulent field strain 野外強毒株virulent mutant strain 毒力菌株Virulent field strain of NDV NDV 野外強毒株very virulent strain 超強毒株F48E10 virulent strain F48E10 強毒株strong virulent strain 致瘤毒株less -virulent strain 弱毒菌株 返回 virulent strain