不产毒的白喉棒状杆菌,携带了β-棒状杆菌噬菌体后便可产生毒素,这种现象称为()。 ["A.转导","B.转化","C.结合","D.溶原性转换","E.原生质体融合"]
ABO血型系统中,抗A抗体主要是() ["IgG型","IgA型","IgM型","IgD型","IgE型"]
领事发票
左侧结肠癌主要临床表现为() ["全身症状、贫血、腹部肿块","梗阻、便血","类癌综合征","高血压","呕血"]
一般妊娠后多长时间血清HCG达峰值() ["1~3周","3~5周","6~7周","8~10周","20~25周"]
抓好综合治理的关键环节是什么?