遗传性球红细胞增多症出现“再生障碍危象”，下列哪些说法是正确的() ["A．骨髓造血功能暂时性抑制","B．可有严重贫血","C．与“微小病毒”感染有关","D．持续数天或1～2周自然缓解","E．是遗传性球形红细胞增多症的严重并发症之一"]
测量二尖瓣口面积的切面为() ["A．左心长轴切面","B．心底短轴切面","C．心室短轴鱼口水平切面","D．心室短轴腱索水平切面","E．心室四腔切面"]
房间隔缺损最常见类型是() ["A．原发孔型","B．下腔型","C．静脉窦型","D．卵圆孔型","E．混合型"]
胎儿通过胎盘从母体获得铁，以孕后期3个月获铁量最多，足月儿从母体所获得的铁足够其生后____个月内之需。
室间隔前2/3部分由下列哪支冠脉供血() ["A．左旋支","B．右主干支","C．右后降支","D．左前降支","E．对角支"]
红细胞较小，染色浅，中央浅染区扩大，多提示___________。
