某化合物结构如图所示。
其结构类型属于() ["甲型强心苷元","乙型强心苷元","螺甾烷醇类甾体皂苷元","异螺甾烷醇类甾体皂苷元","变形螺甾烷醇类甾体皂苷元"]
女性,32岁,1小时前被汽车撞伤,右膝部闭合性损伤,伤后患者不能主动背侧伸展,原因() ["坐骨神经损伤","胫后神经损伤","胫后神经损伤","胫前神经损伤","腓总神经损伤"]
数字万用表的表头是() ["磁电式直流电流表","数字式直流电压表","数字式直流电流表","电动式直流电流表"]
磺脲类口服降糖药不适用于() ["1型糖尿病","B细胞功能很差的2型糖尿病","儿童糖尿病","孕妇、哺乳期妇女","大手术围术期"]
()是指用软壳和薄膜代替三维构造物,用软壳和薄膜将一个物体或系统从外部环境中隔离出来。 ["气压和液压结构原理","柔性壳体或薄膜原理","颜色改变原理","多孔材料原理"]
铁路运输有哪些方式?