轨道电路由钢轨线路、钢轨绝缘、钢轨接续线、引接线、送电设备、受电设备等组成。
参考答案：对
It is thought that extracellular ligand binding to a receptor tyrosine kinase activates the intracellular catalytic domain by propagating a conformational change across the lipid bilayer through the single transmembrane a helix.
子宫内膜异位症大多数位于盆腔内，最常侵犯的部位是（）
A.子宫骶骨韧带
B.输卵管
C.子宫直肠陷凹
D.子宫膀胱陷凹
E.卵巢
