交感舒血管神经作用骨骼肌血管的受体是()。
A.M受体
B.N1受体
C.N2受体
D.α受体
E.β受体
参考答案:E
After so many hardships, the scientist his motherland at last.
A.set on his foot
B.set foot on
C.set feet on
D.set his feet on
闭合系统中的机械能和内能之间可以相互转换,但只有通过系统内气压场压缩功才能实现。