关于下列激素反馈系统哪项只有正反馈()
A.下丘脑-垂体-性腺轴
B.肾素-血管紧张素-醛固酮
C.下丘脑-垂体-肾上腺轴
D.下丘脑-垂体-甲状腺轴
E.甲状旁腺素-血钙
参考答案:A
The nurse administers racemic epinephrine to a child. Ten minutes after administration, the nurse should be alert for
A. respiratory distress.B. profound tachycardia.C. signs of improved oxygenation.D. diminished cyanosis.
蒸馏与分馏有何等区别?