以下治疗骨质疏松药物中,属于骨吸收抑制剂的药物是
A. 降钙素
B. 甲状旁腺
C. 雌激素
D. 双膦酸盐
E. 氟制剂
It is conventional to take the current flow as the movement of .
A. negative charges
B. positive charges
C. any charge
D. protons
Electric current is the time rate of charge, measured in .
A. watts
B. volts
C. joules
D. amperes
The energy required to move a unit charge through an element is .
A. . current
B. . power
C. . voltage
D. . potential