药物治疗作用确证阶段是（）
A．I期临床试验
B．Ⅱ期临床试验
C．Ⅲ期临床试验
D．Ⅳ期临床试验
E．生物等效性试验
参考答案：C
_______the people have become masters of their country _______ science can really serve the people.
A．It is only then; that
B．It was that; when
C．It is only when; that
D．It was when; then
在计划工作中，强调抓影响目标的决定性因素的原理是（）
A.灵活性原理
B.限定因素原理
C.许诺原理
D.改变航道原理
