A nuclear holocaust seemed a very real possibility in the 1950s.核灾难在20世纪50年代似乎真的非常可能发生。It is unthinkable that we shall allow a nuclear holocaust to occur.我们若竟让核武器大屠杀的惨剧发生,简直是匪夷所思。Viewing this holocaust , they gave up any...
Astronauts in flight must adjust to weightlessness.宇航员在飞行中得适应失重状态.Objective To observe bone mass changes during convalescence after simulated weightlessness.目的观察模拟失重恢复期骨质的变化.To apply engineering Methods : To the study of...