【简答题】螺栓受拉力 F 作用,尺寸如图。若螺栓材料的拉伸许用应力为 [ σ ] ,许用 切应力为 [ τ ] ,按拉伸与剪切等强度设计,螺栓杆直径 d 与螺栓头高度 h 的比值应取 d / h = 。
【单选题】婴幼儿患化脓性脑膜炎时,最常见的病原菌是
【判断题】为确保农业的可持续发展,农业生产用水尽可能要采取地下水。
【单选题】婴幼儿患化脓性脑膜炎时,最常见的病原菌是
【单选题】The poor student did not force his rich friend to tell the truth because( ).
A.
he was too proud to know the fact
B.
he appreciated his friend's thoughtfulness
C.
he was suspicious of the rich student's intention
D.
he did not want to know the truth
【单选题】婴幼儿患化脓性脑膜炎时,最常见的病原菌是