【单选题】If the normal stress on the cross section of the axial tensile rod is σ , then the normal stress and shear stress on the 45 ° degrees section are .
【简答题】Mr. Lee was in bed and was trying to go to sleep when he heard the bell ring. He turned on the light and looked at his clock. It was twelve o'clock. "Who can it be at this time of night?" He thought. ...
【单选题】A 55-year-old man felt a lump near his shoulder 1 week ago On physical examination, there is an enlarged, nontender, supraclavicular lymph node and enlargement of the Waldeyer ring of oropharyngeal ly...