腰椎间盘突出症的治疗中,骨盆牵引的作用
A.增加椎间盘外压力
B.降低椎间盘内压力
C.扩大椎间孔和神经根管
D.减轻突出物对神经根的压迫
E.调节后关节紊乱
参考答案:B,C,D
How does the price-yield relationship for a callable bond compare to the same relationship for an option-free bond The price-yield relationship is:()
A. concave for low yields for the callable bond and always convex for the option-free bond.
B. concave for an option-free bond and convex for a callable bond.
C. concave for the callable bond and convex for an option-free bond.
北京的地形为()。
A.东北高、西南低、平原占1/3
B.西北高、东南低、山地占1/3
C.西南离、东北低、山地占2/3
D.西北低、东北山、山地占33%
E.西高东低山地占67%
F.西北高、东南低、山地占2/3