—支15W的紫外线在lm内杀死芽胞需要的射线剂量是
A. 38μW·s/cm2
B. 380μW·s/cm2
C. 1800-6500μW·s/cm2
D. 18000-65OOOμW·s/cm2
E. 180000-650000μW·s/cm
（）是临床上分娩镇痛最常用的方法。
A. 患者自控硬膜外镇痛
B. 鞍区阻滞
C. 氯胺酮麻醉
D. 连续骶管阻滞
E. 双侧宫颈旁及阴部神经阻滞
《铁路客运运价规则》中规定残疾军人票可享受客票和附加票的优惠，残疾军人票票价按相应客票和附加票票价的()计算。
A. 40%
B. 60%
C. 50%
D. 30%
A centrifugal pump produces flow with a resulting discharge head by energy conversionIt is
A. mechanical energy to kinetic energy to potential energy
B. mechanical energy to potential energy to kinetic energy
C. potential energy to mechanical energy to kinetic energy
D. kinetic energy to mechanical energy to potential energy
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