腹壁静脉曲张患者,血流方向为脐以上向上,脐以下向下,临床可能的诊断是()
A.上腔静脉阻塞
B.下腔静脉阻塞
C.右心衰竭
D.门脉性肝硬化
E.心包积液
参考答案:D
The short in a deliverable forward contract:()
A. makes a cash payment to the long at settlement.
B. receives a payment at contract initiation.
C. is obligated to deliver the specified asset.
阀控式密封蓄电池的优点有哪些?