搜题请搜索小程序“爱下问搜题”
问题 单项选择题 B型题

钙拮抗药药理作用中，“钙拮抗药可明显松弛支气管，还能减少组胺释放，减少支气管黏液的分泌，故可防治哮喘”属于（）

A.对血管的作用

B.负性肌力作用

C.负性频率作用

D.负性传导作用

E.对支气管平滑肌的作用

答案

参考答案：E

选择题

下列国家中人均国民生产总值由高到低排序正确的是[ ]

A．沙特阿拉伯、新加坡、中国

B．韩国、新加坡、尼泊尔

C．印度、哈萨克斯坦、蒙古

D．日本、新加坡、中国
查看答案
单项选择题

Routing protocols use different techniques for assigning ______ to individual networks. Further, each routing protocol forms a metric aggregation in a different way. Most routing protocols can use multiple paths if the paths have an equal ______ . Some routing protocols can even use multiple paths when paths have an unequal cost. In either case, load ______ can improve overall allocation of network bandwidth. When multiple paths are used, there are several ways to distribute the packets. The two most common mechanisms are per-packet load balancing and per-destination load balancing. Per-packet load balancing distributes the ______ across the possible routes in a manner proportional to the route metrics. Per-destination load balancing distributes packets across the possible routes based on ______.

A. bandwidthsB. sources C. destinations D. delays
查看答案