在以下哪个时期,给心室肌一个阈上刺激,可以产生一次期前收缩() A.动作电位的快速复

题型:多项选择题

问题:

在以下哪个时期,给心室肌一个阈上刺激,可以产生一次期前收缩()

A.动作电位的快速复极中期

B.动作电位的快速复极末期

C.心室收缩期

D.动作电位的快速复极初期

E.心房收缩期

考点:麻醉科住院医师麻醉与循环麻醉与循环题库
题型:多项选择题

免疫增强剂有:

A.转移因子

B.环孢素

C.结核菌素

D.胸腺素

E.硫唑嘌呤

题型:多项选择题

已知风险组合的期望报酬率和标准差分别为15%和20%,无风险报酬率为8%,某投资者除自有资金外,还借入占自有资金20%的资金,并将所有的资金投资于市场组合,则总期望报酬率和总标准差分别为()。

A.16.4%和24%

B.13.6%和16%

C.16.4%和16%

D.13.6%和24%

题型:多项选择题

进入有限空间作业人员应按()上签署的任务、地点、时间作业。

题型:多项选择题

在压制过程中物料结构发生了哪些变化?

题型:多项选择题

Looking back on my childhood, I am convinced (1) naturalists are born and not made. Although we were all brought (2) in the same way, my brothers and sisters soon gave up their pressed flowers and insects. (3) them, I had no ear (4) music and languages, I was not an early reader and I could not do mental arithmetic.Before World War I we (5) our summer holidays in Hungary. I have only the memory of the house we lived (6) , of my room and my toys. I can hardly (7) clearly the large family of grandparents, aunts, uncles and cousins who gathered (8) door. But I do have a clear memory of the dogs, the farm (9) , the local birds and, (10) all, the insects.I am a (11) , not a scientist. I have a p (12) of the natural world, and my enthusiasm has led me into varied investigation. I love discussing my favorite topics and enjoy (13)  the midnight oil  (14)  reading about other people’s observations and discoveries. Then  (15)  happens that brings these observations together  (16)  my conscious mind. Suddenly you fancy (想象), you see the answer  (17)  the riddle, and books, of which some might honor with the title of scientific research.But curiosity, a keen eye, a good memory and enjoyment of the animal and plant world do not make a scientist; one of the outstanding and essential  (18)  required is self-discipline, a quality I lack. A scientist requires not only  (19)  but also hard training, determination and a goal. A scientist, up to a point, can be made. A naturalist is  (20) . If you can combine the two, you get the best of both worlds.

 

第(8)空应选择()

A.near

B.next

C.far

D.little

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