简述用递增剂量法评价蓄积毒作用的过程。_爱下问搜题

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问题问答题论述题

简述用递增剂量法评价蓄积毒作用的过程。

答案

参考答案：

取一组受试动物，每天染毒一次，以4天为一期，第一期每天染毒剂量为1/10ED50或LD50，随后染毒剂量每隔4天按1.5依次递增，如连续染毒已达20天，此时染毒总剂量已累计达到5.3倍ED50或LD50，受试动物中出现某种毒性效应或死亡的动物数未达到50%，则表示该受试物的蓄积毒性不明显，试验可终止。若受试过程中相继出现某种毒效应或死亡的动物数累计达到50%，即可计算出蓄积系数，并对蓄积毒性强度作出评估。

完形填空

The teacher stood before his class and was going to hand out the final exam papers. “I know how   1  you have worked to prepare for this test,” he said. “And because I know you can do it well, I am willing to offer a B to those who   2  not to take the test.”
Many students thanked the teacher and left. The teacher looked at the students left and said, “Does anyone else want to get a ‘B’? This is your last   3 .” Two more students decided to go.
Only seven students were still in the classroom. The teacher then handed out the papers. There were only three sentences on the paper: Congratulations! You have just   4  an ‘A’ in this class. Keep believing in   5 .
I never had a teacher like that, but I think it is a test that any teacher could give. Students who are not 6  in what they have learned are ‘B’ students at most.
The same is   7  in our daily life. The ‘A’ students are those who believe in what they are doing because they have   8  both successes and failures. They have got life’s lessons, not only from normal education, but from events in their   9 , and have become   10  people. You see, one should always believe in himself.

C．learned from

单项选择题

测试是否容易被记住的产品名称测试称为（）。

A、学习测试

B、记忆测试

C、偏好测试

D、联想测试