在计划生育工作中,常采用结扎输卵管的措施达到避孕目的,其原理是[ ]
A.使卵细胞不能形成
B.使卵细胞不能受精
C.使受精卵不能进人子宫
D.使性激素不能分泌
答案:B
— Americans spend more on health care than most other people .
— You’re right . But a new study shows that life ___ in the United States is falling . [ ]
A. development
B. position
C. experience
D. expectancy
粪便中粪胆原含量明显增加主要见于()
A.溶血性黄疸
B.肝细胞性黄疸
C.胆道部分梗阻
D.胆道完全梗阻
E.胆管结石性黄疸