问题 问答题

什么是小脑幕切迹上疝

答案

参考答案:颅后窝病变迫使小脑蚓部上端和前叶一部分,经小脑幕切迹向上疝出,所以又称小脑蚓部疝。此疝常与枕骨大孔疝同时发生。此疝临床上似乎少见,但实际上要多,常为临床忽视。因此,临床上应引起重视。疝入四叠体池内可压迫中脑后部的四叠体和被盖部以及大脑大静脉。中脑受压产生软化,导致严重后果。

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单项选择题

Throughout the 19th century and into the 20th, citizens of the United States maintained a bias against big cities. Most lived on farms and in small towns and believed cities to be centres of (1) , crime, poverty and moral (2) Their distrust was caused, (3) , by a national ideology that (4) farming the greatest occupation and rural living (5) to urban living. This attitude (6) even as the number of urban dwellers increased and cities became an essential (7) of the national landscape. Gradually, economic reality overcame ideology. Thousands (8) the precarious (不稳定的) life on the farm for more secure and better paying jobs in the city. But when these people (9) from the countryside, they carried their fears and suspicions with them. These new urbanities, already convinced that cities were (10) with great problems, eagerly (11) the progressive reforms that promised to bring order out of the (12) of the city.

One of many reforms came (13) the area of public utilities. Water and sewerage systems were usually operated by (14) governments, but the gas and electric networks were privately owned. Reformers feared that the privately owned utility companies would (15) exorbitant (过渡的) rates for these essential services and (16) them only to people who could afford them. Some city and state governments responded by (17) the utility companies, but a number of cities began to supply these services themselves. (18) of these reforms argued that public ownership and regulation would (19) widespread access to these utilities and guarantee a (20) price.

(14)()

A.public

B.municipal

C.republican

D.national