【单选题】All of the following are common symptoms of hypertensive crisis except:
【单选题】从事疏浚作业的船舶,操作能力受到限制时,在白天应显示()。
【单选题】往复泵发生“气穴现象”的原因不包括_______。
【单选题】从事疏浚作业的船舶, 操纵能力受到限制时,在白天应显示:
【单选题】Houses built during the last ten years have been found to contain indoor air pollution at levels that are, on average, much higher than the levels found in older houses. The reason air-pollution level...
A.
Many new houses are built with air-filtration systems that remove from the house pollutants that are generated indoors.
B.
The easing of standards for smokestack emissions has led to an increase in air-pollution levels in homes.
C.
New houses built in secluded rural areas are relatively free of air pollutants.
D.
Warm-weather conditions tend to slow down the movement of air, thus keeping pollution trapped near its source.
E.
Pressboard, an inexpensive new plywood substitute now often used in the construction of houses, emits the pollutant formaldehyde into the house.
【单选题】Which of the following can occur in hypertensive heart disease?
【单选题】对于同时掺有施主杂质( N D =1x10 15 cm -3 ),受主杂质( N A =1x10 15 cm -3 )的半导体, T=0K 时的费米能级位置 _________ 。