物体做平抛运动时,描述物体在竖直方向分速度vy(竖直向下为正)随时间变化图象正确

题型:选择题

问题:

物体做平抛运动时,描述物体在竖直方向分速度vy(竖直向下为正)随时间变化图象正确的是( )

考点:平抛运动
题型:选择题

跌开式熔断器熔丝位置应在消弧管()。

A、中部

B、中部偏下

C、内部

D、中部偏上

题型:选择题

患者男性,42岁,体检时B超发现肝内多发实质占位性病变,无寒战、高热等症状,否认乙肝、肝硬化及血吸虫病史。查体:肝肋下未扪及,Hb 105g/L,WBC 5.3×109/L,血AFP 6.1μg/L,CEA2.5μg/L,SCC-Ag 121.5μg/L。血囊虫、弓形虫、血吸虫及绦虫抗体均阴性。18F-FDG PET/CT显像示:肝内多发低密度影放射性分布异常浓聚,SUVave3.6~5.2,SUVmax 4.5~8.6,双肺胸膜下多发小结节,结节未见放射性分布异常浓聚,食管胸下段可见一长约3cm放射性分布异常浓聚影,SUVave 4.9,SUVmax 6.5。

若行进一步检查,应首选的检查方法是

A.胸部增强CT
B.纵隔镜检查
C.胸腔镜检查
D.食管吞钡检查
E.食管镜检查组织活检

题型:选择题

以下叙述中正确的是______。

A.当对文件的读(写)操作完成之后,必须将它关闭,否则可能导致数据丢失

B.打开一个已存在的文件并进行了写操作后,原有文件中的全部数据必定被覆盖

C.在一个程序中当对文件进行了写操作后,必须先关闭该文件然后再打开,才能读到第1个数据

D.C语言中的文件是流式文件,因此只能顺序存取数据

题型:选择题

WAP简单的说就是手机直接上网,其全称是“无线应用协议(Wireless Application Protocol)”,它提供了通过手机访问互联网的途径。

题型:选择题

American Museum of Natural History is one of the largest natural and historic museums in the world and one of the main natural history research and education centres in the United States, set up in 1869 and located in the west of the Central Park, Manhattan District, New York. It (1) 7 hectares in its total area, (2) classical types of buildings. The (3) of ancient creatures and humanity is (4) the first place of all the museums in the world, (5) the representative samples from South America, Africa, Europe, Asia and Australia were collected, besides those from the (6) country, the United States.In the museum, there are five kinds of exhibits, including astronomy, mineralogy, human history, and animals in the (7) times and those in modern times. There are thirty-eight exhibition halls with different (8) from 500 to 1,500 square metres. Besides these, there is a Roosevelt Memorial Hall in (9) of President Roosevelt who supported the (10) of the museum, which is also used to have a special exhibition, showing the new important (11) on natural sciences and (12) affairs and social problems, and special topics connected closely with the life of the citizens. Besides this, it is also used for avocation (13) to have all kinds of scientific activities in the laboratories, centres of natural science and centres for citizens. There are more than 10 (14) research departments mainly(15) for collection of samples, research and work of publication.In the museum, there are (16) and sub-libraries of Aulspond ancient amniote, with about 300 thousand books and magazines (17) natural history, many of(18) are very valuable monographs for the first edition. It has published many expert books and magazines, and a large number of propaganda materials, (19) which are the two magazines, Natural History and Members of Museum that have the biggest (20) of their magazines.

3()

A.display

B.fossil

C.analysis

D.collection

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