石棉属于生产性粉尘中的（）。 A.无机粉尘 B.有机粉尘 C.混合性粉尘

股骨颈骨折后是否发生股骨头缺血性坏死，相关因素包括（）。

A.年龄

B.骨折线高度

C.骨折原始移位程度

D.骨折后的复位与内固定

E.以上都是

A transport layer protocol usually has several responsibilities．One is to create a process-to-process communication；UDP uses (1) numbers to accomplish this．Another responsibility is to provide control mechanisms at the transport level．UDP does this task at a very minimal level．There is no flow control mechanism and there is no(2) for received packet．UDP, however, does provide error control to some extent．If UDP detects an error in the received packet，it will silently drop it． The transport layer also provides a connection mechanism for the processes．The (3) must be able to send streams of data to the transport layer．It is the responsibility of the transport layer at (4) station to make the connection with the receiver, chop the stream into transportable units，number them，and send them one by one．It is the responsibility of the transport layer at the receiving end to wait until all the different units belonging to the same process have arrived，check and pass those that are (5) free, and deliver them to the receiving process as a stream．

（3）处应填（）。

A．jobs

B．processes

C．programs

D．users

肾上腺皮质激素的免疫调节作用为

A．只对T细胞产生抑制

B．只对B细胞产生抑制

C．只对树突状细胞产生抑制

D．只对MΦ产生抑制

E．对所有免疫细胞产生抑制

下列指标中()是目前临床诊断甲型病毒性肝炎采用的

A．HAV-IgM

B．HAV-RNA

C．HAV-IgG

D．HAV组织培养分离病毒

E．绒猴接种分离病毒

波传播所经过的媒质中各质点的运动具有( )性质。

A．相同的相位
B．相同的振幅
C．相同的机械能
D．相同的频率