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问题 单项选择题 A1/A2型题

患者男，37岁，左股骨下端疼痛、肿胀，膝关节活动轻微受限7天，查体：股骨下端偏外侧局限性隆起，压痛，皮温不高。X线检查：股骨外侧髁可见偏心性生长的骨吸收病灶，皮质向外膨隆，无骨膜反应，基于该疾病，以下描述正确的是（）。

A.可能起源于骨髓内间叶组织的溶骨性肿瘤

B.一种潜在恶性或介于良、恶性之间的溶骨性肿瘤

C.主要症状为疼痛、局部肿胀、压痛和运动受限

D.好发于20～40岁，好发部位为股骨下端和胫骨上端

E.以上都正确

答案

参考答案：E

解析：本患者考虑骨巨细胞瘤，骨巨细胞瘤可能起源于骨髓内间叶组织的溶骨性肿瘤，是一种潜在恶性或介于良、恶性之间的溶骨性肿瘤。主要症状为疼痛、局部肿胀、压痛和运动受限。好发于20～40岁，好发部位为股骨下端和胫骨上端。

单项选择题

A transport layer protocol usually has several responsibilities．One is to create a process-to-process communication；UDP uses (71) numbers to accomplish this．Another responsibility is to providecontrol mechanisms at the transport level．UDP does this task at a very minimal level．There is no flowcontrol mechanism and there is no (72) for received packet．UDP, however,does provide errorcontrol 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 (73) must be able to send streams of data to the transport layer．It is the responsibility of the transport layer at (74) station to make the connection with the receiver,chop the stream into transportable units，numberthem，and send them one by one．It is the responsibility of the transport layer at the receiving end to waituntil all the different units belonging to the same process have arrived，check and pass those that are (75) flee，and deliver them to the receiving process as a stream．

A．call

B．state

C．cost

D．error
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单项选择题 A1型题

半衰期指血药浓度下降一半所需要的时间，它的意义在于（）

A.它反映了药物消除的快慢程度，确定给药的时间间隔

B.根据半衰期的大小可以将药物分类

C.机体的肝肾损伤时，药物半衰期变长

D.以上全是
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