进行性脊肌萎缩与多灶性运动神经病最重要鉴别手段是（） A.临床体征 B.静脉注射免疫

胆总管的血液供应主要来源于下列哪个动脉的分支

A．胃右动脉
B．肝左动脉
C．肝固有动脉
D．胃十二指肠动脉
E．胆囊动脉

下列不属于事故致因因素安全评价方法有（）。

A.危险和可操作性研究

B.事故树分析

C.安全检查表法

D.模糊矩阵法

头颈部鳞状细胞癌术后同步放射化学治疗的适应证（ⅠA类证据）包括（）

A.切缘安全距离≤5cm

B.多个或多站淋巴结转移

C.淋巴结包膜外受侵

D.肿瘤累及外周神经

E.脉管内有瘤栓

老年病人吸入麻醉加深慢的主要原因是()

A．心排血量低

B．心排血量升高

C．气道阻力小

D．肺活量大

E．功能残气量大

A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port (1) to accomplish this. Another responsibility of a transport layer protocol is to create a  (2) and error-control mechanism at the transport level. TCP uses a sliding (3) protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve  (4) control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends  (5) of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.

空白（2）处应选择（）

A.procedure

B.function

C.route

D.flow