问题 单项选择题

下列有关门脉高压症的叙述,错误的是

A.门静脉的主干是肠系膜下静脉和脾静脉

B.脾静脉的血流约占门静脉血流的20%

C.门静脉高压症是指门静脉压力至少达24cmH2O

D.门静脉主干血栓形成引起的门静脉高压症属于肝前型

答案

参考答案:C

解析:
正常门静脉压力为13~24cmH2O。门静脉高压症时门静脉压力大都增至30~50cmH2O。C错,其他各项均正确。

单项选择题
单项选择题

Questions from 36 to 40 are based on the following passage: Generally, cargo is carried in containers, but sometimes it is still shipped as breakbulk cargo. During the voyage, goods may be stacked on top of or come into violent contact with other goods. And the cargo might be dragged, pushed, rolled, or dropped during unloading, while moving through customs, or in transit to the final destination.Moisture is a constant concern because condensation may develop in the hold of a ship even if it is equipped with air conditioning and a dehumidifier(除湿机). Another aspect of this problem is that cargo may also be unloaded in precipitation, or the foreign port may not have covered storage facilities. Buyers are often familiar with the port systems overseas, so they will often specify packaging requirements. If the buyer does not specify this, be sure the goods are prepared using these guidelines:Pack in p containers, adequately sealed and filled when possible.To provide proper bracing in the container, regardless of size, make sure the weight is evenly distributed.Goods should be palletized when possible containerized.Packages and packing filler should be made of moisture-resistant material.To avoid pilferage, avoid writing contents or brand names on packages. Other safeguards include using straps, seals, and shrink wrapping.Observe any product-specific hazardous materials packing requirements.Normally, air shipments require less heavy packing than ocean shipments, though they should still be adequately protected, especially if they are highly pilferable.Finally, because transportation costs are determined by volume and weight, specially reinforced and lightweight packing materials have been developed for exporting. Packing goods to minimize volume and weight while reinforcing them may save money, as well as ensure that the goods are properly packed.

Moisture has long been the concern in export business, of which the reasons are stated except().

A.human-caused factors

B.unloading in precipitation

C.condensation in the ship’s hold

D.poor storage facilities