已知某疾病患者8人的潜伏期(天)分别为:13,5,9,12,10,8,11,7。其潜

题型:单项选择题 A1型题

问题:

已知某疾病患者8人的潜伏期(天)分别为:13,5,9,12,10,8,11,7。其潜伏期的平均水平为()

A.9天

B.9.5天

C.10天

D.10.2天

E.11天

考点:疾病控制基础知识卫生统计学卫生统计学题库
题型:单项选择题 A1型题

典型的食管癌症状特点是()。

A.持续性胸骨后异物感

B.渐进加重的吞困难

C.间断吞咽困难伴呕吐

D.胸痛

E.反酸、烧心伴吞咽困难

题型:单项选择题 A1型题

阅读理解

     Shoppers who carefully plan their visit to the grocery store  can save money on their grocery bills.

 _1__

Shoppers should visit the grocery store on a full stomach  by scheduling their trip immediately after a

large meal. If that's not possible, they should find something healthy to eat while preparing a grocery

list.  __2__

     Although having a list and sticking to it is the most important factor in saving money, shoppers must

prepare lists wisely in order to save.   __3__ Many special buys are announced  through the local

newspapers, so buying the "grocery issue" is  worth the investment(投资). However, it's important to

remember that many newer, more expensive products first offered  through coupons(优惠券) may

not yield enough savings for shoppers to  give up the product they usually buy.

     __4__ Once at the store, the shopper who wants to save  money should follow a few more rules.

The shopper should not stay longer than necessary, because bills go up each minute the shopper is in

the store. So, setting a time limit and a cost limit can hold down the bill.   __5__  If the grocery list is

a short one, some shoppers choose to use the small handheld basket instead of the roomy grocery cart.

A. A carefully planned list should include in season produce and any items on sale or discounted

     through coupons.

B. Of course, the shopper should stick strictly to the shopping list and resist the temptation

     to buy additional items.

C. People who are full are less tired and more likely to buy what they want.

D. Now that the shopper has completed the grocery list, it's time to leave for the store.

E. You should keep your shopping list carefully in case you can exchange it for coupons.

F. Most shoppers are less persuaded to buy extra goods when they are not hungry.

G. Shopping when not hungry, sticking to a grocery list, and following a few simple rules will

     cut down the grocery bill.

题型:单项选择题 A1型题

质量为1kg的水,温度降低了20℃,求水放出的热量Q。[c=4.2×103J/(kg·℃)]

题型:单项选择题 A1型题

下列可以设置为索引的字段是( )。

A) 备注
B) OLE对象
C) 主关键字
D) 超级链接

题型:单项选择题 A1型题

已知一段信使RNA上有18个碱基C和T,该信使RNA上共有40个碱基,那么转录成信使RNA的一段DNA分子中应有A和G多少个()

A.18

B.24

C.36

D.40

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