问题 单项选择题

为明确诊断,抽血培养的最佳时间是()

A.先用抗生素3天,体温不退再抽血

B.停用抗生素2天后,抽取3次血培养,每次间隔1小时

C.在抗生素使用前,24小时内于畏寒发热时抽3次血培养

D.抽血时间与抗生素使用无关

E.停用抗生素1~2周后再抽血

答案

参考答案:C

解析:血培养标本一般在患者发热初期或高峰期采集,或根据不同的发热情况在未用抗生素前采集。但怀疑细菌性心内膜炎时,血培养不少于3次。

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单项选择题

Electronic mail has become an extremely important and popular means of communication.

The convenience and efficiency of electronic mail are threatened by the extremely rapid growth in the volume of unsolicited commercial electronic mail. Unsolicited commercial electronic mail is currently estimated to account for over half of all electronic mall traffic, up from an estimated 7 percent in 2001, and the volume continues to rise. Most of these messages are fraudulent or deceptive in one or more respects.

The receipt of unsolicited commercial electronic mail may result in costs to recipients who cannot refuse to accept such mail and who incur costs for the storage of such mail, or for the time spent accessing, reviewing, and discarding such mail, or for both. The receipt of a large number of unwanted messages also decreases the convenience of electronic mall and creates a risk that wanted electronic mail messages, both commercial and noncommercial, will be lost, overlooked, or discarded amidst the larger volume of unwanted messages, thus reducing the reliability and usefulness of electronic mail to the recipient. Some commercial electronic mail contains material that many recipients may consider vulgar or pornographic in nature.

The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services, businesses, and educational and nonprofit institutions that carry and receive such mail, as there is a finite volume of mail that such providers, businesses, and institutions can handle without further investment in infrastructure. Many senders of unsolicited commercial electronic mail purposefully disguise the source of such mall.

Many senders of unsolicited commercial electronic mall purposefully include misleading information in the messages’ subject lines in order to induce the recipients to view the messages. While some senders of commercial electronic mail messages provide simple and reliable ways for recipients to reject (or ’opt-out’ of) receipt of commercial electronic mall from such senders in the future, other senders provide no such ’opt-out’ mechanism, or refuse to honor the requests of recipients not to receive electronic mail from such senders in the future, or both.

Many senders of bulk unsolicited commercial electronic mail use computer programs to gather large numbers of electronic mail addresses on an automated basis from Internet websites or online services where users must post their addresses in order to make full use of the website or service.

The problems associated with the rapid growth and abuse of unsolicited commercial electronic mall cannot be solved by the government alone. The development and adoption of techno-logical approaches and the pursuit of cooperative efforts with other countries will be necessary as well.

It can be inferred from Paragraph 6 that bulk unsolicited commercial e-mail will probably spread ().

A. harmful virus

B. unpleasant news

C. advertisements

D. adult jokes