下列有关慢性化脓性骨髓炎的X线表现的描述中不正确的是() A.长条状死骨 B.骨包壳

题型:单项选择题 A1/A2型题

问题:

下列有关慢性化脓性骨髓炎的X线表现的描述中不正确的是()

A.长条状死骨

B.骨包壳形成

C.一虫蚀状、小片状骨质破坏

D.广泛软组织肿胀

E.骨质增生、硬化

考点:泌尿外科主治医师现代外科诊疗技术现代外科诊疗技术题库
题型:单项选择题 A1/A2型题

甲、乙实心球体积相同,在调节好的托盘天平的左右两盘分别放的3个甲球和2个乙球,天平恰好平衡,则组成甲球、乙球的物质的密度之比为

A.2:3

B.3:2

C.1:1

D.无法确定

题型:单项选择题 A1/A2型题

通过护理可以纠正的冠心病的危险因素是()

A.此病人为男性病人

B.此病人的年龄为67岁

C.其母亲72岁时死于急性心肌梗死

D.病人身高174cm,体重94kg

E.以上都不是

题型:单项选择题 A1/A2型题

Most people know precious gemstones (宝石) by their appearances. An emerald flashes deep green, a ruby seems to hold a red fire inside, and a diamond shines like a star. It’s more difficult to tell where the gem was mined, since a diamond from Australia or Arkansas may appear the same to one from the Democratic Republic of the Congo. However, recently, a team of scientists has found a way to identify a gemstone’s origin.

Beneath the surface of a gemstone, on the tiny level of atoms and molecules(分子), lie clues (线索) to its origin. At this year’s meeting of the Geological Society of America in Minneapolis, Catherine McManus reported on a technique that uses lasers (激光) to clarify these clues and identify a stone’s homeland. McManus directs scientific research at Materialytics, in Killeen, Texas. The company is developing the technique. “With enough data, we could identify which country, which mining place, even the individual mine a gemstone comes from,” McManus told Science News.

Some gemstones, including many diamonds, come from war-torn countries. Sales of those “blood minerals” may encourage violent civil wars where innocent people are injured or killed. In an effort to reduce the trade in blood minerals, the U.S. government passed law in July 2010 that requires companies that sell gemstones to determine the origins of their stones.

To figure out where gemstones come from, McManus and her team focus a powerful laser on a small sample of the gemstone. The technique is called laser-induced breakdown spectroscopy. Just as heat can turn ice into water or water into steam, energy from the laser changes the state of matter of the stone. The laser changes a miniscule part of the gemstone into plasma, a gas state of matter in which tiny particles(微粒)called electrons separate from atoms.

The plasma, which is superhot, produces a light pattern. (The science of analyzing this kind of light pattern is called spectroscopy.) Different elements(元素)produce different patterns, but McManus and her team say that gemstones from the same area produce similar patterns. Materialytics has already collected patterns from thousands of gemstones, including more than 200 from diamonds. They can compare the light pattern from an unknown gemstone to patterns they do know and look for a match. The light pattern acts like a signature, telling the researchers the origin of the gemstone.

In a small test, the laser technique correctly identified the origins of 95 out of every 100 diamonds. For gemstones like emeralds and rubies, the technique proved successful for 98 out of every 100 stones. The scientists need to collect and analyze more samples, including those from war-torn countries, before the tool is ready for commercial use.

Scientists like Barbara Dutrow, a mineralogist from Louisiana State University in Baton Rouge, find the technique exciting. “This is a basic new tool that could provide a better fingerprint of a material from a particular locality,” she told Science News.

小题1:We learn from Paragraph 1 that __________________.

A.an emerald and a ruby are names of diamonds.

B.it’s not difficult to tell where the gem was mined.

C.appearances help to identify the origin of gemstones.

D.diamonds from different places may appear the same.小题2:Why did the U.S. government pass law that requires companies selling gemstones to determine the origins of their stones?

A.To look for more gemstones.

B.To encourage violent civil wars.

C.To reduce the trade in blood minerals.

D.To develop the economy.小题3:Which of the following facts most probably helps McManus and her team in identifying the origin of stones?

A.Heat can turn ice into water or water into steam.

B.Gemstones from the same area produce similar light patterns.

C.Laser can changes a miniscule part of the gemstone into plasma.

D.Materialytics has already collected patterns from thousands of gemstones.小题4:From the last two paragraphs, what can be inferred about the laser technique?

A.It is ready for commercial use.

B.People can use the new tool to find more gemstones.

C.It can significantly reduce the gemstones trade in blood minerals.

D.It will bring about a revolutionary change in identifying the origin of minerals.小题5:The author wrote this passage mainly to ________.

A.tell us how to identify the origin of diamonds.

B.introduce a laser technique in identifying a stone’s origin

C.prove identifying the origin of gemstones are difficult

D.attract our attention to reducing trade in blood minerals

题型:单项选择题 A1/A2型题

引起急性原发性肺脓肿的诱因是()

A.人体抵抗力减弱

B.熟睡时误咽

C.昏迷状态下呛咽

D.麻醉和手术

E.败血症细菌栓子经血流进入肺

题型:单项选择题 A1/A2型题

对单户贷款金额()万元以上“速贷通”客户,每半年至少进行一次现场检查(低风险业务除外)。对于具备小企业客户评级条件的,应进行信用等级评定。

A、300

B、400

C、500

D、1000

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