问题 单项选择题

梅毒树胶肿病灶中绝少见到()

A.凝固性坏死

B.上皮样细胞

C.朗格汉斯巨细胞

D.淋巴细胞和浆细胞

E.钙化

答案

参考答案:E

解析:梅毒树胶样肿病灶灰白色,大小不一,小至镜下可见,大到数厘米不等。该肉芽肿质韧而有弹性,如树胶,故而得名树胶样肿。镜下结构颇似结核结节,中央为凝固性坏死,形态类似干酪样坏死,弹力纤维尚保存。坏死灶周围肉芽组织中富含淋巴细胞和浆细胞,而上皮样细胞和朗格汉斯巨细胞较少,且必有闭塞性小动脉内膜炎和动脉周围炎。此又是有别于典型结核结节的形态特征。树胶样肿后期可被吸收、纤维化,最后使器官变形,但绝少钙化,这又和结核结节截然不同。

多项选择题
单项选择题

If there is one thing scientists have to hear, it is that the game is over. Raised on the belief of an endless voyage of discovery, they recoil from the suggestion that most of the best things have already been located. If they have, today’s scientists can hope to contribute no more than a few grace notes to the symphony of science.

A book to be published in Britain this week, The End of Science, argues persuasively that this is the case. Its author, John Horgan, is a senior writer for Scientific American magazine, who has interviewed many of today’s leading scientists and science philosophers. The shock of realizing that science might be over came to him, he says, when he was talking to Oxford mathematician and physicist Sir Roger Penrose.

The End of Science provoked a wave of denunciation in the United States last year. "The reaction has been one of complete shock and disbelief, "Mr. Horgan says.

The real question is whether any remaining unsolved problems, of which there are plenty, lend themselves to universal solutions. If they do not, then the focus of scientific discovery is already narrowing. Since the triumphs of the 1960s—the genetic code, plate tectonics, and the microwave background radiation that went a long way towards proving the Big Bang—genuine scientific revolutions have been scarce. More scientists are now alive, spending more money on research, that ever. Yet most of the great discoveries of the 19th and 20th centuries were made before the appearance of state sponsorship, when the scientific enterprise was a fraction of its present size.

Were the scientists who made these discoveries brighter than today’s That seems unlikely. A far more reasonable explanation is that fundamental science has already entered a period of diminished returns. "Look, don’t get me wrong," says Mr Horgan. "There are lots of important things still to study, and applied science and engineering can go on for ever. I hope we get a cure for cancer, and for mental disease, though there are few real signs of progress.\

The term "the Big Bang" probably refers to()

A. the genetic code theory

B. a geological theory

C. a theory of the origin of the universe

D. the origin and the power of atomic energy