题目内容
整流的目的是______。
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患者，男性，60岁，20年前曾患肝炎。近2个月来食欲缺乏、消瘦，肝区疼痛明显。查体：轻度黄疸，面部有蜘蛛痣，腹膨隆，肝肋下50px、剑下100px，质硬，压痛，脾肋下75px，移动性浊音阳性。拟诊为肝癌。现首先应检测的是
下列各项中，对我国社保基金认识不正确的是（）。
Genetic Engineering
Genetic engineering began when the DNA molecule (分子), the most basic unit of life, was first described in 1953 by James Watson and Francis Crick. An understanding of DNA led to the altering of normal cell reproduction. Experiments with altering human cells began in 1970. In one of the first ex- periments, patients were injected with a virus that would produce a life-saving enzyme, but their bodies would not accept it. In 1980 patients with a rare but fatal blood disease were injected with a pu- rified gene that was cloned through DNA technology. Another failure.
Genetic engineering got a legal boost (激励) in 1980. The U. S. Supreme Court said that a patent could be granted on a genetically engineered "oil-eating" bacterium (细菌). This bacterium would help clean up oil spills. The ruling encouraged companies to invent new life forms, and three important medical products were quickly developed.
Human interferon (干扰素)-a possible solution to some cancers and viral disease A newly engineered bac-terium produced hurnan interferon as a by-product. This new product reduced the cost of interferon.
Human growth hormone-for children whose bodies do not grow to normal height. An expensive growth hormone (荷尔蒙) was previously produced from human cadavers, but by changing the genetic make-up of the single-cell bacterium E. coli, and affordable growth hormone could be produced.
Human insulin (胰岛素)-for the treatment of diabetes. People with diabetes used to rely on a beef-or pork-based product until 1982. Now insulin can be manufactured by genetically altered bacteria.
Advances in genetic engineering have continued, though they constantly must be weighted against the safety of procedures. There is clearly much more to discover.
This passage is mainly about
在单相桥式整流电路中，若有一只整流管接反，则______。
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