单词：pyrroetioporphyrin
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Egyptian archaeologists have discovered the bottom part of an unknown pyramid in the Sakkara area about 18 miles south of Cairo. NationalGeographic explorer-in-residence Dr. Zahi Hawass, the Secretary General of the Egyptian Supreme Council for Anti
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GWEN IFILL:Forty years after it became legal, the debate over abortion has not gone away. According to a new Wall Street Journal/NBC News poll released today, 70 percent of Americans do not want to see Roe v. Wade, the Supreme Court decision which le
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Roe versus Wade is one of the best known Supreme Court cases. The issue is whether a healthy woman has a right to end a pregnancy through an abortion. In Texas in the early 1970s, state law barred such operations. A 22-year-old pregnant woman living
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Adam Phillips For many Americans, Memorial Day means the beginning of the summer vacation season. But Memorial Day was set aside as a national day of remembrance for those who have died in America's w
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One main goal in the renewable energy field is to find an efficient, inexpensive way to split water into hydrogen and oxygen. The hydrogen could then be used as a fuel source for vehicles or fuel cells. Typically, an electric current breaks the water
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Egyptian archaeologists have discovered the bottom part of an unknown pyramid in the Sakkara area about 18 miles south of Cairo. National Geographic explorer-in-residence Dr. Zahi Hawass, the Secretary General of the Egyptian Supreme Council for Anti
自然百科2008年