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认为GX实验取得了很大成功. 其教学符合数学素质教育的全体性、全面性、主体性、基础性、发展性特征; 能有效培养学生的数学认知与方式、多种数学能力、数学意识与观念; 能促进学生情感、态度和个性品质的发展; 实现了数学素质教育的基本目标, 具有较强的可操作性、可接受性和可迁移性, 是数学素质教育的重要实践与成功范例. GX实验对目前我国基础教育数学课程改革具有启发与借鉴意义.  相似文献   

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[目的]研究比较豹猫和金猫针毛红外光谱。[方法]使用傅立叶红外光谱对豹猫和金猫两种野生动物毛发进行了检测和分析。[结果]在豹猫和金猫针毛的中部红外图谱及其二阶导数谱均具有明显的种间差异,如648 cm-1和654 cm-1波数处金猫出现明显 M 形双峰吸收峰,而豹猫没有;金猫的二阶导数谱在709-763 cm-1范围内以峰强较大的单峰为主,豹猫则以峰强较小的 M 形双峰为主,这均说明两种动物毛发的蛋白侧链的构成上则存在较大的差异。[结论]红外光谱分析方法可以应用于动物毛发的种间识别,在毛发的研究领域有较好的应用前景。  相似文献   

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The evolutionary dynamics underlying the latitudinal gradient in biodiversity have been controversial for over a century. Using a spatially explicit approach that incorporates not only origination and extinction but immigration, a global analysis of genera and subgenera of marine bivalves over the past 11 million years supports an "out of the tropics" model, in which taxa preferentially originate in the tropics and expand toward the poles without losing their tropical presence. The tropics are thus both a cradle and a museum of biodiversity, contrary to the conceptual dichotomy dominant since 1974; a tropical diversity crisis would thus have profound evolutionary effects at all latitudes.  相似文献   

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Koenig R 《Science (New York, N.Y.)》2000,289(5486):1863-1865
Bulgaria created a pioneering center in late 1990 to tackle the threat that its homegrown computer viruses posed to the world; according to experts, it has been a major force in reining in that threat. Now the lab is struggling to stave off obsolescence on a budget of roughly half of what a single Western whiz kid fresh out of college might earn in a year.  相似文献   

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Kormendy J 《Science (New York, N.Y.)》2000,289(5484):1484-1485
Supermassive black holes (BHs) have long been implicated in explaining active galactic nuclei such as quasars. In his Perspective, Kormendy discusses recent work that suggests a larger role for these objects. The Hubble Space Telescope has provided many new detections of BHs, and these new results indicate that they play an important role in the galaxy formation processes.  相似文献   

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Koenig R 《Science (New York, N.Y.)》2000,290(5496):1484-1487
Two decades after Iran's Islamic revolution, science in this politically isolated but oil-rich nation may be on the verge of resurgence. The nation's reform-minded president, Mohammad Khatami, and his allies are promising more money for R&D, reorganizing universities to beef up graduate education and research, and cracking open the door to closer cooperation with scientists abroad, including those in the United States. But Iran's government is walking a tightrope between hard-liners on the right who oppose reforms and liberal university students eager for change.  相似文献   

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This year's Nobel Prize in chemistry was awarded to a trio of researchers--Alan Heeger of the University of California, Santa Barbara; Alan MacDiarmid of the University of Pennsylvania in Philadelphia; and Hideki Shirakawa of the University of Tsukuba in Japan--for discovering that plastics can be made electrically conductive. The discovery paved the way for revolutionary applications such as full-color displays for cellular phones and plastic electronics for computerized merchandise.  相似文献   

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中国豹猫6个群体的RAPD分析   总被引:4,自引:0,他引:4  
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新世纪的信仰教育:困境及出路   总被引:2,自引:0,他引:2  
文章通过对大学生信仰状况调查,分析了高校信仰教育面临的困境,并对信仰教育的重构与出路作了探讨。  相似文献   

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观察分析了捕鼠猫对褐家鼠的控制能力,结果表明,当捕鼠猫覆盖度达8只/km<'2>左右时,可将褐家鼠控制在较低密度水平,且捕鼠猫覆盖度与平均捕鼠率及平均盗食率均呈显著负相关.  相似文献   

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The impact of gene patents on downstream research and innovation are unknown, in part because of a lack of empirical data on the extent and nature of gene patenting. In this Policy Forum, the authors show that 20% of human gene DNA sequences are patented and that some genes are patented as many as 20 times. Unsurprisingly, genes associated with health and disease are more patented than the genome at large. The intellectual property rights for some genes can become highly fragmented between many owners, which suggests that downstream innovators may face considerable costs to gain access to gene-oriented technologies.  相似文献   

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剖析了图书馆在信息时代边缘化的现状,从"注意力的逃离"、"传统模式的弊端"和"Web2.0的冲击"三方面因素分析了网络时代图书馆出现边缘化走势的原因,在此基础上提出了扭转图书馆边缘化走势的对策。  相似文献   

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充分发挥标准化生产的作用稳定烟叶质量   总被引:2,自引:0,他引:2  
烟叶质量的不稳定是卷烟质量波动的主要原因之一。加强烟叶标准化生产,促进烟叶生产技术和措施在一定区域内达到协调统一,利用标准化农业基础设施建设和种植规划,可以部分抵消外部环境的影响,从而达到稳定烟叶质量的作用,使烟叶产区“特色烟叶”的风格得到保持。  相似文献   

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