排序方式: 共有459条查询结果,搜索用时 17 毫秒
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2007年洞庭湖东方田鼠再次暴发成灾,引起了全国轰动,在没有采取有效防控的堤垸形成严重危害。实地考察发现,没有筑“防鼠墙”的中洲镇靠近防洪大堤的西瓜地、玉米地和花生地损失近2/3。应该怎样看待东方田鼠此次的大暴发?是什么原因导致这场灾难?其暴发成灾难道不可控制吗?以后这样的灾难还会发生吗?面对干军万马涌现大堤和农田的老鼠,我们应该怎么办?是否应该赶尽杀绝? 相似文献
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2005年11月13日,中石油吉林石公分公司双苯厂发生爆炸;11天后,污染水顺松花江而下流经黑龙江省省会哈尔滨市,造成该市自来水停供达4天时间;之后甚至波及到黑龙江下游的俄罗斯部分地区……12月2日,原因家环保总局局长解振华引咎辞职。 相似文献
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野生动物狞猎权被拍卖,国家林业局、专家、普通民众,许多人表达了自己的观点,许多人随声附和,整个社会喧嚣声一片。可是,在这片喧嚣声中,我们没有发现有谁可以拿出第一手资料作为有力证据来说服其他人。或许是因为我们这个社会太浮躁了,浮躁得已经失去了理性.就连一向以严谨著称的科学也是如此。
本组文章将力求通过对羚牛(国家一级保护动物,此次被拍卖野生功物之一)的介绍来追问这样一个问题:面对类似的新闻事件,我们除了喧嚣之外,目光首先应该关注何方? 相似文献
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《生物技术评论》(CriticalReviewinBiotechnology)该刊是美国著名的出版公司———CRC出版有限责任股份公司出版的系列期刊之一 ,原名为CRCCriticalReviewinBiotechnology ,是 1983年创刊的。该刊为季刊 ,每年 1卷 ,每卷末期附带全年作者索引和主题索引。该刊收录的文章涉及生物技术的各个领域 ,包括与食品和饮料工业、燃料生产、化学及制药业、废物处置以及其它与社会、环境和经济领域密切相关的从发酵技术到遗传操作和蛋白质工程的技术。该刊刊登世界不同地区的技术现… 相似文献
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ZHANG Jinzhu 《中国科学:生命科学英文版》1997,40(5):488-495
Changes of sodium ionic concentration of human erythrocytes applied to pulsed electrical field (PEF) were studied by using shift reagent and NMR spectroscopy. The results show that the concentration of intracellular Na+ increases with the increasing intensity of PEF when the erythrocytes are applied to PEF with higher intensities. The relationship between intracellular Na concentrations and the intensities of PEF does not follow linear or exponen-tial behavior. As the intensities increase, the intracellular Na+concentrations increase even faster by an exponential curve. However under effects of PEF at lower intensities, intracellular Na+ concentration decreases. Ouabain can in-hibit the decrease of intracellular Na concentration, and the inhibition increases with the increasing concentration of ouabain, suggesting that Na+ , K+ -ATPase on cell membrane can be activated by PEF at lower intensities. Direct measurement of activities of the enzyme by using Malachite green method has confirmed this observation. Cell perme-abilities to ions, activation of enzymes by electrical fields and transmission of physical signals like PEF across cell mem-branes are discussed. 相似文献
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Zhang Jintun 《生物数学学报》1996,(4)
IIntroductionSuccessionstudyIsaspeclalfleldInvegetationecology(Greig—Smith1983).ItreferstocummulatlvechangeInvegetationovertime.Florl幻IcgradientsIndicativeofsuccessionaltrendsmayemergefromconventionalordinationIfextrinsic!nformatlonallowsthemtobel-dentlfledassuch.Inthespedalcaseofforestvegetation,forInstance,Informationonthesize—classesoftreespedespresentmaypermitsuccessionalgradientslobeldentlfleddirectly(Goff1968,Carleton&Maycock1978).Fewauthors,however,haveattempted… 相似文献
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XUSHIXIONG 《Cell research》1993,3(1):93-101
The pattern of change of the microtubule cytoskeleton of the root-tip cells of rice during mitosis was studied using immunofluorescence technic and confocal laser scanning microscopy. All the major stages of ceil division including preprophase, prophase, metaphase, anaphase and telophase were observed. The most significant finding was that in the preprophase cells microtubules radiating from the nuclear surface to the cortex were frequently seen. During development these microtubules became closely associated with the preprophase band and prophase spindie indicating that the microtubules radiating from the nuclear surface, the preprophase band and the prophazc spindle were structurally and functionally closely related to each other. Granule-like anchorage sites for the radiating microtubules at the muclear surface were often seen and the possibility that these gramle-like anchorage sites might represent the microtubule organizing centres was discussed. 相似文献
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