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晓君 《大科技.科学之谜》2001,(9):45-46
这是一群看不见但无处不在,微小却拥挤的东西,它们几乎把人类包围了起来,但它们还不算是微生物。这些自然的创造物的历史也很悠久,自4亿年前的远古时代就存在于我们的地球上。它们的生存适应能力非常强,几亿年来几乎没有什么变化。正如人们所说的那样,“除了天上(它们没有翅膀,上不了天),它们无处不在:从南极冰原到洋底热泉,从沙漠到森林,不管是陆地海洋,还是动物植物,谁也逃不过它们的侵扰”。这些神秘的小东西就是螨虫。 相似文献
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《课堂内外(小学版)》2014,(9):38-39
正冰激凌冰激凌,看到就让你眼馋了吧?在享受它带给你奇特美味感受的同时,知道这美味的秘密吗?冰激凌之所以细腻目松软可口,要感谢隐藏于它体内的空气,现在你该明白冰激凌制作时需要疯狂搅拌的原因了吧,就是要把空气请进去。虽然冰激凌已经有450年的历史,但现在的冰激凌于1774年诞生于法国国王的厨师手下, 相似文献
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正巨藻是一种既不开花,也不结果的低等绿色植物。它的"近亲"是人们所熟悉的海带、裙带菜等,不过,巨藻远比它的这些近亲高大得多,犹如海洋中的参天大树。在巨藻林中,生活着许多鱼类以及其他小型无脊椎动物。在这个天然的立体隐蔽所里,鱼儿们可以逃避湍急的海流并躲避天敌,海胆、鲍鱼则以巨藻为主要食源,海豹、海狮、海獭、海鸟们也会云集而来,在这里寻找美味佳肴。海胆是巨藻林中的主要成员。它的大多数种类都像略扁 相似文献
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K. D. Simon Y. Bakar A. Samat C. C. Zaidi A. Aziz A. G. Mazlan 《Journal of Zhejiang University. Science. B》2009,10(12):902-911
Population growth, trophic level, and some aspects of reproductive biology of two congeneric archer fish species, Toxotes chatareus and Toxotes jaculatrix, collected from Johor coastal waters, Malaysia, were studied. Growth pattern by length-weight relationship (W=aL~b) for the sexes differed, and exhibited positive allometric growth (male, female and combined sexes of T. chatareus; female and combined sexes of T. jaculatrix) and isometric growth (male samples of T. jaculatrix only). Trophic levels of both species were analyzed based on 128 specimens. The results show that, in both species, crustaceans and insects were the most abundant prey items, and among crustaceans the red clawed crab Sesarma bidens and Formicidae family insects were the most represented taxa. The estimated mean trophic levels for T. chatareus and T. jaculatrix were 3.422±0.009 and 3.420±0.020, respectively, indicating that they are largely carnivores. Fecundity of T. chatareus ranged from 38354 to 147185 eggs for females with total length ranging from 14.5 to 22.5 cm and total body weight from 48.7 to 270.2 g, and T. jaculatrix 25 251 to 150456 eggs for females with total length ranging from 12.2 to 23.0 cm and total body weight from 25.7 to 275.0 g. Differences in values of gonadosomatic and hepatosomatic indexes calculated for both species in this study may have resulted from uneven sample size ranges. 相似文献
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In recognition of his valuable work to the marine shellfish farming research Prof. ZHANG Fusui a marine biologist aquaculture expert from the CAS Institute of Oceanology was honored with a prize of outstanding contributions by the US National Shellfisheries Association on March.…… 《中国科学院院刊(英文版)》2007,21(2):115-115
In recognition of his valuable work to the marine shellfish farming research, Prof. ZHANG Fusui, a marine biologist and aquaculture expert from the CAS Institute of Oceanology, was honored with a prize of outstanding contributions by the US National Shellfisheries Association on 1 March. 相似文献
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由于蚊子传播的登革热每年导致全世界5,000万人感染,并至少要夺去12,000条生命。为了直接消灭这种吸血生物,澳大利亚皇家布里斯班医院的Brian Kay和越南河内卫生部的Vu Sinh Nam用甲壳类动物剑水蚤来对付伊蚊的幼虫孑孓。从1998至2003年,这种细小的食肉动物被撒播到水池中,而且村民清理了所有可能盛水的废弃容器。结果发表在《柳叶刀》(Lancet)杂志上: 相似文献