共查询到20条相似文献,搜索用时 15 毫秒
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Extinctions: a paleontological perspective 总被引:2,自引:0,他引:2
Jablonski D 《Science (New York, N.Y.)》1991,253(5021):754-757
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V K Farris 《Science (New York, N.Y.)》1968,160(833):1245-1246
Dissociation of the ovotestes of Helix pomatia requires the presence of carbohydrates as well as trypsin, but is independent of cation content. Dispersed cells obtained from the ovotestes reaggregate rapidly into histotypically organized tissue. The role of cellular adhesiveness is facilitated by centrifugation, but pseudopodial activity of the cells is suggested as another factor in reaggregation. 相似文献
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Yochelson EL 《Science (New York, N.Y.)》1970,167(3917):398-400
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Redmond JR 《Science (New York, N.Y.)》1963,139(3561):1294-1295
The hemocyanin of the keyhole limpet, Diodora aspera, shows no Bohr effect within the pH range 6.88 to 7.84. At 10 degrees C the pressure of half-saturation is 5 mm-Hg of oxygen pressure. A moderately positive interaction occurs among the oxygen-combining sites during oxygenation. The heat of oxygenation is calculated to be approximately -12.6 kcal/mole of oxygen. The pH of normal blood of Diodora is lower than that of many other marine molluscs. 相似文献
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The recent appearance of large populations of certain adult marine mollusks in Bermuda shallows, unreported in previous surveys, suggests that an invasion is taking place, probably from Florida or the Bahamas, or from both. "Newcomers" grow to sizes larger than any known elsewhere, suggesting that the characteristically large sizes of some species in Bermuda reflect environmentalrather than genetic causes. 相似文献
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Stokstad E 《Science (New York, N.Y.)》2001,291(5502):234-235
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Guber AL 《Science (New York, N.Y.)》1969,166(3906):744-746
Paleosalinity values in certain rocks determined by the sedimentary phosphate method differ from salinity estimates based upon contained fossil assemblages, geochemical methods, and existing stratigraphic controls. Some anomalous values are related to the abundance of fossil organisms known to be concentrators of calcium phosphate. Because of the abundance and diversity of organisms which might introduce significant errors into paleosalinity estimates, the sedimentary phosphate method seemingly is of limited applicability. 相似文献
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Shapiro JA 《Science (New York, N.Y.)》1985,230(4730):1155-1156
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Lauder GV 《Science (New York, N.Y.)》1988,239(4847):1547-1548
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Field KG Olsen GJ Giovannoni SJ Raff EC Pace NR Raff RA 《Science (New York, N.Y.)》1989,243(4890):550-551
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Schopf TJ 《Science (New York, N.Y.)》1982,217(4558):438-440
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