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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
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M. Blunck W. -D. Busse G. Meister E. Möller A. Mullen L. A. A. van Rooijen 《Die Naturwissenschaften》1989,76(3):96-98
Online searching in publically available patent files opens up interesting possibilities to provide a rapid response to critical questions. A computerized analysis of all patents of leading German pharmaceutical companies over the last decade in important indication areas is described. Supported by subsequent manual processing of individual patents it is shown that duplicate experiments on animals practically never occur. 相似文献
195.
This study investigated the influence of cat urine odour in suppressing development and fertility in Campbell's hamster males.
Exposure to this odour from postnatal day 11 until day 45 (sexual maturation) resulted in reduced sex organ weights, reduced
testosterone levels and in an increase in abnormalities of the synaptonemal complex in both sex chromosomes and autosomes.
Subsequent breeding experiments revealed a significant decrease in litter size. All these data indicate a severe effect of
predator odour on the breeding success of potential prey species. It is assumed that these effects are caused by the sulphurous
compounds in the urine; however, the underlying mechanisms are not yet known.
Received: 31 January 2000 / Accepted in revised form: 6 June 2000 相似文献
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The basic principles of dc-tandem and high-frequency linear accelerator are discussed by referring to the pioneering work of H. Kallmann and R. Wideröe. The 30 MV Supertandem in Daresbury, the Heidelberg combination of tandem and linac, and the universal linear accelerator Unilac of the GSI at Darmstadt serve as examples of modern heavy-ion accelerators. 相似文献
199.
E. Kuhn-Schnyder 《Die Naturwissenschaften》1979,66(12):587-592
Lorenz Oken, 1. Aug. 1779 Bohlsbach (Baden, Germany) — 11. Aug. 1851 Zurich (Switzerland). Philosopher and Zoologist. He studied at Freiburg i. Br. and Würzburg, was called from Göttingen to the university of Jena (1807–1819), München (1827–1832), Zurich (1833–1851). Oken came very early under the influence of Schelling and became the typical German Naturphilosoph. This did not prevent him from doing distinguished biological work. Oken was one of the best comparative anatomists of his days, his works on embryology are classics. He gave an interesting forecast of the modern cell doctrine. He founded a biological journal (Isis, 1816–1848) which for thirty years published articles of unquestioned value. He instituted the meetings of the “Gesellschaft Deutscher Naturforscher und Ärzte” (1821). By his “Naturgeschichte für alle Stände”, 13 vols. (1833–1845) he is one of the first to popularize natural science. 相似文献
200.
Extended screening tests on the cercaricidal activity of various plants from northeast Brazil have shown that the extracts of the leaves and fruits ofPiper marginatum,Protium heptaphyllum, andCapsicum annuum show a remarkable effect on the cercaria ofSchistosoma mansoni. In the case of the oils ofPiper marginatum andCapsicum annuum, 90–96% of the cercaria ofSchistosoma mansoni were killed within 15 min. According to the NMR spectra, the active principles of the extracts seem to be water-soluble unsaturated compounds from the oils or their hydrolysis products. Natural substances provide an attractive alternative for preventive actions against schistosomiasis, as the perturbation of the ecological equilibrium of natural waters can be avoided in this manner. 相似文献