全文获取类型
收费全文 | 61篇 |
免费 | 0篇 |
国内免费 | 4篇 |
专业分类
系统科学 | 2篇 |
教育与普及 | 1篇 |
现状及发展 | 17篇 |
研究方法 | 4篇 |
综合类 | 36篇 |
自然研究 | 5篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 1篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1962年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 15 毫秒
21.
The risk of a doomsday scenario in which high-energy physics experiments trigger the destruction of the Earth has been estimated to be minuscule. But this may give a false sense of security: the fact that the Earth has survived for so long does not necessarily mean that such disasters are unlikely, because observers are, by definition, in places that have avoided destruction. Here we derive a new upper bound of one per billion years (99.9% confidence level) for the exogenous terminal-catastrophe rate that is free of such selection bias, using calculations based on the relatively late formation time of Earth. 相似文献
22.
Homozygous HOXA1 mutations disrupt human brainstem, inner ear, cardiovascular and cognitive development 总被引:2,自引:0,他引:2
Tischfield MA Bosley TM Salih MA Alorainy IA Sener EC Nester MJ Oystreck DT Chan WM Andrews C Erickson RP Engle EC 《Nature genetics》2005,37(10):1035-1037
We identified homozygous truncating mutations in HOXA1 in three genetically isolated human populations. The resulting phenotype includes horizontal gaze abnormalities, deafness, facial weakness, hypoventilation, vascular malformations of the internal carotid arteries and cardiac outflow tract, mental retardation and autism spectrum disorder. This is the first report to our knowledge of viable homozygous truncating mutations in any human HOX gene and of a mendelian disorder resulting from mutations in a human HOX gene critical for development of the central nervous system. 相似文献
23.
G.Q.Max Lu 《科学通报(英文版)》2014,59(18):2071-2071
正The ever increasing concerns over energy security due to the depletion of fossil fuel give rise to heightened interest in and greater effort towards more sustainable energy supply and utilisation.In the meantime,the climate change as a result of CO2emission from fossil fuel use is undoubtedly another key driver for renewable energy development.Unfortunately,renewable energy such as solar,hydroelectric,wind and geothermal only constitutes a very small 相似文献
24.
We have simulated a time varying wind field using the lattice Boltzmann model, and its effect on blades of grass with a simple mass-spring model. We present a global illumination model for multiple scattering of incident sun and sky illumination within the field of grass. We model the grass as a continuous distribution of infinitesimal colored scattering flakes and solve a system of differential equations for the radiance transport. We repeat this for a collection of grass bending directions and amounts, an... 相似文献
25.
26.
27.
Pre-mRNA splicing and mRNA export linked by direct interactions between UAP56 and Aly. 总被引:25,自引:0,他引:25
Recent studies indicate that splicing of pre-messenger RNA and export of mRNA are normally coupled in vivo. During splicing, the conserved mRNA export factor Aly is recruited to the spliced mRNA-protein complex (mRNP), which targets the mRNA for export. At present, it is not known how Aly is recruited to the spliced mRNP. Here we show that the conserved DEAD-box helicase UAP56, which functions during spliceosome assembly, interacts directly and highly specifically with Aly. Moreover, UAP56 is present together with Aly in the spliced mRNP. Significantly, excess UAP56 is a potent dominant negative inhibitor of mRNA export. Excess UAP56 also inhibits the recruitment of Aly to the spliced mRNP. Furthermore, a mutation in Aly that blocks its interaction with UAP56 prevents recruitment of Aly to the spliced mRNP. These data suggest that the splicing factor UAP56 functions in coupling the splicing and export machineries by recruiting Aly to the spliced mRNP. 相似文献
28.
Seibert MM Ekeberg T Maia FR Svenda M Andreasson J Jönsson O Odić D Iwan B Rocker A Westphal D Hantke M DePonte DP Barty A Schulz J Gumprecht L Coppola N Aquila A Liang M White TA Martin A Caleman C Stern S Abergel C Seltzer V Claverie JM Bostedt C Bozek JD Boutet S Miahnahri AA Messerschmidt M Krzywinski J Williams G Hodgson KO Bogan MJ Hampton CY Sierra RG Starodub D Andersson I Bajt S Barthelmess M Spence JC Fromme P Weierstall U Kirian R Hunter M Doak RB Marchesini S Hau-Riege SP Frank M 《Nature》2011,470(7332):78-81
X-ray lasers offer new capabilities in understanding the structure of biological systems, complex materials and matter under extreme conditions. Very short and extremely bright, coherent X-ray pulses can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus or a cell before the sample explodes and turns into plasma. The continuous diffraction pattern of non-crystalline objects permits oversampling and direct phase retrieval. Here we show that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source. Calculations indicate that the energy deposited into the virus by the pulse heated the particle to over 100,000?K after the pulse had left the sample. The reconstructed exit wavefront (image) yielded 32-nm full-period resolution in a single exposure and showed no measurable damage. The reconstruction indicates inhomogeneous arrangement of dense material inside the virion. We expect that significantly higher resolutions will be achieved in such experiments with shorter and brighter photon pulses focused to a smaller area. The resolution in such experiments can be further extended for samples available in multiple identical copies. 相似文献
29.
Max Lu 《自然科学进展(英文版)》2012,22(6):521-521
Max Lu has been serving as Deputy Vice-Chancellor and Vice President (Research) since 2009 at the University of Queensland,Australia.He was also the Foundation Director of the ARC Centre of Excellence for Functional Nanomaterials from 2003 to 2009.
Professor Lu's research expertise is in the areas of materials chemistry and nanotechnology.He is known for his work on nanoparticles and nanoporous materials for clean energy and environmental technologies.With over 500 journal publications in high impact journals including Nature,Journal of the American Chemical Society,Angewandte Chemie,and Advanced Materials;he is also co-inventor of 20 international patents.Professor Lu is an Institute for Scientific Information (ISI) Highly Cited Author in Materials Science with over 17,500 citations (h-index of 63).He has received numerous prestigious awards nationally and internationally including the Chinese Academy of Sciences International Cooperation Award,China International Science and Technology Cooperation Award,Orica Award,RK Murphy Medal,Le Fevre Prize,ExxonMobil Award,Chemeca Medal (2011),and Top 100 Most Influential Engineers in Australia (2004,2010,2012).He is an elected Fellow of ATSE and Fellow of Institution of Chemical Engineers (IChemE).He is an editor and editorial board member of 12 major international journals including Colloid and Interface Science and Carbon. 相似文献
30.