首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   120篇
  免费   3篇
  国内免费   1篇
化学   57篇
力学   2篇
数学   2篇
物理学   63篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   2篇
  2016年   1篇
  2013年   2篇
  2012年   1篇
  2011年   5篇
  2010年   4篇
  2009年   4篇
  2007年   1篇
  2005年   5篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1999年   3篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1990年   7篇
  1989年   8篇
  1988年   9篇
  1987年   6篇
  1986年   3篇
  1985年   2篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1968年   1篇
  1966年   1篇
  1944年   2篇
  1942年   4篇
  1941年   2篇
  1940年   1篇
  1939年   2篇
  1937年   4篇
  1936年   2篇
  1935年   1篇
  1934年   2篇
  1933年   2篇
  1932年   6篇
  1931年   1篇
  1930年   3篇
  1928年   2篇
  1926年   4篇
排序方式: 共有124条查询结果,搜索用时 484 毫秒
1.
2.
Backward proton and pion production is studied in ν and \(\bar v\) charged current interactions in neon. The results are compared with other experiments and theory. The complete backward proton data is compatible with protons produced by reinteractions in the nucleus. However in events with only one proton, muon variables appear correlated to those for the backward proton, as expected by the two-nucleon correlation model.  相似文献   
3.
The cross section for coherent production of a single π? meson in charged current antineutrino interactions on neon nuclei has been measured in BEBC to be (175±25) 10?40 cm2/neon nucleus, averaged over the energy spectrum of the antineutrino wide band beam at the CERN SPS; this corresponds to (0.9±0.1) % of the total charged current \(\bar v_\mu \) cross section. The distributions of kinematical variables are in agreement with theoretical predictions based on the PCAC hypothesis and the meson dominance model; in particular, theQ 2 dependence is well described by a propagator containing a massm=(1.35±0.18) GeV. The absolute value of the cross section is also in agreement with the model. This analysis thus provides a test of the PCAC hypothesis in the antineutrino energy range 5–150 GeV.  相似文献   
4.
The VIDAS Immuno-concentration Salmonella (ICS) plus selective plate method (Hektoen enteric, bismuth sulfite, Salmonella identification) method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1,283 of the 1,440 test samples. Of the 157 test samples not in agreement, 82 were VIDAS ICS plus selective plate-positive and BAM/AOAC-negative, and 75 were VIDAS ICS plus selective plate-negative and BAM/AOAC-positive.  相似文献   
5.
6.
7.
[reaction: see text] A synthesis of the glutarimide-derived metabolite of thalidomide, 5'-hydroxythalidomide (2), is described. The synthesis employed the lactone derivative of N-benzyloxycarbonyl (CBZ)-protected 4-hydroxyglutamic acid 12, which is prepared by a de novo route from diethyl acetamidomalonate. The reaction of 12 with 4-methoxybenzylamine gave the corresponding isoglutamine, which then provided the key CBZ-protected N-PMB-glutarimide 14 after dehydration. Deprotection of both the CBZ and PMB groups followed by phthalimidation and deacetylation of the 3-amino-5-acetoxyglutarimide 16 afforded 2.  相似文献   
8.
Stress concentrations in the vicinity of cutouts can often be regarded to be the limiting factor for a whole structure. As a further development of prior research at the Institute of Lightweight Engineering and Polymer Technology, an analytical method for the determination of the whole stress-strain fields in the vicinity of holes in multilayered textile-reinforced composites has been developed, which takes into consideration the influences of a finite outer boundary of the specimen. The analytical method is based on the classical laminate theory and the use of complex-valued potential functions. To account for the shape of the specimen, the method of conformal mappings is applied for the inner boundary, while a combination of boundary collocation and least squares method is used for the outer boundary. The method allows a layer-by-layer analysis of stress concentrations. For the verification of the developed calculation model, extensive experimental and numerical finite-element (FE) studies have been carried out on multilayered GF/PP plates with different laminate layups, notches, and specimen dimensions. The comparison of the experimentally or numerically determined results with the analytically calculated ones shows a very good correlation, of which the numerical studies are presented here for the first time. In a second step, the applicable boundary conditions on the outer boundary have been extended in such a way that varying stress and moment resultants can be applied, so that the calculation method can be used as an analytical sub-model in combination with FE techniques.  相似文献   
9.
Void swelling is an important phenomenon observed in both nuclear fuels and cladding materials in operating nuclear reactors. In this work we develop a phase-field model to simulate void evolution and void volume change in irradiated materials. Important material processes, including the generation of defects such as vacancies and self-interstitials, their diffusion and annihilation, and void nucleation and evolution, have been taken into account in this model. The thermodynamic and kinetic properties, such...  相似文献   
10.
We report on a high statistics search for the Ξ??(1860) resonance in Σ?-nucleus collisions at 340 GeV/c. No evidence for this resonance is found in our data sample which contains 676000 Ξ? candidates above bakground. For the decay channel Ξ??(1860)→Ξ? π ? and the kinematic range 0.15<xF<0.9 we find a 3σ upper limit for the production cross section of 3.1 and 3.5 μb per nucleon, for reactions with carbon and copper, respectively.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号