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   1394篇
  免费   38篇
  国内免费   73篇
化学   373篇
晶体学   1篇
力学   23篇
综合类   2篇
数学   140篇
物理学   966篇
  2022年   10篇
  2021年   10篇
  2020年   9篇
  2019年   6篇
  2018年   13篇
  2017年   17篇
  2016年   41篇
  2015年   19篇
  2014年   26篇
  2013年   21篇
  2012年   27篇
  2011年   69篇
  2010年   55篇
  2009年   38篇
  2008年   40篇
  2007年   29篇
  2006年   69篇
  2005年   91篇
  2004年   138篇
  2003年   139篇
  2002年   81篇
  2001年   86篇
  2000年   22篇
  1999年   33篇
  1998年   27篇
  1997年   17篇
  1996年   22篇
  1995年   22篇
  1994年   8篇
  1993年   24篇
  1992年   20篇
  1991年   11篇
  1990年   22篇
  1989年   30篇
  1988年   45篇
  1987年   19篇
  1986年   23篇
  1985年   15篇
  1984年   17篇
  1983年   8篇
  1982年   7篇
  1981年   13篇
  1980年   8篇
  1979年   6篇
  1977年   3篇
  1919年   3篇
  1911年   4篇
  1910年   3篇
  1909年   3篇
  1907年   3篇
排序方式: 共有1505条查询结果,搜索用时 31 毫秒
91.
We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at square root[s(NN)] = 200 GeV. For the 5% most central events we obtain dN(ch)/deta/(eta = 0) = 625+/-55 and N(ch)/(-4.7< or =eta < or =4.7) = 4630 +/- 370, i.e., 14% and 21% increases, respectively, relative to square root[s(NN)] = 130 GeV collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy.  相似文献   
92.
Total and differential cross sections for the exclusive reaction pp-->pp rho observed via the pi(+)pi(-) decay channel have been measured at p(beam)=3.67 GeV/c. The observed total meson production cross section is determined to be (23.4+/-0.8+/-8) mu b and is significantly lower than typical cross sections used in model calculations for heavy-ion collisions. The differential cross sections measured indicate a strong anisotropy (approximately cos(theta(CM)(rho)) in the rho(0) meson production.  相似文献   
93.
94.
掺杂PVK薄膜的荧光谱及电荷转移   总被引:5,自引:3,他引:2  
根据PVK掺杂后荧光谱的变化,说明掺杂PVK薄膜的电致发光存在着从基质分子向掺杂分子的能量传递,用一个由单链模型扩展到包括杂质的哈密顿量进行数值求解,结果表明:在PVK和杂质分子之间有效的能量传递是源于它僮之间的电荷转移,且随着杂质浓度的变化,其荧光谱峰位的移动与掺杂前后系统总能量的改变及荧光谱强度与掺杂后转移的电荷数之间分别存在对应关系。该模型较好地解释了有关的实验结果。  相似文献   
95.
The Second Séminaire sur les Techniques Nouvelles de Traitement des Matrices Creuses pour les Problèmes Industriels (Second Symposium on New Techniques for the Treatment of Sparse Matrices for Industrial Problems) was held at the Universitédes Sciences et Technologies de Lille, April 28–29, 1997. It followed the first one in Grenoble in February 1995. The organizing committee consisted of C. Brezinski (Université Lille), L. Colombet (CEA Grenoble), J. David (CEA Saclay), S. Petiton (Universitée Lille), N. Revol (Université Lille), Y. Saad (DCS Minneapolis) and D. Trystram (IMAG Grenoble).The local organizing committee consisted of C. Brezinski, C. Le Calvez, S. Petitonand N. Revol, all from the University of Lille. Around 100 participants attended the congress. They came from various universities and industries, some of them from Belgium, Great Britain, Morocco and the USA. The congress consisted of 13 one hour invited talks and a round table on methods and software for industrial problems. We thank all speakers for giving very interesting talks, thus making the congress very lively. Various aspects of numerical computations with sparse matrices were treated: new algorithms, effective handling of very large sparse systems, parallel techniques, preconditioning, direct and iterative methods, etc. This issue contains the papers corresponding to five of these invited talks and we very much appreciated the additional effort of their authors. We would like to thank the Université des Sciences et Technologies de Lille,the Commissariat à l'Energie Atomique, the Conseil Général de la Région Nord - Pasde Calais, the Laboratoire d'Informatique Fondamentale de Lille and the Laboratoired' Analyse Numérique et d'Optimisation de l'Université des Sciences et Technologies de Lille whose financial and logistic support made possible the organization and the success of the congress. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
96.
对重氢原子进入钯或钛晶体中可能引起常温核聚变的机理探讨与实验研究结果,已在文献[1]中作了报导。后来又对钛阴极材料,在使用前后进行了X射线结构分析。发现在电解过程中发生过“过热”现象的钛阴极材料的晶体结构由原来的密排六方结构转变为立方结构,而没有发生“过热”现象的钛阴极材料的晶体仍然保持电解前的密排六方结构  相似文献   
97.
Inclusive cross sections of η production by e+e- annihilation for c.m. energies between 4.0 and 5.0 GeV are presented. The η production is shown to be correlated with the production of a weakly decaying particle, indicating that its main source is F production. At the 4.42 GeV resonance it is correlated with a low energy photon, suggesting or production. A mass determination of the F is made at 4.42 GeV using the F → ηπ decay channel.  相似文献   
98.
99.
Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities . The data were taken at the ep collider HERA with centre-of-mass energy using the ZEUS detector and correspond to an integrated luminosity of . Jets were identified in the Breit frame using the kT cluster algorithm in the longitudinally invariant inclusive mode. Measurements of differential dijet and trijet cross sections are presented as functions of jet transverse energy ( ), pseudorapidity ( ) and Q2 with and . Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant , determined from the ratio of the trijet to dijet cross sections, is . Received: 1 April 2005, Revised: 28 June 2005, Published online: 30 August 2005  相似文献   
100.
Results are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the center of mass energy range 142 < W < 266 GeV. The cross sections are measured for the transverse momentum range of the photons GeV and for associated jets with E T jet > 4.5 GeV. They are measured differentially as a function of , the pseudorapidities and and estimators of the momentum fractions and x p of the incident photon and proton carried by the constituents participating in the hard process. In order to further investigate the underlying dynamics, the angular correlation between the prompt photon and the jet in the transverse plane is studied. Predictions by perturbative QCD calculations in next to leading order are about below the inclusive prompt photon data after corrections for hadronisation and multiple interactions, but are in reasonable agreement with the results for prompt photons associated with jets. Comparisons with the predictions of the event generators PYTHIA and HERWIG are also presented.Received: 13 July 2004, Revised: 15 November 2004, Published online: 17 December 2004  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