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   283588篇
  免费   2167篇
  国内免费   711篇
化学   150347篇
晶体学   4495篇
力学   12413篇
综合类   14篇
数学   31030篇
物理学   88167篇
  2019年   2393篇
  2018年   3221篇
  2017年   3232篇
  2016年   4677篇
  2015年   2794篇
  2014年   4496篇
  2013年   11353篇
  2012年   8533篇
  2011年   10387篇
  2010年   7448篇
  2009年   7258篇
  2008年   9753篇
  2007年   9977篇
  2006年   9349篇
  2005年   8469篇
  2004年   7785篇
  2003年   7107篇
  2002年   7006篇
  2001年   7846篇
  2000年   6059篇
  1999年   4703篇
  1998年   4133篇
  1997年   4091篇
  1996年   3831篇
  1995年   3637篇
  1994年   3760篇
  1993年   3438篇
  1992年   3905篇
  1991年   3967篇
  1990年   3867篇
  1989年   3728篇
  1988年   3818篇
  1987年   3700篇
  1986年   3517篇
  1985年   4668篇
  1984年   4943篇
  1983年   4123篇
  1982年   4250篇
  1981年   4196篇
  1980年   4158篇
  1979年   4128篇
  1978年   4447篇
  1977年   4347篇
  1976年   4425篇
  1975年   4063篇
  1974年   4114篇
  1973年   4294篇
  1972年   3011篇
  1971年   2511篇
  1967年   2435篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Granted the post-Lorentzian relativistic kinematic transformations are described in the Finslerian framework, the uniformity between the actual light-velocity anisotropy change and the anisotropic deformation of measuring rods can be the reason proper for the null results of the Michelson-Morley-type experiments at the first-order level.  相似文献   
62.
The angular distributions of fragments originating from the binary decay of oriented spherical and deformed nuclei are investigated with allowance for correct transformation properties of wave functions under time inversion. It is shown that, as in the case of protonic decay, the adiabatic approximation for collective rotational degrees of freedom of the systems under investigation is inapplicable in describing the angular distributions of fragments of the deep-subbarrier alpha and cluster decays of nuclei. It is demonstrated that this approximation is justified in describing spontaneous and induced low-energy nuclear fission. The dependence of partial fission widths on the orientation of intrinsic axes, spins, and projections of spins and relative orbital angular momenta of fission fragments is analyzed by using the formalism of the unified theory of nuclear reactions and the theory of open Fermi systems. It is shown that the adiabatic approximation leads to the coherent interference between the wave functions for the relative motion of fragments, whereby the universal angular distributions of fission fragments of oriented nuclei is formed. Deviations from the A. Bohr formula are investigated for these distributions.  相似文献   
63.
A systematic investigation of the forward-angle inclusive yields of 2≤Z≤11 isotopes produced in collisions of 18O projectile nuclei with a 9Be target in the Fermi energy region (35A MeV) is performed. The measurements were based on the use of the COMBAS double achromatic kinematical separator in the spectrometry mode at the Flerov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research, FLNR (JINR, Dubna). The velocity, isotopic, and element distributions are presented. There is no unique mechanism that would explain the total set of results obtained in this experiment. A dominant role of low-energy reaction mechanisms is observed. The intensity of secondary beams of halolike nuclei 11Li, 12Be, and 14Be is determined.  相似文献   
64.
A feedback mechanism that involves the proteins p53 and mdm2, induces cell death as a controlled response to severe DNA damage. A minimal model for this mechanism demonstrates that the response may be dynamic and connected with the time needed to translate the mdm2 protein. The response takes place if the dissociation constant k between p53 and mdm2 varies from its normal value. Although it is widely believed that it is an increase in k that triggers the response, we show that the experimental behaviour is better described by a decrease in the dissociation constant. The response is quite robust upon changes in the parameters of the system, as required by any control mechanism, except for few weak points, which could be connected with the onset of cancer. Received 8 May 2002 / Received in final form 9 July 2002 Published online 17 September 2002  相似文献   
65.
We prove that the diffusion semigroups generated by the second order differential ultraspherical (Gegenbauer) operator are pseudomeasure operators.  相似文献   
66.
The properties of Skyrmions in finite nuclei are considered. The deformation effect is taken into account through the external-field-induced distortion of the profile function of a chiral field. The masses of classical Skyrmions and the distribution of their baryon number versus the Skyrmion position within a nucleus are discussed.  相似文献   
67.
The European Physical Journal E - The temperature-induced microphase separation of the binary liquid system iso-butyric acid+heavy water (iBA + D2O) in a mesoporous silica glass (CPG-10-75) of...  相似文献   
68.
Frank  A. I.  Nosov  V. G. 《JETP Letters》2004,79(7):313-315
JETP Letters - The problem of storing ultracold neutrons over a plane magnetic mirror in the presence of gravity is considered. For neutrons with a definite polarization, the sum of the magnetic...  相似文献   
69.
Bibliography: 42 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 306, 2003, pp. 7–15.  相似文献   
70.
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