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   1180篇
  免费   167篇
  国内免费   90篇
化学   42篇
晶体学   8篇
力学   277篇
综合类   7篇
数学   102篇
物理学   537篇
综合类   464篇
  2024年   5篇
  2023年   14篇
  2022年   20篇
  2021年   29篇
  2020年   17篇
  2019年   16篇
  2018年   21篇
  2017年   26篇
  2016年   32篇
  2015年   42篇
  2014年   60篇
  2013年   53篇
  2012年   55篇
  2011年   63篇
  2010年   52篇
  2009年   59篇
  2008年   47篇
  2007年   80篇
  2006年   61篇
  2005年   72篇
  2004年   62篇
  2003年   66篇
  2002年   54篇
  2001年   55篇
  2000年   53篇
  1999年   44篇
  1998年   29篇
  1997年   46篇
  1996年   32篇
  1995年   30篇
  1994年   24篇
  1993年   23篇
  1992年   12篇
  1991年   20篇
  1990年   11篇
  1989年   14篇
  1988年   12篇
  1987年   4篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   4篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1975年   1篇
  1969年   1篇
排序方式: 共有1437条查询结果,搜索用时 0 毫秒
991.
The deuteron transverse charge density ρC(b) is the two-dimensional Fourier transform of its charge form factor in the impact space. We show that different parameterizations of the charge form factors provide different ρC(b),in particular at the central value of impact parameter(b = 0), although all the parameterizations can well reproduce the form factors in the region of small Q2. In addition, we also check the explicit contributions from the different coordinate intervals of the deuteron wave function to its root-mean-square radius.  相似文献   
992.
Free and steady state forced transverse vibrations of non-uniform beams are investigated with a proposed method, leading to a series solution. The obtained series is verified to be convergent and linearly independent in a convergence test and by the non-zero value of the corresponding Wronski determinant, respectively. The obtained solution is rigorous, which can be reduced to a classical solution for uniform beams. The proposed method can deal with arbitrary non-uniform Euler-Bernoulli beams in principle, but the methods in terms of special functions or elementary functions can only work in some special cases.  相似文献   
993.
This paper deals with the study of the laminar free‐convection boundary‐layer flow about a heated and rotating down‐pointing vertical cone in the presence of a transverse magnetic field. Two cases of heat transfer analysis are discussed. These are: (i) the rotating cone with prescribed surface temperature and (ii) the rotating cone with prescribed surface heat flux. By means of similarity transformation, the governing partial differential equations are reduced into highly non‐linear ordinary differential equations. The resulting non‐linear system has been solved analytically using a very efficient technique, namely homotopy analysis method. Expressions for velocity and temperature fields are developed in a series form. The influence of various pertinent parameters is also seen on the velocity and temperature fields. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
994.
研究具有两个驰豫时间的、两个不同弹性和热性质的、广义传热立方晶体固体半空间的有缺陷结合面上,热弹性平面波的反射和折射问题.具有两个驰豫时间的广义热弹性理论,是1972年由Green和Lindsay提出并应用于问题的研究.对有缺陷边界,给出了反射系数和折射系数(即反射波和折射波振幅与入射波振幅之比)的表达式,并推演了法向刚性边界、横向刚性边界、接触传热边界、滑动边界和结合面边界时的表达式.给出了在不同边界条件及出射角时,不同的反射波和折射波的振幅比,在不同的入射波时的变化图.发现反射波和折射波振幅比受到介质刚性和热性质的影响.  相似文献   
995.
High-resolution solution NMR experiments are extremely useful to characterize the location and the dynamics of hydrating water molecules at atomic resolution. However, these methods are severely limited by undesired incoherent transfer pathways such as those arising from exchange-relayed intra-molecular cross-relaxation. Here, we review several complementary exchange network editing methods that can be used in conjunction with other types of NMR hydration experiments such as magnetic relaxation dispersion and 1JNC′ measurements to circumvent these limitations. We also review several recent contributions illustrating how the original solution hydration NMR pulse sequence architecture has inspired new approaches to map other types of non-covalent interactions going well beyond the initial scope of hydration. Specifically, we will show how hydration NMR methods have evolved and have been adapted to binding site mapping, ligand screening, protein-peptide and peptide-lipid interaction profiling.  相似文献   
996.
In this paper, we present a series of basic theorems for transversely isotropic plates characterized by a state of bending. More precisely, we show a reciprocal theorem and a uniqueness result without positive definiteness assumptions on the elastic coefficients. Moreover, we establish some variational and minimum principles. Finally, we give a Galerkin representation of the solution. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
997.
Co纳米线磁矩反转动态过程的有限元微磁学模拟   总被引:2,自引:0,他引:2       下载免费PDF全文
采用有限元微磁学模拟方法研究了Co纳米线在不同外加恒磁场下磁矩的翻转过程.研究结果表明在直径为10 nm的Co纳米线内,经过一定的形核时间将在其一端形成一个反向磁畴.磁畴壁的类型为横向畴壁,该畴壁将在一外加恒定磁场的驱动下匀速地从一端运动到另一端.畴壁的运动速度与外加磁场大小呈线性关系.在H为1000 kA/m时,发现在纳米线的两端均会形成一个“头对头”的反向磁畴.计算结果表明,畴壁内磁矩的方向旋转一个周期所导致的畴壁运动的距离相同,与外加磁场强度无关. 关键词: 磁性纳米线 微磁学模拟 磁畴 横向畴壁  相似文献   
998.
高温熔盐横纹管传热特性与强化机理研究   总被引:2,自引:0,他引:2  
本文对以熔融盐为传热工质的横纹管传热过程进行了实验研究。研究温度、热流密度对横纹管传热性能的影响,并与光管的传热性能进行比较,探讨了强化传热的机理,确定了强化传热的范围和途径。实验结果表明:横纹管比光管具有更好的传热性能。  相似文献   
999.
The transverse momentum distributions of final-state particles produced in collisions at high en-ergies are studied by using a two-component Rayleigh-like distribution.This representation is based on Liu's multisource ideal gas model which describes protons and fragments in high energy nucleus-nucleus collisions.The calculated results are in good agreement with the experimental data of Au-Au,Cu-Cu,d-Au,and pp collisions at the relativistic heavy ion collider energies.The experimental particle momentum distributions of p-Be collisions at 6.4,12.3,and 17.5 GeV/c,as well as Au-Au collisions at 1.5 AGeV are well described by a model based on a single Rayleigh-like distribution of particle transverse momenta.  相似文献   
1000.
The HERMES measured azimuthal amplitudes of cross sections and their transverse target single spin asymmetries for hadron productions in semi-inclusive deep inelastic scattering.From the extracted amplitudes,novel patton distribution functions can be studied.The recent results related to Sivers and Boer-Mulders distribution functions are discussed.  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