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   2690篇
  免费   544篇
  国内免费   273篇
化学   813篇
晶体学   20篇
力学   211篇
综合类   106篇
数学   1069篇
物理学   1288篇
  2024年   9篇
  2023年   75篇
  2022年   147篇
  2021年   176篇
  2020年   142篇
  2019年   93篇
  2018年   86篇
  2017年   103篇
  2016年   137篇
  2015年   170篇
  2014年   255篇
  2013年   230篇
  2012年   343篇
  2011年   252篇
  2010年   254篇
  2009年   230篇
  2008年   204篇
  2007年   170篇
  2006年   172篇
  2005年   86篇
  2004年   43篇
  2003年   14篇
  2002年   21篇
  2001年   39篇
  2000年   6篇
  1999年   30篇
  1998年   16篇
  1959年   4篇
排序方式: 共有3507条查询结果,搜索用时 46 毫秒
1.
Zhao  Tianqi  Luo  Tianzi  Fang  Bo  Shi  Lijiang  Jin  Yongxing  Zhou  Pengwei  Yao  Dong  Li  Chenxia  Jing  Xufeng  Hong  Zhi 《Journal of Russian Laser Research》2021,42(5):586-597
Journal of Russian Laser Research - The zero-refractive-index metamaterials have excellent electromagnetic properties, which provide new ideas and methods to realize the control of electromagnetic...  相似文献   
2.
International Journal of Theoretical Physics - In this paper, we will consider the exact calculation of differential entropy of induced random state ensemble by partial tracing a subsystem over...  相似文献   
3.
4.
In this paper we show that, for a sub-Laplacian Δ on a 3-dimensional manifold M, no point interaction centered at a point q0M exists. When M is complete w.r.t. the associated sub-Riemannian structure, this means that Δ acting on C0(M?{q0}) is essentially self-adjoint in L2(M). A particular example is the standard sub-Laplacian on the Heisenberg group. This is in stark contrast with what happens in a Riemannian manifold N, whose associated Laplace-Beltrami operator acting on C0(N?{q0}) is never essentially self-adjoint in L2(N), if dim?N3. We then apply this result to the Schrödinger evolution of a thin molecule, i.e., with a vanishing moment of inertia, rotating around its center of mass.  相似文献   
5.
Flow, Turbulence and Combustion - The laminar flow on a curved surface transits to turbulent induced by streamline curvature which generates pressure gradient field and separated shear layer flow....  相似文献   
6.
Lin  Hui-Min  Mu  Chao  Li  Ao  Liu  Xu-Feng  Li  Yu-Long  Jiang  Zhong-Qing  Wu  Hong-Ke 《Transition Metal Chemistry》2019,44(5):491-498
Transition Metal Chemistry - In this paper, four diiron toluene-3,4-dithiolate complexes with phosphine ligands were synthesized and characterized. Treatment of complex...  相似文献   
7.
流动环是一款魔术玩具,具有丰富的力学行为。制作流动环时应用了预应力储存技术,使得环内部储存了弹性弯曲变形能。一经外界扰动,流动环会迅速张开,进入一种新的稳定平衡状态;若给张开的流体环输入某种形式的能量,环会合拢,恢复原有的稳定平衡状态。本文从能量的角度对流动环张开与合拢等现象进行力学分析。  相似文献   
8.
9.
Annals of the Institute of Statistical Mathematics - In this paper, a model averaging approach is developed for the linear regression models with response missing at random. It is shown that the...  相似文献   
10.
The collisional dynamics of two symmetric droplets with equal intraspecies scattering lengths and particle number density for each component is studied by solving the corresponding extended Gross−Pitaevskii equation in two dimensions by including a logarithmic correction term in the usual contact interaction. We find the merging droplet after collision experiences a quadrupole oscillation in its shape and the oscillation period is found to be independent of the incidental momentum for small droplets. With increasing collision momentum the colliding droplets may separate into two, or even more, and finally into small pieces of droplets. For these dynamical phases we manage to present boundaries determined by the remnant particle number in the central area and the damped oscillation of the quadrupole mode. A stability peak for the existence of droplets emerges at the critical particle numberNc ≃ 48 for the quasi-Gaussian and flat-top shapes of the droplets.  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