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   36204篇
  免费   6149篇
  国内免费   5391篇
化学   27905篇
晶体学   542篇
力学   1767篇
综合类   346篇
数学   3799篇
物理学   13385篇
  2024年   96篇
  2023年   727篇
  2022年   1147篇
  2021年   1331篇
  2020年   1490篇
  2019年   1549篇
  2018年   1272篇
  2017年   1329篇
  2016年   1804篇
  2015年   1877篇
  2014年   2296篇
  2013年   2924篇
  2012年   3543篇
  2011年   3782篇
  2010年   2643篇
  2009年   2496篇
  2008年   2598篇
  2007年   2433篇
  2006年   2065篇
  2005年   1667篇
  2004年   1275篇
  2003年   1017篇
  2002年   1009篇
  2001年   868篇
  2000年   691篇
  1999年   631篇
  1998年   465篇
  1997年   388篇
  1996年   360篇
  1995年   306篇
  1994年   283篇
  1993年   243篇
  1992年   225篇
  1991年   171篇
  1990年   139篇
  1989年   141篇
  1988年   80篇
  1987年   77篇
  1986年   72篇
  1985年   64篇
  1984年   39篇
  1983年   23篇
  1982年   15篇
  1981年   15篇
  1980年   8篇
  1979年   11篇
  1977年   6篇
  1976年   9篇
  1975年   6篇
  1957年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Fan  K.  Lu  R. S.  Liang  K. K.  Hou  Z. C. 《High Energy Chemistry》2022,56(4):264-269
High Energy Chemistry - Modification of Polyvinylidene fluoride (PVDF) by radiation grafting is a research hotspot in recent years. In this study, the monomer 2-Hydroxyethyl methacrylate (HEMA) was...  相似文献   
2.
International Journal of Theoretical Physics - In this work, we give an analytical derivation of the reduced density matrix between two qubits in a cavity field, which is described by the quantum...  相似文献   
3.
A numerical model was developed and validated to investigate the fluid–structure interactions between fully developed pipe flow and core–shell-structured microcapsule in a microchannel. Different flow rates and microcapsule shell thicknesses were considered. A sixth-order rotational symmetric distribution of von Mises stress over the microcapsule shell can be observed on the microcapsule with a thinner shell configuration, especially at higher flow rate conditions. It is also observed that when being carried along in a fully developed pipe flow, the microcapsule with a thinner shell tends to accumulate stress at a higher rate compared to that with a thicker shell. In general, for the same microcapsule configuration, higher flow velocity would induce a higher stress level over the microcapsule shell. The deformation gradient was used to capture the microcapsule's deformation in the present study. The effect of Young's modulus on the microcapsule shell on the microcapsule deformation was investigated as well. Our findings will shed light on the understanding of the stability of core–shell-structured microcapsule when subjected to flow-induced shear stress in a microfluidic system, enabling a more exquisite control over the breakup dynamics of drug-loaded microcapsule for biomedical applications.  相似文献   
4.
Computational Optimization and Applications - We develop a globalized Proximal Newton method for composite and possibly non-convex minimization problems in Hilbert spaces. Additionally, we impose...  相似文献   
5.
Hu  Duo-Duo  Gao  Qian  Dai  Jing-Cheng  Cui  Ru  Li  Yuan-Bo  Li  Yuan-Ming  Zhou  Xiao-Guo  Bian  Kang-Jie  Wu  Bing-Bing  Zhang  Kai-Fan  Wang  Xi-Sheng  Li  Yan 《中国科学:化学(英文版)》2022,65(4):753-761
Science China Chemistry - A light-induced, nickel-catalyzed three-component arylsulfonation of 1,3-enynes in the absence of photocatalyst is reported. This methodology exhibited mild conditions,...  相似文献   
6.
7.
International Journal of Theoretical Physics - The Majorana representation, which provides an intuitive way to represent the quantum state by stars on the Bloch sphere, has drawn considerable...  相似文献   
8.
Acridone as a new kind of visible light photocatalyst has been developed to catalyze metal free atom transfer radical polymerization (ATRP). The photocatalyst possess low excited state potential as can undergo an oxidative quenching pathway to initiate ATRP of vinyl monomers. Kinetic study and light on/off reaction demonstrate the “living”/controlled nature of the polymerization by light. Block copolymers can be achieved by using PMMA as macroinitiator to reinitiate polymerization of other vinyl monomers, which shows highly preserved Br chain-end functionality in the synthesized polymers. Moreover, the polymerization can be conducted under air atmosphere as most photocatalysts need anaerobic condition, which may give inspiration of further application of this kind of photocatalyst.  相似文献   
9.
In this paper, let (Mn,g,dμ) be n-dimensional noncompact metric measure space which satisfies Poincaré inequality with some Ricci curvature condition. We obtain a Liouville theorem for positive weak solutions to weighted p-Lichnerowicz equation
p,fv+cvσ=0,
where c0,m>n1,1<p<m?1+(m?1)(m+3)2,σp?1 are real constants.  相似文献   
10.
We study the full counting statistics of transport electrons through a semiconductor two-level quantum dot with Rashba spin–orbit (SO) coupling, which acts as a nonabelian gauge field and thus induces the electron transition between two levels along with the spin flip. By means of the quantum master equation approach, shot noise and skewness are obtained at finite temperature with two-body Coulomb interaction. We particularly demonstrate the crucial effect of SO coupling on the super-Poissonian fluctuation of transport electrons, in terms of which the SO coupling can be probed by the zero-frequency cumulants. While the charge currents are not sensitive to the SO coupling.  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