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   10498篇
  免费   1843篇
  国内免费   1399篇
化学   7662篇
晶体学   232篇
力学   616篇
综合类   134篇
数学   1173篇
物理学   3923篇
  2024年   7篇
  2023年   175篇
  2022年   234篇
  2021年   364篇
  2020年   460篇
  2019年   507篇
  2018年   424篇
  2017年   440篇
  2016年   591篇
  2015年   585篇
  2014年   675篇
  2013年   923篇
  2012年   1000篇
  2011年   992篇
  2010年   742篇
  2009年   729篇
  2008年   746篇
  2007年   626篇
  2006年   551篇
  2005年   449篇
  2004年   385篇
  2003年   297篇
  2002年   288篇
  2001年   227篇
  2000年   159篇
  1999年   172篇
  1998年   119篇
  1997年   115篇
  1996年   93篇
  1995年   115篇
  1994年   80篇
  1993年   70篇
  1992年   63篇
  1991年   44篇
  1990年   47篇
  1989年   24篇
  1988年   19篇
  1987年   13篇
  1986年   28篇
  1985年   31篇
  1984年   19篇
  1983年   19篇
  1982年   14篇
  1981年   12篇
  1980年   10篇
  1979年   10篇
  1977年   4篇
  1974年   7篇
  1973年   7篇
  1969年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
International Journal of Theoretical Physics - We investigate the monogamy relations related to the concurrence, the entanglement of formation, convex-roof extended negativity, Tsallis-q...  相似文献   
2.

We study the Bell nonlocality of high dimensional quantum systems based on quantum entanglement. A quantitative relationship between the maximal expectation value B of Bell operators and the quantum entanglement concurrence C is obtained for even dimension pure states, with the upper and lower bounds of B governed by C.

  相似文献   
3.
Journal of Radioanalytical and Nuclear Chemistry - To analyze the effect of scintillator detectors on the fast neutron multiplicity, this paper uses Geant4 and Matlab to simulate and study three...  相似文献   
4.
Liu  Jingze  Fei  Qingguo  Wu  Shaoqing  Tang  Zhenhuan  Zhang  Dahai 《Nonlinear dynamics》2021,106(3):1869-1890
Nonlinear Dynamics - Rolling bearing and squeeze film damper will introduce structural nonlinearity into the dynamic model of aeroengine. Rubbing will occur due to the clearance reduction design of...  相似文献   
5.
By linking the carbazole unit to the nitrogen atom of acridone through phenyl or pyridyl, two compounds, named 10-(4-(9H-carbazol-9-yl)phenyl)acridin-9(10H)-one (AC-Ph-Cz) and 10-(5-(9H-carbazol-9-yl)pyridin-2-yl)acridin-9(10H)-one (AC-Py-Cz) were designed and synthesized. These two materials, characterized with highly twisted and rigid structure, good thermal stability, and balanced carrier-transporting properties, were employed as host materials for green phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes (OLEDs). The carbazole group, despite its small contribution to the highest occupied molecular orbitals (HOMOs) of these two materials, plays an essential role as an intramolecular host in energy delivering and improving the hole transporting ability of these two hosts. The incorporation of the electron-deficient pyridyl group as a linking group slightly improves the electron transporting capability of AC-Py-Cz. The green phosphorescent OLED (PhOLED) based on AC-Py-Cz exhibited excellent device performance with a turn-on voltage of 2.5 V, a maximum power efficiency and an external quantum efficiency (ηext) of 89.8 lm W−1 and 25.2 %, respectively, benefitting from the better charge-balancing ability of AC-Py-Cz host due to the presence of the pyridyl bridge. More importantly, all the devices based on these two hosts showed low efficiency roll-off at high brightness due to the suppressed non-radiative transition in the emitting layer. In particular, the AC-Py-Cz-hosted green PhOLED exhibited an efficiency roll-off of 1.6 % from the maximum next at a high brightness of 1000 cd m−2 and a roll-off of 15.9 % at an extremely high brightness of 10000 cd m−2. This study manifests that acridone-based host materials have great potential in fabricating OLEDs with low efficiency roll-off.  相似文献   
6.
Liu  Qingrong  Li  Hanfeng  Zhu  Fei  Zhang  Xianfu 《Nonlinear dynamics》2021,103(3):2659-2669
Nonlinear Dynamics - This paper proposes an output feedback control strategy to achieve the global regulation of a class of large-scale feedforward nonlinear systems with discrete and distributed...  相似文献   
7.
International Journal of Theoretical Physics - Quantifying the quantumness of ensembles is a vital and practical task in quantum information theory. In this paper, we quantify the quantumness of...  相似文献   
8.
Science China Mathematics - We prove that if a compact Riemannian 4-manifold with positive sectional curvature satisfies a strengthened Kato type inequality, then it is definite. We also discuss...  相似文献   
9.
Wan  Qiuzhen  Yan  Zidie  Li  Fei  Liu  Jiong  Chen  Simiao 《Nonlinear dynamics》2022,109(3):2085-2101
Nonlinear Dynamics - This paper investigates a Hopfield neural network under the simulation of external electromagnetic radiation and dual bias currents, in which the fluctuation of magnetic flux...  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