全文获取类型
收费全文 | 14412篇 |
免费 | 3808篇 |
国内免费 | 4925篇 |
专业分类
化学 | 5483篇 |
晶体学 | 121篇 |
力学 | 2241篇 |
综合类 | 539篇 |
数学 | 3633篇 |
物理学 | 11128篇 |
出版年
2024年 | 146篇 |
2023年 | 471篇 |
2022年 | 606篇 |
2021年 | 635篇 |
2020年 | 493篇 |
2019年 | 510篇 |
2018年 | 380篇 |
2017年 | 534篇 |
2016年 | 593篇 |
2015年 | 667篇 |
2014年 | 1303篇 |
2013年 | 1024篇 |
2012年 | 1089篇 |
2011年 | 1236篇 |
2010年 | 1168篇 |
2009年 | 1348篇 |
2008年 | 1622篇 |
2007年 | 1103篇 |
2006年 | 1036篇 |
2005年 | 962篇 |
2004年 | 879篇 |
2003年 | 818篇 |
2002年 | 644篇 |
2001年 | 647篇 |
2000年 | 467篇 |
1999年 | 355篇 |
1998年 | 300篇 |
1997年 | 301篇 |
1996年 | 275篇 |
1995年 | 276篇 |
1994年 | 218篇 |
1993年 | 179篇 |
1992年 | 181篇 |
1991年 | 156篇 |
1990年 | 177篇 |
1989年 | 161篇 |
1988年 | 61篇 |
1987年 | 49篇 |
1986年 | 24篇 |
1985年 | 22篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1959年 | 3篇 |
1934年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This paper proposes a scheme to teleport an arbitrary mixture of diagonal states of multiqutrit via classical correlation and classical communication. To teleport an arbitrary mixture of diagonal states of N qutrits, N classically correlated pairs of two qutrits are used as channel. The sender (Alice) makes Fourier transform and conditional gate (i.e., XOR(3) gate) on her qutrits and does measurement in appropriate computation bases. Then she sends N ctrits to the receiver (Bob). Based on the received information, Bob performs the corresponding unitary transformation on his qutrits and obtains the teleported state. Teleportation of an arbitrary mixture of diagonal states of multiqudit is also discussed. 相似文献
992.
Exponential stability of Takagi-Sugeno fuzzy systems with impulsive effects and small delays 下载免费PDF全文
This paper deals with the exponential stability of impulsive Takagi-Sugeno fuzzy systems with delay. Impulsive control and delayed fuzzy control are applied to the system, and the criterion on exponential stability expressed in terms of linear matrix inequalities (LMIs) is presented. 相似文献
993.
ZHOU Li-Juan GU Yun-Ting MA Wei-Xing MENG Cheng-Ju PAN Ji-Huan 《理论物理通讯》2008,49(1):181-188
Based on the Global Color Symmetry Model, the non-perturbative Q, CD vacuum is investigated in the parameterized fully dressed quark propagator. Our theoretical predictions for various quantities characterized the QCD vacuum are in agreement with those predicted by many other phenomenologieal QCD inspired models. The successful predictions clearly indicate the extensive validity of our parameterized quark propagator used here. A detailed discussion on the arbitrariness in determining the integration cut-off parameter ofμ in calculating QCD vacuum condensates and a good method, which avoided the dependence of calculating results on the cut-off parameter is also strongly recommended to readers. 相似文献
994.
YU Xiao-Ling WU Xiao ZHANG Duan-Ming LI Zhi-Hao LIANG Fang WANG Xiao-Yu 《理论物理通讯》2008,49(5):1357-1360
We have studied the topology and epidemic spreading behaviors on the networks in which deactivation mechanism and long-rang connection are coexisted. By means of numerical simulation, we find that the clustering coefficient C and the Pearson correlation coefficient r decrease with increasing long-range connection μ and the topological state of the network changes into that of BA model at the end (when μ = 1). For the Susceptible-Infect-Susceptible model of epidemics, the epidemic threshold can reach maximum value at μ = 0.4 and presents two different variable states around μ= 0.4. 相似文献
995.
基于Labview的光学空间滤波远程虚拟实验 总被引:4,自引:0,他引:4
提出了一种利用Labview实现光学空间滤波模拟的新方法,并对经典的阿贝-波特实验设计了仿真程序.该程序可根据用户设置的参量生成二维网格光栅作为整个物理过程的输入物,允许用户选择多种不同的滤波方式,如低通、高通、方向滤波等,并可依次操纵成像的各个步骤.程序可脱离编程环境独立运行,具有跨平台、界面友好、易于操作等优点,并可架设基于浏览器的远程虚拟实验. 相似文献
996.
Inverse scattering method and soliton solutionfamily for the Einstein--Maxwell theory with multiple Abelian gauge fields 下载免费PDF全文
A Hauser-Ernst-type extended hyperbolic complex linear system given in our previous paper [Gao Y J 2004 Chin. Phys. 13 602] is slightly modified and used to develop a new inverse scattering method for the stationary axisymmetric Einstein-Maxwell theory with multiple Abelian gauge fields. The reduction procedures in this inverse scattering method are found to be fairly simple, which makes the inverse scattering method be fine and effective in practical application. As an example, a concrete family of soliton solutions for the considered theory is obtained. 相似文献
997.
In this paper, a new type of resonant Brewster filters (RBF) with surface relief structure for the multiple channels is first presented by using the rigorous coupled-wave analysis and the S-matrix method. By tuning the depth of homogeneous layer which is under the surface relief structure, the multiple channels phenomenon is obtained. Long range, extremely low sidebands and multiple channels are found when the RBF with surface relief structure is illuminated with Transverse Magnetic incident polarization light near the Brewster angle calculated with the effective media theory of sub wavelength grating. Moreover, the wavelengths of RBF with surface relief structure can be easily shifted by changing the depth of homogeneous layer while its optical properties such as low sideband reflection and narrow band are not spoiled when the depth is changed. Furthermore, the variation of the grating thickness does not effectively change the resonant wavelength of RBF, but have a remarkable effect on its line width, which is very useful for designing such filters with different line widths at desired wavelength. 相似文献
998.
采用密度泛函理论结合投影缀加波方法,对掺杂Cd导致ZnO禁带宽度下降的机理进行了研究. 通过对掺杂前后电子能带结构,态密度以及分态密度的计算和比较,发现CdxZn1-xO价带顶端(VBM)始终由O-2p占据;而导带顶端(CBM)则由Cd-5s与Zn-4s杂化轨道控制. 随着掺杂浓度的增加,决定带隙宽度的CBM的位置下降,同时VBM的位置上升,从而导致了带隙的变窄,出现了红移现象. 此外,Cd掺杂会使晶胞发生膨胀,这种张应变也是导致Cd 相似文献
999.
以扩散理论为基础,建立以“基本微观过程” 为核心的新模型,引入交换比的概念,对存在表面活化剂时薄膜生长的微观过程进行Kinetic Monte Carlo模拟.模拟发现,活化层原子和沉积原子都会发生跨层间的扩散,跨层扩散主要是单个原子的扩散,层间扩散的原子数目随着温度的升高或沉积厚度的增加而增多.RLA模型中的“交换作用”只是若干个“基本微观过程”的组合,大多数交换不是位置的“完全交换”,交换比也并非恒为1.
关键词:
扩散理论
薄膜生长
交换作用
RLA 相似文献
1000.