全文获取类型
收费全文 | 7939篇 |
免费 | 1025篇 |
国内免费 | 4705篇 |
专业分类
化学 | 8217篇 |
晶体学 | 94篇 |
力学 | 591篇 |
综合类 | 311篇 |
数学 | 1959篇 |
物理学 | 2497篇 |
出版年
2024年 | 53篇 |
2023年 | 210篇 |
2022年 | 228篇 |
2021年 | 232篇 |
2020年 | 177篇 |
2019年 | 244篇 |
2018年 | 164篇 |
2017年 | 259篇 |
2016年 | 329篇 |
2015年 | 320篇 |
2014年 | 712篇 |
2013年 | 480篇 |
2012年 | 591篇 |
2011年 | 599篇 |
2010年 | 593篇 |
2009年 | 534篇 |
2008年 | 672篇 |
2007年 | 542篇 |
2006年 | 525篇 |
2005年 | 559篇 |
2004年 | 594篇 |
2003年 | 489篇 |
2002年 | 501篇 |
2001年 | 485篇 |
2000年 | 397篇 |
1999年 | 341篇 |
1998年 | 370篇 |
1997年 | 317篇 |
1996年 | 293篇 |
1995年 | 322篇 |
1994年 | 273篇 |
1993年 | 241篇 |
1992年 | 200篇 |
1991年 | 214篇 |
1990年 | 185篇 |
1989年 | 186篇 |
1988年 | 93篇 |
1987年 | 51篇 |
1986年 | 23篇 |
1985年 | 20篇 |
1984年 | 20篇 |
1983年 | 23篇 |
1982年 | 6篇 |
1979年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
31.
32.
33.
The adsorption of asymmetrical triblock copolymers from a non-selective solvent on solid surface has been studied by using Scheutjens-Fleer mean-field theory and Monte Carlo simulation method on lattice model. The main aim of this paper is to provide detailed computer simulation data, taking A8-kB20Ak as a key example, to study the influence of the structure of copolymer on adsorption behavior and make a comparison between MC and SF results. The simulated results show that the size distribution of various configurations and density-profile are dependent on molecular structure and adsorption energy. The molecular structure will lead to diversity of adsorption behavior. This discrepancy between different structures would be enlarged for the surface coverage and adsorption amount with increasing of the adsorption energy. The surface coverage and the adsorption amount as well as the bound fraction will become larger as symmetry of the molecular structure becomes gradually worse. The adsorption layer becomes thicker with increasing of symmetry of the molecule when adsorption energy is smaller but it becomes thinner when adsorption energy is higher. It is shown that SF theory can reproduce the adsorption behavior of asymmetrical triblock copolymers. However, systematic discrepancy between the theory and simulation still exists.The approximations inherited in the mean-filed theory such as random mixing and the allowance of direct back folding may be responsible for those deviations. 相似文献
34.
一类对称三对角矩阵的合同对角化算法的实现 总被引:1,自引:0,他引:1
从一个对称三对角矩阵的合同变换出发 ,阐述了对称三对角矩阵对应的二次型标准化的一种方法 . 相似文献
35.
Theoretical Calculation of Rotational Bands of ^179Pt in the Particle-Triaxial-Rotor Model 下载免费PDF全文
Theoretical calculations have been performed for nucleus ^179Pt in the particle-triaxial-rotor model with variable moment of inertia. The obtained energy spectrum agrees with the experimental data quite well. The calculated results indicate that the bands 1/2^- and 7/2^ are triaxial deformation bands and originate mainly from the v[521]1/2^- and v[633]7/2^ configurations respectively. 相似文献
36.
Theoretical Study on the Rotational Bands and Shape Coexistence of^179,181,183Au in the Particle-Triaxial-Rotor Model 下载免费PDF全文
We perform a series of theoretical calculations and investigation for nuclei 179,181,183Au in the particle-triaxialrotor model with variable moment of inertia. The calculated energy spectra in^179,181,183Au agree well with the experimental data globally. The obtained results indicate that the nuclei^179,181,183Au have prolate deformation and involve shape coexistence with different deformation parameters in different bands. The main configuration of bands 1, 2, 3 and 5 in these nuclei are identified as [541]1/2^- (πh9/2, α = 1/2), [541]1/2- (πh9/2, α= -1/2),[530] 1/2- (πf7/2) and [660] 1/2^ (πi13/2), respectively. 相似文献
37.
38.
39.
报道了KDP晶体中的三倍频产生的实验研究,计算了比较了直接三倍频过程和级联过程对KDP晶体三阶有效非线性系数的贡献,并探讨了KDP作为非线性晶体材料三阶非线性系数测量基准的可行性。 相似文献
40.