全文获取类型
收费全文 | 10312篇 |
免费 | 1713篇 |
国内免费 | 1308篇 |
专业分类
化学 | 6643篇 |
晶体学 | 225篇 |
力学 | 530篇 |
综合类 | 84篇 |
数学 | 510篇 |
物理学 | 5341篇 |
出版年
2024年 | 28篇 |
2023年 | 92篇 |
2022年 | 223篇 |
2021年 | 285篇 |
2020年 | 345篇 |
2019年 | 330篇 |
2018年 | 323篇 |
2017年 | 322篇 |
2016年 | 434篇 |
2015年 | 386篇 |
2014年 | 420篇 |
2013年 | 1252篇 |
2012年 | 577篇 |
2011年 | 656篇 |
2010年 | 512篇 |
2009年 | 655篇 |
2008年 | 626篇 |
2007年 | 578篇 |
2006年 | 600篇 |
2005年 | 549篇 |
2004年 | 496篇 |
2003年 | 485篇 |
2002年 | 407篇 |
2001年 | 299篇 |
2000年 | 367篇 |
1999年 | 283篇 |
1998年 | 210篇 |
1997年 | 201篇 |
1996年 | 203篇 |
1995年 | 143篇 |
1994年 | 166篇 |
1993年 | 134篇 |
1992年 | 116篇 |
1991年 | 101篇 |
1990年 | 74篇 |
1989年 | 67篇 |
1988年 | 55篇 |
1987年 | 36篇 |
1986年 | 49篇 |
1985年 | 43篇 |
1984年 | 47篇 |
1983年 | 10篇 |
1982年 | 24篇 |
1981年 | 22篇 |
1980年 | 15篇 |
1979年 | 14篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
991.
The shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers is studied theoretically. A modification of the previous models of main-chain liquid crystals to the case of side chain liquid-crystalline polymers is proposed. Orientational and rheological properties of the model are studied in plane-shear flow. Predictions of the present model agree qualitatively with experimental results (Pujolle-Robic, Noirez in Nature 409:167, 2001). 相似文献
992.
993.
In a previous paper[1], a method has been developed to study the stability characteristics of laminar boundary layers over compliant walls. In this
paper, the effect of double layered compliant wall and Kramer type compliant wall on delaying the transition is investigated,
and it is shown that there does exist the possibility to delay the transition by applying such compliant walls.
The project supported by the National Natural Science Foundation of China. 相似文献
994.
Chandan Dasgupta 《Pramana》2005,64(5):679-694
Theoretical approaches to the development of an understanding of the behaviour of simple supercooled liquids near the structural
glass transition are reviewed and our work on this problem, based on the density functional theory of freezing and replicated
liquid state theory, are summarized in this context. A few directions for further work on this problem are suggested. 相似文献
995.
996.
997.
This paper reports the observation of an isostructural electronic phase transition in CeAl2 near 77 Kbar pressure at ambient temperature. The present volume compression data obtained under truly hydrostatic pressure
conditions gives a clear indication of the first order nature of this phase transformation. 相似文献
998.
实验研究了La2/3CamMnO3样品零磁场下的电阻率和低磁场下的磁化强度随温度的变化行为.结果表明,除了居里温度(Tc)外还存在另一特征温度Tonset,高于Tonset的样品为典型的顺磁绝缘体,而低于Tc的样品为典型的铁磁金属,但在Lonset和Tc之间,样品的磁化率大大偏离居里一外斯定律,同时其导电特性显示出明显的反常.对观察到的不寻常导电特性,根据铁磁金属集团在顺磁绝缘体背景上随机分布的假设,进行了分析与探讨。 相似文献
999.
The ionic conduction of cation substituted CuBrTe, CuxAg1−xBrTe solid solutions, is investigated in the temperature range between 100 and 400 K. The change of electrical conductivities with temperature in the range of 0.94≤x<1 shows the characteristics of second-order rather than first-order phase transitions. The replacement of Cu with the Ag cation in CuxAg1−xBrTe leads to an increase in conductivity especially in the β and γ-phases. 相似文献
1000.
Quantum mechanical ab initio simulation of the electron screening effect in metal deuteride crystals
A. Huke K. Czerski S. M. Chun A. Biller P. Heide 《The European Physical Journal A - Hadrons and Nuclei》2008,35(2):243-252
In antecedent experiments the electron screening energies of the d+d reactions in metallic environments have been determined
to be enhanced by an order of magnitude in comparison to the case of gaseous deuterium targets. The analytical models describing
averaged material properties have not been able to explain the experimental results so far. Therefore, a first effort has
been undertaken to simulate the dynamics of reacting deuterons in a metallic lattice by means of an ab initio Hartree-Fock calculation of the total electrostatic force between the lattice and the successively approaching deuterons
via path integration. The calculations have been performed for Li and Ta, clearly showing a migration of electrons from host
metallic to the deuterium atoms. However, in order to avoid more of the necessary simplifications in the model the utilization
of a massive parallel supercomputer would be required. 相似文献