全文获取类型
收费全文 | 15372篇 |
免费 | 3186篇 |
国内免费 | 3450篇 |
专业分类
化学 | 11286篇 |
晶体学 | 378篇 |
力学 | 1028篇 |
综合类 | 363篇 |
数学 | 2000篇 |
物理学 | 6953篇 |
出版年
2024年 | 36篇 |
2023年 | 249篇 |
2022年 | 469篇 |
2021年 | 530篇 |
2020年 | 682篇 |
2019年 | 672篇 |
2018年 | 610篇 |
2017年 | 614篇 |
2016年 | 763篇 |
2015年 | 807篇 |
2014年 | 939篇 |
2013年 | 1243篇 |
2012年 | 1481篇 |
2011年 | 1521篇 |
2010年 | 1165篇 |
2009年 | 1226篇 |
2008年 | 1370篇 |
2007年 | 1196篇 |
2006年 | 1032篇 |
2005年 | 887篇 |
2004年 | 720篇 |
2003年 | 526篇 |
2002年 | 503篇 |
2001年 | 471篇 |
2000年 | 433篇 |
1999年 | 332篇 |
1998年 | 191篇 |
1997年 | 167篇 |
1996年 | 161篇 |
1995年 | 136篇 |
1994年 | 141篇 |
1993年 | 102篇 |
1992年 | 101篇 |
1991年 | 84篇 |
1990年 | 78篇 |
1989年 | 64篇 |
1988年 | 54篇 |
1987年 | 38篇 |
1986年 | 38篇 |
1985年 | 32篇 |
1984年 | 28篇 |
1983年 | 27篇 |
1982年 | 22篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1974年 | 4篇 |
1965年 | 5篇 |
1964年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
91.
Xin Tao YE Chong LI 《数学学报(英文版)》2007,23(1):65-76
The BCQ and the Abadie CQ for infinite systems of convex inequalities in Banach spaces are characterized in terms of the upper semi-continuity of the convex cones generated by the subdifferentials of active convex functions. Some relationships with other constraint qualifications such as the CPLV and the Slate condition are also studied. Applications in best approximation theory are provided. 相似文献
92.
93.
Excitation Properties of the Biological Neurons with Side-Inhibition Mechanism in Small-World Networks 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We have studied the excitation properties of biophysical Hodgkin-Huxley neurons with the side-inhibition mechanism in small-world networks. The result shows that the excitation properties in the networks are preferably consistent with the characteristic properties of a brain neural system under external constant stimuli, such as fatigue effect, extreme excitation principle, and the brain neural excitation response induced by different in- tensity of noise and coupling. The results of the study might shed some light on the study of the brain nerve electrophysiology and epistemological science. 相似文献
94.
Incident intensity, defined by the amount of particles deposited per pulse, is an important parameter in the film growth process of pulsed laser deposition (PLD). Different from previous models, we investigate the irreversible and reversible growth processes by using a kinetic Monte Carlo method and find that island density and film morphology strongly depend on pulse intensity. At higher pulse intensities, lots of adatoms instantaneously diffuse on the substrate surface, and then nucleation easily occurs between the moving adatoms resulting in more smaller-size islands. In contrast, at the lower pulse intensities, nucleation event occurs preferentially between the single adatom and existing islands rather than forming new islands, and therefore the average island size becomes larger in this case. Additionally, our results show that substrate temperature plays an important role in film growth. In particular, it can determine the films shape and weaken the effect of pulse intensity on film growth at the lower temperatures by controlling the mobility rate of atoms. Our results can match the related theoretical and experimental results. 相似文献
95.
DING Ning FANG Jian-Hui 《理论物理通讯》2006,46(2):265-268
In this paper the Lie symmetry and conserved quantities for nonholonomic Vacco dynamical systems are studied. The determining equation of the Lie symmetry for the system is given. The general Hojman conserved quantity and the Lutzky conserved quantity deduced from the symmetry are obtained. 相似文献
96.
97.
We propose a thermodynamic framework for describing the microwave drying process of aqueous dielectrics based on Maxwell-Lorentz Field equations and mixture theory. Several issues are discussed such as the form of entropy equation; the constitutive relations for the macroscopic electric polarization vectors, Cauchy stresses, heat fluxes, internal momentum supplies, etc., for each component of the mixture: porous solid, water and gas in different regions; and the interfacial jump conditions between different regions in the mixture. A brief examination of the status of material frame indifference within the context of our framework is presented. 相似文献
98.
在40—700cm-1波数和4.2—300K温度范围内研究了不同组份液相外延n型CaAs1-xPx样品的红外反射谱。对反射谱进行了赝谐振子拟合与K-K关系计算。从而获得了有关描述CaAs1-xPx样品的光学声子模、等离子体激元、LO声子-等离子体激元耦合模的重要物理参量及红外光学常数信息。基于这些计算结果,提出了双导带谷并计及与X能谷相联系的施主能级模型,用它解释等离子体激元频率和实验观察的三支主要的耦合模的温度变化规律。
关键词: 相似文献
99.
1974年,Neal根据Kac和Siegert的思想,给出了一个在电子工程、海洋工程、建筑工程、航空工程、自动控制的随机振动中有重要应用的二阶Volterra非线性系统对平稳正态输入的统计响应的表示定理.1984年,Naess对此定理又给出了一个数学证明.经过研究后发现,他们对定理条件的叙述都是模糊的,而且其数学证明都是有问题的.本文重新讨论了这个表示定理,给出了明确的定理条件及严格的数学证明,为它的广泛应用奠定了理论基础. 相似文献
100.