全文获取类型
收费全文 | 15885篇 |
免费 | 2845篇 |
国内免费 | 3202篇 |
专业分类
化学 | 11721篇 |
晶体学 | 335篇 |
力学 | 1017篇 |
综合类 | 338篇 |
数学 | 2276篇 |
物理学 | 6245篇 |
出版年
2024年 | 32篇 |
2023年 | 196篇 |
2022年 | 428篇 |
2021年 | 476篇 |
2020年 | 531篇 |
2019年 | 569篇 |
2018年 | 496篇 |
2017年 | 545篇 |
2016年 | 657篇 |
2015年 | 732篇 |
2014年 | 891篇 |
2013年 | 1185篇 |
2012年 | 1314篇 |
2011年 | 1522篇 |
2010年 | 1137篇 |
2009年 | 1241篇 |
2008年 | 1404篇 |
2007年 | 1237篇 |
2006年 | 1132篇 |
2005年 | 922篇 |
2004年 | 723篇 |
2003年 | 551篇 |
2002年 | 565篇 |
2001年 | 525篇 |
2000年 | 504篇 |
1999年 | 390篇 |
1998年 | 248篇 |
1997年 | 221篇 |
1996年 | 251篇 |
1995年 | 221篇 |
1994年 | 155篇 |
1993年 | 143篇 |
1992年 | 120篇 |
1991年 | 110篇 |
1990年 | 88篇 |
1989年 | 91篇 |
1988年 | 64篇 |
1987年 | 61篇 |
1986年 | 53篇 |
1985年 | 32篇 |
1984年 | 27篇 |
1983年 | 34篇 |
1982年 | 25篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1972年 | 4篇 |
1965年 | 7篇 |
1964年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
91.
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
92.
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
93.
Gold in ores was determined by flame atomic absorption spectrometry following on-line preconcentration by sorbent extraction in a flow-injection system. The medium polarity adsorption resin Amberlite XAD-8 packed in a 220-μl micro-column was used to collect gold(III) from hydrochloric acid sample solutions for 40 s at 7.6 ml/min. Ethanol was used to elute the adsorbed analytes into the nebulizer. Optimization studies were made on sample loading rate, elution rate and sample acidity. Some possible interferences on the determination are discussed. A 35-fold enrichment was achieved at a sampling frequency of 60 h?1 and with an RSD of 1.4%. The detection limit (3σ) and 2 μg l?1. Results for gold in ore samples showed good agreement with those obtained using activated carbon adsorption preconcentration. The recoveries were 97–108%. 相似文献
94.
本文介绍了利用喷油脉宽大小的变化来分析电控发动机电控系统、燃油供给等系统故障的一种方法,在汽车故障检测与诊断中有着广泛的应用。 相似文献
95.
Features of the total disintegration events of heavyemulsion targets caused by 4.5A GeV/c16O
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Total disintegration events produced by 4.5\,A GeV/c $^{16}$O--AgBr interactions are
analysed to investigate the characteristics of secondary charged particles produced
in such collisions. The multiplicity distributions of grey, black, and relativistic
charged particles can be well represented by Gaussian distribution. The average
multiplicity of grey particles is found to increase with the mass of projectile
increasing, while that of black particles is found to decrease with the mass of
projectile increasing. This result is in good agreement with the prediction of
fireball model. Finally, the linear dependence between grey and black particles is
observed, but there is no distinct dependence between the production of relativistic
charged particles and the target excitation. 相似文献
96.
97.
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
98.
99.
100.