全文获取类型
收费全文 | 829篇 |
免费 | 67篇 |
国内免费 | 40篇 |
专业分类
化学 | 105篇 |
晶体学 | 7篇 |
力学 | 222篇 |
综合类 | 1篇 |
数学 | 133篇 |
物理学 | 380篇 |
综合类 | 88篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 24篇 |
2019年 | 18篇 |
2018年 | 18篇 |
2017年 | 19篇 |
2016年 | 26篇 |
2015年 | 25篇 |
2014年 | 26篇 |
2013年 | 45篇 |
2012年 | 24篇 |
2011年 | 40篇 |
2010年 | 42篇 |
2009年 | 33篇 |
2008年 | 42篇 |
2007年 | 44篇 |
2006年 | 56篇 |
2005年 | 42篇 |
2004年 | 45篇 |
2003年 | 36篇 |
2002年 | 29篇 |
2001年 | 26篇 |
2000年 | 32篇 |
1999年 | 22篇 |
1998年 | 26篇 |
1997年 | 23篇 |
1996年 | 13篇 |
1995年 | 25篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1969年 | 1篇 |
1957年 | 2篇 |
排序方式: 共有936条查询结果,搜索用时 0 毫秒
91.
S. Laha Y. C. Chen P. Gupta C. E. Simien Y. N. Martinez P. G. Mickelson S. B. Nagel T. C. Killian 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):51-56
A study of ion equilibration in annular regions of ultracold strontium plasmas is reported. Plasmas are formed by photoionizing
laser-cooled atoms with a pulsed dye laser. The experimental probe is spatially-resolved absorption spectroscopy using the
2S1/2-2P1/2 transition of the Sr+ ion. The kinetic energy of the ions is calculated from the Doppler broadening of the spectrum, and it displays clear oscillations
during the first microsecond after plasma formation. The oscillations, which are a characteristic of strong coulomb coupling,
are fit with a simple phenomenological model incorporating damping and density variation in the plasma. 相似文献
92.
93.
J. U. Keller 《Adsorption》1995,1(4):283-290
The gas adsorbed on the inner surface of a highly porous material like activated carbon or zeolite can be measured by slow damped oscillations of a torsional pendulum. The physical principles and the theory of this method are outlined. Formulas are given relating the increase in mass due to adsorption to changes of the frequency and the logarithmic decrement of slow, damped rotational oscillations of the pendulum. Preliminary measurements of gas adsorption equilibria of nitrogen on activated carbon show that the ratio of the mass adsorbedm, to the mass of the adsorbentm
s
, can be determined by this method with mean absolute error |m/m
s
|0.04%.Dedicated to the memory of Joseph Kestin (1913–1993). 相似文献
94.
通过数值模拟方法, 研究了在具有稳定次阈值振荡特性的二维映射神经元体系中, 噪声对体系非线性动力学的调控作用. 通过计算发现了噪声诱导的动作电位和随机共振现象. 另外,还研究了体系的控制参数及输入信号的频率对体系动力学的影响, 发现了该体系中频率依赖的随机共振现象.
关键词:
二维映射神经元模型
次阈值振荡
高斯白噪声
随机共振 相似文献
95.
96.
Cross-frequency phase–amplitude coupling (PAC) plays an important role in neuronal oscillations network, reflecting the interaction between the phase of low-frequency oscillation (LFO) and amplitude of the high-frequency oscillations (HFO). Thus, we applied four methods based on permutation analysis to measure PAC, including multiscale permutation mutual information (MPMI), permutation conditional mutual information (PCMI), symbolic joint entropy (SJE), and weighted-permutation mutual information (WPMI). To verify the ability of these four algorithms, a performance test including the effects of coupling strength, signal-to-noise ratios (SNRs), and data length was evaluated by using simulation data. It was shown that the performance of SJE was similar to that of other approaches when measuring PAC strength, but the computational efficiency of SJE was the highest among all these four methods. Moreover, SJE can also accurately identify the PAC frequency range under the interference of spike noise. All in all, the results demonstrate that SJE is better for evaluating PAC between neural oscillations. 相似文献
97.
本文给出了中立型微分方程的强迫振动准则,且根据方程的不同特点得到了不同的振动性条件。 相似文献
98.
Peter Heering 《Physics in Perspective (PIP)》2006,8(1):52-63
I discuss our replication of the wire-torsion experiments that Charles Augustin Coulomb (1736–1806) reported in a session
of the Paris Académie des Sciences in 1784. I first explain the nature and purpose of the replication method and then apply it to an analysis of Coulomb’s experiments.
I conclude by placing Coulomb’s presentation of his memoir into its specific historical contest. 相似文献
99.
I. Yu. Malakhov K. A. Sveshnikov P. K. Silaev 《Theoretical and Mathematical Physics》2005,143(1):529-540
We propose a subtraction-free method for calculating the quantum-field vacuum energy in the presence of nontrivial boundary conditions and logarithmically divergent terms caused by them. The method can also be used in the case where the energy levels of a system are known only numerically. Moreover, its use requires neither knowledge of the analytic form of equations for certain levels or a detailed analysis of their asymptotic behavior.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 143, No. 1, pp. 49–63, April, 2005. 相似文献
100.
We present some physics possibilities with an iron calorimeter detector (ICAL) and a status report on the feasibility study
to construct such a detector at a future possible India-based Neutrino Observatory (INO). This talk was given at the workshop
on high energy physics phenomenology, WHEPP-8, in Jan. 2004, at IIT Bombay. 相似文献