全文获取类型
收费全文 | 1789篇 |
免费 | 171篇 |
国内免费 | 312篇 |
专业分类
化学 | 1182篇 |
晶体学 | 19篇 |
力学 | 19篇 |
综合类 | 7篇 |
数学 | 21篇 |
物理学 | 1024篇 |
出版年
2024年 | 6篇 |
2023年 | 103篇 |
2022年 | 47篇 |
2021年 | 50篇 |
2020年 | 70篇 |
2019年 | 47篇 |
2018年 | 36篇 |
2017年 | 64篇 |
2016年 | 65篇 |
2015年 | 56篇 |
2014年 | 84篇 |
2013年 | 123篇 |
2012年 | 112篇 |
2011年 | 106篇 |
2010年 | 100篇 |
2009年 | 129篇 |
2008年 | 107篇 |
2007年 | 129篇 |
2006年 | 114篇 |
2005年 | 68篇 |
2004年 | 77篇 |
2003年 | 62篇 |
2002年 | 57篇 |
2001年 | 43篇 |
2000年 | 54篇 |
1999年 | 65篇 |
1998年 | 66篇 |
1997年 | 37篇 |
1996年 | 33篇 |
1995年 | 25篇 |
1994年 | 28篇 |
1993年 | 18篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2272条查询结果,搜索用时 0 毫秒
1.
2.
We show that, contrary to earlier reports, application of the one-parameter variational technique to the classical (image) model for H in front of an Al surface leads to energy shifts for the ground state which are very close to those obtained numerically with a more sophisticated model of the system. 相似文献
3.
The association of complex formation with static quenching in CT systems was investigated. Evaluation of the data made evident
that the inner filter effect must be allowed for. Time-resolved and temperature-dependent stationary measurements of fluorescence
led to the separation of dynamic and static quenching components. The static quenching constant is discussed with respect
to the equilibrium constant of complex formation determined by absorption spectroscopy. 相似文献
4.
5.
I. A. Anoshko V. S. Ermachenko L. E. Sandrigailo 《Journal of Applied Spectroscopy》2007,74(1):102-106
We present the results of a spectroscopic study of a nonequilibrium plasma in a Hall accelerator, in particular for such an
important parameter as the electron temperature. For the studied conditions, we used the semicoronal equilibrium model, which
relates the intensity ratios for two successive ionization steps for the same element.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 93–96, January–February, 2007. 相似文献
6.
X.X. Guo 《Surface science》2004,549(3):211-216
We studied parallel conductivities of pure BaF2 films with thicknesses ranging from 35 to 300 nm, epitaxially grown on Al2O3(0 1 2) substrates by molecular beam epitaxy technique. The overall conductivities of the films are found to increase with decreasing thickness. The detailed investigation of the overall conductance as a function of the thickness permits the deconvolution of bulk and boundary effects, the latter being attributed to distinct space charge effects in the interface between BaF2 film and Al2O3 substrate. The (extrinsic) Debye length (λ) is estimated to be about 8 nm at T=593 K, which corresponds to an impurity content of 1018/cm3 (singly ionized dopant assumed). This is consistent with the fact that we observed a constant boundary contribution for all investigated films (film thickness >4λ). It is also consistent with the Debye length observed in a previous report on CaF2/BaF2 heterolayers fabricated by the same technique, in which the low temperature enhancement was also attributed to space charges in BaF2 [Nature 408 (2000) 946]. Only at low temperatures (below 370 °C), the conductance seems to be influenced by strain effect. 相似文献
7.
J.E. Lorenzo H. Requardt 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(2):185-186
Eur. Phys. J. B 24, 315 (2001) Here we comment on a recently published paper on the presence of a phason contribution in the low temperature heat capacity data of the charge-density-wave compounds K0.3MoO3 and (TaSe4)2I. We have shown that the anomaly in the C
P
/
T
3
data reported by Odin et al. is straightforwardly interpreted in terms of low energy phonon modes resulting from the peculiar topology of these compounds.
Received 21 February 2002 Published online 19 July 2002 相似文献
8.
在自旋-轨道劈裂阵模型下,通过类铜的内壳层激发组态计算了类镍Gd的双电子复合速率系数,其中考虑了共振和非共振辐射平衡跃迁对自电离能级的影响,而忽略了因碰撞跃迁引起的电子俘获,非共振辐射平衡跃迁在低电子温度条件下主要影响双电子复合过程;本文讨论了双电子复合系数及双电子伴线强度比随电子温度的变化. 相似文献
9.
A simple microscopic model of charge ordering in the NaxCoO2 system is presented. The model takes into account the interplane interactions between the ordered Na ions and d electrons from the CoO2 layers as well as the nearest-neighbor intraplane Coulomb interactions between d electrons. It is shown that a driving force of charge ordering in the CoO2 layers is the interplane interaction that alone is able to describe various types of inhomogeneous charge ordering (e.g., the striped phases) as well as to predict correctly the conducting properties of the system. 相似文献
10.
M. Froese C. Champagne J. R. Crespo López-Urrutia S. Epp G. Gwinner A. Lapierre J. Pfister G. Sikler J. Ullrich J. Dilling 《Hyperfine Interactions》2006,173(1-3):85-92
The precision of atomic mass measurements in a Penning trap is directly proportional to the charge state q of the ion and,
hence, can be increased by using highly charged ions (HCI). For this reason, charge breeding with an electron beam ion trap
(EBIT) is employed at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) on-line facility in Vancouver, Canada. By bombarding
the injected and trapped singly charged ions with an intense beam of electrons, the charge state of the ions is rapidly increased
inside the EBIT. To be compatible with the on-line requirements of short-lived isotopes, very high electron beam current densities
are needed. The TITAN EBIT includes a 6 Tesla superconducting magnet and is designed to have electron beam currents and energies
of up to 5 A and 60 keV, respectively. Once operational at full capacity, most species can be bred into a He-like configuration
within tens of ms. Subsequently, the HCI are extracted, pass a Wien filter to reduce isobaric contamination, are cooled, and
injected into a precision Penning trap for mass measurement. We will present the first results and current status of the TITAN
EBIT, which has recently been moved to TRIUMF after assembly and commissioning at the Max-Planck-Institute (MPI) for Nuclear
Physics in Heidelberg, Germany. 相似文献