全文获取类型
收费全文 | 520篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 387篇 |
晶体学 | 5篇 |
力学 | 11篇 |
数学 | 20篇 |
物理学 | 99篇 |
出版年
2020年 | 3篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 14篇 |
2012年 | 16篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 11篇 |
2006年 | 21篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1991年 | 7篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 9篇 |
1985年 | 18篇 |
1984年 | 18篇 |
1983年 | 12篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 18篇 |
1978年 | 20篇 |
1977年 | 14篇 |
1976年 | 17篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 14篇 |
1972年 | 5篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 6篇 |
1966年 | 3篇 |
1965年 | 5篇 |
1963年 | 5篇 |
1957年 | 4篇 |
排序方式: 共有522条查询结果,搜索用时 0 毫秒
71.
72.
Summary After preliminary experiments in different gases the arc between carbon electrodes in nitrogen is investigated more closely.
The axial electric field strength between homogeneous carbon electrodes (mainly at 3–6 A and 1–4 atm) and also in arcs with
KCl in the anode (at 4 A and 1–5 atm) proves to be a linear function of the pressure. The field strength is higher than in
air and is reduced by the KCl. The sum of cathode- and anode-fall is found to be independent of the pressure. The central
temperature in the arc without KCl was hard to measure, because self-absorption influenced the intensity ratios of the molecular
bands in the spectrum. With KCl this difficulty did not appear, and temperatures were measured of about 7000°K, slightly increasing
with the nitrogen pressure. Because the carbon electrodes evaporate much more slowly than in air, the arc in nitrogen is less
stationary than in air; this hindered the measurements. 相似文献
73.
A model consisting of the B.C.S.-Hamiltonian and Zener's s-d exchange interaction is solved rigorously in the thermodynamic limit. Coexistence of superconductivity and magnetism is only possible for an impurity spin concentration smaller than a half at T ≠ 0. 相似文献
74.
By time-resolved spectroscopy the intrinsic emission spectrum of UO2MoO4 at 4.2 K is obtained. The main progressions in the vibronic structure are identified as couplings with the Ag correlation field components of the symmetric and asymmetric UO2 stretching modes. The intrinsic zero-phonon line in the emission and excitation spectrum is shown to be split both by the crystal field and correlation field. The steady-state emission spectrum at 4.2 K is dominated by emission from traps. The vibronic structure of the trap emission reveals that all traps are distorted uranyl groups. 相似文献
75.
76.
77.
O. V. Lyubinskaya V. A. Smit A. V. Semenovskii V. F. Kucherov 《Russian Chemical Bulletin》1976,25(8):1698-1701
Conclusions Acylation of the 2-butene isomers with acyl salts can lead either to the formation of , -unsaturated ketones or of conjugate addition products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1803–1806, August, 1976. 相似文献
78.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 198–199, January, 1988. 相似文献
79.
80.
The definition of suitable pure geometrical reference coordinates for the comparison of dipole moment derivatives is discussed. Methods for the calculation of the chosen reference coordinates are presented and illustrated with a few examples. It is shown that useful reference coordinates for stretching and bending modes can be obtained from properly chosen heavy isotope molecules. 相似文献