全文获取类型
收费全文 | 112633篇 |
免费 | 1804篇 |
国内免费 | 116篇 |
学科分类
数理化 | 114553篇 |
出版年
2021年 | 1147篇 |
2020年 | 1428篇 |
2019年 | 1407篇 |
2018年 | 2013篇 |
2017年 | 2085篇 |
2016年 | 3081篇 |
2015年 | 1822篇 |
2014年 | 2603篇 |
2013年 | 5249篇 |
2012年 | 4388篇 |
2011年 | 5079篇 |
2010年 | 3564篇 |
2009年 | 3400篇 |
2008年 | 4726篇 |
2007年 | 4562篇 |
2006年 | 4232篇 |
2005年 | 3736篇 |
2004年 | 3265篇 |
2003年 | 2952篇 |
2002年 | 2968篇 |
2001年 | 2913篇 |
2000年 | 2229篇 |
1999年 | 1676篇 |
1998年 | 1501篇 |
1997年 | 1416篇 |
1996年 | 1382篇 |
1995年 | 1261篇 |
1994年 | 1275篇 |
1993年 | 1358篇 |
1992年 | 1315篇 |
1991年 | 1263篇 |
1990年 | 1225篇 |
1989年 | 1179篇 |
1988年 | 1101篇 |
1987年 | 1077篇 |
1986年 | 1003篇 |
1985年 | 1310篇 |
1984年 | 1378篇 |
1983年 | 1205篇 |
1982年 | 1243篇 |
1981年 | 1151篇 |
1980年 | 1079篇 |
1979年 | 1103篇 |
1978年 | 1272篇 |
1977年 | 1278篇 |
1976年 | 1117篇 |
1975年 | 1065篇 |
1974年 | 1067篇 |
1973年 | 1054篇 |
1972年 | 675篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
For an Ising ferromagnet with nearest-neighbour interactions of strengthK and surface magnetic fieldh, the surface free energy in the presence of a positively (or negatively) magnetized zero-field bulk phase is shown to be analytic inh for Reh<K–/, where =2.96 ... and is the inverse temperature. This puts the lower boundK–/ on the values ofh at which wetting and layering transitions can take place. 相似文献
992.
Linear mode conversion of waves near the maxima or minima of the density in a warm magnetized plasma
Behaviour of the h. f. electrostatic waves near the plasma or upper hybrid resonances was studied in the case that these resonances are situated at the maxima or minima of the plasma density. Supposing the parabolic density profile in these regions we obtained the connection formulae for the WKB solutions. In a weakly inhomogeneous magnetoplasma the effect of the parabolic profile manifests itself only in narrow frequency band centred at the resonance frequency corresponding to the extreme value of the density. The whole process can be then described by only two coefficients, viz. the power conversion and power transmission coefficients. 相似文献
993.
D. Macko V. Hajko Jr. J. Billy P. Makroczy V. Kavečanský O. Hudák 《Czechoslovak Journal of Physics》1988,38(12):1383-1386
Quasicrystalline Al-14 at. % Mn alloy was prepared by melt-spinning and its structural and electrical properties were studied. This alloy consists of icosahedral grains with sizes from 1 to 4 m and of crystalline aluminium phase. The electrical resistivity was almost temperature independent with a value of about 765 n gWm at 4·2 K. 相似文献
994.
During ageing the Al-2·0 at. %Zn-1·0 at. % Mg alloy at elevated temperatures the width of the precipitation free zone (PFZ) at both sides of the grain boundaries (GB) is identical with that free of quenched-in dislocation loops (DL). After sufficiently long ageing a band of precipitates is growing inside the former PFZ and the DLs in the midgrain regions act as sites for the heterogeneous nucleation of the-phase. Two precipitation processes significantly affect the mechanical properties. TEM correlates grain boundary precipitate density and morphology with grain boundary misorientation. 相似文献
995.
996.
R. O. Genga 《International Journal of Theoretical Physics》1988,27(7):835-849
A cold electron gas fills the lowest Landau level for high enough magnetic fields and for low enough densities. Such a situation is expected to occur for the Malmberg-O'Neil experiment and also for pulsar crusts and atmospheres. Such plasmas behave as a quasi-one-dimensional system and exhibit some peculiarities in their wave structure. We study the dispersion and damping of the low frequencies, i.e., the whistler mode, and the extraordinary mode for zero temperature. The behavior of the whistler mode depends critically on the filling number
Fc=F/ , where F is the Fermi energy and is the cyclotron frequency. The one-dimensional character of the system affects the pair excitation spectrum and thus the decay of modes. We find that, in contrast to the three-dimensional situation, the plasma mode and the extraordinary mode remain undamped, while the whistler mode is undamped for all but very highk values. 相似文献
997.
998.
999.
Claudio Albanese Jürg Fröhlich Thomas Spencer 《Communications in Mathematical Physics》1988,119(4):677-699
This is our second paper devoted to the study of some non-linear Schrödinger equations with random potential. We study the non-linear eigenvalue problems corresponding to these equations. We exhibit a countable family of eigenfunctions corresponding to simple eigenvalues densely embedded in the band tails. Contrary to our results in the first paper, the results established in the present paper hold for an arbitrary strength of the non-linear (cubic) term in the non-linear Schrödinger equation. 相似文献
1000.