全文获取类型
收费全文 | 237404篇 |
免费 | 6677篇 |
国内免费 | 5022篇 |
专业分类
化学 | 130818篇 |
晶体学 | 3587篇 |
力学 | 11495篇 |
综合类 | 325篇 |
数学 | 25113篇 |
物理学 | 77765篇 |
出版年
2022年 | 2400篇 |
2021年 | 3045篇 |
2020年 | 3375篇 |
2019年 | 3630篇 |
2018年 | 4347篇 |
2017年 | 4289篇 |
2016年 | 5793篇 |
2015年 | 3866篇 |
2014年 | 5662篇 |
2013年 | 10680篇 |
2012年 | 9626篇 |
2011年 | 10967篇 |
2010年 | 8153篇 |
2009年 | 8162篇 |
2008年 | 9836篇 |
2007年 | 9365篇 |
2006年 | 8890篇 |
2005年 | 8037篇 |
2004年 | 7241篇 |
2003年 | 6610篇 |
2002年 | 6611篇 |
2001年 | 7875篇 |
2000年 | 5830篇 |
1999年 | 4552篇 |
1998年 | 3547篇 |
1997年 | 3431篇 |
1996年 | 3241篇 |
1995年 | 2891篇 |
1994年 | 2943篇 |
1993年 | 2685篇 |
1992年 | 3156篇 |
1991年 | 3277篇 |
1990年 | 3120篇 |
1989年 | 2997篇 |
1988年 | 2865篇 |
1987年 | 2879篇 |
1986年 | 2662篇 |
1985年 | 3161篇 |
1984年 | 3178篇 |
1983年 | 2621篇 |
1982年 | 2584篇 |
1981年 | 2351篇 |
1980年 | 2323篇 |
1979年 | 2715篇 |
1978年 | 2806篇 |
1977年 | 2742篇 |
1976年 | 2803篇 |
1975年 | 2585篇 |
1974年 | 2589篇 |
1973年 | 2602篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
The paper considers the problem of constructing an efficient automatic procedure for reducing the block size in the block conjugate gradient method insuring that the resulting rate of convergence is comparable with that of the block conjugate gradient method with constant block size. The numerical results provided show that, independently of the type of distribution of the smallest eigenvalues of the preconditioned matrix, the procedure suggested always leads to a decrease of the arithmetic costs with respect to those of the block method with constant block size. Bibliography: 8 titles. 相似文献
74.
M. Yu. Kulikov 《Radiophysics and Quantum Electronics》2004,47(9):662-673
On the example of the effect of an atmospheric wave with given amplitude on the density oscillations of minor gas constituents near the mesopause (at heights 80–90 km, we consider the influence of the quasi-resonant periodic spatial transport on a distributed system responding subharmonically to a periodic external action (diurnal sunlight variations). Numerical modeling revealed the formation of a coherent horizontal distribution of the dynamical variables (i.e., the concentrations of small constituents). Application of this effect to the mesopause conditions is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 47, No. 9, pp. 739–752, September, 2004. 相似文献
75.
76.
77.
We consider a particular case of the matrix Carleman problem for two pairs of functions in a ring and find a constructive
solution of this problem. In addition, we propose an algorithm for the construction of solutions for two infinite systems
of smooth transition and for a system of two singular equations of special type.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 49, No. 5, pp. 662–671, May, 1997 相似文献
78.
It is shown that the dephasing which suppresses the weak localization correction to the conductivity has the same physical origin than pair-breaking in superconductors and thus-following de Gennes-may be expressed in terms of the correlation function of the operator for time reversal. 相似文献
79.
H. Glatzel R. Schneider T. Fauster V. Dose 《Zeitschrift für Physik B Condensed Matter》1992,88(1):53-61
Inverse photoemission spectra were taken for thin epitaxial iron films on Cu(100). For a film thickness of eight monolayers the observed electronic states are characteristic for a fcc(100) surface. Thed-bands of iron show a ferromagnetic exchange splitting of 1.1 eV, considerably smaller than the bulk value of 1.8 eV, which we observe for film thicknesses above 18 monolayers. 相似文献
80.
A broad range echelle spectrograph with a CCD matrix detector is developed for different applications in atomic spectroscopy. The compact optical design in combination with a dispersive entrance slit illumination offers a low stray light level and high throughput in the UV spectral region comparable only with spectrographs of higher focal length. Ray tracing calculations for typical wavelengths and the multi-line spectrum of an iron arc show the excellent overall spectrum quality. The subtraction of two partial spectra of different steel alloys demonstrates the spectra evaluation possibilities of the CCD spectrograph. 相似文献