全文获取类型
收费全文 | 1349515篇 |
免费 | 29724篇 |
国内免费 | 7692篇 |
专业分类
化学 | 672271篇 |
晶体学 | 20456篇 |
力学 | 75116篇 |
综合类 | 105篇 |
数学 | 242618篇 |
物理学 | 376365篇 |
出版年
2021年 | 13508篇 |
2020年 | 15920篇 |
2019年 | 16047篇 |
2018年 | 13819篇 |
2016年 | 28416篇 |
2015年 | 20869篇 |
2014年 | 30452篇 |
2013年 | 74399篇 |
2012年 | 38527篇 |
2011年 | 36190篇 |
2010年 | 37738篇 |
2009年 | 40079篇 |
2008年 | 35022篇 |
2007年 | 31087篇 |
2006年 | 35956篇 |
2005年 | 28944篇 |
2004年 | 30082篇 |
2003年 | 28226篇 |
2002年 | 29156篇 |
2001年 | 29040篇 |
2000年 | 24952篇 |
1999年 | 22599篇 |
1998年 | 21092篇 |
1997年 | 21085篇 |
1996年 | 21118篇 |
1995年 | 19186篇 |
1994年 | 18640篇 |
1993年 | 18171篇 |
1992年 | 18228篇 |
1991年 | 18499篇 |
1990年 | 17709篇 |
1989年 | 17762篇 |
1988年 | 17317篇 |
1987年 | 17322篇 |
1986年 | 16264篇 |
1985年 | 22670篇 |
1984年 | 23876篇 |
1983年 | 20055篇 |
1982年 | 21691篇 |
1981年 | 20915篇 |
1980年 | 20265篇 |
1979年 | 20503篇 |
1978年 | 21747篇 |
1977年 | 21353篇 |
1976年 | 21059篇 |
1975年 | 19721篇 |
1974年 | 19368篇 |
1973年 | 19820篇 |
1972年 | 14304篇 |
1967年 | 12554篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
L. A. Khalfin 《Journal of Mathematical Sciences》1987,36(5):616-626
The article surveys the main results of the statistical approach to the solution of ill-posed problems of mathematical physics, in application to specific ill-posed inverse problems in geophysics.Invited paper presented at the International Seminar on Mathematical Foundations of the Interpretation of Geophysical Fields, Moscow, May–June 1972.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 79, pp. 67–81, 1978. 相似文献
973.
We consider the growth of a spherical crystal in a supersaturatedsolution. In the first part, existence and uniqueness resultsfor radially symmetric growth are obtained, provided that thesupersaturation is not too large; conversely, when the far-fieldsupersaturation exceeds a critical value, it is shown that theradially symmetric solution ceases to exist in finite time.In the second part, we examine the linear stability of a radiallysymmetric similarity solution (in which the radius grows ast?) to shape perturbations. The results are compared with previousquasi-static analyses, and, in particular, the critical radiusat which the crystal becomes unstable is found to be largerfor small supersaturations, but smaller for large supersaturations,than those predicted by the quasi-static analysis 相似文献
974.
975.
M. Mirvaliev 《Journal of Mathematical Sciences》1987,38(6):2357-2363
One obtains a formula for the transformation of a vector with a given covariance matrix. The sum of the squares of the components of the transformed vector is equal to a chi-square type quadratic form, constructed with the aid of the initial vector. Taking into account this property, one finds the components of the Pearson statistic, Pearson-Fisher statistic, etc.Translated from Veroyatnostnye Raspredeleniya i Matematicheskaya Statistika, pp. 337–350, 1986. 相似文献
976.
977.
A convenient method is proposed for the synthesis of all the individual methyl ethers of methyl 2-acetamido-2-deoxy-α-D-glucopyranoside based on the partial methylation of 2-acetamido-2-deoxy-α-D-glucopyranoside with dimethyl sulfate in an alkaline medium followed by preparative liquid column chromatography on silica gel of the resulting mixture of methyl ethers. 相似文献
978.
Supposa that f(x) is a quasidifferentiable function, defined on S(?)R~n where S is an open set, with a -equivalent bounded quasidifferential subfam ily. Lenma I 相似文献
979.
Transport as a consequence of state-dependent diffusion 总被引:1,自引:0,他引:1
M. Büttiker 《Zeitschrift für Physik B Condensed Matter》1987,68(2-3):161-167
Overdamped particles subject to a drift in a force field with sinusoidal space dependence and also a sinusoidally modulated space-dependent diffusion, with the same period as the drift, experience a net driving force. The resulting current depends on the amplitude of the modulation of the diffusion and is a periodic function of the phase difference between the sinusoidal drift and the sinusoidal modulation of the diffusion. For small modulation amplitudes a particle subject to state-dependent noise behaves the same way as a particle subject to thermal noise but with a drift which, in addition to the sinusoidal term, contains a net force term.Dedicated to Professor Harry Thomas on the occasion of his 60th birthday 相似文献
980.
K. Y. Lin 《Journal of statistical physics》1987,49(1-2):269-279
The spontaneous magnetization of the Ising model on a 4–8 lattice with six different coupling constants and two different magnetic moments is studied. A formula for the spontaneous magnetization is proposed. The result agrees with the exact low-temperature series expansions up to the 12th order. 相似文献