全文获取类型
收费全文 | 20426篇 |
免费 | 2253篇 |
国内免费 | 2063篇 |
专业分类
化学 | 2255篇 |
晶体学 | 30篇 |
力学 | 1752篇 |
综合类 | 523篇 |
数学 | 14037篇 |
物理学 | 6145篇 |
出版年
2024年 | 25篇 |
2023年 | 168篇 |
2022年 | 339篇 |
2021年 | 366篇 |
2020年 | 422篇 |
2019年 | 436篇 |
2018年 | 452篇 |
2017年 | 581篇 |
2016年 | 653篇 |
2015年 | 504篇 |
2014年 | 1019篇 |
2013年 | 1320篇 |
2012年 | 1056篇 |
2011年 | 1285篇 |
2010年 | 1146篇 |
2009年 | 1412篇 |
2008年 | 1390篇 |
2007年 | 1459篇 |
2006年 | 1310篇 |
2005年 | 1255篇 |
2004年 | 1035篇 |
2003年 | 942篇 |
2002年 | 786篇 |
2001年 | 735篇 |
2000年 | 665篇 |
1999年 | 581篇 |
1998年 | 521篇 |
1997年 | 484篇 |
1996年 | 362篇 |
1995年 | 295篇 |
1994年 | 243篇 |
1993年 | 184篇 |
1992年 | 154篇 |
1991年 | 127篇 |
1990年 | 140篇 |
1989年 | 93篇 |
1988年 | 86篇 |
1987年 | 75篇 |
1986年 | 68篇 |
1985年 | 83篇 |
1984年 | 69篇 |
1983年 | 48篇 |
1982年 | 66篇 |
1981年 | 60篇 |
1980年 | 38篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 28篇 |
1976年 | 30篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
利用概率论与组合数学的方法,研究了与Riemann-zeta函数ξ(k)的部分和ξ_n(k)有关的一些级数,计算出了一些重要的和式.特别的,Euler的著名结果5ξ(4)= 2ξ~2(2)能够从四阶和式直接推出.因此,通过计算全部的11个六阶和式,研究它们之间的非平凡关系,就有可能得到ξ(3)的数值. 相似文献
122.
在不定积分第二积分换元定理的条件中,要求变换x=φ(t)不含有稳定点,即:φ′(t)≠0.当变换x=φ(t)中含有孤立稳定点时,给出了变换中含有孤立稳定点的第二积分换元定理.拓宽了第二积分换元定理的应用范围. 相似文献
123.
A theoretical study of the electron dynamics in image potential states on Cu(1 0 0) surfaces with different types of adsorbates is presented. Scattering of the image state electron by an adsorbate induces inter-band and intra-band transitions leading respectively to the population decay and to the dephasing of the image state. We compare results obtained with low coverage (typically 1 adsorbate atom per 1000 surface atoms) Cs, Ar, and a model electronegative adsorbates. As follows from our results, Cs adsorbates lead to both appreciable dephasing and decay, while electronegative adsorbates mostly affect the dephasing rate. The effect of low coverage Ar adsorbates is small, consistent with their neutrality. 相似文献
124.
Yan Xu 《Journal of Mathematical Analysis and Applications》2007,329(2):1343-1354
In this paper, we obtain some normality criteria for families of meromorphic functions that concern the exceptional functions of derivatives. 相似文献
125.
We obtain asymptotic lower bounds for the spectral function of the Laplacian and for the remainder in local Weyl’s law on
manifolds. In the negatively curved case, thermodynamic formalism is applied to improve the estimates. Key ingredients of
the proof include the wave equation parametrix, a pretrace formula and the Dirichlet box principle. Our results develop and
extend the unpublished thesis of A. Karnaukh [Ka].
The first author was supported by NSERC, FQRNT, Alfred P. Sloan Foundation Fellowship and Dawson Fellowship. The second author
was supported by NSERC and FQRNT.
Received: April 2006 Revision: October 2006 Accepted: October 2006 相似文献
126.
We investigate a multicomponent anisotropic liquid system. The first spatial moment of the direct correlation function is taken into account to obtain asymptotic expressions for the pairwise correlation functions. In this approximation, we obtain the pairwise correlation functions that describe the system behavior not only in the critical-state neighborhood but also in the noncritical domain. We show that the critical parameters for the anisotropic system differ from those for the isotropic system. 相似文献
127.
New variants of the generalized level method for minimization of convex nondifferentiable functions taking infinite values 总被引:1,自引:1,他引:0
N. A. Sokolov 《Computational Mathematics and Mathematical Physics》2007,47(12):1952-1969
New variants of the generalized level method for minimization of convex Lipschitz functions on a compact set with a nonempty interior are proposed. These variants include the well-known generalized and classical level methods. For the new variants, an estimate of the convergence rate is found, including the variants in which the auxiliary problems are solved approximately. 相似文献
128.
For any given positive integer n≥1,the Euler functionφ(n) is defined to be the number of positive integers not exceeding n,which is relatively prime to n.ω(n) is defined to be the number of different prime divisors of n.In order to know the solvability of the function ofφ(φ(φ(n)))=2~(ω(n)),properties of the number theoretical functionφ(φ(n)) is studied in the paper. 相似文献
129.
Chin-Yuan Hu 《Journal of Mathematical Analysis and Applications》2007,328(1):201-219
Recently we established Matysiak and Szablowski's conjecture [V. Matysiak, P.J. Szablowski, Theory Probab. Appl. 45 (2001) 711-713] about a lower bound of real-valued characteristic functions. In this paper, applying an alternative approach we are able to give explicitly the ranges of argument for which the obtained inequalities hold true for general characteristic functions. 相似文献
130.
Bünyamin Demir Vakif Dzhafarov ?ahin Koçak Mehmet Üreyen 《Journal of Mathematical Analysis and Applications》2007,332(1):735-740
We give an iterated function system (IFS) on the plane with the circle as attractor. In doing this, we also give a sufficient condition for radially contracting functions on the plane (or on Rn) to be a contraction. A counterexample shows that radial contractiveness is not enough to be a contraction. 相似文献