全文获取类型
收费全文 | 26706篇 |
免费 | 4592篇 |
国内免费 | 3799篇 |
专业分类
化学 | 20473篇 |
晶体学 | 330篇 |
力学 | 1461篇 |
综合类 | 211篇 |
数学 | 2985篇 |
物理学 | 9637篇 |
出版年
2024年 | 51篇 |
2023年 | 469篇 |
2022年 | 762篇 |
2021年 | 869篇 |
2020年 | 968篇 |
2019年 | 1061篇 |
2018年 | 897篇 |
2017年 | 866篇 |
2016年 | 1236篇 |
2015年 | 1297篇 |
2014年 | 1556篇 |
2013年 | 1988篇 |
2012年 | 2446篇 |
2011年 | 2372篇 |
2010年 | 1713篇 |
2009年 | 1654篇 |
2008年 | 1851篇 |
2007年 | 1685篇 |
2006年 | 1532篇 |
2005年 | 1417篇 |
2004年 | 1114篇 |
2003年 | 883篇 |
2002年 | 939篇 |
2001年 | 743篇 |
2000年 | 620篇 |
1999年 | 598篇 |
1998年 | 501篇 |
1997年 | 456篇 |
1996年 | 411篇 |
1995年 | 345篇 |
1994年 | 305篇 |
1993年 | 252篇 |
1992年 | 205篇 |
1991年 | 181篇 |
1990年 | 203篇 |
1989年 | 137篇 |
1988年 | 110篇 |
1987年 | 70篇 |
1986年 | 77篇 |
1985年 | 73篇 |
1984年 | 36篇 |
1983年 | 37篇 |
1982年 | 34篇 |
1981年 | 22篇 |
1980年 | 12篇 |
1979年 | 3篇 |
1977年 | 6篇 |
1936年 | 7篇 |
1930年 | 2篇 |
1916年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
On Polynomial Functions over Finite Commutative Rings 总被引:1,自引:0,他引:1
Jian Jun JIANG Guo Hua PENG Qi SUN Qi Fan ZHANG 《数学学报(英文版)》2006,22(4):1047-1050
Let R be an arbitrary finite commutative local ring. In this paper, we obtain a necessary and sufficient condition for a function over R to be a polynomial function. Before this paper, necessary and sufficient conditions for a function to be a polynomial function over some special finite commutative local rings were obtained. 相似文献
92.
Let X be a metric space, B the σ-algebra of Borel subsets of X, and μ a probability measure on (X,B). In this note, for a measure-preserving map T (respectively a measure-preserving semi-flow φ) on (X,B,μ), we prove that if suppμ=X, and T (respectively φ) is weak-mixing, then T (respectively φ) has sensitive dependence. 相似文献
93.
岳华 《数学的实践与认识》2003,33(6):96-104
本文证明了可分无穷维 Hilbert空间上每个有界线性算子均可写成两个强不可约算子之和 .这回答了文献 [9]中提出一个公开问题 相似文献
94.
Bing-sheng He Zhen-hua Yang Xiao-ming Yuan 《Journal of Mathematical Analysis and Applications》2004,300(2):139-374
Proximal point algorithms (PPA) are attractive methods for monotone variational inequalities. The approximate versions of PPA are more applicable in practice. A modified approximate proximal point algorithm (APPA) presented by Solodov and Svaiter [Math. Programming, Ser. B 88 (2000) 371–389] relaxes the inexactness criterion significantly. This paper presents an extended version of Solodov–Svaiter's APPA. Building the direction from current iterate to the new iterate obtained by Solodov–Svaiter's APPA, the proposed method improves the profit at each iteration by choosing the optimal step length along this direction. In addition, the inexactness restriction is relaxed further. Numerical example indicates the improvement of the proposed method. 相似文献
95.
Zhimin He 《Journal of Mathematical Analysis and Applications》2004,296(1):97-109
In this paper, by means of a new twin fixed-point theorem in a cone, the existence of at least two positive solutions of m-point boundary value problem for second order dynamic equations on time scales is considered. 相似文献
96.
97.
98.
Qingfa Wang Li Wang Yaquan Wang Fei He Zhenhua Li Zhentao Mi 《Reaction Kinetics and Catalysis Letters》2004,81(2):297-304
Deactivated palladium catalysts in the hydrogenation of anthraquinione were regenerated with ethanol, nitric acid, hydrogen
peroxide, boiling water and steam, respectively. The deactivated and regenerated catalysts were characterized by XPS, ICP,
TG, FTIR, TPD, XRD, etc., and studied in the hydrogenation of anthraquinone. The results showed that the main cause of catalyst deactivation is the
coverage of the active component by deposits. The treatments by hydrogen peroxide and boiling water can effectively regenerate
the deactivated catalysts.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
99.
Shui Cao ZHENG Huo Nan LIN Di He HU 《数学学报(英文版)》2005,21(5):1137-1148
In this paper, we investigate the Hausdorff measure for level sets of N-parameter Rd-valued stable processes, and develop a means of seeking the exact Hausdorff measure function for level sets of N-parameter Rd-valued stable processes. We show that the exact Hausdorff measure function of level sets of N-parameter Rd-valued symmetric stable processes of index α is Ф(r) = r^N-d/α (log log l/r)d/α when Nα 〉 d. In addition, we obtain a sharp lower bound for the Hausdorff measure of level sets of general (N, d, α) strictly stable processes. 相似文献
100.
ChunXiaLI YingXiaLI LingBoYU HuaZHANG SiftDongCHU HuaShiGUAN 《中国化学快报》2003,14(8):776-778
A convenient synthetic route was developed for the synthesis of the novel glycolipids: 1,2-di-O-acyl-3-O-(2‘-acylamide-2‘-denxy-ct-D-glucopyranosyl)-sn-glycerols. 10 new compounds of glycolipids with different acyl groups were obtained. 相似文献