全文获取类型
收费全文 | 158596篇 |
免费 | 7153篇 |
国内免费 | 9537篇 |
专业分类
化学 | 26952篇 |
晶体学 | 301篇 |
力学 | 6796篇 |
综合类 | 1260篇 |
数学 | 25460篇 |
物理学 | 21778篇 |
综合类 | 92739篇 |
出版年
2024年 | 229篇 |
2023年 | 938篇 |
2022年 | 1677篇 |
2021年 | 1881篇 |
2020年 | 2042篇 |
2019年 | 2287篇 |
2018年 | 1949篇 |
2017年 | 2345篇 |
2016年 | 2603篇 |
2015年 | 3292篇 |
2014年 | 5780篇 |
2013年 | 7051篇 |
2012年 | 7209篇 |
2011年 | 8148篇 |
2010年 | 6911篇 |
2009年 | 8388篇 |
2008年 | 9105篇 |
2007年 | 10884篇 |
2006年 | 10426篇 |
2005年 | 9809篇 |
2004年 | 8365篇 |
2003年 | 8078篇 |
2002年 | 7078篇 |
2001年 | 6055篇 |
2000年 | 5486篇 |
1999年 | 4677篇 |
1998年 | 3964篇 |
1997年 | 3494篇 |
1996年 | 3202篇 |
1995年 | 2879篇 |
1994年 | 2724篇 |
1993年 | 2352篇 |
1992年 | 2231篇 |
1991年 | 1956篇 |
1990年 | 1728篇 |
1989年 | 1655篇 |
1988年 | 1393篇 |
1987年 | 885篇 |
1986年 | 627篇 |
1985年 | 503篇 |
1984年 | 443篇 |
1983年 | 210篇 |
1982年 | 343篇 |
1981年 | 403篇 |
1980年 | 304篇 |
1979年 | 293篇 |
1978年 | 221篇 |
1977年 | 205篇 |
1976年 | 154篇 |
1974年 | 110篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
给出了介观耗散互感耦合电路的量子化方法,并在介观电路中电荷量子化的基础上给出了介观耗散互感耦合电路的库仑阻塞条件. 相似文献
902.
We consider a trader who wants to direct his or her portfolio towards a set of acceptable wealths given by a convex risk measure. We propose a Monte Carlo algorithm, whose inputs are the joint law of stock prices and the convex risk measure, and whose outputs are the numerical values of initial capital requirement and the functional form of a trading strategy for achieving acceptability. We also prove optimality of the capital obtained. Explicit theoretical evaluations of hedging strategies are extremely difficult, and we avoid the problem by resorting to such computational methods. The main idea is to utilize the finite Vapnik–C?ervonenkis dimension of a class of possible strategies. 相似文献
903.
We prove that there is a first-order sentence ϕ such that the group of all computable automorphisms of the ordering of the
rational numbers is its only model among the groups that are embeddable in the group of all computable permutations.
Supported by a Scheme 2 grant from the London Mathematical Society.
__________
Translated from Algebra i Logika, Vol. 46, No. 5, pp. 649–662, September–October, 2007. 相似文献
904.
S. V. Dil’man 《Mathematical Notes》2006,79(5-6):625-631
In 1996, D. Deng established an analog of the Baum—Katz theorem on the convergence rate in the law of large numbers for multi-indexed random variables. The series describing the convergence rate depends, in a natural way, on the parameter characterizing the excess of the normalized sums over some level. In this paper, we find the precise asymptotics of the sum of this series with respect to the above-mentioned parameter. Thus, a generalization of a recent result due to A. Gut and A. Spataru is obtained. 相似文献
905.
In the present paper, we study the rate of convergence in simultaneous approximation for the Bézier variant of the Baskakov-Beta operators by using the decomposition technique of functions of bounded variation. 相似文献
906.
907.
Cai-yun Jin Cao-zong Cheng Yong-tao Jin Jing Li 《应用数学学报(英文版)》2006,22(4):607-614
Two two-function minimax theorems are proved.The concavity-convexity conditions of the twofunctions involve strictly monotone transformations and mixing of the values of the two functions,and aredescribed by the inequalities as upward and weakly downward conditions. 相似文献
908.
The mechanism of X-ray waveguide-resonance propagation or the radiation superstream model, which can become the ground of X-ray nanophotonics, is discussed briefly. Some attention is devoted to features consideration of the simplest devices characterized by the waveguide-resonance transportation of X-ray beams. The experimental data showing the user possibilities of a simplest waveguide-resonators application for diffractometry are presented. We discuss the main reasons to improve the metrological characteristics for total reflection X-ray fluorescence (TXRF) analytical method in case when the target exciting beam is formed by a waveguide-resonator. Some problems appearing during the waveguide-resonator application are formulated. 相似文献
909.
Xin Tao YE Chong LI 《数学学报(英文版)》2007,23(1):65-76
The BCQ and the Abadie CQ for infinite systems of convex inequalities in Banach spaces are characterized in terms of the upper semi-continuity of the convex cones generated by the subdifferentials of active convex functions. Some relationships with other constraint qualifications such as the CPLV and the Slate condition are also studied. Applications in best approximation theory are provided. 相似文献
910.
史奎凡 《济南大学学报(自然科学版)》1987,(2)
本文用时间序列分析方法分析水泥生产过程,笔者假设水泥生产过程为一个平稳的随机过程,它的二十八天抗压强度为具有控制项的自回归模型。用30组数据建立了28天水泥抗压强度动态模型,并做了跟踪,分析了七天抗压强度、细度、SO_3等与二十八天抗压强度的关系。最后,把生产中实际值和预测值进行了比较。 相似文献