全文获取类型
收费全文 | 4045篇 |
免费 | 378篇 |
国内免费 | 246篇 |
专业分类
化学 | 1105篇 |
力学 | 148篇 |
综合类 | 58篇 |
数学 | 2417篇 |
物理学 | 941篇 |
出版年
2024年 | 9篇 |
2023年 | 54篇 |
2022年 | 73篇 |
2021年 | 71篇 |
2020年 | 104篇 |
2019年 | 130篇 |
2018年 | 114篇 |
2017年 | 140篇 |
2016年 | 165篇 |
2015年 | 119篇 |
2014年 | 194篇 |
2013年 | 314篇 |
2012年 | 191篇 |
2011年 | 220篇 |
2010年 | 205篇 |
2009年 | 261篇 |
2008年 | 241篇 |
2007年 | 256篇 |
2006年 | 224篇 |
2005年 | 189篇 |
2004年 | 159篇 |
2003年 | 164篇 |
2002年 | 141篇 |
2001年 | 103篇 |
2000年 | 101篇 |
1999年 | 102篇 |
1998年 | 70篇 |
1997年 | 91篇 |
1996年 | 55篇 |
1995年 | 59篇 |
1994年 | 46篇 |
1993年 | 33篇 |
1992年 | 31篇 |
1991年 | 26篇 |
1990年 | 35篇 |
1989年 | 23篇 |
1988年 | 21篇 |
1987年 | 15篇 |
1986年 | 19篇 |
1985年 | 18篇 |
1984年 | 20篇 |
1983年 | 6篇 |
1982年 | 15篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 14篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有4669条查询结果,搜索用时 15 毫秒
31.
32.
Jean-Pierre Dedieu Gregorio Malajovich Mike Shub 《Foundations of Computational Mathematics》2005,5(2):145-171
We prove a linear bound on the average total curvature of the
central path of linear programming theory in terms of the number
of independent variables of the primal problem, and independent of
the number of constraints. 相似文献
33.
周忆 《数学年刊B辑(英文版)》2003,24(3)
This paper considers the following Cauchy problem for semilinear wave equations in n spacedimensions□φ = F( φ),φ(0, x) = f(x), tφ(0, x) = g(x),The minimal value of s is determined such that the above Cauchy problem is locally well-posed in Hs. It turns out that for the general equation s must satisfyThis is due to Ponce and Sideris (when n = 3) and Tataru (when n ≥ 5). The purpose of thispaper is to supplement with a proof in the case n = 2, 4. 相似文献
34.
35.
Various problems associated with optimal path planning for mobile observers such as mobile robots equipped with cameras to obtain maximum visual coverage of a surface in the three-dimensional Euclidean space are considered. The existence of solutions to these problems is discussed first. Then, optimality conditions are derived by considering local path perturbations. Numerical algorithms for solving the corresponding approximate problems are proposed. Detailed solutions to the optimal path planning problems for a few examples are given. 相似文献
36.
J. Schulte 《Journal of statistical physics》1993,70(5-6):1343-1347
The thermodynamic stability of4He4–13 at 3.2 K is investigated with the classical Monte Carlo method, with the semiclassical path-integral Monte Carlo (PIMC) method, and with the semiclassical all-order many-body method. In the all-order many-body simulation the dipole-dipole approximation including short-range correction is used. The resulting stability plots are discussed and related to recent TOF experiments by Stephens and King. It is found that with classical Monte Carlo of course the characteristics of the measured mass spectrum cannot be resolved. With PIMC, switching on more and more quantum mechanics. by raising the number of virtual time steps results in more structure in the stability plot, but this did not lead to sufficient agreement with the TOF experiment. Only the all-order many-body method resolved the characteristic structures of the measured mass spectrum, including magic numbers. The result shows the influence of quantum statistics and quantum mechanics on the stability of small neutral helium clusters. 相似文献
37.
Hossam A. Zaki 《Computational Optimization and Applications》1995,4(1):23-45
State-of-the-art computational results have shown that the shortest augmenting path (SAP) methods are more efficient than other primal-dual and primal-simplex based methods for solving the linear assignment problem on uniprocessor computers. There is, however, some controversy concerning their merits when compared with Bertsekas' auction algorithm on multiprocessor computers. In this study we investigate the performance of these competing methods on the Alliant FX/8. For each method, theoretical motivation, sources of parallelism and computational results are presented. 相似文献
38.
针对一般的非线性规划问题,利用某些Lagrange型函数给出了一类Lagrangian对偶问题的一般模型,并证明它与原问题之间存在零对偶间隙.针对具体的一类增广La- grangian对偶问题以及几类由非线性卷积函数构成的Lagrangian对偶问题,详细讨论了零对偶间隙的存在性.进一步,讨论了在最优路径存在的前提下,最优路径的收敛性质. 相似文献
39.
Tetsushi Nishida Kokichi Sugihara Masato Kimura 《Journal of Computational and Applied Mathematics》2007
The Voronoi diagram in a flow field is a tessellation of water surface into regions according to the nearest island in the sense of a “boat-sail distance”, which is a mathematical model of the shortest time for a boat to move from one point to another against the flow of water. The computation of the diagram is not easy, because the equi-distance curves have singularities. To overcome the difficulty, this paper derives a new system of equations that describes the motion of a particle along the shortest path starting at a given point on the boundary of an island, and thus gives a new variant of the marker-particle method. In the proposed method, each particle can be traced independently, and hence the computation can be done stably even though the equi-distance curves have singular points. 相似文献
40.
对于线性型多目标半定规划问题,引进加权中心路径的概念,并利用单目标半定规划的中心路径法,提出了求解多目标半定规划问题的加权中心路径法,先得型对一个叔向量的有效解,然后在此基础上,提出了通过一次迭代得到对应一定范围内其他任意权向量的有效解的一步修正方法. 相似文献