全文获取类型
收费全文 | 18961篇 |
免费 | 1714篇 |
国内免费 | 1285篇 |
专业分类
化学 | 809篇 |
晶体学 | 12篇 |
力学 | 1348篇 |
综合类 | 196篇 |
数学 | 6897篇 |
物理学 | 2921篇 |
综合类 | 9777篇 |
出版年
2024年 | 59篇 |
2023年 | 180篇 |
2022年 | 289篇 |
2021年 | 387篇 |
2020年 | 395篇 |
2019年 | 395篇 |
2018年 | 415篇 |
2017年 | 555篇 |
2016年 | 562篇 |
2015年 | 585篇 |
2014年 | 917篇 |
2013年 | 1196篇 |
2012年 | 964篇 |
2011年 | 1061篇 |
2010年 | 870篇 |
2009年 | 1015篇 |
2008年 | 1067篇 |
2007年 | 1320篇 |
2006年 | 1147篇 |
2005年 | 965篇 |
2004年 | 853篇 |
2003年 | 786篇 |
2002年 | 716篇 |
2001年 | 696篇 |
2000年 | 652篇 |
1999年 | 557篇 |
1998年 | 475篇 |
1997年 | 416篇 |
1996年 | 344篇 |
1995年 | 322篇 |
1994年 | 275篇 |
1993年 | 238篇 |
1992年 | 213篇 |
1991年 | 188篇 |
1990年 | 162篇 |
1989年 | 129篇 |
1988年 | 124篇 |
1987年 | 96篇 |
1986年 | 56篇 |
1985年 | 59篇 |
1984年 | 34篇 |
1983年 | 20篇 |
1982年 | 29篇 |
1981年 | 29篇 |
1980年 | 31篇 |
1979年 | 35篇 |
1978年 | 9篇 |
1977年 | 18篇 |
1976年 | 7篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Using the iterative scheme we prove the local existence and uniqueness of solutions of the spherically symmetric Einstein-Vlasov-Maxwell system with small initial data. We prove a continuation criterion to global in-time solutions. 相似文献
92.
93.
具有种内互惠作用的Lotka-Volterra互惠共存模型 总被引:1,自引:0,他引:1
对具有种内互惠作用的Lotka-Volterra互惠共存模型进行了完整的全局分析,得到了一些新的结果。 相似文献
94.
95.
L.G. Casado I. García T. Csendes V.G. Ruíz 《Journal of Optimization Theory and Applications》2003,118(1):27-43
Based on the investigation carried out in Ref. 1, this paper incorporates new studies about the properties of inclusion functions on subintervals while a branch-and-bound algorithm is solving global optimization problems. It is found that the relative place of the global minimum value within the inclusion function value of the objective function at the current interval indicates mostly whether the given interval is close to a minimizer point. This information is used in a heuristic interval rejection rule that can save a considerable amount of computation. Illustrative examples are discussed and an extended numerical study shows the advantages of the new approach. 相似文献
96.
We prove that the sequence of finite reflecting branching Brownian motion forests defined by Burdzy and Le Gall ([1]) converges in probability to the “super-Brownian motion with reflecting historical paths.” This solves an open problem posed in [1], where only tightness was proved for the sequence of approximations. Several results on path behavior were proved in [1] for all subsequential limits–they obviously hold for the unique limit found in the present paper.Mathematics Subject Classification (2000): Primary 60H15, Secondary 35R60Supported in part by NSF Grant DMS-0071486, Israel Science Foundation Grants 12/98 and 116/01 - 10.0, and the U.S.-Israel Binational Science Foundation (grant No. 2000065). 相似文献
97.
Marianne Gerny Burkhard Alpers 《International Journal of Computers for Mathematical Learning》2004,9(1):25-57
In this article we describe a mathematical microworld for investigating car motion on a racing course and its use with a group of grade 12 students. The microworld is concerned with the mathematical construction of courses and functions which describe car motion. It is implemented in the computer algebra system, Maple®, which provides the means to represent courses and functions symbolically and graphically. We describe the learning opportunities offered by the microworld in relation to the research literature on functions. Various facets and layers of the function concept are addressed in the microworld, and we suggest how work in the microworld might help in overcoming some well-known misconceptions.This revised version was published online in September 2005 with corrections to the Cover Date. 相似文献
98.
In this paper a predictive control strategy is applied to a periodic-review dynamic inventory system with deteriorating items.
Given the current inventory level, we determine the optimal production rates to be implemented at the beginning of each of
the following periods over the control horizon. The effectiveness of this approach is the use of future information of the
inventory target level and the desired production rate, which are available, along the fixed horizon. The deterioration coefficient
may be known or unknown and both cases are considered. In the case where it is unknown, the self-tuning predictive control
is applied. The proposed control algorithms are illustrated by simulations. 相似文献
99.
Y. Brihaye S. Giller C. Gonera P. Kosinski P. Maslanka 《Czechoslovak Journal of Physics》2004,54(11):1185-1190
The dynamical systems of identical particles admitting quadratic integrals of motion are classified. The relevant integrals are explicitly constructed and their relation to separation of variables in Hamilton-Jacobi equation is clarified. 相似文献
100.
Arnold Neumaier 《Journal of Global Optimization》2003,25(2):175-181
A family of multivariate rational functions is constructed. It has strong local minimizers with prescribed function values at prescribed positions. While there might be additional local minima, such minima cannot be global. A second family of multivariate rational functions is given, having prescribed global minimizers and prescribed interpolating data. 相似文献