全文获取类型
收费全文 | 7306篇 |
免费 | 1030篇 |
国内免费 | 635篇 |
专业分类
化学 | 981篇 |
晶体学 | 91篇 |
力学 | 667篇 |
综合类 | 148篇 |
数学 | 5264篇 |
物理学 | 1820篇 |
出版年
2024年 | 4篇 |
2023年 | 68篇 |
2022年 | 93篇 |
2021年 | 120篇 |
2020年 | 188篇 |
2019年 | 223篇 |
2018年 | 194篇 |
2017年 | 241篇 |
2016年 | 281篇 |
2015年 | 208篇 |
2014年 | 376篇 |
2013年 | 662篇 |
2012年 | 377篇 |
2011年 | 471篇 |
2010年 | 425篇 |
2009年 | 464篇 |
2008年 | 506篇 |
2007年 | 489篇 |
2006年 | 421篇 |
2005年 | 389篇 |
2004年 | 339篇 |
2003年 | 300篇 |
2002年 | 326篇 |
2001年 | 269篇 |
2000年 | 262篇 |
1999年 | 225篇 |
1998年 | 182篇 |
1997年 | 181篇 |
1996年 | 117篇 |
1995年 | 78篇 |
1994年 | 69篇 |
1993年 | 47篇 |
1992年 | 36篇 |
1991年 | 44篇 |
1990年 | 24篇 |
1989年 | 31篇 |
1988年 | 27篇 |
1987年 | 21篇 |
1986年 | 14篇 |
1985年 | 34篇 |
1984年 | 29篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 16篇 |
1978年 | 12篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1973年 | 3篇 |
排序方式: 共有8971条查询结果,搜索用时 15 毫秒
991.
In this note new Rosenbrock methods for ODEs, DAEs, PDEs and PDAEs of index 1 are presented. These solvers are of order 3,
have 3 or 4 internal stages, and fulfil certain order conditions to obtain a better convergence if inexact Jacobians and approximations
of
are used. A comparison with other Rosenbrock solvers shows the advantages of the new methods.
AMS subject classification (2000) 34A09, 65L80 相似文献
992.
993.
Let X(ω) be a random element taking values in a linear space endowed with the partial order ≤; let 0 be the class of nonnegative order-preserving functions on such that, for each g∈0, E[g(X)] is defined; and let 1?0 be the subclass of concave functions. A version of Markov's inequality for such spaces in P(X ≥ x) ≤ inf0E[g(X)]/g(x). Moreover, if E(X) = ξ is defined and if Jensen's inequality applies, we have a further inequality P(X≥x) ≤ inf1E[g(X)]/g(x) ≤ inf1g(ξ)/g(x). Applications are given using a variety or orderings of interest in statistics and applied probability. 相似文献
994.
This article solves the problem of finding a set of group decisions that satisfy the classical Pareto unanimity principle for the case of initial data represented as fuzzy relations of individual preference. The solution proceeds from results obtained in studying the structure of convex (in the sense defined here) sets and their convex hulls. In the first part that study is carried out for spaces of arbitrary fuzzy binary relations. 相似文献
995.
996.
Markku Tamminen 《BIT Numerical Mathematics》1982,22(1):27-41
The extendible cell method is an application of order preserving extendible hashing to multidimensional point files. We derive some of its performance characteristics and show its expected case optimality for closest point problems. 相似文献
997.
研究一类三阶非线性分布时滞动力方程的振动性,通过构造广义Riccati变换得到一类新的广义Riccati不等式,利用积分平均技巧等方法,建立了保证该方程一切解均振动或收敛于0的若干新的振动结果,推广和改进了近期文献的相关结论,并给出了若干例子。 相似文献
998.
A nematogenic side-chain polysiloxane is investigated by means of absorption and fluo-rescence spectroscopy.4-Dimethylamino-4′-nitrostilbene (DANS) is dissolved in the poly-meric matrix as a guest probe. The orientational order and the molecular distribution function have been determined from measurements of polarized absorption and fluorescence spectra. It has been found that fluorescence spectroscopy affords a method for determination of the phase transition temperatures of liquid–crystalline polymers. © 1993 John Wiley & Sons, Inc. 相似文献
999.
Yoshihiro Saito Taketomo Mitsui 《Annals of the Institute of Statistical Mathematics》1993,45(3):419-432
A lot of discrete approximation schemes for stochastic differential equations with regard to mean-square sense were proposed. Numerical experiments for these schemes can be seen in some papers, but the efficiency of scheme with respect to its order has not been revealed. We will propose another type of error analysis. Also we will show results of simulation studies carried out for these schemes under our notion. 相似文献
1000.
Very recently, we obtained a simple characterization of the chaotic order log A≥log B among positive invertible operators AB on a Hilbert space. In this note, we discuss Furuta's type operator inequalities as applications of our characterization of the chaotic order. 相似文献