全文获取类型
收费全文 | 5529篇 |
免费 | 439篇 |
国内免费 | 402篇 |
专业分类
化学 | 1193篇 |
晶体学 | 2篇 |
力学 | 349篇 |
综合类 | 87篇 |
数学 | 3367篇 |
物理学 | 1372篇 |
出版年
2024年 | 10篇 |
2023年 | 52篇 |
2022年 | 100篇 |
2021年 | 138篇 |
2020年 | 130篇 |
2019年 | 143篇 |
2018年 | 115篇 |
2017年 | 193篇 |
2016年 | 220篇 |
2015年 | 144篇 |
2014年 | 235篇 |
2013年 | 369篇 |
2012年 | 319篇 |
2011年 | 287篇 |
2010年 | 248篇 |
2009年 | 363篇 |
2008年 | 370篇 |
2007年 | 394篇 |
2006年 | 332篇 |
2005年 | 288篇 |
2004年 | 231篇 |
2003年 | 227篇 |
2002年 | 244篇 |
2001年 | 153篇 |
2000年 | 156篇 |
1999年 | 144篇 |
1998年 | 117篇 |
1997年 | 91篇 |
1996年 | 88篇 |
1995年 | 71篇 |
1994年 | 63篇 |
1993年 | 36篇 |
1992年 | 34篇 |
1991年 | 28篇 |
1990年 | 25篇 |
1989年 | 17篇 |
1988年 | 24篇 |
1987年 | 29篇 |
1986年 | 20篇 |
1985年 | 21篇 |
1984年 | 22篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有6370条查询结果,搜索用时 15 毫秒
31.
本文得到了广义区间空间中几个参数型非空交定理,并用此结果证明了一些新型极大极小定理,截口定理,重合定理,以及变分不等式解的存在性定理。本文中的结果包含(1,3,5-12,14-16)中相应结果。 相似文献
32.
本文提出了一类特殊的n人合作对策模型─—弱1—凸对策,研究了弱1—凸对策的解的性质,并证明弱1—凸对策的解满足所有常见的公理化特征. 相似文献
33.
S. V. Tyshkevich 《Mathematical Notes》2007,81(5-6):851-853
34.
In this paper, we establish the existence of upper and lower solutions for a periodic boundary value problems (PBVP for short) of impulsive differential equations. which guarantees the existence of at least one solution for the problem. As an application, these results are applied to PBVP of ODE and some examples are given to illustrate our results. 相似文献
35.
Summary We study the integration theory for general integral metrics when restricted to upper integrals q, finding improvements in the relation between the classes of the q-integrable and the ql-integrable functions. We give new results and notions which lead to the desirable characterizations of q-integrable functions as ql-integrable f with q(|f|) < ∞, and of ql-integrable functions via the integrability of their upper truncations, under natural conditions which are fulfilled in most
finitely additive integration theories. 相似文献
36.
Xiangtong Qi 《Discrete Applied Mathematics》2007,155(3):416-422
We study a machine scheduling model in which job scheduling and machine maintenance activities have to be considered simultaneously. We develop the worst-case bounds for some heuristic algorithms, including a sharper worst-case bound of the SPT schedule than the results in the literature, and another bound of the EDD schedule. 相似文献
37.
A. A. Maleev 《Computational Mathematics and Mathematical Physics》2006,46(12):2031-2039
Stationary and nonstationary Jacobi-like iterative processes for solving systems of linear algebraic equations are examined. For a system whose coefficient matrix A is an H-matrix, it is shown that the convergence rate of any Jacobi-like process is at least as high as that of the point Jacobi method as applied to a system with 〈A〉 as the coefficient matrix, where 〈A〉 is a comparison matrix of A. 相似文献
38.
In this paper, we introduce a new concept of semi-preemptive scheduling and we show how it can be used to derive a maximum-flow-based lower bound for the P|rj|Lmax which dominates the well-known preemptive lower bound. We show that, in some cases, the proposed bound strictly dominates the preemptive one while having the same complexity. 相似文献
39.
This paper investigates the existence of positive solutions of a singular boundary value problem with negative exponent similar
to standard Emden-Fowler equation. A necessary and sufficient condition for the existence of C[0, 1] positive solutions as
well as C1[0, 1] positive solutions is given by means of the method of lower and upper solutions with the Schauder fixed point theorem. 相似文献
40.
Tristrom Cooke 《Journal of multivariate analysis》2004,89(2):191-383
The quadratic discriminant function is often used to separate two classes of points in a multidimensional space. When the two classes are normally distributed, this results in the optimum separation. In some cases however, the assumption of normality is a poor one and the classification error is increased. The current paper derives an upper bound for the classification error due to a quadratic decision surface. The bound is strict when the class means and covariances and the quadratic discriminant surface satisfy certain specified symmetry conditions. 相似文献