全文获取类型
收费全文 | 11843篇 |
免费 | 556篇 |
国内免费 | 641篇 |
专业分类
化学 | 1277篇 |
晶体学 | 69篇 |
力学 | 301篇 |
综合类 | 82篇 |
数学 | 2161篇 |
物理学 | 1510篇 |
综合类 | 7640篇 |
出版年
2024年 | 18篇 |
2023年 | 87篇 |
2022年 | 159篇 |
2021年 | 168篇 |
2020年 | 166篇 |
2019年 | 192篇 |
2018年 | 160篇 |
2017年 | 207篇 |
2016年 | 211篇 |
2015年 | 277篇 |
2014年 | 590篇 |
2013年 | 699篇 |
2012年 | 695篇 |
2011年 | 764篇 |
2010年 | 736篇 |
2009年 | 793篇 |
2008年 | 701篇 |
2007年 | 718篇 |
2006年 | 676篇 |
2005年 | 648篇 |
2004年 | 551篇 |
2003年 | 473篇 |
2002年 | 404篇 |
2001年 | 376篇 |
2000年 | 355篇 |
1999年 | 273篇 |
1998年 | 245篇 |
1997年 | 263篇 |
1996年 | 178篇 |
1995年 | 190篇 |
1994年 | 171篇 |
1993年 | 120篇 |
1992年 | 128篇 |
1991年 | 87篇 |
1990年 | 90篇 |
1989年 | 101篇 |
1988年 | 89篇 |
1987年 | 35篇 |
1986年 | 24篇 |
1985年 | 23篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 23篇 |
1981年 | 32篇 |
1980年 | 25篇 |
1979年 | 19篇 |
1978年 | 18篇 |
1977年 | 16篇 |
1976年 | 17篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
41.
In this paper, the notion of gap functions is extended from scalar case to vector one. Then, gap functions and generalized
functions for several kinds of vector equilibrium problems are shown. As an application, the dual problem of a class of optimization
problems with a system of vector equilibrium constraints (in short, OP) is established, the concavity of the dual function,
the weak duality of (OP) and the saddle point sufficient condition are derived by using generalized gap functions.
This work was supported by the National Natural Science Foundation of China (10671135) and the Applied Research Project of
Sichuan Province (05JY029-009-1). 相似文献
42.
By using the averaging technique, we obtain new oscillation criteria for second order delay differential equation with nonlinear neutral term. These results generalize and improve some known results about neutral delay differential equation of second order. 相似文献
43.
在LP(1 P<∞)空间研究了板模型中一类带广义边界条件具各向异性、连续能量、均匀介质迁移算子的谱,证明了该迁移算子生成C0半群的D yson—Ph illips展开式的二阶余项在LP(1
相似文献
44.
本文讨论了生长曲线模型中多组数据对回归分析的联合影响问题,给出了度量准则及其化简式与统计解释,推广了已有文献中的有关结果. 相似文献
45.
二阶系统性能参数的研究 总被引:2,自引:0,他引:2
系统地总结了二阶系统动力学方程、传递函数、状态方程、时间响应及各种性能指标,并对其进行了详细的讨论,同时揭示了各种方法之间的内在联系及应用中注意的问题。 相似文献
46.
在本文中,我们讨论了非线性常微分方程y"=a0|x|αy3 a1|x|βy2 α2|x|γy α3|x|δ振荡解的渐近表示.在这个方程中将α0,α,α1,β,α2,γ,α3,δ分别换成0,0,6,0,0,0,sgn(x),1就是著名的第一类Painleve方程,而将α0,α,α1,β,α2,γ,α3,δ分别换成2,0,0,0,sgn(x),1,α0,就是著名的第二类Painleve方程.当α0,α,α1,β,α2,γ,α3,δ分别换成-β/3γ,0,0,0,1/γ,1,α,0时,可用于组合KdV方程孤立子解的化简. 相似文献
47.
利用密度泛函理论研究了Al12N和Al12B团簇的原子结构和电子性质,通过各种异构体的比较,发现两种掺杂团簇的最低能量结构都是完好的二十面体(Ih)结构,N(B)原子占据在二十面体的中心.高对称性团簇形成稀疏离散的电子态密度和大的电子能隙.在Al-N之间发生较大的电荷转移.因此我们建议把Al12N团簇看作是碱金属超原子,Al12B团簇看作是卤素超原子,用来构造团簇组装固体. 相似文献
48.
Zhangxin Chen 《Numerical Methods for Partial Differential Equations》2002,18(2):203-217
In this article we prove uniform convergence estimates for the recently developed Galerkin‐multigrid methods for nonconforming finite elements for second‐order problems with less than full elliptic regularity. These multigrid methods are defined in terms of the “Galerkin approach,” where quadratic forms over coarse grids are constructed using the quadratic form on the finest grid and iterated coarse‐to‐fine intergrid transfer operators. Previously, uniform estimates were obtained for problems with full elliptic regularity, whereas these estimates are derived with less than full elliptic regularity here. Applications to the nonconforming P1, rotated Q1, and Wilson finite elements are analyzed. The result applies to the mixed method based on finite elements that are equivalent to these nonconforming elements. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 203–217, 2002; DOI 10.1002/num.10004 相似文献
49.
A. S. Belenky 《Mathematical and Computer Modelling》2002,36(11-13)
Two games of interacting between a coalition of players in a marketplace and the residual players acting there are discussed, along with two approaches to fair imputation of gains of coalitions in cooperative games that are based on the concepts of the Shapley vector and core of a cooperative game. In the first game, which is an antagonistic one, the residual players try to minimize the coalition's gain, whereas in the second game, which is a noncooperative one, they try to maximize their own gain as a coalition. A meaningful interpretation of possible relations between gains and Nash equilibrium strategies in both games considered as those played between a coalition of firms and its surrounding in a particular marketplace in the framework of two classes of n-person games is presented. A particular class of games of choosing partners and forming coalitions in which models of firms operating in the marketplace are those with linear constraints and utility functions being sums of linear and bilinear functions of two corresponding vector arguments is analyzed, and a set of maximin problems on polyhedral sets of connected strategies which the problem of choosing a coalition for a particular firm is reducible to are formulated based on the firm models of the considered kind. 相似文献
50.