全文获取类型
收费全文 | 37331篇 |
免费 | 4510篇 |
国内免费 | 2469篇 |
专业分类
化学 | 4504篇 |
晶体学 | 38篇 |
力学 | 4198篇 |
综合类 | 495篇 |
数学 | 24225篇 |
物理学 | 10850篇 |
出版年
2024年 | 85篇 |
2023年 | 400篇 |
2022年 | 461篇 |
2021年 | 605篇 |
2020年 | 1085篇 |
2019年 | 1099篇 |
2018年 | 1049篇 |
2017年 | 1066篇 |
2016年 | 1163篇 |
2015年 | 979篇 |
2014年 | 1658篇 |
2013年 | 3140篇 |
2012年 | 1862篇 |
2011年 | 2237篇 |
2010年 | 2105篇 |
2009年 | 2331篇 |
2008年 | 2491篇 |
2007年 | 2430篇 |
2006年 | 2103篇 |
2005年 | 2094篇 |
2004年 | 1744篇 |
2003年 | 1602篇 |
2002年 | 1466篇 |
2001年 | 1094篇 |
2000年 | 1096篇 |
1999年 | 994篇 |
1998年 | 901篇 |
1997年 | 771篇 |
1996年 | 597篇 |
1995年 | 531篇 |
1994年 | 419篇 |
1993年 | 310篇 |
1992年 | 298篇 |
1991年 | 279篇 |
1990年 | 253篇 |
1989年 | 154篇 |
1988年 | 139篇 |
1987年 | 134篇 |
1986年 | 128篇 |
1985年 | 121篇 |
1984年 | 113篇 |
1983年 | 63篇 |
1982年 | 118篇 |
1981年 | 107篇 |
1980年 | 80篇 |
1979年 | 79篇 |
1978年 | 58篇 |
1977年 | 53篇 |
1976年 | 42篇 |
1973年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Soliton interaction under the influence of higher-order effects 总被引:6,自引:0,他引:6
In this paper, we present exact N-soliton solution by employing simple, straightforward Darboux transformation based on the Lax pair for Hirota equation, a higher-order nonlinear Schrödinger (HNLS) equation. As examples, one- and two-soliton solutions in explicit forms are given and their properties are also analyzed. A bound solution without interaction will be theoretically predicted if one can adjust frequency shift for each soliton appropriately. Further, we obtain the approximate eigenvalues by employing two-soliton solution and discuss analytically the interaction between neighboring solitons under the influence of the higher-order effects. It is shown that the combined effects of the higher-order effects can restrain the interaction between neighboring solitons to some extent. The results are proved by directly solving HNLS equation numerically. 相似文献
93.
Equilibrium Problems with Applications to Eigenvalue Problems 总被引:5,自引:0,他引:5
In this paper, we consider equilibrium problems and introduce the concept of (S)+ condition for bifunctions. Existence results for equilibrium problems with the (S)+ condition are derived. As special cases, we obtain several existence results for the generalized nonlinear variational inequality studied by Ding and Tarafdar (Ref. 1) and the generalized variational inequality studied by Cubiotti and Yao (Ref. 2). Finally, applications to a class of eigenvalue problems are given. 相似文献
94.
一类积分不等式的推广 总被引:1,自引:0,他引:1
对一些基本的积分不等式进行了推广,给出了含有n个无关变元的更广泛的非线性积分不等式.利用所得的不等式讨论了某些非线性积分方程解的有界性. 相似文献
95.
96.
This paper undertakes a systematic treatment of the low regularity local wellposedness and ill-posedness theory in Hs andHs for semilinear wave equations with polynomial nonlinearity in u and (e)u. This ill-posed result concerns the focusing type equations with nonlinearity on u and (e)tu. 相似文献
97.
98.
99.
We discuss the problem of transmitting polarized pulses along optical fibers with variable dispersion. The dissipation and mean dispersion are assumed to be zero, which allows using the model of the vector nonlinear Schrödinger equation. We consider an optical fiber consisting of arms of equal length, which is assumed to be large. We propose an asymptotic recursive procedure for calculating the amplitude and the phase of an optical pulse propagating along the optical cable with variable dispersion. 相似文献
100.
We establish a relation between stable distributions in probability theory and the fractional integral. Moreover, it turns out that the parameter of the stable distribution coincides with the exponent of the fractional integral. It follows from an analysis of the obtained results that equations with the fractional time derivative describe the evolution of some physical system whose time degree of freedom becomes stochastic, i.e., presents a sum of random time intervals subject to a stable probability distribution. We discuss relations between the fractal Cantor set (Cantor strips) and the fractional integral. We show that the possibility to use this relation as an approximation of the fractional integral is rather limited. 相似文献