全文获取类型
收费全文 | 2601篇 |
免费 | 503篇 |
国内免费 | 185篇 |
专业分类
化学 | 145篇 |
晶体学 | 3篇 |
力学 | 155篇 |
综合类 | 28篇 |
数学 | 2028篇 |
物理学 | 930篇 |
出版年
2024年 | 3篇 |
2023年 | 39篇 |
2022年 | 58篇 |
2021年 | 65篇 |
2020年 | 43篇 |
2019年 | 65篇 |
2018年 | 55篇 |
2017年 | 69篇 |
2016年 | 91篇 |
2015年 | 68篇 |
2014年 | 133篇 |
2013年 | 232篇 |
2012年 | 120篇 |
2011年 | 175篇 |
2010年 | 155篇 |
2009年 | 200篇 |
2008年 | 207篇 |
2007年 | 215篇 |
2006年 | 192篇 |
2005年 | 139篇 |
2004年 | 132篇 |
2003年 | 139篇 |
2002年 | 79篇 |
2001年 | 92篇 |
2000年 | 87篇 |
1999年 | 58篇 |
1998年 | 52篇 |
1997年 | 53篇 |
1996年 | 51篇 |
1995年 | 30篇 |
1994年 | 39篇 |
1993年 | 18篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 14篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有3289条查询结果,搜索用时 0 毫秒
11.
Zhimin He 《Journal of Mathematical Analysis and Applications》2004,296(1):97-109
In this paper, by means of a new twin fixed-point theorem in a cone, the existence of at least two positive solutions of m-point boundary value problem for second order dynamic equations on time scales is considered. 相似文献
12.
O. Hugon 《Fiber and Integrated Optics》2003,22(5):283-288
A very simple and efficient technique for the remote sensing of a noncooperative target is presented. This technique is based on the frequency-shifted reinjection of light in a class B laser. Ytterbium- and erbium-doped fiber lasers have both been used to measure displacements with a submicrometric resolution and the vibration power spectrum of an object. 相似文献
13.
14.
The properties of pulsed laser vapor doping on p-Si(1 0 0) with a KrF (248 nm) excimer pulsed laser (248 nm) and BCl3 gas are reported in this paper. The doped samples are characterized by the resistance measured using a four-probe method, since the sheet resistance changes with the carrier concentration of the sample. The doping effects with the variation of laser energy density, pulse number, and the pressure of BCl3 were investigated in terms of the sheet resistance. In this way, the optimized parameters were obtained and used for the positive heavy doping on p-Si(1 0 0) and p-Si(1 1 1). Then, using a square mesh under the above conditions, an image doping was completed. Finally, the metal–semiconductor Ohmic contacts were realized by plating Ag and Cu films on the doped surface. 相似文献
15.
Jiqin Deng 《Journal of Mathematical Analysis and Applications》2007,332(1):475-486
In this paper, by using the fixed point theory, under quite general conditions on the nonlinear term, we obtain an existence result of bounded positive solutions of Schrödinger equations in two-dimensional exterior domains. 相似文献
16.
关于《一类奇异边值问题的正解》的注记 总被引:3,自引:0,他引:3
文[4]通过构造反例断言文[1]中定理的必要性证明有误,本文首先指出文[4] 的这个断言不正确,然后对文[4]中定理2.1作了本质性的改进. 相似文献
17.
Most of the few known examples of compact Riemannian manifolds with positive sectional curvature are the total space of a
Riemannian submersion. In this article we show that this is true for all known examples, if we enlarge the category to orbifold
fibrations. For this purpose we study all almost free isometric circle actions on positively curved Eschenburg spaces, which
give rise to principle orbifold bundle structures, and we examine in detail their geometric properties. In particular, we
obtain a new family of 6-dimensional orbifolds with positive sectional curvature whose singular locus consists of just two
points.
相似文献
18.
Lei Liu 《Journal of Mathematical Analysis and Applications》2007,328(2):1484-1486
In this note, we generalize the inequality about the trace of positive semidefinite matrix trk(AB)?k(trA)k(trB) to Hilbert space, and obtain a relevant inequality about positive trace class operator. 相似文献
19.
考虑一类p-Laplacian算子型泛函微分方程的奇异边值问题,利用锥不动点定理,得到了其正解及多个正解存在的充分条件. 相似文献
20.
Henrik Stetkær 《Journal of Functional Analysis》2007,252(1):1-33
We extend results on square integrable representations of a locally compact group to subrepresentations of a representations induced from a character of a closed subgroup. We do so working in the framework of quotient representations of ∗-algebras. 相似文献