全文获取类型
收费全文 | 9017篇 |
免费 | 997篇 |
国内免费 | 6277篇 |
专业分类
化学 | 11053篇 |
晶体学 | 124篇 |
力学 | 296篇 |
综合类 | 375篇 |
数学 | 2101篇 |
物理学 | 2342篇 |
出版年
2024年 | 34篇 |
2023年 | 229篇 |
2022年 | 244篇 |
2021年 | 245篇 |
2020年 | 218篇 |
2019年 | 335篇 |
2018年 | 193篇 |
2017年 | 276篇 |
2016年 | 315篇 |
2015年 | 354篇 |
2014年 | 677篇 |
2013年 | 644篇 |
2012年 | 599篇 |
2011年 | 586篇 |
2010年 | 637篇 |
2009年 | 630篇 |
2008年 | 781篇 |
2007年 | 731篇 |
2006年 | 751篇 |
2005年 | 735篇 |
2004年 | 792篇 |
2003年 | 645篇 |
2002年 | 597篇 |
2001年 | 580篇 |
2000年 | 447篇 |
1999年 | 447篇 |
1998年 | 403篇 |
1997年 | 457篇 |
1996年 | 370篇 |
1995年 | 346篇 |
1994年 | 338篇 |
1993年 | 290篇 |
1992年 | 273篇 |
1991年 | 310篇 |
1990年 | 227篇 |
1989年 | 224篇 |
1988年 | 107篇 |
1987年 | 63篇 |
1986年 | 59篇 |
1985年 | 44篇 |
1984年 | 21篇 |
1983年 | 24篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 5篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
一类平面七次多项式系统赤道环的稳定性与极限环分支 总被引:2,自引:0,他引:2
本文研究一类平面七次多项式系统赤道环的稳定性和极限环分支,给出了系统的前12个奇点量公式,可积性条件及在赤道附近存在3个极限环的条件,较为精细地指出了极限环的存在位置。 相似文献
52.
On Polynomial Functions over Finite Commutative Rings 总被引:1,自引:0,他引:1
Jian Jun JIANG Guo Hua PENG Qi SUN Qi Fan ZHANG 《数学学报(英文版)》2006,22(4):1047-1050
Let R be an arbitrary finite commutative local ring. In this paper, we obtain a necessary and sufficient condition for a function over R to be a polynomial function. Before this paper, necessary and sufficient conditions for a function to be a polynomial function over some special finite commutative local rings were obtained. 相似文献
53.
Single Qubit and Its Universal Logic Gate Made of a Heisenberg Spin Cluster with Five Particles 下载免费PDF全文
We investigate an anisotropic Heisenberg spin cluster with five particles controlled by a time-dependent magnetic field. With the algebraic dynamical method, we obtain the exact analytical solution to the time dependent Schr6dinger equation. Based on the analytical solution, it is shown that the system can be used as a universal single qubit logic gate controlled by the strength and frequency of the magnetic field, and the six special single qubit logic gates can be realized physically. We also discuss the anti-decoherence property of the qubit and its logic gates resulted from particle coupling effect and collectivity of the cluster. 相似文献
54.
A Multi-component Matrix Loop Algebra and Its Application 总被引:3,自引:0,他引:3
DONG Huan-He ZHANG Ning 《理论物理通讯》2005,44(6):997-1001
A set of multi-component matrix Lie algebra is constructed. It follows that a type of new loop algebra A^- M-1 is presented. An isospectral problem is established. Integrable multi-component hierarchy is obtained by Tu pattern, which possesses tri-Hamiltonian structures. Furthermore, it can be reduced to the well-known AKNS hierarchy and BPT hierarchy. Therefore, the major result of this paper can be regarded as a unified expression integrable model of the AKNS hierarchy and the BPT hierarchy. 相似文献
55.
G.A.Gamal M.AbouZied A.A.Ebnalwaled 《中国物理快报》2005,22(6):1530-1532
Single crystals of red Tl2S5 were prepared by a special modified vertical Bridgman and Stockbarger technique.This growth was performed in our laboratory. The influences of temperature on the electrical conductivity, Hall mobility, carrier concentration, and thermoelectric power (TEP) were carried out in the temperature range 277-413K. Throughout these measurements, various physical parameters such as effective mass of charge carriers,carrier mobility, diffusion coefficient, and the relaxation time for both majority and minority carriers were found. 相似文献
56.
57.
58.
选用新方法合成了2-碘—N-甲基苯磺酰胺,通过^1H NMR,^13C NMR,^13C DEPT NMR(Distortionless Enhancement by Polarization Transfer NMR)和MS确证的其结构。 相似文献
59.
A new method for indirect determination of cetyl-trimethyl ammonium bromide (CTMAB) with NaCl and NH4SCH by floatation and separation of zinc has been studied.The study shows that Zn(Ⅱ) can associate with NH4SCN and CTMAB to form insoluble ternary ion-association complex,and the precipitate can float on the surface of the liquid phase.A good linear relationship is observed between the floatation yield(E%) of Zn(Ⅱ) and the amount of CTMAB.On the ground,CTMAB Can be indirectly determined by determining E% of Zn(Ⅱ).The results were satisfactory. 相似文献
60.