全文获取类型
收费全文 | 75058篇 |
免费 | 4310篇 |
国内免费 | 8142篇 |
专业分类
化学 | 48303篇 |
晶体学 | 693篇 |
力学 | 3855篇 |
综合类 | 727篇 |
数学 | 12313篇 |
物理学 | 21619篇 |
出版年
2024年 | 118篇 |
2023年 | 705篇 |
2022年 | 1841篇 |
2021年 | 1787篇 |
2020年 | 1803篇 |
2019年 | 1911篇 |
2018年 | 1661篇 |
2017年 | 1927篇 |
2016年 | 2190篇 |
2015年 | 1873篇 |
2014年 | 2660篇 |
2013年 | 5608篇 |
2012年 | 3667篇 |
2011年 | 3616篇 |
2010年 | 3050篇 |
2009年 | 4300篇 |
2008年 | 4664篇 |
2007年 | 5166篇 |
2006年 | 4501篇 |
2005年 | 3737篇 |
2004年 | 3214篇 |
2003年 | 3254篇 |
2002年 | 3514篇 |
2001年 | 2620篇 |
2000年 | 2512篇 |
1999年 | 2101篇 |
1998年 | 1962篇 |
1997年 | 1338篇 |
1996年 | 1289篇 |
1995年 | 1136篇 |
1994年 | 1127篇 |
1993年 | 869篇 |
1992年 | 927篇 |
1991年 | 643篇 |
1990年 | 572篇 |
1989年 | 484篇 |
1988年 | 404篇 |
1987年 | 363篇 |
1986年 | 307篇 |
1985年 | 286篇 |
1984年 | 294篇 |
1983年 | 177篇 |
1982年 | 237篇 |
1981年 | 211篇 |
1980年 | 141篇 |
1979年 | 172篇 |
1978年 | 153篇 |
1977年 | 125篇 |
1976年 | 81篇 |
1973年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
It is shown that the potential perturbation that shifts a chosen standing wave in space is a block of potential barrier and well for every wave bump between neighbouring knots. The algorithms shifting the range of the primary localization of a chosen bound state in a potential well of finite width are as well applicable to the scattering functions if states of the continuous spectrum are considered as bound states normalized to unity but distributed on an infinite interval with vanishing density. The potential perturbations of the same type on the half-axis concentrate the scattering wave at the origin, thus creating a bound state embedded into the continuous spectrum (zero width resonance). 相似文献
112.
Yan Zhibin 《东北数学》1998,(2)
SomeNotesaboutTanaka'sEquationYanZhibin(严质彬)(DepartmentofMathematics,HarbinInstituteofTechnology,Harbin,150001)AbstractLet{Wt... 相似文献
113.
本文是[1,12]的继续,研究描述架中概念的结构;本文讨论后半部分,内容涉及概念内涵与外延的转换,清晰关系的内投影与内变换,概念的结构*以及有关问题的注记。 相似文献
114.
本文首先提出逆(反)对策这一新问题,给出了数学模型;探讨了“奇门遁甲”预测理论(术)中的数学问题;通过系统分析“专门遁甲”预测过程,可知它的预测过程隐含着一个特殊的逆(反)对策问题;最后指出逆(反)对策问题的广泛存在并给出案例分析. 相似文献
115.
Xu Tianzhou 《东北数学》1997,(1)
ModulesoverOperatorAlgebrasandItsModuleMapsXuTianzhou(许天周)(DepartmentofMathematics,NanjingUniersity,Nanjing,210093)AbstractLe... 相似文献
116.
117.
对一类变形的变分不等式:求,使得提出了一类投影收缩算法,并得到了该算法的收敛性及相关性质. 相似文献
118.
A complete study of the spectrum of a finite-dimensional Bose operator is carried out in the paper. The cases in which the
spectrum is discrete or continuous are studied.
Translated fromMatematicheskie Zametki, Vol. 61, No. 6, pp. 835–854, June, 1997.
Translated by A. M. Chebotarev 相似文献
119.
E. Hatta H. Hosoi H. Akiyama T. Ishii K. Mukasa 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,2(3):347-349
We have observed a remarkable two-armed spiral in the collapse process of a floating monolayer at the air-water interface
by phase contrast microscopy. This demonstrates that the floating monolayer as a form of soft condensed matter reorganizes
itself due to a certain kind of macroscopic or collective behavior of molecules as it collapses. This pattern formation is
caused by the breakdown of a critical dynamical balance between the deformation of solid domain and the applied surface pressure.
The fragility as well as the flexibility of the floating monolayer can be associated with the observed pattern growth. There
are also observed interesting, periodically arranged collections of molecules in numerous collapsed regions.
Received: 8 July 1997 / Accepted: 4 November 1997 相似文献
120.
A method employing a wide pore polymeric reversed phase column has been developed for the separation of most of the chlorophylls and related compounds previously described as occurring in marine microalgae. The high selectivity toward molecular shape of this kind of stationary phase has enabled compounds of very similar structure, such as chlorophylls c1, c2 and Mg-divinylpheoporphyrin a5 monomethyl ester, and chlorophyll a and the phytol-substituted chlorophyll c-like pigments, which commonly coelute on monomeric bonded phases, to be resolved in a single run. Some of these pigments, formerly thought to be a single compound, have, in fact, been demonstrated to be groups of two or more. The method has been successfully applied to both algal cultures and natural sea water samples. When visible light absorbance detection was used, the method proved suitable for separation of various carotenoids. 相似文献