全文获取类型
收费全文 | 117457篇 |
免费 | 25015篇 |
国内免费 | 7359篇 |
专业分类
化学 | 101496篇 |
晶体学 | 764篇 |
力学 | 7085篇 |
综合类 | 580篇 |
数学 | 11588篇 |
物理学 | 28318篇 |
出版年
2024年 | 547篇 |
2023年 | 4953篇 |
2022年 | 3783篇 |
2021年 | 4961篇 |
2020年 | 6907篇 |
2019年 | 4783篇 |
2018年 | 4351篇 |
2017年 | 2657篇 |
2016年 | 8331篇 |
2015年 | 8430篇 |
2014年 | 8535篇 |
2013年 | 9987篇 |
2012年 | 9284篇 |
2011年 | 7394篇 |
2010年 | 7607篇 |
2009年 | 7515篇 |
2008年 | 5436篇 |
2007年 | 4724篇 |
2006年 | 3859篇 |
2005年 | 3342篇 |
2004年 | 2701篇 |
2003年 | 2088篇 |
2002年 | 1867篇 |
2001年 | 1722篇 |
2000年 | 1528篇 |
1999年 | 1690篇 |
1998年 | 1430篇 |
1997年 | 1305篇 |
1996年 | 1377篇 |
1995年 | 1253篇 |
1994年 | 1139篇 |
1993年 | 1106篇 |
1992年 | 885篇 |
1991年 | 752篇 |
1990年 | 627篇 |
1989年 | 567篇 |
1988年 | 495篇 |
1987年 | 455篇 |
1986年 | 389篇 |
1985年 | 403篇 |
1977年 | 361篇 |
1976年 | 411篇 |
1975年 | 514篇 |
1974年 | 520篇 |
1973年 | 341篇 |
1972年 | 396篇 |
1971年 | 375篇 |
1970年 | 567篇 |
1969年 | 431篇 |
1968年 | 467篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
Dr. Guido Goldschmiedt 《Monatshefte für Chemie / Chemical Monthly》1885,6(1):372-403
Ohne Zusammenfassung 相似文献
63.
A novel algorithm, alternatively minimizing coupled vector (COV) resolution error and PARAFAC error algorithm, is proposed in this paper. This algorithm can overcome the problem of slow convergence and is insensitive to the estimation of component number, such problems are unavoidable while using the traditional parallel factors analysis (PARAFAC) algorithm. In other words, this algorithm is capable of improving the computing speed and providing accurate resolutions provided that the number of factors used in the computation is no less than that of the actual underlying ones. The characteristic performances were demonstrated with a novel fluorescence data array. 相似文献
64.
Gallin Peter Prof. Dr. 《ZDM》2003,35(3):110-119
In order to emphasize functional thinking in mathematical education, arguments are brought forward for an early and frequent use of tree diagrams in teaching stochastics. Since set and tree diagrams can be regarded as two sides of the same matter, Bayes’ theorem, which is strongly associated with predicative set diagrams, need not be dealt with explicitly any longer. Set diagrams are replaced by tree diagrams that are labelled in detail and by tree inversion as a functional instrument of dealing with conditioned probabilities. This technique is demonstrated by three typical problems in the context of conditioned probability. Finally, two letters by Pascal to Fermat are analysed in order to illustrate that predicative and functional approaches were already pursued in the early stages of probability calculus in the 17th century. 相似文献
65.
66.
Chen Yongnian 《模糊系统与数学》1995,(1)
ANTIFUZZYVECTORSPACES(Ⅱ)ChenYongnian(DepartmentofMathematics,XinjiangNormalUniversity,830054,Xinjiang,P.R.China)ANTIFUZZYVECT... 相似文献
67.
Two homologous series of mesogenic materials which incorporate a 1,4-tetrafluorophenylene moiety and a terminal cyano- or nitro-substituent have been synthesized by using palladiumcatalysed coupling procedures. The compounds exhibit nematic and/or smectic A phases. 相似文献
68.
69.
70.
Qian-huo Chen 《Journal of Non》2007,353(4):374-378
A sort of decorated nano ZnO organic sols have been successively prepared by pulsed laser ablation at the interface of ZnO target and a flowing liquid containing polymers. It is found that the decorated nano ZnO ethanol sols, the decorated nano ZnO-PS (polystyrene) cyclohexane sols and the decorated nano ZnO-PMMA (polymethyl methacrylate) ethyl butyrate sols all have strong fluorescence emission at 329 nm and 411 nm, 308 nm and 317 nm, and at 330 nm and 400 nm, respectively. The results show the decorating for nano ZnO will intensely affect their luminescence, and the wavelength and intensity of luminescence can be adjusted or controlled by the different decoration. 相似文献