全文获取类型
收费全文 | 2848篇 |
免费 | 453篇 |
国内免费 | 354篇 |
专业分类
化学 | 1356篇 |
晶体学 | 13篇 |
力学 | 69篇 |
综合类 | 31篇 |
数学 | 311篇 |
物理学 | 1875篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 45篇 |
2021年 | 55篇 |
2020年 | 61篇 |
2019年 | 86篇 |
2018年 | 66篇 |
2017年 | 73篇 |
2016年 | 86篇 |
2015年 | 83篇 |
2014年 | 167篇 |
2013年 | 217篇 |
2012年 | 149篇 |
2011年 | 168篇 |
2010年 | 190篇 |
2009年 | 198篇 |
2008年 | 206篇 |
2007年 | 227篇 |
2006年 | 212篇 |
2005年 | 161篇 |
2004年 | 163篇 |
2003年 | 143篇 |
2002年 | 120篇 |
2001年 | 76篇 |
2000年 | 108篇 |
1999年 | 70篇 |
1998年 | 84篇 |
1997年 | 55篇 |
1996年 | 51篇 |
1995年 | 41篇 |
1994年 | 35篇 |
1993年 | 28篇 |
1992年 | 32篇 |
1991年 | 31篇 |
1990年 | 17篇 |
1989年 | 29篇 |
1988年 | 19篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有3655条查询结果,搜索用时 0 毫秒
1.
Back Cover: Reactions of Group 4 Metallocenes with Monosubstituted Acetonitriles: Keteniminate Formation versus CC Coupling (Chem. Eur. J. 8/2015) 下载免费PDF全文
2.
3.
4.
5.
Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)
Zhou Dongmei Zheng Yongnan Du Enpeng Xu Yongjun Zhu Jiazheng Yuan Daqing Wang Zhiqiang Luo Hailong Zuo Yi Ma Ruigang Duan Xiao M. Mihara M. Fukuda K. Matsuta T. Minamisono Zhu Shengyun 《中国科学G辑(英文版)》2004,47(5):531-539
The spin polarized β-emitting nuclei12B (I
π=1+,T
1/2=20.18 ms) were produced by the nuclear reaction11B(d, p)12B and by the selection technique of the incident deuteron energy and the12B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei12B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment
of12B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift. 相似文献
6.
Leonard M Khalilov Ludmila V Parfenova Askhat G Ibragimov Usein M Dzhemilev 《Journal of organometallic chemistry》2004,689(2):444-453
This paper is dedicated to a study of properties of the following novel optically active organoaluminium compounds (OACs): (1S,2S)-l,7,7-trimethyl-2-[(dialkylalumina)oxy]-bicyclo[2.2.1]heptanes and (1S)-N-(dialkylalumina)-6,7-dimethoxy-1-methyl-1,2,3,4- tetrahydroisoquinolines. The synthesis of the chiral OACs was carried out in the reaction of either natural camphor or salsolidine with both AlEt3 and i-Bu2AlH. The main goal of the research was to investigate the stereodifferentiating activity of the chiral OACs in the olefin carbo- and cycloalumination reactions, catalyzed by Cp2ZrCl2. 相似文献
7.
Takanori Shiba 《Tetrahedron letters》2004,45(16):3211-3213
Rhodium-catalyzed carbonylation of 2-alkynylbenzylamines under water-gas shift reaction conditions gives a seven-membered heterocyclic product, 2,4-disubstituted-1,4-dihydrobenz[c]azepin-3-ones, in a good yield. 相似文献
8.
《Magnetic resonance in chemistry : MRC》2003,41(9):731-734
An NMR study of one new and several known abietane diterpenes isolated from the roots of Aegiphila lhotzkyana is described. In addition to 1D NMR, several 2D shift‐correlated NMR pulse sequences (1H–1H‐COSY, NOESY, HMQC and HMBC) were used to establish all the structures, and unambiguously perform the 1H and 13C chemical shift assignments of the new natural diterpene and three derivatives, the NMR data for which have not been reported previously. Revision of current data assignment for teuvincenone H is also suggested. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
9.
V. A. Morozov E. M. Mukhamadiev A. B. Nazimov 《Computational Mathematics and Mathematical Physics》2007,47(12):1885-1892
Regularization of singular systems of linear algebraic equations by shifts is examined. New equivalent conditions for the shift regularizability of such systems are derived. 相似文献
10.
In this article,the Hausdorff dimension and exact Hausdorff measure function of any random sub-self-similar set are obtained under some reasonable conditions.Several examples are given at the end. 相似文献