全文获取类型
收费全文 | 926篇 |
免费 | 39篇 |
国内免费 | 2篇 |
专业分类
化学 | 654篇 |
晶体学 | 1篇 |
力学 | 13篇 |
数学 | 186篇 |
物理学 | 113篇 |
出版年
2023年 | 9篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 25篇 |
2019年 | 25篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 34篇 |
2015年 | 29篇 |
2014年 | 27篇 |
2013年 | 36篇 |
2012年 | 50篇 |
2011年 | 53篇 |
2010年 | 35篇 |
2009年 | 37篇 |
2008年 | 62篇 |
2007年 | 65篇 |
2006年 | 51篇 |
2005年 | 60篇 |
2004年 | 40篇 |
2003年 | 48篇 |
2002年 | 31篇 |
2001年 | 20篇 |
2000年 | 27篇 |
1999年 | 20篇 |
1998年 | 13篇 |
1997年 | 13篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1979年 | 4篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1962年 | 3篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1920年 | 2篇 |
排序方式: 共有967条查询结果,搜索用时 797 毫秒
51.
The fluorescence of thiazole orange as artificial base in PNA was investigated in a nearest neighbour analysis; library-to-library hybridisation allowed the identification of probe sequences suitable for homogeneous DNA detection. 相似文献
52.
We demonstrate the controlled coherent transport and splitting of atomic wave packets in spin-dependent optical lattice potentials. Such experiments open intriguing possibilities for quantum state engineering of many body states. After first preparing localized atomic wave functions in an optical lattice through a Mott insulating phase, we place each atom in a superposition of two internal spin states. Then state selective optical potentials are used to split the wave function of a single atom and transport the corresponding wave packets in two opposite directions. Coherence between the wave packets of an atom delocalized over up to seven lattice sites is demonstrated. 相似文献
53.
The variability of carbon-carbon single bonds by steric and electronic effects is probed by DFT calculations of sterically crowded bicyclo[1.1.0]butanes and their radical cations. The interplay of sterics and electronics on the gradual weakening and breaking of bonds was studied by investigating bridgehead substitution in 1,3-di-tert-butylbicyclo[1.1.0]butane and 2,2',4,4'-tetramethyl-1,3-di-tert-butylbicyclo[1.1.0]butane and geminal substitution in 2,2'-di-tert-butylbicyclo[1.1.0]butane and 2,2',4,4'-tetra-tert-butylbicyclo[1.1.0]butane. Bridgehead substitution leads to a lengthening of the central bond, whereas bisubstitution on the geminal carbon leads to a shortening of this bond due to a Thorpe-Ingold effect. Although the character of the central bond can be modulated by substitution and electron transfer over a range of 0.35 A, the state forbidden ring planarization does not occur. Sterically crowded bicyclo[1.1.0]butane radical cations are therefore promising candidates for the investigation of extremely long carbon-carbon single bonds. 相似文献
54.
55.
56.
57.
Daniel Lenz Norbert Peyerimhoff Olaf Post Ivan Veselić 《Japanese Journal of Mathematics》2008,3(1):121-161
We first analyze the integrated density of states (IDS) of periodic Schrödinger operators on an amenable covering manifold. A criterion for the continuity of the IDS at a prescribed energy is given along with examples of operators with both continuous and discontinuous IDS. Subsequently, alloy-type perturbations of the periodic operator are considered. The randomness may enter both via the potential and the metric. A Wegner estimate is proven which implies the continuity of the corresponding IDS. This gives an example of a discontinuous “periodic” IDS which is regularized by a random perturbation. 相似文献
58.
59.
60.