全文获取类型
收费全文 | 1538篇 |
免费 | 16篇 |
国内免费 | 6篇 |
专业分类
化学 | 1420篇 |
晶体学 | 7篇 |
力学 | 2篇 |
数学 | 65篇 |
物理学 | 66篇 |
出版年
2020年 | 6篇 |
2018年 | 6篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 14篇 |
2013年 | 31篇 |
2012年 | 30篇 |
2011年 | 31篇 |
2010年 | 17篇 |
2009年 | 21篇 |
2008年 | 21篇 |
2007年 | 34篇 |
2006年 | 25篇 |
2005年 | 28篇 |
2004年 | 22篇 |
2003年 | 16篇 |
2002年 | 23篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 16篇 |
1991年 | 8篇 |
1990年 | 19篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1986年 | 6篇 |
1985年 | 16篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 12篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1966年 | 76篇 |
1965年 | 129篇 |
1964年 | 143篇 |
1963年 | 123篇 |
1962年 | 125篇 |
1961年 | 146篇 |
1960年 | 124篇 |
1959年 | 62篇 |
排序方式: 共有1560条查询结果,搜索用时 78 毫秒
61.
62.
Ursula Baumann 《Fresenius' Journal of Analytical Chemistry》1964,204(3):230
Ohne Zusammenfassung 相似文献
63.
Ursula Baumann 《Fresenius' Journal of Analytical Chemistry》1964,201(4):292-293
Ohne Zusammenfassung 相似文献
64.
Within density functional theory, a variational particle number approach for rational compound design (RCD) is presented. An expression for RCD is obtained in terms of minimization of a suitably defined energy penalty functional whose gradients are the nuclear and the electronic chemical potential. Using combined quantum and molecular mechanics, a nonpeptidic anticancer drug candidate is designed. 相似文献
65.
Optimization of effective atom centered potentials for london dispersion forces in density functional theory 总被引:1,自引:0,他引:1
von Lilienfeld OA Tavernelli I Rothlisberger U Sebastiani D 《Physical review letters》2004,93(15):153004
We add an effective atom-centered nonlocal term to the exchange-correlation potential in order to cure the lack of London dispersion forces in standard density functional theory. Calibration of this long-range correction is performed using density functional perturbation theory and an arbitrary reference. Without any prior assignment of types and structures of molecular fragments, our corrected generalized gradient approximation density functional theory calculations yield correct equilibrium geometries and dissociation energies of argon-argon, benzene-benzene, graphite-graphite, and argon-benzene complexes. 相似文献
66.
We show that attosecond pulse trains have a natural application in the control of strong field processes. In combination with an intense infrared laser field, the pulse train can be used to microscopically select a single quantum path contribution to a process that would otherwise consist of several interfering components. We present calculations that demonstrate this by manipulating the time-frequency properties of high order harmonics at the single atom level. This quantum path selection can also be used to define a high resolution attosecond clock. 相似文献
67.
Loss S Magistrato A Cataldo L Hoffmann S Geoffroy M Röthlisberger U Grützmacher H 《Angewandte Chemie (International ed. in English)》2001,40(7):1143
The cover picture shows the metalloporphyrin heterodimer [(tpp)Mo$\rm{\mathop{-}^{4}}$Re(oep)](+) with the novel [Mo$\rm{\mathop{-}^{4}}$Re](5+) core. The core represents the first example of a quadruple bond between elements of different triads, thus proving that heterometallic quadruple bonds are not limited to the Group 6 metals. From the space-filling model it is clear that there is no interaction between the stabilizing porphyrin ligands. The ORTEP plot in a projection along the Re-Mo axis emphasizes the perfectly eclipsed geometry of the porphyrins, which is unambiguous proof of the existence of the quadruple bond in the solid state. The diamagnetism and large magnetic anisotropy of the cation, as determined by (1)H NMR spectroscopy, indicate that the quadruple bond is retained in solution. A logical and well-defined synthetic route was used to synthesize the dimer, and can be extended to other metalloporphyrins to generate further novel quadruple bonds (the picture was generated by Marina Boulan, St. Petersburg, Russia), full details are reported by J. P. Collman et al. on p. 1271 ff. 相似文献
68.
69.
70.