全文获取类型
收费全文 | 138篇 |
免费 | 8篇 |
专业分类
化学 | 102篇 |
力学 | 1篇 |
数学 | 3篇 |
物理学 | 40篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 2篇 |
2008年 | 13篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2004年 | 5篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有146条查询结果,搜索用时 0 毫秒
1.
2.
3.
Virve A. Karttunen Mikko Linnolahti Tapani A. Pakkanen Janne Maaranen Päivi Pitkänen 《Theoretical chemistry accounts》2007,118(5-6):899-913
The performance of quantum chemical methods for geometry prediction of hafnocenes was evaluated. HF, B3LYP and MP2 in combination
with nonrelativistic (MHF) and relativistic (MWB and LANL2DZ) basis sets for hafnium together with standard basis sets 3-21G*,
6-31G* and 6-311G** for other elements were applied. Five basic structural parameters of the optimized structures of the hafnocenes
were compared with experimental crystal structures obtained from the Cambridge structural database. Altogether 80 hafnocenes
were included in the analysis. The results show that relativistic corrections are necessary for Hf atom. However, even the
Hartree–Fock (HF) method, when combined with relativistic pseudopotentials, reproduces the experimental crystal structures
with significant accuracy. The good performance of the HF method can be understood to originate from the absence of significant
near-degeneracy correlations for hafnium. On average, the B3LYP and MP2 methods provide structural parameters somewhat closer
to the experimental ones. 相似文献
4.
5.
Alexander Mutschke Annika Schulz Marko Bertmer Clemens Ritter Antti J. Karttunen Gregor Kieslich Nathalie Kunkel 《Chemical science》2022,13(26):7773
The four compounds A3MO4H (A = Rb, Cs; M = Mo, W) are introduced as the first members of the new material class of the transition oxometalate hydrides. The compounds are accessible via a thermal synthesis route with carefully controlled conditions. Their crystal structures were solved by neutron diffraction of the deuterated analogues. Rb3MoO4D, Cs3MoO4D and Cs3WO4D crystallize in the antiperovskite-like K3SO4F-structure type, while Rb3WO4D adopts a different orthorhombic structure. 2H MAS NMR, Raman spectroscopy and elemental analysis prove the abundance of hydride ions next to oxometalate ions and experimental findings are supported by quantum chemical calculations. The tetragonal phases are direct and wide band gap semiconductors arising from hydride states, whereas Rb3WO4H shows a unique, peculiar valence band structure dominated by hydride states.The synthesis, structures and electronic properties of the first four heteroanionic compounds containing both hydride and transition oxometalate ions are reported. 相似文献
6.
Alena Shlyaykher Marvin Ehmann Dr. Antti J. Karttunen Dr. Frank Tambornino 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(54):13552-13557
The full series of quasibinary alkali-metal selenocyanates was synthesized either by oxidation of the respective cyanides (A=Li−Rb) or by metathesis (A=Cs). For Li[SeCN] only ball-milling and subsequent annealing led to the isolation of the quasibinary selenocyanate. Their structures were refined from single-crystal and powder X-ray data. The respective solid-state IR and Raman spectra were interpreted with the aid of solid-state quantum-mechanical calculations and DSC-TGA measurements allowed for extraction of melting points. Only for Li[SeCN] a possible phase transition was observed that is discussed on the basis of VT-PXRD experiments. It is also the only quasibinary selenocyanate to form a hydrate (Li[SeCN] ⋅ 2H2O). 相似文献
7.
CM Silva MF Duarte ML Mira MH Florêncio K Versluis AJ Heck 《Rapid communications in mass spectrometry : RCM》1999,13(12):1098-1103
Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
8.
9.
10.
We develop a semi-quantitative analytical theory to describe adhesion between two identical planar charged surfaces embedded in a polymer-containing electrolyte solution. Polymer chains are uncharged and differ from the solvent by their lower dielectric permittivity. The solution mimics physiological fluids: It contains 0.1 M of monovalent ions and a small number of divalent cations that form tight bonds with the headgroups of charged lipids. The components have heterogeneous spatial distributions. The model was derived self-consistently by combining: (a) a Poisson-Boltzmann like equation for the charge densities, (b) a continuum mean-field theory for the polymer profile, (c) a solvation energy forcing the ions toward the polymer-poor regions, and (d) surface interactions of polymers and electrolytes. We validated the theory via extensive coarse-grained Molecular Dynamics (MD) simulations. The results confirm our analytical model and reveal interesting details not detected by the theory. At high surface charges, polymer chains are mainly excluded from the gap region, while the concentration of ions increases. The model shows a strong coupling between osmotic forces, surface potential and salting-out effects of the slightly polar polymer chains. It highlights some of the key differences in the behaviour of monomeric and polymeric mixed solvents and their responses to Coulomb interactions. Our main findings are: (a) the onset of long-ranged ion-induced polymer depletion force that increases with surface charge density and (b) a polymer-modified repulsive Coulomb force that increases with surface charge density. Overall, the system exhibits homeostatic behaviour, resulting in robustness against variations in the amount of charges. Applications and extensions of the model are briefly discussed. 相似文献