全文获取类型
收费全文 | 511篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
化学 | 248篇 |
晶体学 | 2篇 |
力学 | 8篇 |
数学 | 75篇 |
物理学 | 186篇 |
出版年
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 7篇 |
2013年 | 9篇 |
2012年 | 7篇 |
2011年 | 21篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 24篇 |
2007年 | 17篇 |
2006年 | 17篇 |
2005年 | 40篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 17篇 |
2000年 | 13篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1992年 | 4篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1972年 | 4篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1968年 | 7篇 |
1967年 | 3篇 |
1966年 | 5篇 |
1937年 | 3篇 |
排序方式: 共有519条查询结果,搜索用时 15 毫秒
1.
Laurens Kooijman Dr. Matthias Schuster Christian Baumann Simon Jurt Dr. Frank Löhr Dr. Boris Fürtig Prof. Dr. Peter Güntert Prof. Dr. Oliver Zerbe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21151-21158
To achieve efficient proton pumping in the light-driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark-adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side-chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground-state bR. 相似文献
2.
3.
Monika Schuster Robert Inführ Claudia Turecek Jürgen Stampfl Franz Varga Robert Liska 《Monatshefte für Chemie / Chemical Monthly》2006,4(4):843-853
To substitute cross-linked photopolymers in rapid prototyping of mold materials and therefore extend the range of materials
which can be casted, organo-soluble photopolymers were developed. Branched bisalkylacrylamides were suitable as base component
for such formulations, due to their high reactivity, good mechanical properties, and excellent solubility of the formed polymers.
These molding materials were used to prepare cellular biocompatible materials which could be used as bone replacement materials.
Biocompatible crosslinkers based on methacrylates from hydrolyzed gelatine or lactic acid ethyleneglycol blockcopolymers and
commercially available reactive diluents are the base components of such a formulation. Biocompatibility was investigated
by osteoblast-like cells. Cellular biocompatible parts were obtained by thermal polymerization in soluble mould materials
prepared by 3D-photoshaping. 相似文献
4.
Analysis of K-shell excitation spectra of gas-phase molecules containing at least two atoms of either B, C. N. O or F reveals the existence of a striking correlation between the bond length of the atomic pair. the sum of their atomic numbers and the associated α-shape resonance energy. Empirical rules are established which allow the derivation of intramolecular distances with accuracies reliably better than ± 0.05 A from the K-.shell absorption spectrum of one of the atoms in the Molecule. 相似文献
5.
Vladislav?Tomi?i?Email author Vjekoslav?Butorac Jadranka?Viher Vladimir?Simeon 《Journal of solution chemistry》2005,34(6):613-616
The effect of temperature on the π∗←π transition band in the UV absorption spectrum of NO3−(aq) centered at ≈200 nm was studied in the temperature range 10–70 ∘C. The observed temperature independence of this band was in contrast to the significant influence of temperature on the nitrate π∗←n transition reported recently by us. However, taking into account the electronic states involved in both the transitions, it was concluded that this finding was in accordance with our previous assumption that interconversion between spectrally distinct (with respect to π∗←n band) nitrate species included the rupture/formation of hydrogen bond(s) in the hydration shell of the nitrate ion. 相似文献
6.
Ruth-Maria Olk A. Rhr J. Sieler K. Khler R. Kirmse W. Dietzsch E. Hoyer B. Olk 《无机化学与普通化学杂志》1989,577(1):206-216
Coordination Chemistry of 1,3-Dithiole-2-thione-4,5-diselenolate (dsit) — Comparison with 1,3-Dithiole-2-thione-4,5-dithiolate (dmit) Synthesis and properties of metal(II) and/or metal(III) bis-chelates of 1,3-dithiole-2-thione-4,5-diselenolate (dsit) of general type (Bu4N)n[M(dsit)2] (n = 2: M ? Zn, Cd, Hg, Cu, Ni, Pd, Pt; n = 1: M ? Ni, Au) are described. By comparison of the ir, 13C nmr, epr spectra, cyclovoltammetric data, and x-ray investigations (nickel-bis-chelates) of chelates of dsit and those of the chelates of 1,3-dithiole-2-thione-4,5-dithiolate (dmit) the consequences of selenium for sulfur substitution on position 4 and 5 of the heterocyclic ligand are discussed. 相似文献
7.
Caroline Rhr 《无机化学与普通化学杂志》1995,621(9):1496-1500
Novel Suboxide Clusters [O5Ba18] in the Crystal Structures of Ba21M2O5 (M = Si, Ge) The compounds Ba21M2O5 (M = Si, Ge) crystallize in the cubic system with space group Fd3m, lattice constants 2 038.3(10) pm (Si), 2 039.8(9) pm (Ge) resp. and Z = 8. The crystal structure contains isolated Si/Ge atoms coordinated by barium atoms in an icosahedral arrangement. The oxygen atoms are situated in the centers of barium octahedra, four of which share common faces with an additional central octahedron. The novel clusters [O5Ba18] in principal are related to those in the crystal structures of the binary Cs/Rb suboxides. 相似文献
8.
A New High Temperature Form of TiO: H? TiO Single crystals of a high temperature form of TiO (H? TiO) were prepared above 3 000°C by CO2-LASER technique. They crystallize with a hitherto unobserved crystal structure of oxides with titanium in the oxidation state two, isotypic to tungsten carbide with Ti2+ in a trigonal prismatic surrounding by oxygen. Space group D–P6 m2, a = 3.0310, c = 3.2377 Å, Z = 1. 相似文献
9.
10.
V. N. Fedoseyev Y. Jading O. C. Jonsson R. Kirchner K. -L. Kratz M. Krieg E. Kugler J. Lettry T. Mehren V. I. Mishin H. L. Ravn T. Rauscher F. Scheerer O. Tengblad P. Van Duppen A. Wöhr 《Zeitschrift für Physik A Hadrons and Nuclei》1995,353(1):9-10
The continuum part of the6Li (a,a)6Li (1.47–2.47 MeV) scattering data at Ea=50 MeV are extracted in two discretized bins. Coupled-channel calculations are carried out coupling the 1+ ground state of6Li with both the resonant, 3+
1 state, and two non-resonant continuum states. The discretized continuum of the6Li (p,p)6Li (1.75–3.25 MeV) scattering data at Ep=65 MeV are also analysed on the same footing. In both the cases the effect of coupling is found to be minimal. 相似文献