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排序方式: 共有79条查询结果,搜索用时 953 毫秒
11.
We report the implementation of a 3-qubit quantum error-correction code on a quantum information processor realized by the magnetic resonance of carbon nuclei in a single crystal of malonic acid. The code corrects for phase errors induced on the qubits due to imperfect decoupling of the magnetic environment represented by nearby spins, as well as unwanted evolution under the internal Hamiltonian. We also experimentally demonstrate sufficiently high-fidelity control to implement two rounds of quantum error correction. This is a demonstration of state-of-the-art control in solid state nuclear magnetic resonance, a leading test bed for the implementation of quantum algorithms. 相似文献
12.
Dr. Colm Browne William J. Ramsay Dr. Tanya K. Ronson John Medley‐Hallam Prof. Jonathan R. Nitschke 《Angewandte Chemie (International ed. in English)》2015,54(38):11122-11127
The subcomponent self‐assembly of a bent dialdehyde ligand and different cationic and anionic templates led to the formation of two new metallosupramolecular architectures: a FeII4L6 molecular rectangle was isolated following reaction of the ligand with iron(II) tetrafluoroborate, and a M5L6 trigonal bipyramidal structure was constructed from either zinc(II) tetrafluoroborate or cadmium(II) trifluoromethanesulfonate. The spatially constrained arrangement of the three equatorial metal ions in the M5L6 structures was found to induce small‐molecule transformations. Atmospheric carbon dioxide was fixed as carbonate and bound to the equatorial metal centers in both the Zn5L6 and Cd5L6 assemblies, and sulfur dioxide was hydrated and bound as the sulfite dianion in the Zn5L6 structure. Subsequent in situ oxidation of the sulfite dianion resulted in a sulfate dianion bound within the supramolecular pocket. 相似文献
13.
Jose B Mallon CT Forster RJ Keyes TE 《Physical chemistry chemical physics : PCCP》2011,13(32):14705-14714
Spherical cap gold nanocavity arrays with internal diameters of 240, 430, 600 and 820 nm were fabricated on smooth gold films using nanosphere lithography with electrochemical metal deposition. Each array was prepared to the same normalized film thickness to diameter ratios, t(N), of 0.8 ± 0.04. Selective modification of the top surface and interior walls of the gold nanocavity arrays with [Ru(bpy)(2)(Qbpy)](2+), where bpy is 2,2'-bipyridyl and Qbpy is 2,2':4,4':4,4'-quarterpyridyl, was accomplished using a two step adsorption process exploiting the assembled polystyrene spheres as masks. This selective modification approach permitted direct quantitative comparison, for the first time, of plasmonic enhancement of Raman signal and luminescence signal from a monolayer adsorbed at the top surface versus interior walls of all-gold nanocavity arrays. For all cavity sizes, significantly greater Raman and luminescence signal enhancement was observed from [Ru(bpy)(2)(Qbpy)](2+) monolayer adsorbed at the top surface of the array compared with the cavity walls. This disparity in Raman intensity from top versus cavity interior increased as the cavity dimensions decreased. For example, the Raman signal intensity from [Ru(bpy)(2)(Qbpy)](2+) adsorbed at the top surface of 240 nm gold arrays was 170 times greater than SERS signal for this material adsorbed at the interior walls of this array, whereas the relative Raman signal enhancement was 6 from top versus interior for the 820 nm internal radius arrays under 785 nm excitation. The origin of the relatively greater signal at the top surface is discussed in the context of plasmonic distribution at each surface. 相似文献
14.
Hanrahan JR Mewett KN Chebib M Matos S Eliopoulos CT Crean C Kumar RJ Burden P Johnston GA 《Organic & biomolecular chemistry》2006,4(13):2642-2649
A divergent synthesis of both diastereoisomers of (+/-)-(3-aminocyclopentane)alkylphosphinic acid is described. Both diastereoisomers are obtained in 5 steps from the key (+/-)-(3-hydroxycyclopent-1-ene)alkylphosphinate esters which are prepared via a palladium catalysed C-P bond forming reaction. 相似文献
15.
A multiwavelength fiber ring laser comprising of a Lyot filter and hybrid gain medium is presented. A wavelength channel spacing of 100 GHz is achieved by appropriate tuning of the Lyot filter length. Four wavelength channels are simultaneously mode-locked at 10 GHz using an electroabsorption modulator. We highlight how the intra-cavity modulator can affect the stability of the mode-locked laser spectrum when used in conjunction with a Lyot filter. We show that, due its reduced polarization sensitivity, an electroabsorption modulator significantly improves the stability of the mode-locked laser spectrum when compared to using a Mach-Zehnder modulator. 相似文献
16.
基于大规模分子动力学仿真,研究了包含多个晶粒的柱状银纳米线在不同温度下沿轴向拉伸形变的行为。结果表明,当温度低于200 K时,含较大晶粒的体系中位错滑移是其形变的主要机理,最大应力随温度变化不显著。当环境温度高于200 K时,晶粒的滑动逐渐成为形变的主导因素,这一特征在含更小晶粒的体系内表现更明显。同时最大应力随温度显著降低。基于上述结果,进一步讨论了温度对Hall-Petch关系的影响。 相似文献
17.
Rogach AL Gaponik N Lupton JM Bertoni C Gallardo DE Dunn S Li Pira N Paderi M Repetto P Romanov SG O'Dwyer C Sotomayor Torres CM Eychmüller A 《Angewandte Chemie (International ed. in English)》2008,47(35):6538-6549
Colloidal semiconductor nanocrystals are promising luminophores for creating a new generation of electroluminescence devices. Research on semiconductor nanocrystal based light-emitting diodes (LEDs) has made remarkable advances in just one decade: the external quantum efficiency has improved by over two orders of magnitude and highly saturated color emission is now the norm. Although the device efficiencies are still more than an order of magnitude lower than those of the purely organic LEDs there are potential advantages associated with nanocrystal-based devices, such as a spectrally pure emission color, which will certainly merit future research. Further developments of nanocrystal-based LEDs will be improving material stability, understanding and controlling chemical and physical phenomena at the interfaces, and optimizing charge injection and charge transport. 相似文献
18.
A catalytic quantity of ZrCl 4 (20 mol %) was found to be an efficient catalyst for the one-pot esterification and deprotection of (5 S,6 R)-5,6-diacetoxyoct-7-enoic acid in good yields (44-62%) with a lactone formed as a minor byproduct. ZrCl 4 (10-20 mol %) was also sufficient to deprotect 1,3-dioxalane, bis-TBDMS ethers, and diacetate functional groups in excellent yields of up to 93%. ZrCl 4 (1-10 mol %) also promoted diol protection as the acetonide in 90% yield and acted as a trans-esterification catalyst for a range of esters. 相似文献
19.
Priya Gupta David Noone Joseph Galewsky Colm Sweeney Bruce H. Vaughn 《Rapid communications in mass spectrometry : RCM》2009,23(16):2534-2542
This study demonstrates the application of Wavelength‐Scanned Cavity Ring‐Down Spectroscopy (WS‐CRDS) technology which is used to measure the stable isotopic composition of water. This isotopic water analyzer incorporates an evaporator system that allows liquid water as well as water vapor to be measured with high precision. The analyzer can measure HO, HO and HD16O content of the water sample simultaneously. The results of a laboratory test and two field trials with this analyzer are described. The results of these trials show that the isotopic water analyzer gives precise, accurate measurements with little or no instrument drift for the two most common isotopologues of water. In the laboratory the analyzer has a precision of 0.5 per mil for δD and 0.1 per mil for δ18O which is similar to the precision obtained by laboratory‐based isotope ratio mass spectrometers. In the field, when measuring vapor samples, the analyzer has a precision of 1.0 per mil for δD and 0.2 per mil for δ18O. These results demonstrate that the isotopic water analyzer is a powerful tool that is appropriate for use in a wide range of applications and environments. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
20.
Walsh JJ Mallon CT Bond AM Keyes TE Forster RJ 《Chemical communications (Cambridge, England)》2012,48(30):3593-3595
Thin films of polyoxometalates that are sensitized with a Ru(II) metallopolymer generate significant photocurrents in the presence of benzyl alcohol and visible light. Significantly, the photocurrent generated by the tungstate based adduct, α-[P(2)W(18)O(62)](6-), is approximately seven fold larger than that found for the Dawson polyoxomolybdate α-[S(2)Mo(18)O(62)](4-). 相似文献