全文获取类型
收费全文 | 186篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 133篇 |
晶体学 | 2篇 |
力学 | 3篇 |
数学 | 7篇 |
物理学 | 49篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2017年 | 4篇 |
2016年 | 1篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 9篇 |
2011年 | 14篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 13篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有194条查询结果,搜索用时 15 毫秒
51.
A.J. Window A. Hentz D.C. Sheppard G.S. Parkinson D.P. Woodruff W. Unterberger T.C.Q. Noakes P. Bailey M.V. Ganduglia-Pirovano J. Sauer 《Surface science》2012,606(21-22):1716-1727
Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~ 200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V′O3V) and vanadyl (….V′O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV′′V ′O3. This result is consistent with the predictions of thermodynamic equilibrium at the surface under the surface preparation conditions, but is at variance with the conclusions of earlier studies of this system that have favoured the vanadyl termination. The results of these previous studies are re-evaluated in the light of the new result. 相似文献
52.
The emerging role of 4D synchrotron X‐ray micro‐tomography for climate and fossil energy studies: five experiments showing the present capabilities at beamline 8.3.2 at the Advanced Light Source 下载免费PDF全文
Marco Voltolini Abdelmoula Haboub Shan Dou Tae-Hyuk Kwon Alastair A. MacDowell Dilworth Y. Parkinson Jonathan Ajo-Franklin 《Journal of synchrotron radiation》2017,24(6):1237-1249
Continuous improvements at X‐ray imaging beamlines at synchrotron light sources have made dynamic synchrotron X‐ray micro‐computed tomography (SXR‐µCT) experiments more routinely available to users, with a rapid increase in demand given its tremendous potential in very diverse areas. In this work a survey of five different four‐dimensional SXR‐µCT experiments is presented, examining five different parameters linked to the evolution of the investigated system, and tackling problems in different areas in earth sciences. SXR‐µCT is used to monitor the microstructural evolution of the investigated sample with the following variables: (i) high temperature, observing in situ oil shale pyrolysis; (ii) low temperature, replicating the generation of permafrost; (iii) high pressure, to study the invasion of supercritical CO2 in deep aquifers; (iv) uniaxial stress, to monitor the closure of a fracture filled with proppant, in shale; (v) reactive flow, to observe the evolution of the hydraulic properties in a porous rock subject to dissolution. For each of these examples, it is shown how dynamic SXR‐µCT was able to provide new answers to questions related to climate and energy studies, highlighting the significant opportunities opened recently by the technique. 相似文献
53.
Xiao Ma Victoria Beltran Georg Ramer Georges Pavlidis Dilworth Y. Parkinson Mathieu Thoury Tyler Meldrum Andrea Centrone Barbara H. Berrie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11778-11782
Oil paints comprise pigments, drying oils, and additives that together confer desirable properties, but can react to form metal carboxylates (soaps) that may damage artworks over time. To obtain information on soap formation and aggregation, we introduce a new tapping‐mode measurement paradigm for the photothermal induced resonance (PTIR) technique that enables nanoscale IR spectroscopy and imaging on highly heterogenous and rough paint thin sections. PTIR is used in combination with μ‐computed tomography and IR microscopy to determine the distribution of metal carboxylates in a 23‐year old oil paint of known formulation. Results show that heterogeneous agglomerates of Al‐stearate and a Zn‐carboxylate complex with Zn‐stearate nano‐aggregates in proximity are distributed randomly in the paint. The gradients of zinc carboxylates are unrelated to the Al‐stearate distribution. These measurements open a new chemically sensitive nanoscale observation window on the distribution of metal soaps that can bring insights for understanding soap formation in oil paint. 相似文献
54.
Reactions of Au(III) with biomolecules are of interest in relation to understanding the mechanism of action of therapeutic gold compounds. NMR investigations of 13C and 15N isotopically‐labelled glycine and alanine show that Au(III) induces deamination and subsequent decarboxylation of both amino acids with the same mechanism. For comparison, reactions of Au(III) with sarcosine and the dicarboxylic acid malonic acid were also investigated. The major intermediates and products have been identified. 相似文献
55.
56.
Iakovos Vittorias Matthew Parkinson Katja Klimke Benoît Debbaut Manfred Wilhelm 《Rheologica Acta》2007,46(3):321-340
The significance of sparse long-chain branching in polyolefines towards mechanical properties is well-known. Topology is a
very important structural property of polyethylene, as is molecular weight distribution. The method of Fourier-transform rheology
(FTR) and melt state nuclear magnetic resonance (NMR) is applied for the detection and quantification of branching topology
(number of branches per molecule), for industrial polyethylenes of various molecular weight and molecular weight distributions.
FT rheology consists of studying the development of higher harmonics contribution of the stress response to a large amplitude
oscillatory shear deformation. In particular, when applying large-amplitude oscillatory shear (LAOS), one observes the development
of mechanical higher harmonic contributions at 3ω
1, 5ω
1,..., in the shear stress response. We correlate the relative intensity, I
3/1, and phase Φ
3 of these harmonics with structural properties of industrial polyethylene, i.e. polymer topology and molecular weight distribution.
Experiments are complemented by numerical simulations, using a multimode differential Pom-pom constitutive model (DCPP formulation),
by fitting to the experimental linear and nonlinear viscoelastic behaviours. Simulation results in the nonlinear regime are
correlated with molecular properties of the “pom-pom” macromolecular architecture. Qualitative agreement is found between
predicted and experimental FT rheology results. 相似文献
57.
58.
Campbell NH Parkinson GN Reszka AP Neidle S 《Journal of the American Chemical Society》2008,130(21):6722-6724
The crystal structure of a complex between the bimolecular human telomeric quadruplex d(TAGGGTTAGGGT)2 and the experimental anticancer drug BRACO-19, has been determined, to 2.5 A resolution. The binding site for the BRACO-19 molecule is at the interface of two parallel-folded quadruplexes, sandwiched between a G-tetrad surface and a TATA tetrad, and held in the site by networks of water molecules. The structure rationalizes the existing structure-activity data and provides a starting-point for the structure-based design of quadruplex-binding ligands 相似文献
59.
Observation of the coexistence of sodium and calcium ions in a DNA G-quadruplex ion channel 总被引:1,自引:0,他引:1
Lee MP Parkinson GN Hazel P Neidle S 《Journal of the American Chemical Society》2007,129(33):10106-10107
60.
One- and two-color, three-pulse photon echo peak shift spectroscopy (1C and 2C3PEPS) was used to estimate the electronic coupling between the accessory bacteriochlorophyll (B) and the bacteriopheophytin (H) in the reaction center of the purple photosynthetic bacterium Rhodobacter sphaeroides as approximately 170 +/- 30 cm-1. This is the first direct experimental determination of this parameter; it is within the range of values found in previously published calculations. The 1C3PEPS signal of the Qy band of the bacteriochlorophyll B shows that it is weakly coupled to nuclear motions of the bath, whereas the 1C3PEPS signal of the Qy band of the bacteriopheophytin, H, shows that it is more strongly coupled to the bath, but has minimal inhomogeneous broadening. Our simulations capture the major features of the data with the theoretical framework developed in our group to separately calculate the response functions and population dynamics. 相似文献