全文获取类型
收费全文 | 199篇 |
免费 | 1篇 |
专业分类
化学 | 77篇 |
晶体学 | 1篇 |
力学 | 9篇 |
数学 | 9篇 |
物理学 | 104篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 15篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 1篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1931年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有200条查询结果,搜索用时 343 毫秒
101.
102.
103.
104.
Justin D. Holmes Jacqueline A. Farrar David J. Richardson David A. Russell John R. Sodeau 《Photochemistry and photobiology》1997,65(5):811-817
Abstract— The bacterium Klebsiella aerogenes produces extracellular particles of cadmium sulfide in the presence of cadmium ions. The photoactivity of these particles has been studied using electron paramagnetic resonance (EPR) spectroscopy. Bacterial samples containing these semiconductor particles were irradiated with visible light in the presence of a spin trap, either phenyl-tert-butylnitrone (PBN) or 5,5-dimethyl-l-pyrroline-N-oxid(eD MPO). The results obtained reveal that a number of radicals, both oxygen and carbon based, are generated. Bacterial samples grown in the absence of cadmium ions exhibit weak, irradiation-independent EPR signals. These bacterially produced radicals are quenched when CdS particles are present. The observation of light-induced radicals provides evidence that the bacterial CdS particles are photoactive, behaving in a similar manner to inorganic CdS particles, and therefore could be used to mediate photocatalytic reactions. 相似文献
105.
Successive oxidation of transition metal(II) aqua complexes (M(II)OH(2) to M(III)OH) is a domain in which proton-coupled electron transfer reactions are extremely common. The mechanism of these PCET reactions-concerted or stepwise-is an important issue in the understanding and design of natural or artificial systems catalyzing the formation of dioxygen by four-electron oxidation of water. Concerted proton-coupled electron transfer from an aqua metal(II) to a hydroxo metal(III) complex requires the close proximity of a proton-accepting group with a pK value between those of the aqua complexes. Otherwise, stepwise electron-proton or proton-electron pathways involving high-energy intermediates are followed. Concerted proton-electron pathways involving water as proton-acceptor or proton-donor group are inefficient. Cyclic voltammetry of the title complex in buffered aqueous solution and re-examination of previous results for the same complex attached to an electrode surface are used to establish these conclusions, which provide a starting point on the route to higher degrees of oxidation, such as those involved in the catalysis of water oxidation. 相似文献
106.
Roach P Shirtcliffe NJ Farrar D Perry CC 《The journal of physical chemistry. B》2006,110(41):20572-20579
Protein adsorption is of major and widespread interest, being useful in the fundamental understanding of biological processes at interfaces through to the development of new materials. A number of techniques are commonly used to study protein adhesion, but few are directly quantitative. Here we describe the use of Nano Orange, a fluorometric assay, to quantitatively assess the adsorption of bovine fibrinogen and albumin onto model hydrophilic (OH terminated) and hydrophobic (CH3 terminated) surfaces. Results obtained using this method allowed the calibration of previously unquantifiable data obtained on the same surfaces using quartz crystal microbalance measurements and an amido black protein assay. Both proteins were found to adsorb with higher affinity but with lower saturation levels onto hydrophobic surfaces. All three analytical techniques showed similar trends in binding strength and relative amounts adsorbed over a range of protein concentrations, although the fluorometric analysis was the only method to give absolute quantities of surface-bound protein. The versatility of the fluorometric assay was also probed by analyzing protein adsorption onto porous superhydrophobic and superhydrophilic surfaces. Results obtained using the assay in conjunction with these surfaces were surface chemistry dependent. Imbibition of water into the superhydrophilic coatings provided greater surface area for protein adsorption, although the protein surface density was less than that found on a comparable flat hydrophilic surface. Superhydrophobic surfaces prevented protein solution penetration. This paper demonstrates the potential of a fluorometric assay to be used as an external calibration for other techniques following protein adsorption processes or as a supplemental method to study protein adsorption. Differences in protein adsorption onto hydrophilic vs superhydrophilic and hydrophobic vs superhydrophobic surfaces are highlighted. 相似文献
107.
108.
We analyse different error propagation mechanisms for conservativeand nonconservative time-integrators of nonlinear Schrödingerequations. We use a geometric approach based on interpretingwaves as relative equilibria. 相似文献
109.
R.L. Aggarwal L.W. Farrar A. Aspuru-Guzik D.L. Polla 《Solid State Communications》2011,151(7):553-556
The absolute Raman cross section σRS of the first-order 519 cm−1 optical phonon in silicon was measured using a small temperature-controlled blackbody for the signal calibration of the Raman system. Measurements were made with a 25-mil thick (001) silicon sample located in the focal plane of a 20-mm effective focal length (EFL) lens using 785-, 1064-, and 1535-nm CW pump lasers for the excitation of Raman scattering. The pump beam was polarized along the [100] axis of the silicon sample. Values of 1.0±0.2×10−27, 3.6±0.7×10−28, and 1.1±0.2×10−29 cm2 were determined for for 785-, 1064-, and 1535-nm excitation, respectively. The corresponding values of the Raman scattering efficiency S are 4.0±0.8×10−6, 1.4±0.3×10−6, and 4.4±0.8×10−8 cm−1 sr−1.The values of the Raman polarizability |d| for 785-, 1064-, and 1535-nm excitation are 4.4±0.4×10−15, 5.1±0.5×10−15, and 1.9±0.2×10−15 cm2, respectively. The values of 4.4±0.4×10−15 and 5.1±0.5×10−15 cm2 for |d| for 785- and 1064-nm excitation, respectively, are 1.3 and 2.0 times larger than the values of 3.5×10−15 and 2.5×10−15 cm2 calculated by Wendel. The Raman polarizability |d| computed using the density functional theory in the long-wavelength limit is consistent with the general trend of the measured data and Wendel’s model. 相似文献
110.
Robert A. Burrow Janaina T. Facco Ernesto S. Lang David H. Farrar Alan J. Lough 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):m7-m9
The structure of the title compound, [PtCl2(C5H5N)(C2H6S)], consists of discrete molecules in which the Pt‐atom coordination is slightly distorted square planar. The Cl atoms are trans to each other, with a Cl—Pt—Cl angle of 176.60 (7)°. The pyridine ligand is rotated 64.5 (2)° from the Pt square plane and one of the Pt—Cl bonds essentially bisects the C—S—C angle of the dimethyl sulfide ligand. In the crystal structure, there are extensive weak C—H⋯Cl interactions, the shortest of which connects molecules into centrosymmetric dimers. A comparison of the structural trans influence on Pt—S and Pt—N distances for PtS(CH3)2 and Pt(pyridine) fragments, respectively, in square‐planar PtII complexes is presented. 相似文献