全文获取类型
收费全文 | 83篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 64篇 |
晶体学 | 2篇 |
力学 | 3篇 |
数学 | 3篇 |
物理学 | 14篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 9篇 |
2007年 | 2篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1958年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有86条查询结果,搜索用时 19 毫秒
1.
Cecile Veerman Leonard M. C. Sagis Paul Venema Erik van der Linden 《Rheologica Acta》2005,44(3):244-249
To probe the behaviour of fibrillar assemblies of ovalbumin under oscillatory shear, close to the percolation concentration, cp (7.5%), rheo-optical measurements and Fourier transform rheology were performed. Different results were found close to cp (7.3%), compared to slightly further away from cp (6.9 and 7.1%). For 6.9 and 7.1%, a decrease in complex viscosity, and a linear increase in birefringence, n, with increasing strain was observed, indicating deformation and orientation of the fibril clusters. For 7.3%, a decrease in complex viscosity was followed by an increase in complex viscosity with increasing strain, which coincided with a strong increase in n, dichroism, n, and the intensity of the normalized third harmonic (I3/I1). This regime was followed by a second decrease in complex viscosity, where n,n and I3/I1 decreased. In the first regime where the viscosity was decreasing with increasing strain, deformation and orientation of existing clusters takes place. At higher oscillatory shear, a larger deformation occurs and larger structures are formed, which is most likely aggregation of the clusters. Finally, at even higher strains, the clusters break up again. An increase in complex viscosity, n, n and I3/I1 was observed when a second strain sweep was performed 30 min after the first. This indicates that the shear-induced cluster formation and break up are not completely reversible, and the initial cluster size distribution is not recovered after cessation of flow. 相似文献
2.
Charlotte Duval Cécile Nouvel Jean‐Luc Six 《Journal of polymer science. Part A, Polymer chemistry》2014,52(8):1130-1138
Poly(d,l ‐lactide‐co‐glycolide) (PLGA) copolyesters are commonly used in biomedical applications. Researches were carried out on nontoxic or low‐toxic catalysts that are enough efficient to provide short polymerization times, adequate microstructure chains and similar properties than the commercial PLGA materials. In this study, PLGA were synthesized by ring‐opening copolymerization (ROP) using three different catalysts. Stannous octoate is the first catalyst we used, as it is very efficient, even its toxicity is still on debate. Two others low‐toxic catalysts [zinc lactate and bismuth subsalicylate (BiSS)] were also evaluated. The comparison of these ROP was realized in terms of kinetics and control of the polymerization. Then, the influence of the catalyst on the PLGA microstructure chains is reported. Finally, abiotic hydrolytic degradation rate is studied. Results described in this article show that BiSS is one very attractive catalyst to produce low toxic PLGA for biomedical applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1130–1138 相似文献
3.
Carmen Festa Valentina Sepe Paolo Luciano Cecile Débitus Valentina Vellecco 《Tetrahedron》2009,65(50):10424-1496
Two new metabolites, perthamides C and D, have been isolated from the marine sponge Theonella swinhoei. Their structures were determined by interpretation of NMR and ESIMS data. All compounds exhibited in vivo potent anti-inflammatory activity. Biological activity and structural elucidation are reported. 相似文献
4.
Oscar M. Moradei Cecile M. du Mortier Alicia Fernández Cirelli 《Journal of carbohydrate chemistry》2013,32(6):709-719
ABSTRACT The Horner-Wadsworth-Emmons (HWE) reaction was performed on methyl 3,6-di-O-benzoyl-2-deoxy-α-D-glycero-hex-2-enopyranosid-4-ulose (1) with the potassium enolates of dimethyl [(methoxycarbonyl)methyl]phosphonate (2) or diethyl [(ethoxycarbonyl) methyl]phosphonate (3) under different conditions (metallic cation and solvent) in order to study regio- and stereochemical aspects of the reaction. In the presence of lithium ions, no reaction took place. When sodium enolates were employed, 1,2-addition was the main reaction in chelating solvents, whereas the 1,4-adduct is favoured in the less polar, non chelating toluene. Only 1,2-addition was observed with potassium enolates. Evidence of phosphonate-phosphate rearrangements through five membered cyclic intermediates is described. 相似文献
5.
Cecile Canlet Bing M. Fung Frederick Roussel Karine Leblanc Philippe Berdague Jean-Pierre Bayle 《Liquid crystals》2013,40(5):635-641
Mesogenic compounds containing four rings in the core usually have very high melting points. However, when two identical lateral benzyloxy groups are introduced on the same side of one of the central rings, the melting point is lowered dramatically and a large nematic range is retained. This range is affected by the bulkiness of the para-substituents in the lateral rings. Methyl groups can be introduced in the ortho- or meta-positions with a consequent decrease in the melting temperature without much affecting the nematic range. These compounds exhibit a rich solid polymorphism which is certainly related to the effect of the conformations of the lateral substituent on the molecular arrangment in the solid phase. Some preliminary NMR experiments on the nematic phase indicate that the molecular long axis coincides with the core axis, whereas the para-axis of the lateral fragment makes an angle close to the magic angle with respect to the molecular long axis. 相似文献
6.
Fornberg Bengt; Flyer Natasha; Hovde Susan; Piret Cecile 《IMA Journal of Numerical Analysis》2008,28(1):121-142
7.
The evolution of the martensitic twin microstructure in In77.5Tl22.5 single crystals was investigated by atomic force microscopy. During the reverse martensitic transformation the twins gradually flatten to disappear completely at the austenite finish temperature. The experimentally determined temperature dependence of the height of the twin profile agrees with the theoretical predictions of Barsch and Krumhansl. 相似文献
8.
Uwe EilitzChristoph Böttcher Lothar HennigAlois Haas Cecile BoyerKlaus Burger 《Journal of fluorine chemistry》2002,115(2):149-154
Homochiral 2-C-perfluoroalkyl substituted d- and l-riboses were synthesized via Barbier, Grignard and Ruppert type reactions. The influence of the size of the perfluoroalkyl groups, attached to C-2, on the furanose/pyranose as well as on the α-furanose/β-furanose and α-pyranose/β-pyranose ratio in solution was studied. 相似文献
9.
We report quasi-elastic neutron scattering experiments at two resolutions that probe timescales of picoseconds to nanoseconds for the hydration dynamics of water, confined in a concentrated solution of N-acetyl-leucine-methylamide (NALMA) peptides in water over a temperature range of 248 K to 288 K. The two QENS resolutions used allow for a clean separation of two observable translational components, and ultimately two very different relaxation processes, that become evident when analyzed under a combination of the jump diffusion model and the relaxation cage model. The first translational motion is a localized beta-relaxation process of the bound surface water, and exhibits an Arrhenius temperature dependence and a large activation energy of approximately 8 kcal mol(-1). The second non-Arrhenius translational component is a dynamical signature of the alpha-relaxation of more fluid water, exhibiting a glass transition temperature of approximately 116 K when fit to the Volger Fulcher Tamman functional form. These peptide solutions provide a novel experimental system for examining confinement in order to understand the dynamical transition in bulk supercooled water by removing the unwanted interface of the confining material on water dynamics. 相似文献
10.
Olive AG Parkan K Givelet C Michl J 《Journal of the American Chemical Society》2011,133(50):20108-20111
Supramolecular self-assembly using weak interactions under quasi-equilibrium conditions has provided easy access to very complex but often quite fragile molecules. We now show how a labile structure obtained from reversible transition-metal-directed self-assembly of rods and connectors serves as a template that can be converted into a sturdy structure of identical topology and similar geometry. The process consists of Cu(I)-catalyzed replacement of all rods or connectors terminated with pyridines for analogues terminated with ethynyls, converting dative N→Pt(+) bonds into covalent C-Pt bonds. The procedure combines the facility and high yield of reversible self-assembly with the robustness of covalent synthesis. 相似文献