全文获取类型
收费全文 | 81篇 |
免费 | 3篇 |
专业分类
化学 | 70篇 |
数学 | 7篇 |
物理学 | 7篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2019年 | 4篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有84条查询结果,搜索用时 0 毫秒
21.
Aparicio S Alcalde R Dávila MJ García B Leal JM 《The journal of physical chemistry. B》2008,112(36):11361-11373
This work reports on the properties and structure of N-methyl-2-pyrrolidone in binary and ternary liquid mixtures with water and/or methanol. A comprehensive set of thermophysical properties have been measured at 298.15 K and 0.1 MPa over the whole composition range. On the basis of the derived excess and mixing properties, the fluid structure was analyzed by looking into the forces and geometry factors that effectively control the mixture behavior. Application of the inverted Kirkwood-Buff theory provides a reasonable link between the macroscopic properties and the microscopic features. A density functional theory computation was carried out to analyze the structure and energy features of the hydrogen bonded complexes formed between the components. Use of semiempirical models in the framework of molecular-based equations of state according to the PC-SAFT approach led to unsatisfactory predicted thermophysical properties. The conclusions arrived at give away the existence of strong heteroassociations and hydrogen bonding self-associations that determine the complex nature of the fluid structure. 相似文献
22.
Fernando Alcalde Cuesta María P. Fernández de Córdoba 《Monatshefte für Mathematik》2011,75(1):389-414
Lyons has defined an average number of branches per vertex of an infinite locally finite rooted tree. This number has an important
role in several probabilistic processes such as random walk and percolation. In this paper, we extend the notion of branching
number to any measurable graphed pseudogroup of finite type acting on a probability space. We prove that such a pseudogroup
is Liouvillian (i.e. almost every orbit does not admit non-constant bounded harmonic functions) if its branching number is
equal to 1. In order to prove that this actually generalizes results of C. Series and V. Kaimanovich on equivalence relations
with polynomial and subexponential growth, we describe an example of minimal lamination whose holonomy pseudogroup has exponential
growth and branching number equal to 1. 相似文献
23.
Fernando Alcalde Cuesta María P. Fernández de Córdoba 《Monatshefte für Mathematik》2011,163(4):389-414
Lyons has defined an average number of branches per vertex of an infinite locally finite rooted tree. This number has an important role in several probabilistic processes such as random walk and percolation. In this paper, we extend the notion of branching number to any measurable graphed pseudogroup of finite type acting on a probability space. We prove that such a pseudogroup is Liouvillian (i.e. almost every orbit does not admit non-constant bounded harmonic functions) if its branching number is equal to 1. In order to prove that this actually generalizes results of C. Series and V. Kaimanovich on equivalence relations with polynomial and subexponential growth, we describe an example of minimal lamination whose holonomy pseudogroup has exponential growth and branching number equal to 1. 相似文献
24.
Patricia Gomez de Santos Alejandro González-Benjumea Angela Fernandez-Garcia Carmen Aranda Yinqi Wu Andrada But Patricia Molina-Espeja Diana M. Maté David Gonzalez-Perez Wuyuan Zhang Jan Kiebist Prof. Katrin Scheibner Prof. Martin Hofrichter Katarzyna Świderek Prof. Vicent Moliner Prof. Julia Sanz-Aparicio Prof. Frank Hollmann Prof. Ana Gutiérrez Prof. Miguel Alcalde 《Angewandte Chemie (International ed. in English)》2023,62(9):e202217372
The hydroxylation of fatty acids is an appealing reaction in synthetic chemistry, although the lack of selective catalysts hampers its industrial implementation. In this study, we have engineered a highly regioselective fungal peroxygenase for the ω-1 hydroxylation of fatty acids with quenched stepwise over-oxidation. One single mutation near the Phe catalytic tripod narrowed the heme cavity, promoting a dramatic shift toward subterminal hydroxylation with a drop in the over-oxidation activity. While crystallographic soaking experiments and molecular dynamic simulations shed light on this unique oxidation pattern, the selective biocatalyst was produced by Pichia pastoris at 0.4 g L−1 in a fed-batch bioreactor and used in the preparative synthesis of 1.4 g of (ω-1)-hydroxytetradecanoic acid with 95 % regioselectivity and 83 % ee for the S enantiomer. 相似文献
25.
Alcalde E Mesquida N Alvarez-Rúa C Cuberes R Frigola J García-Granda S 《Molecules (Basel, Switzerland)》2008,13(2):301-318
The synthesis of a set of 1-aryl-2-aryl(3-pyridyl)ethanones 1-5 and the corresponding ketoximes 6-9 is reported. Structural studies of oximes 6, 7 and 9 were performed in solution using (1)H-NMR and in the solid state by X-ray crystallography, providing evidence of H-bonding networks. The crystal packing was controlled by homomeric intermolecular oxime...oxime H-bond interactions for 6 and cooperative oxime...N(pyridyl) and CH/pi interactions for 7 and 9. 相似文献
26.
Florian Tieves Sbastien Jean‐Paul Willot Morten Martinus Cornelis Harald vanSchie Marine Charlne Rene Rauch Sabry Hamdy Hamed Younes Wuyuan Zhang JiaJia Dong Patricia GomezdeSantos John Mick Robbins Bettina Bommarius Miguel Alcalde Andreas Sebastian Bommarius Frank Hollmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7955-7959
27.
The 1-NH structure for 3-azidoindazole has been demonstrated by the observation of 1H? 1H and 13C? 1H couplings involving the hydrogen atom attached to nitrogen. A comparison between 3-azidoindazole and indazole shows that both compounds have the same tautomeric structure. 相似文献
28.
Mercedes Alvarez Alcalde Alvaro Antelo Aida Jover Francisco Meijide José Vázquez Tato 《Journal of inclusion phenomena and macrocyclic chemistry》2009,63(3-4):309-317
Two βCD dimers (linked by succinic acid, 2, or ethylenediaminetetraacetic acid, EDTA, 3, bridges) and a negatively charged monomer derivative of βCD, 1, have been synthesized and their ability to solubilize cholesterol in aqueous solution was studied. The three compounds exhibit a great capacity in solubilizing cholesterol as, for instance, concentrations up to 6 mM of cholesterol were measured in the presence of 25 mM of 3. The phase-solubility diagrams of the two dimers exhibit A L type profiles while the monomer 1 follows an A P isotherm. The cholesterol/dimer complexes have 1:1 stoicheiometries while monomer 1 forms two complexes with molar ratios of 1:1 and 1:2 (cholesterol/1). The equilibrium constants are K 1:1 = (5.9 ± 0.3) × 104 M?1 and K 1:1 = (8.8 ± 0.2) × 104 M?1 for 2 and 3, respectively, and K 1:1 = 73 ± 19 M?1 and K 1:2 = 204 ± 65 M?1 for 1. The comparison of K 1:1(3) with the product K 1:1 × K 1:2 (1) reveals that a chelate effect in binding the cholesterol by 3 exists. The structure of the cholesterol/3 complex was studied by ROESY experiments and by molecular dynamics simulations. 相似文献
29.
Alcalde M Zumárraga M Polaina J Ballesteros A Plou FJ 《Combinatorial chemistry & high throughput screening》2006,9(10):719-727
Combinatorial saturation mutagenesis -CSM- is a valuable tool for improving enzymatic properties from hot-spot residues discovered by directed enzyme evolution or performing semi-rational studies. CSM coupled to a reliable high-throughput screening assay -coefficient of variance below 10%- has been used to enhance turnover rates in the fungal laccase variant T2 from Myceliophthora thermophila. The influence of the highly conserved pentapeptide 509-513 on the redox potential of blue-copper containing enzymes is well described. We focused combinatorial saturation mutagenesis in residues Ser510 and Leu513. Libraries were constructed in Saccharomyces cerevisiae by in vivo overlap extension -IVOE- of the PCR products. This methodology provides a simple manner to build CSM libraries avoiding extra PCR reactions, by-products formation and in vitro ligation steps. After exploring more than 1,700 clones, mutant (7E1) with approximately 3-fold higher kinetics than parent type was found. 7E1 showed one synonymous mutation (L513L, CGT/TTG) and one beneficial mutation S510G (TCG/GGG) that can not be achieved by conventional error-prone PCR techniques. Mutation S510G seems to affect the C-terminal plug, which modulates the transit of water and oxygen to the trinuclear copper cluster. 相似文献
30.
Dr. Xiaomin Xu Dr. Jacob M. A. van Hengst Yejia Mao Mireia Martinez Sergi Roda Dr. Martin Floor Prof. Victor Guallar Dr. Caroline E. Paul Prof. Dr. Miguel Alcalde Prof. Dr. Frank Hollmann 《Angewandte Chemie (International ed. in English)》2023,62(24):e202302844
A peroxygenase-catalysed hydroxylation of organosilanes is reported. The recombinant peroxygenase from Agrocybe aegerita (AaeUPO) enabled efficient conversion of a broad range of silane starting materials in attractive productivities (up to 300 mM h−1), catalyst performance (up to 84 s−1 and more than 120 000 catalytic turnovers). Molecular modelling of the enzyme-substrate interaction puts a basis for the mechanistic understanding of AaeUPO selectivity. 相似文献