全文获取类型
收费全文 | 83篇 |
免费 | 8篇 |
专业分类
化学 | 63篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 4篇 |
物理学 | 20篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 2篇 |
1997年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
排序方式: 共有91条查询结果,搜索用时 15 毫秒
31.
32.
Goldcamp MJ Edison SE Squires LN Rosa DT Vowels NK Coker NL Krause Bauer JA Baldwin MJ 《Inorganic chemistry》2003,42(3):717-728
A library of tripodal amine ligands with two oxime donor arms and a variable coordinating or noncoordinating third arm has been synthesized, including two chiral ligands based on l-phenylalanine. Their Ni(II) complexes have been synthesized and characterized by X-ray crystallography, UV-vis absorption, circular dichroism, and FTIR spectroscopy, mass spectrometry, and room-temperature magnetic susceptibility. At least one crystal structure is reported for all but one Ni/ligand combination. All show a six-coordinate pseudo-octahedral coordination geometry around the nickel center, with the bis(oxime)amine unit coordinating in a facial mode. Three distinct structure types are observed: (1) for tetradentate ligands, six-coordinate monomers are formed, with anions and/or solvent filling out the coordination sphere; (2) for tridentate ligands, six-coordinate monomers are formed with Ni(II)(NO(3))(2), with one monodentate and one bidentate nitrate filling the remaining coordination positions; (3) for tridentate ligands, six-coordinate, bis(mu-Cl) dimers are formed with Ni(II)Cl(2), with one terminal and two bridging chlorides filling the coordination sphere. The UV-vis absorption spectra of the complexes show that the value of 10 Dq varies according to the nature of the third arm of the ligand. The trend based on the third arm follows the order alkyl/aryl < amide < carboxylate < alcohol < pyridyl < oxime. 相似文献
33.
Fen Qiu John R. Edison Zdenek Preisler Yan‐Fang Zhang Guo Li Aizhao Pan Chih‐Hao Hsu Tracy M. Mattox Peter Ercius Chengyu Song Karen Bustillo Michael A. Brady Edmond W. Zaia Sohee Jeong Jeffrey B. Neaton Shixuan Du Stephen Whitelam Jeffrey J. Urban 《Angewandte Chemie (International ed. in English)》2018,57(40):13172-13176
We demonstrate the guiding principles behind simple two dimensional self‐assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe3O4) NCs into a uniform two‐dimensional bi‐layered superstructure. This self‐assembly process can be controlled by the energy of ligand–ligand interactions between surface ligands on Fe3O4 NCs and Zr6O4(OH)4(fumarate)6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy‐dispersive X‐ray spectroscopy and TEM tomography confirm the hierarchical co‐assembly of Fe3O4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First‐principles calculations and event‐driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand–surface and ligand–ligand interactions. This study opens a new avenue for design and self‐assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self‐assembly process, which could be a guide for designing functional materials with desired structure. 相似文献
34.
Jose Luis Valin Rivera J.M. Monteiro H.M. Lopes M.A.P. Vaz Francisco Palacios Edison Gonalves Gilberto Garcia del Pino Jorge Ricardo Prez 《Optics and Lasers in Engineering》2009,47(11):1139-1144
The purpose of this article is to study the application of the holographic interferometry techniques in the structural analysis of submarine environment. These techniques are widely used today, with applications in many areas. Nevertheless, its application in submarine environments presents some challenges. The application of two techniques, electronic speckle pattern interferometry (ESPI) and digital holography, comparison of advantages and disadvantages of each of them is presented. A brief study is done on the influence of water properties and the optical effects due to suspended particles as well as possible solutions to minimize these problems. 相似文献
35.
Gliseida Z. Melgar Edison P. Wendler Alcindo A. dos Santos André L.M. Porto 《Tetrahedron: Asymmetry》2010,21(18):2271-2274
Hydroxypropargylpiperidones rac-1–3 were efficiently obtained by a one-pot three-component coupling reaction; enantioenriched propargylpiperidones were then obtained by a kinetic resolution process using the lipase from Candida antarctica. Lipase CALB has been shown to efficiently catalyse the stereocontrolled acetylation of hydroxypropargylpiperidones rac-3 by promoting stereodiscrimination at the carbinolic centre. The enzymatic catalytic processes allow the separation of the (S,R)- and (S,S)-3 diastereoisomers into the corresponding acetates produced as a (R,S)- and (R,R)-6 diastereoisomeric pair. The CALB was able to discriminate the stereogenic centre of the secondary (R)-enantiomer of rac-3 according to the Kaslauzkas rule. The remote stereogenic centre was not discriminated by the lipase. The functionalised enantioenriched diastereoisomers obtained are important building blocks in organic synthesis. 相似文献
36.
Osorio E Olson JK Tiznado W Boldyrev AI 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(31):9677-9681
We performed global minimum searches for the B(n) H(n+2) (n=2-5) series and found that classical structures composed of 2c-2e B-H and B-B bonds become progressively less stable along the series. Relative energies increase from 2.9?kcal?mol(-1) in B(2) H(4) to 62.3?kcal?mol(-1) in B(5) H(7). We believe this occurs because boron atoms in the studied molecules are trying to avoid sp(2) hybridization and trigonal structure at the boron atoms, as in that case one 2p-AO is empty, which is highly unfavorable. This affinity of boron to have some electron density on all 2p-AOs and avoiding having one 2p-AO empty is a main reason why classical structures are not the most stable configurations and why multicenter bonding is so important for the studied boron-hydride clusters as well as for pure boron clusters and boron compounds in general. 相似文献
37.
Alexander C. Edison Stephen G. Naculich 《Nuclear Physics B》2012,858(3):488-501
Color-ordered amplitudes for the scattering of n particles in the adjoint representation of SU(N) gauge theory satisfy constraints arising solely from group theory. We derive these constraints for n=5 at all loop orders using an iterative approach. These constraints generalize well-known tree-level and one-loop group theory relations. 相似文献
38.
39.
Fabio Simonelli F.A. Marques Alberto Wisniewski Jr. Edison P. Wendler 《Tetrahedron letters》2004,45(43):8099-8101
The oxazoline cyanocuprates addition to conjugated cyanoalkenes, was shown to be an efficient method for the synthesis of a variety of γ-cyanooxazolines, interesting intermediates with different, but convertible, functions in a symmetrical position. 相似文献
40.
We present an application of a recently developed dynamic mean field theory to the study of relaxation dynamics in adsorption
and desorption from pore networks. The theory predicts the evolution of density distribution in the system, based on an underlying
free energy functional from static mean field theory and the system evolves to equilibrium or metastable equilibrium states
consistent with the static theory. The theory makes it possible to follow the evolution of the density distribution with time
in response to a change in the bulk pressure or chemical potential. We compare uptake dynamics for a 2D slit pore network
with that in a single slit pore. We see more rapid uptake dynamics in the pore network in some cases, due to the greater access
of the pore space to the bulk. We also observe that the formation of liquid bridges can slow down the mass transfer in the
pore network in certain situations. 相似文献