全文获取类型
收费全文 | 92篇 |
免费 | 11篇 |
国内免费 | 12篇 |
专业分类
化学 | 35篇 |
晶体学 | 1篇 |
力学 | 23篇 |
数学 | 43篇 |
物理学 | 13篇 |
出版年
2023年 | 3篇 |
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有115条查询结果,搜索用时 15 毫秒
1.
Yi Han Zibo Xue Dr. Guangwu Li Dr. Yanwei Gu Dr. Yong Ni Dr. Shaoqiang Dong Prof. Chunyan Chi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):9111-9116
Incorporation of a non-hexagonal ring into a nanographene framework can lead to new electronic properties. During the attempted synthesis of naphthalene-bridged double [6]helicene and heptagon-containing nanographene by the Scholl reaction, an unexpected azulene-embedded nanographene and its triflyloxylated product were obtained, as confirmed by X-ray crystallographic analysis and 2D NMR spectroscopy. A 5/7/7/5 ring-fused substructure containing two formal azulene units is formed, but only one of them shows an azulene-like electronic structure. The formation of this unique structure is explained by arenium ion mediated 1,2-phenyl migration and a naphthalene to azulene rearrangement reaction according to an in-silico study. This report represents the first experimental example of the thermodynamically unfavorable naphthalene to azulene rearrangement and may lead to new azulene-based molecular materials. 相似文献
2.
A lattice Boltzmann model for the fractional sub‐diffusion equation is presented. By using the Chapman–Enskog expansion and the multiscale time expansion, several higher‐order moments of equilibrium distribution functions and a series of partial differential equations in different time scales are obtained. Furthermore, the modified partial differential equation of the fractional sub‐diffusion equation with the second‐order truncation error is obtained. In the numerical simulations, comparisons between numerical results of the lattice Boltzmann models and exact solutions are given. The numerical results agree well with the classical ones. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
3.
Dr. Guangwu Li Prof. Taisuke Matsuno Yi Han Dr. Hoa Phan Shaofei Wu Dr. Qing Jiang Ya Zou Prof. Hiroyuki Isobe Prof. Jishan Wu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9814-9822
Synthesis of fully conjugated cyclophanes containing large-size polycyclic aromatics is challenging. Now, three benzidine-linked, hexa-peri-hexabenzocoronene (superbenzene)-based ortho-, para-, and meta-cyclophanes are synthesized through intermolecular Yamamoto coupling reaction of structurally pre-organized precursors. Subsequent oxidative dehydrogenation gave the corresponding quinoidal benzidine-linked cyclophanes. Their geometries were confirmed by X-ray crystallographic analysis and their electronic properties were investigated by electronic absorption, cyclic voltammetry, and DFT calculations. The quinoidal benzidine-linked cyclophanes show thermally populated paramagnetic activity with a relatively large singlet-triplet energy gap. Two enantiomers for the ortho-cyclophanes ( 1-NH and 1-N ) were isolated and their chiral figure-of-eight macrocyclic structures were identified. The cage-like cyclophanes 2-NH and 3-NH with concave surface can selectively encapsulate fullerene C70. 相似文献
4.
Yi Han Zibo Xue Guangwu Li Yanwei Gu Yong Ni Shaoqiang Dong Chunyan Chi 《Angewandte Chemie (International ed. in English)》2020,59(23):9026-9031
Incorporation of a non‐hexagonal ring into a nanographene framework can lead to new electronic properties. During the attempted synthesis of naphthalene‐bridged double [6]helicene and heptagon‐containing nanographene by the Scholl reaction, an unexpected azulene‐embedded nanographene and its triflyloxylated product were obtained, as confirmed by X‐ray crystallographic analysis and 2D NMR spectroscopy. A 5/7/7/5 ring‐fused substructure containing two formal azulene units is formed, but only one of them shows an azulene‐like electronic structure. The formation of this unique structure is explained by arenium ion mediated 1,2‐phenyl migration and a naphthalene to azulene rearrangement reaction according to an in‐silico study. This report represents the first experimental example of the thermodynamically unfavorable naphthalene to azulene rearrangement and may lead to new azulene‐based molecular materials. 相似文献
5.
Guangwu Li Taisuke Matsuno Yi Han Hoa Phan Shaofei Wu Qing Jiang Ya Zou Hiroyuki Isobe Jishan Wu 《Angewandte Chemie (International ed. in English)》2020,59(24):9727-9735
Synthesis of fully conjugated cyclophanes containing large‐size polycyclic aromatics is challenging. Now, three benzidine‐linked, hexa‐peri‐hexabenzocoronene (superbenzene)‐based ortho‐, para‐, and meta‐cyclophanes are synthesized through intermolecular Yamamoto coupling reaction of structurally pre‐organized precursors. Subsequent oxidative dehydrogenation gave the corresponding quinoidal benzidine‐linked cyclophanes. Their geometries were confirmed by X‐ray crystallographic analysis and their electronic properties were investigated by electronic absorption, cyclic voltammetry, and DFT calculations. The quinoidal benzidine‐linked cyclophanes show thermally populated paramagnetic activity with a relatively large singlet‐triplet energy gap. Two enantiomers for the ortho‐cyclophanes ( 1‐NH and 1‐N ) were isolated and their chiral figure‐of‐eight macrocyclic structures were identified. The cage‐like cyclophanes 2‐NH and 3‐NH with concave surface can selectively encapsulate fullerene C70. 相似文献
6.
[reaction: see text] Olefin cross-metathesis has been used to prepare alpha-C-galactosylceramide derivatives. The metathesis process merged vinyl and propenyl glycosides with vinyl derivatives of phytosphingosine. The use of ethylene enhanced the yield of the methathesis step. 相似文献
7.
Pan Hong Huang Xiaoxiao Zhang Rui Zhang Tao Chen Yanting Hoang Tuan K. A. Wen Guangwu 《Journal of Solid State Electrochemistry》2018,22(11):3557-3568
Journal of Solid State Electrochemistry - With up to fivefold higher in energy density vs. lithium-ion battery, lithium–sulfur (Li–S) battery is a compelling energy storage system,... 相似文献
8.
A lattice Boltzmann model with higher‐order accuracy for the wave motion is proposed. The new model is based on the technique of the higher‐order moment of equilibrium distribution functions and a series of lattice Boltzmann equations in different time scales. The forms of moments are derived from the binary wave equation by designing the higher‐order dissipation and dispersion terms. The numerical results agree well with classical ones. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
9.
In this paper, we propose a new lattice Boltzmann model for the compressible Euler equations. The model is based on a three‐energy‐level and three‐speed lattice Boltzmann equation by using a method of higher moments of the equilibrium distribution functions. In order to obtain second‐order accuracy, we employ the ghost field distribution functions to remove the non‐physical viscous parts. We also use the conditions of the higher moment of the ghost field equilibrium distribution functions to obtain the equilibrium distribution functions. In the numerical examples, we compare the numerical results of this scheme with those obtained by other lattice Boltzmann models for the compressible Euler equations. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
一阶模糊谓词逻辑公式的解释模型真度理论及其应用 总被引:5,自引:0,他引:5
基于一阶模糊谓词逻辑公式的有限和可数解释真度的理论,引入了一阶模糊谓词逻辑公式的解释模型及解释模型真度的概念,并讨论了它们的一系列性质及其在近似推理中的应用. 相似文献