全文获取类型
收费全文 | 529篇 |
免费 | 46篇 |
国内免费 | 119篇 |
专业分类
化学 | 602篇 |
力学 | 7篇 |
综合类 | 5篇 |
数学 | 20篇 |
物理学 | 60篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2014年 | 34篇 |
2013年 | 48篇 |
2012年 | 48篇 |
2011年 | 11篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 22篇 |
2007年 | 22篇 |
2006年 | 18篇 |
2005年 | 21篇 |
2004年 | 43篇 |
2003年 | 39篇 |
2002年 | 87篇 |
2001年 | 194篇 |
2000年 | 32篇 |
1999年 | 20篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1993年 | 1篇 |
1992年 | 3篇 |
排序方式: 共有694条查询结果,搜索用时 31 毫秒
611.
ZHAO Ganqing XIE Jimin* LU Xiaoqing SUN Lu . College of Chemistry & Chemical Engineering Jiangsu University Zhenjiang China . College of Chemistry Chem. Eng. Pingdingshan University Pingdingshan China 《Chinese Journal of Reactive Polymers》2006,(2)
1. INTRODUCTION The partial oxidation of alkenes (forming acids, aldehydes and alcohols) is of considerable interest to the chemical industry. In most cases, more than one oxygenated product is formed from a given starting material and all products are susceptible to complete oxidation to carbon dioxide and water [1]. As mimetic oxygen carrier or oxidation catalyst, metalloporphyrins have been widly studied [2~7]. Among the non-porphyrin systems, the manganese complexes of Schiff base are… 相似文献
612.
A Theoretical Study on the Stereoisomerism in the Complex of Cucurbit[8]uril with 2,6-Bis(4,5-dihydro-1H-imidazol-2-yl)naphthalene 总被引:2,自引:0,他引:2
Ting Wei MU Lei LIU Ke Chun ZHANG Qing Xiang GUO* Department of Chemistry University of Science Technology of China Hefei 《中国化学快报》2001,(9)
Cucurbit[n]urils (CB [n]),macropolycyclic compounds self-assembled from an acid-catalyzed condensation of glycoluril and formaldehyde1, can form inclusion complexes with a number of organic substrates in water2. Usually, CB [6] is used in the studies because of its easy synthesis, and the driving forces for its binding are considered to be the hydrophobic effect and dipole-dipole interactions. CB[n] 1Very recently, Kim et al reported the synthesis of CB [5], CB [7], and CB [8]3. They fou… 相似文献
613.
Lanthanum doped lead zirconate titanate (PLZT) ceramics display excellent electrooptic and photostriction properties because of the existence of cavities in the perovskite structure1-3. The PLZT powders are conventionally prepared by solid state reaction4-5, and the wet chemical methods such as sol-gel techniques are then introduced6-7. However, the homogeneity, morphology and size of the particles, which greatly affect the sinterability and the property of the resulting ceramics, are dif… 相似文献
614.
Synthesis and Crystal Structure of N′-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl)acetohydrazide
LI Wei-hua ZHANG Shu-fang + HOU Bao-rong YU Zhi-gang *. Institute of Oceanology Chinese Academy of Sciences Qingdao P. R. China. College of Chemistry Chemical Engineering Ocean University of China Qingdao P. R. China 《高等学校化学研究》2006,(5)
IntroductionBoth triazole derivatives and Schiff base have beenreported to possess significant antifungal[1—3]and plantgrowth regulatory activities[4—6].Triazole drugs are alsovery common in the medical field,which has given animmense impetus to the res… 相似文献
615.
XU Wei-Xing* 《物理化学学报》2007,(2)
Nano-materials have been extensively studied in the past[1]. The quantum effect makes the properties of nano-materials dif- ferent from that of bulk materials. A few of publications regard- ing the catalysis, electronic structure, and optics of the nanome… 相似文献
616.
Lian De ZHU Ying Xiu LI Guo Yi ZHU* State key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 《中国化学快报》2002,13(11)
Histidine is one of the necessary basic amino acids in biological bases, which often controls the catalytic activity of enzymes and acts in holding the higher structure of proteins. Furthermore, it is also an important ingredient in pharmaceutical preparations used for treatment of hetpatosis and nephropathy. Therefore, the determination of histidine in biological fluids and pharmaceutical preparations is of great importance. Various methods have been proposed for the detection of histidine … 相似文献
617.
618.
Yong Hui WANG Man Zhou ZHU Tao LIU Qing Xiang GUO* Department of Chemistry University of Science Technology of China Hefei 《中国化学快报》2003,(2)
Photoinduced electron-transfer (PET) reactions are fundamentally important in biology and technology1,2. Because of the complexity of PET in biological systems, many simple compounds were synthesized to look into its detailed mechanism3. In previous papers, we reported the electron transfer reaction in the supramolecular systems assembled by mono-6-p-nitrobenzoyl-b-cyclodextrin 6 and naphthalene derivatives in aqueous solution4. In the present paper the intermolecular electron transfer from … 相似文献
619.
Wei WANG Guang Ming XIA Gui Bao XU Zhi Qiang LIU Qi FANG* State Key Laboratory of Crystal Materials Shandong University Jinan School of Chemistry Chemical Engineering Jinan University Jinan 《中国化学快报》2005,16(1):85-88
Organic molecules that can simultaneously absorb two or more photons in reaching theirexcited states have recently been the subject in various photon-electronic fields. Tomeet the criteria for various nonlinear optical applications, such as three-dimensionaloptical storage1 and up-converted lasing2, molecules with large two-photon absorption(TPA) cross-section σ are required and have been synthesized. These dyes generallybelong to the structural modes of D-π-D, A-π-A3 or D-π-A, where D… 相似文献
620.
Xiwei LIU~* Tianping CHEN~ 《数学年刊B辑(英文版)》2007,28(6):737-746
In this paper,the authors investigate the synchronization of an array of linearly coupled identical dynamical systems with a delayed coupling.Here the coupling matrix can be asymmetric and reducible.Some criteria ensuring delay-independent and delay- dependent global synchronization are derived respectively.It is shown that if the coupling delay is less than a positive threshold,then the coupled network will be synchronized.On the other hand,with the increase of coupling delay,the synchronization stability of the network will be restrained,even eventually de-synchronized. 相似文献