全文获取类型
收费全文 | 505篇 |
免费 | 45篇 |
国内免费 | 81篇 |
专业分类
化学 | 536篇 |
力学 | 11篇 |
综合类 | 5篇 |
数学 | 20篇 |
物理学 | 59篇 |
出版年
2021年 | 1篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 29篇 |
2013年 | 47篇 |
2012年 | 45篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 20篇 |
2007年 | 19篇 |
2006年 | 15篇 |
2005年 | 18篇 |
2004年 | 28篇 |
2003年 | 35篇 |
2002年 | 85篇 |
2001年 | 193篇 |
2000年 | 31篇 |
1999年 | 21篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有631条查询结果,搜索用时 15 毫秒
521.
Xin Cheng LIAO Xing Wang WANG Jing Chao TAO* Department of Chemistry Zhengzhou University Zhengzhou 《中国化学快报》2002,13(10)
Crown compounds offer a variety of interesting functions based on their specific bindings of organic guest species1,2. In particular, they can act as carriers in ion- extraction, membrane transport, and phase-transfer reactions. In contrast to the large variety of synthetic ionophores for cation transport, there are only a few examples of synthetic anion transport ionophores. Therefore, it appears highly desirable to search for a new class of ionophores with excellent transport abilities fo… 相似文献
522.
HE Feng-qi WANG Bao-lei LI Zheng-ming* Elemento-Organic Chemistry Institute State-Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin P. R. China 《高等学校化学研究》2006,(6)
IntroductionPlants have a more extensive biosynthetic capacitythan animals, which is attributed to the fact that ani-mals rely on their diet for the supply of many biochemi-cal compounds and their precursors. Owing to thisdifference, plants contain numero… 相似文献
523.
Ying DU Wen Jun CHEN Sheng Ying QIN* Department of Chemistry Sichuan University Chengdu 《中国化学快报》2004,15(10)
The fission product 137Cs accounts for a large fraction of the radioactivity in high-levelnuclear waste (HLW). Because of the hazard to environment and the widespreadapplication of 137Cs gamma radiatior1, a need has arisen to develop improved methods forthe removal and recovery of radiocesium from these wastes. Reports have shown thatsome calixcrown compounds may be highly selective for Cs cation2, but, since thesynthesis of them is difficult and the cost is high, it might obviate their use… 相似文献
524.
Zhi Hui HE Wen Rui JIN* School of Chemistry Chemical Engineering Shandong University Jinan 《中国化学快报》2002,13(9):871-873
Capillary electrophoretic immunoassay (CEIA) is a new analytical technique1,2. In CEIA, the detection methods were UV absorbance detection1 and laser induced fluorescence detection (LIF)2. However, The UV detection is lack of sensitivity. The LIF is difficult to use due to its high cost, and furthermore, most biological fluids are strongly luminescent when excited by the laser in the blue or green region of the spectrum. In our present work, a capillary electrophoretic enzyme immuno… 相似文献
525.
Su Qin HAN Er Bao LIU Hua LI* Institute of Analytical Science Northwest University Xi’an School of Chemistry Material Science Shanxi Normal University Linfen College of Chemistry Life Science Tianjin Normal University Tianjin 《中国化学快报》2005,(8)
Tetracycline antibiotics (TCs) are active against a wide range of gram-positive and gram-negative bacteria, being extensively used in human and veterinary medicine to treat and prevent bacterial infections1. Among the TCs, TC, OTC and CTC are commercially available and permitted for human administration. However, the degradation products occurring in storage conditions might induce potential adverse effects. Thus, many studies have focused on the development of a rapid, sensitive and reli… 相似文献
526.
Qixiang Wang* Guoqing Ning Fei Wei Guohua Luo Department of Chemical Engineering Tsinghua University Beijing P. R. China *Author to whom correspondence should be addressed. 《中国颗粒学报》2003,(6)
1. Introduction Carbon nanotubes (CNTs), a kind of the most advanced nanomaterials with novel properties and promising for many applications, have aroused great interest of the world in a number of research fields (Iijima, 1991; Baughman et al., 2002; Iijima & Ichihashi, 1993; Rao & Govindaraj, 2002; Rueckes et al., 2000; Adrian et al., 2001; Javey et al., 2003). Catalytic chemical vapor deposition (CCVD) is re-garded as the most suitable method for the preparation of microstructured CN… 相似文献
527.
IntroductionThispaperisconcernedwiththenumericalsolution ,byfinitedifferencemethod ,ofthefollowingsingularlyperturbednonlocalboundaryvalueproblem :Lu≡-εu″ +a(x)u=f(x) ( 0 <x<l) ,( 1 )L0 u≡-εu′( 0 ) +γu( 0 ) =μ0 , ( 2 )L1u≡u(l) -δu(d) =μl ( 0 <d<l) ,( 3 )whereεisasmallpositiveparameter,… 相似文献
528.
Tong Wen WANG Le Rong DAI * Institute of Physical Chemistry Peking University Beijing Department of Chemistry Yunnan Normal University Kunming 《中国化学快报》2000,11(12)
In 1992, Mobil researchers introduced a novel concept in the synthesis of mesoporous silicas (M41S)1,2 by using a self-assembled molecular array of surfactant molecules as structure-directing template. Depending on the shape of their templates and the respective resulting pore structure, the M41S family was identified : MCM-41(hexagonal), MCM-48(cubic), and other species. MCM-41 with honeycomb arrays of nonintersecting channels was shown to be the easiest to synthesize1. MCM-48 containin… 相似文献
529.
Ze Lin LI* Bin REN Chun Xing SHE Xiao Ming XIAO Zhong Qun TIAN* Department of Chemistry Hunan Normal University Changsha State Key Laboratory for Physical Chemistry of Solid Surfaces Department of Chemistry Xiamen University Xia 《中国化学快报》2001,(10)
The research of electrocatalytic oxidation of small organic molecules such as methanol, formaldehyde and formic acid has been fascinating electrochemists for more than thirty years, owing to its significance in energy conversion and reaction mechanisms. The surface adsorbed species involved in these electrocatalytic reactions, especially reactive and poisoning intermediates, have been investigated by electrochemical, spectroscopic and other physicochemical methods1. However, Raman spectrosco… 相似文献
530.
Gang Li 《高等学校计算数学学报(英文版)》2007,16(4):358-369
The Helmholtz equation is sometimes supplemented by conditions that include the specification of the boundary value of the divergence of the unknown.In this paper, we study the vector Helmholtz problem in domains of both C~(1,1)and Lipschitz.We es- tablish a rigorous variational analysis such as equivalence,existence and uniqueness. And we propose finite element approximations based on the uncoupled solutions.Fi- nally we present a convergence analysis and error estimates. 相似文献