全文获取类型
收费全文 | 358篇 |
免费 | 27篇 |
国内免费 | 146篇 |
专业分类
化学 | 512篇 |
晶体学 | 8篇 |
数学 | 1篇 |
物理学 | 10篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 15篇 |
2015年 | 16篇 |
2014年 | 15篇 |
2013年 | 50篇 |
2012年 | 25篇 |
2011年 | 17篇 |
2010年 | 18篇 |
2009年 | 16篇 |
2008年 | 27篇 |
2007年 | 28篇 |
2006年 | 26篇 |
2005年 | 33篇 |
2004年 | 23篇 |
2003年 | 28篇 |
2002年 | 15篇 |
2001年 | 18篇 |
2000年 | 15篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有531条查询结果,搜索用时 843 毫秒
121.
J. Nurit J. M. Leloup B. Pauvert O. Doumbia P. Chevallet A. Térol 《Journal of Thermal Analysis and Calorimetry》1995,45(3):535-558
The infrared,1H NMR and X-ray diffraction characteristics of a series of 3-(α-hydroxy-imino-aryl)-1,2,2-trimethyl cyclopentane carboxylate are reported. The thermal analysis of this series has been studied by differential scanning calorimetry. The results show a large variety of thermal behaviours with some of the compounds exhibiting polymorphism and the two types of isomers were detected. 相似文献
122.
M. A. Aramendía V. Borau C. Jiménez J. M. Marinas F. J. Romero 《Reaction Kinetics and Catalysis Letters》1996,58(1):183-191
This paper reports on the synthesis and characterization of various mixed orthophosphates [NaMgPO4, Na4Mg(PO4)2 and NaMg4(PO4)3] obtained from freshly prepared Mg3(PO4)2 gel by using various treatments. The solids exhibit excellent selectivity in the gas-phase conversion of cyclohexanol (CHOL) to cyclohexanone (CHONE). 相似文献
123.
LI Hua-Ming YE Xing-Kai YANG Xiang-Guang WU Yue Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun Jilin S China 《中国化学》1997,15(6):512-527
The catalytic oxidation of cyclohexene to cyclohexanone using Pd(OAc)2/HQ/FePc was investigated in an acidic aqueous solution of acetonitrile. The role of each component of this system in the oxidation of cyclohexene was explored by means of UV-VIS, IR, XPS spectroscopy and cyclic voltammetry, respectively. Based on the experimental results, the mechanism of the oxidation of cyelohexene catalyzed by Pd(OAc)2/HQ/FePc was elucidated. 相似文献
124.
Development of a Novel Homogeneous and Heterogeneous Pd Catalytic System for Organic Transformations
The results of our new finding on homogeneous and heterogeneous palladium catalytic system for oxidation of alcohols and alkenes using molecular oxygen are described together with several successful attempts to make the system recyclable from the viewpoint of environmental and economical concerns. In addition, some novel organic transformations of tert-cyclobutanols and cyclobutanone oximes are also presented where -carbon elimination involving C–C bond fission is a key step. 相似文献
125.
《无机化学与普通化学杂志》2018,644(12-13):585-589
The reaction of Hppko (Hppko = phenyl 2‐pyridyl ketone oxime) and CoCl2 · 6H2O in the CH3OH solvent with the presence of triethylamine (NEt3) at room temperature and the exposure to air resulted in the formation of a new pentanuclear, mixed‐valence cobalt complex with the molecular formula [{CoII(CH3O)3}2{CoIII3(μ3‐O)(ppko)3}Cl2]. X‐ray single crystal analysis displays a trigonal bipyramid configuration with the terminal two CoII ions wrapping an triangle [CoIII3O]7+ core. The intermolecular C–H ··· O and C–H ··· Cl interactions form a 2D network framework. The analysis of magnetic susceptibility revealed the dominant antiferromagnetic interactions and strong orbital contribution of CoII ions. 相似文献
126.
Lorena Martínez Livia Arizaga Donatella Armentano Francesc Lloret Ricardo González Carlos Kremer 《Journal of Coordination Chemistry》2018,71(6):748-762
AbstractTwo new mixed-valence iron complexes with 2-pyridyl oximes, [Fe(mpko)3Fe(H2O)2(NO3)](NO3)·2H2O (1) (mpko? = methyl(2-pyridyl)ketone oximate) and [{Fe(dpko)3}2Fe](ClO4)·4H2O (2) (dpko? = bis(2-pyridyl)ketone oximate), have been prepared by reaction of FeIII with mpkoH in methanol (1) and FeII with dpkoH in methanol/water (2). Dinuclear FeII(low-spin)FeIII(high-spin) and trinuclear FeII(low-spin)FeIII(high-spin)FeII(low-spin) cations are present in the crystal structure of 1 and 2, respectively. Intermolecular hydrogen bonds in 1 lead to weak antiferromagnetic interactions between pairs of neighboring FeIII centers, which allows observation of single-ion zero-field splitting effects. 相似文献
127.
Updated Abraham solvation parameter model correlations are derived for describing the partitioning and solubility behaviour of organic nonelectrolyte solutes and inorganic gases in both anhydrous butanone and cyclohexanone solvents. The butanone and cyclohexanone correlations are based on data sets that contain 103 and 72 experimental data points, respectively. The derived correlations for butanone describe the experimental partitioning and solubility behaviour to within a standard deviation of 0.145 log units. A slightly smaller standard deviation of 0.135 was observed between the experimental and back-calculated values for the cyclohexanone solvent correlation equations. 相似文献
128.
129.
Sung Yun Cho Seung Kyu Kang Jin Hee Ahn Jae Du Ha Joong-Kwon Choi 《Tetrahedron letters》2006,47(51):9029-9033
A convenient and facile one-pot synthesis of 5,6-dihydro-4H-[1,2,4]oxadiazine is described. Treatment of aziridin-1-yl-oximes with Scandium(III) triflate readily afforded 5,6-dihydro-4H-[1,2,4]oxadiazine in the presence of chlorotrimethylsilane. 相似文献
130.
M. R. P. Kurup E. Lukose K. Muraleedharan 《Journal of Thermal Analysis and Calorimetry》2000,59(3):815-825
Iron(III) complexes of o-vanillin oxime have been synthesized and characterized by different physicochemical techniques. The complexes containing
thiocyanate, iodide and sulphate ionshave been subjected to non-isothermal decomposition studies in N2 using TGand DTG techniques. The kinetic parameters for both stages of decomposition of these complexes were evaluated by
weighted least-squares method using the general approach as well as the Coats–Redfern and Horowitz–Metzger equations. The
results indicate that the values of kinetic parameters obtained by these three different approaches agree well.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献