全文获取类型
收费全文 | 1970篇 |
免费 | 65篇 |
国内免费 | 346篇 |
专业分类
化学 | 925篇 |
力学 | 116篇 |
综合类 | 7篇 |
数学 | 428篇 |
物理学 | 905篇 |
出版年
2016年 | 4篇 |
2015年 | 15篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 34篇 |
2011年 | 427篇 |
2010年 | 240篇 |
2009年 | 225篇 |
2008年 | 34篇 |
2007年 | 39篇 |
2006年 | 52篇 |
2005年 | 117篇 |
2004年 | 357篇 |
2003年 | 226篇 |
2002年 | 141篇 |
2001年 | 126篇 |
2000年 | 44篇 |
1999年 | 21篇 |
1998年 | 43篇 |
1997年 | 28篇 |
1996年 | 19篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 36篇 |
1992年 | 39篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 22篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有2381条查询结果,搜索用时 359 毫秒
991.
Study on the Phase Equilibrium of the Ternary System Ethanol-Cesium Carbonate-Water at 10, 30 and 50℃ 总被引:3,自引:0,他引:3
Introduction The salting out effect in the systems of aliphatic al-cohol-water is of industrial interest. The addition of or-ganic solvents to the aqueous solution of a salt normally decreases the solubility of the salt. So the method can be used for salting-out of inorganic salts to improve yield and purity.1-3 However, the phase diagrams of the inves-tigated systems are required as basic data. There are lots of aliphatic alcohol-water systems having been deter-mined. The 1-butanol-water-Na… 相似文献
992.
Kui JIAO Tao YAN G Zeng Jian WANG College of Chemistry Molecular Engineering Qingdao University of Science Technology Qingdao College of Chemistry Chemical Engineering Ocean University of China Qingdao 《中国化学快报》2005,(5)
3,3′,5,5′-Tetramethylbenzidine(TMB)-H2O2-horseradish peroxidase(HRP) voltammetric enzyme linked immunoassay system1 has very high sensitivity, low detection limit and wide detection range for the determination of some plant viruses. However, the understanding of the mechanism of HRP catalyzed by H2O2 oxidizing TMB in this system is of significance. In the previous paper, we have reported the spectroelectro- chemical study of TMB on SnO2: F film optically transparent electrode in the … 相似文献
993.
Thickness and stability of films formed by different surfactants are studied by means of thin film balance (TFB) technique to observe the formation and stability of the films. It is demonstrated that stable Newton black films (NBFs) can be easily obtained with non-ionic surfactants (C12E5, C12G2) than ionic surfactants (C12TAB, C16TAB). Common black film (CBF) was obtained with C16TAB at 5×10-3 mol/L, while the film of C12TAB is unstable. It has been demonstrated that the horizontal forces should also be taken into consideration for explaining film stability. 相似文献
994.
Separation of Felted Explosives by Pressurized Microemulsion Electrokinetic Chromatography 总被引:1,自引:0,他引:1
JingJIANG SuXuanGONG HuWeiLIU YongZHANG YuLinDENG JunLingGU AiQinLUO LiXinWANG 《中国化学快报》2004,15(7):831-833
A new MEEKC method assisted with pressure-driven mobile phase was presented for the separation of felted explosives. Microemulsion solution was composed of 80 mmol/L heptane-120 mmol/L SDS (sodium dodecyl sulphate)-900 mmol/L butanol-10 mmol/L borate at pH 9.4 and a pressure-driven flow of 0.020 mL/min under 1.3 MPa was employed to manipulate the separation. Explosives HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane) and TATB(triamino-trinitrobenzene), which were felted on fluorine rubber F2311 (polytrifluorochlorethylene and polyvinylidene fluoride 1/1 co-polymerization) and F2314 (polytrifluorochlorethylene and polyvinylidene fluoride 4/1 co-polymerization) were well separated with very good peak shapes. 相似文献
995.
996.
CHEN Shuixia ZENG Hanmin Materials Science Institute Zhongshan University Guangzhou China 《Chinese Journal of Reactive Polymers》2002,(2)
1. INTRODUCTION The serious environment pollution and natural resources waste is imperiling human existence and development. To counter the exhaustion and dilution of natural resources, and to prevent environment from further pollution, it is their duty … 相似文献
997.
998.
YanPengZHENG JinYuanMO 《中国化学快报》2004,15(10):1209-1211
Enantiomeric separation of epinephrine and salbutamol was investigated by micellar electrokinetic chromatography employing β-cyclodextrin as chiral additive in ammonium chloride-ammonia solution. The analytes were detected by electrochemistry using gold microelectrode at 0.65 V versus SCE reference electrode. The effects of detection potential,concentration of β-cyclodextrin, concentration of sodium dodecyl sulfate, pH value of electrolyte and applied voltage were discussed. 相似文献
999.
JIANFang-fang SUNPing-ping XIAOHai-lian ZHAOPu-su 《高等学校化学研究》2005,21(4):419-422
The crystal structure of [CoCl ( C7H5N2CH2COPh)4] Br has been determined by means of X-ray crystallography. The molecular structure consists of a discrete [CoCl ( C7H5N2CH2COPh)4] ^ cation and one Br^- anion, in the [CoCl ( C7H5N2CH2COPh)4]^ cation, the coordination geometry of the central Co atom is square-pyramidal with four tertiary N atoms of benzimidazole from four α-( benzimidazol-1-yl) -hypnone ligands in the basal position and one chloride anion in the apical position. In the solid state, [CoCl ( C7H5N2CH2COPh)4]^ and Br^- anion possess intermolecular and intramolecular interactions, which stabilize the crystal structure. The characterization of the title compound were also carried out by using elemeutal analysis, FTIR, UV spectrometries and TG-DSC. 相似文献
1000.