全文获取类型
收费全文 | 550篇 |
免费 | 23篇 |
国内免费 | 3篇 |
专业分类
化学 | 414篇 |
晶体学 | 11篇 |
力学 | 17篇 |
数学 | 54篇 |
物理学 | 80篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 15篇 |
2019年 | 21篇 |
2018年 | 28篇 |
2017年 | 22篇 |
2016年 | 17篇 |
2015年 | 20篇 |
2014年 | 41篇 |
2013年 | 51篇 |
2012年 | 30篇 |
2011年 | 52篇 |
2010年 | 24篇 |
2009年 | 31篇 |
2008年 | 32篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 19篇 |
2004年 | 18篇 |
2003年 | 17篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1987年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1928年 | 1篇 |
排序方式: 共有576条查询结果,搜索用时 265 毫秒
571.
572.
A new class of polymer gel electrolyte (PGE) was synthesized using acrylamide as host polymer and LiClO4 as dopant. The polymer gel was subjected to electrochemical AC impedance analysis and thermal analysis. The polymer has conductivity
in the order of 10−3 S cm−1 at ambient temperature. Thermogravimetric analysis (TGA) revealed the effect of dopant on host polymer matrix. A supercapacitor
was fabricated using acrylamide based polymer gel electrolyte with activated carbon as electrode material and it was subjected
to various electrochemical techniques like cyclic voltammetry, electrochemical AC impedance analysis and galvanostatic charge–discharge
tests at various current densities. From cyclic voltammetry a specific capacitance of 28 F/g was obtained at a scan rate of
10 mV/s. The capacitor had good self-discharge behavior and good cycle life of more than 10,000 cycles. The coulombic efficiency
was more than 95%. These results indicate that this acrylamide-based polymer gel electrolyte doped with LiClO4 is a potential electrolyte for electric double-layer capacitors (EDLCs). 相似文献
573.
J. Uchil K. P. Mohanchandra K. Ganesh Kumara K. K. Mahesh T. P. Murali 《Physica B: Condensed Matter》1999,270(3-4)
Phase transformation in the near-equiatomic, cold-worked Nitinol, exhibiting shape memory effect, has been investigated through the study of thermal expansion by employing thermomechanical analyser (TMA). The characteristic transformation temperatures determined by this method are compared with those obtained through DSC thermograms. The reliability and sensitivity of the thermal expansion probe have been discussed. The variation of thermal expansion coefficient with temperature in different heat treated samples has been studied in the range 30–120°C. Thermal expansion coefficient is found to be −ve during M↔A transformation and +ve in R↔A transformations. Thermal expansion coefficient in martensitic region in the presence and absence of R-phase has been determined. 相似文献
574.
575.
V. K. Ganesh S. Banumathi D. Velmurugan K. Ravikumar 《Crystal Research and Technology》1999,34(7):929-934
The crystal structure of the title compound was determined from X-ray diffraction data using direct methods. The crystals are tetragonal, a = b = 17.618 (1) A, c = 10.121(2) A, Z = 8, V = 3141.5(7) A3, space group P4(2)/n. The structure was refined by full-matrix least-squares to a final R value of 0.052. The central dihydropyridine ring is nearly planar while the outer two rings adopt half chair conformation. 相似文献
576.
R. Sathyalakshmi V. Kannan R. Bairava Ganesh P. Ramasamy 《Crystal Research and Technology》2007,42(1):78-83
L(+)Glutamic acid hydrochloride [HOOC (CH2)2CH(NH2) COOH·HCl], a monoamino dicarboxylic acid salt of L‐Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L‐Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV‐Vis‐NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L‐Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X‐ray diffraction analysis and it crystallizes in orthorhombic space group P212121. UV‐Vis‐NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L‐Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L‐Glutamic acid hydrochloride crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献