全文获取类型
收费全文 | 245篇 |
免费 | 16篇 |
国内免费 | 23篇 |
专业分类
化学 | 193篇 |
晶体学 | 2篇 |
力学 | 20篇 |
数学 | 36篇 |
物理学 | 33篇 |
出版年
2023年 | 9篇 |
2022年 | 14篇 |
2021年 | 19篇 |
2020年 | 18篇 |
2019年 | 21篇 |
2018年 | 16篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 22篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2000年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1980年 | 1篇 |
排序方式: 共有284条查询结果,搜索用时 484 毫秒
1.
Europium (Eu+) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu+ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal
was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal
amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions.
The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both
experimentally and theoretically. 相似文献
2.
B.R. Nana Nbendjo R. Yamapi 《Communications in Nonlinear Science & Numerical Simulation》2007,12(8):1550-1559
We study in this paper the active control of a driven class of Van der Pol oscillator which exhibits three limit cycles. We begin by investigating the dynamics and stability analysis of the system under active control. We also analyze the effects of a time periodic perturbation included in the control process. In all these cases the domain of control gain parameters leading to a good control is obtained and verified numerically. 相似文献
3.
4.
Knaggs S Malkin H Osborn HM Williams NA Yaqoob P 《Organic & biomolecular chemistry》2005,3(21):4002-4010
Two novel tyrosinase mediated drug delivery pathways have been investigated for the selective delivery of cytotoxic units to melanocytes from urea and thiourea prodrugs. The synthesis of these prodrugs is reported, as well as oximetry data that illustrate that the targets are substrates for tyrosinase. The stability of each of the prodrugs in (i) phosphate buffer and (ii) bovine serum is discussed, and the urea prodrugs are identified as lead candidates for further studies. Finally, HPLC studies and preliminary cytotoxicity studies in a melanotic and an amelanotic cell line, that illustrate the feasibility of the approach, are presented. 相似文献
5.
Kamoda S Nomura C Kinoshita M Nishiura S Ishikawa R Kakehi K Kawasaki N Hayakawa T 《Journal of chromatography. A》2004,1050(2):211-216
Carbohydrate chains in glycoprotein pharmaceuticals have important roles for the expression of their biological activities. Therefore, development of an assessment method for the carbohydrate chains is an important parameter for quality control of glycoprotein pharmaceuticals such as newly developed therapeutic antibodies. In this report, we applied capillary electrophoresis with laser-induced fluorescence detection to the analysis of carbohydrate chains after releasing with glycoamidase followed by derivatization with 3-aminobenzoic acid. We found that four major oligosaccharides present in antibody pharmaceuticals were successfully separated with good resolution. The present method showed good precision in both migration times and relative peak areas, and gave comparable accuracy with that using a derivatization method with 8-aminopyrene-1,3,6-trisulfonate. 相似文献
6.
Nana Amponsah Kyeremateng Frederic Dumur Philippe Knauth Brigitte Pecquenard Thierry Djenizian 《Comptes Rendus Chimie》2013,16(1):80-88
The electrochemical synthesis of a copolymer electrolyte (PEO-PMMA) into titania nanotubes is described and studied. Compared with the electrochemical systems based on solid electrolytes deposited by top-down techniques, the copolymer/titania nanotube material reveals high electrochemical performance, opening new perspectives for the fabrication of 3D all-solid-state microbatteries. 相似文献
7.
Robert Tchitnga Hilaire Bertrand Fotsin Bonaventure Nana Patrick Hervé Louodop Fotso Paul Woafo 《Chaos, solitons, and fractals》2012,45(3):306-313
This paper shows an experimental evidence of chaos in one of the simplest imaginable autonomous implicit Hartley’s oscillator made simply of a junction field effect transistor (JFET) and a tapped coil. The experimental setup is implemented. The variations of amplitude of the oscillations through the control element are obtained showing the domain of existence of chaos. Phase portraits of the PSpice simulation, of the numerical integration and of the experiment are displayed, confirming a good agreement between theory and praxis. 相似文献
8.
9.
10.