全文获取类型
收费全文 | 103篇 |
免费 | 10篇 |
国内免费 | 2篇 |
专业分类
化学 | 68篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 15篇 |
物理学 | 26篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1987年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有115条查询结果,搜索用时 15 毫秒
61.
62.
63.
MM Ottakam Thotiyl H Basit JA Sánchez C Goyer L Coche-Guerente P Dumy S Sampath P Labbé JC Moutet 《Journal of colloid and interface science》2012,383(1):130-139
Multilayers of poly(diallyldimethylammonium chloride) (PDDA) and citrate capped Au nanoparticles (AuNPs) anchored on sodium 3-mercapto-1-propanesulfonate modified gold electrode by electrostatic layer-by-layer assembly (LbL) technique are shown to be an excellent architecture for the direct electrochemical oxidation of As(III) species. The growth of successive layers in the proposed LbL architecture is followed by atomic force microscopy, UV-vis spectroscopy, quartz crystal microbalance with energy dissipation, and electrochemistry. The first bilayer is found to show rather different physico-chemical characteristics as compared to the subsequent bilayers, and this is attributed to the difference in the adsorption environments. The analytical utility of the architecture with five bilayers is exploited for arsenic sensing via the direct electrocatalytic oxidation of As(III), and the detection limit is found to be well below the WHO guidelines of 10ppb. When the non-redox active PDDA is replaced by the redox-active Os(2,2'-bipyridine)(2)Cl-poly(4-vinylpyridine) polyelectrolyte (PVPOs) in the LbL assembly, the performance is found to be inferior, demonstrating that the redox activity of the polyelectrolyte is futile as far as the direct electro-oxidation of As(III) is concerned. 相似文献
64.
65.
The carburizing of titanium (Ti) is accomplished by utilizing energetic ion pulses of a 1.5 kJ Mather type dense plasma focus (DPF) device operated in methane discharge. X-ray diffraction (XRD) analysis confirms the deposition of polycrystalline titanium carbide (TiC). The samples carburized at lower axial and angular positions show an improved texture for a typical (200)TiC plane. The Williamson-Hall method is employed to estimate average crystallite size and microstrains in the carburized Ti surface. Crystallite size is found to vary from ~ 50 to 100 nm, depending on the deposition parameters. Microstrains vary with the sample position and hence ion flux, and are converted from tensile to compressive by increasing the flux. The carburizing of Ti is confirmed by two major doublets extending from 300 to 390 cm-1 and from 560 to 620 cm-1 corresponding to acoustic and optical active modes in Raman spectra, respectively. Analyses by scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS) have provided qualitative and quantitative profiles of the carburized surface. The Vickers microhardness of Ti is significantly improved after carburizing. 相似文献
66.
Wiley P. Kirk Kevin Clark Eduardo Maldonado Nasir Basit Robert T. Bate Gregory F. Spencer 《Superlattices and Microstructures》2000,28(5-6)
Epitaxial films of the wide-bandgap II–VI beryllium chalcogenide semiconductors, BeTe, BeSe, and BeSeTe were grown on arsenic-terminated silicon substrates by MBE. Silicon was also epitaxially regrown on Be-chalcogenide films. Initial structural characterization revealed the desired smooth two-dimensional nature of the layer growth. The composition of BeSeTe ternary films was governed by the Be/Se flux ratio during deposition rather than by the Se/Te flux ratio. The variation in Be/Se flux ratio or in the sticking coefficients due to temperature gradients led to radial compositional inhomogeneity. Current versus temperature measurements of the Be-chalcogenide films at elevated temperatures analyzed assuming thermionic emission over the heterojunction barrier, showed conduction band offsets of 1.2 eV for the BeSe0.41Te0.59/As/Si and 1.3 eV for the BeSe/As/Si heterostructures. At room temperature, current density through BeSe/Si and BeSe0.41Te0.59/Si films was mid-10 − 9A cm − 2at 0.1 MV cm − 1, similar to previously reported values for ZnS/Si, while BeTe/Si films had orders of magnitude higher current density, possibly due to interfacial recombination. 相似文献
67.
Bashir Ahmad Dar Mohd. Mohsin Abdul Basit Mazahar Farooqui 《Journal of Saudi Chemical Society》2013,17(2):177-180
The aim of this work is to develop a cheap and green chemical process and this paper describes the catalytic commotion of locally collected sand in Friedel–Craft's Acylation of aromatic compounds like benzene, anisole, aniline, naphthalene and phenol etc. The sand consists of silica and alumina as analyzed by means of EDAX and acts as a green Lewis acid. The catalyst was also characterized by using BET, SEM, and XRD techniques. 相似文献
68.
Aluri BR Niaz B Kindermann MK Jones PG Heinicke J 《Dalton transactions (Cambridge, England : 2003)》2011,40(1):211-224
A facile synthesis of functionally substituted 2-(hetero)aryl 1,3-benzazaphospholes via nickel- or palladium-catalyzed phosphonylation of N-acyl-2-bromoanilides 1a-k with triethyl phosphite is presented. Anilidophosphonates 2a-g with naphthoyl-, o-substituted phenyl, furoyl- or thenoyl groups allow direct reductive cyclization with LiAlH(4) to benzazaphospholes 3. The reaction of the o-bromoderivative 2d proceeds with concomitant replacement of bromine by hydrogen, whereas the electron-withdrawing pyridyl group of 2h prevents the synthesis of 3h by this short route. An alternative synthesis of 2-pyridylbenzazaphosphole 3hvia anilidophosphonates succeeded starting from Fmoc-anilinophosphonate 2kvia selective cleavage of the N-protecting group, reduction of the resulting phosphonoaniline to phosphinoaniline and cyclization with pyridine-2-carboxaldehyde via a dihydrobenzazaphosphole 8. N-Substituted pyridylmethylbenzazaphosphole 9 was detected as a side product. The structure elucidation of the new compounds is based on multinuclear NMR data and X-ray crystal structure analyses of a phosphonoanilide, underlining the dominance of N-H···O=P hydrogen bonds over N-H···O=C type hydrogen bonds, of 3h and a supramolecular associate of 3b and its unprecedented air oxidation product 10. 相似文献
69.
Basit Muhammad Abdul Tariq Zeeshan Zahid Saira Khan Sheheryar Siddiqui Farrukh Arsalan Khan Muhammad Farooq Ali Gohar Park Tae Joo 《Journal of Cluster Science》2022,33(6):2443-2454
Journal of Cluster Science - Successive ionic layer adsorption and reaction (SILAR) process has been diversely used for deposition of various metal chalcogenides. SnS is one of them. Owing to the... 相似文献
70.
Zari I. Shafiq Anum Rasool G. Sindhu Tabassum Naz Khan T. S. 《Journal of Thermal Analysis and Calorimetry》2022,147(12):6913-6929
Journal of Thermal Analysis and Calorimetry - The present research is manifested to observe the impact of double stratification in the Marangoni convective flow of the Casson nanoliquid model... 相似文献