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1.
Inside Cover: Ru‐Catalysed CH Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies (Chem. Eur. J. 14/2015) 下载免费PDF全文
2.
Vutukuri DR Bharathi P Yu Z Rajasekaran K Tran MH Thayumanavan S 《The Journal of organic chemistry》2003,68(3):1146-1149
A mild deprotection strategy for allyl ethers under basic conditions in the presence of a palladium catalyst is described. Under these conditions, aryl allyl ethers can be cleaved selectively in the presence of alkyl allyl ethers. These conditions are also effective in the deprotection of allyloxycarbonyl groups. The utility of the current methodology in sequence specific dendrimer synthesis is demonstrated. 相似文献
3.
G. Sivalingam R. Karthik Giridhar Madras 《Journal of Analytical and Applied Pyrolysis》2003,70(2):631-647
The thermal degradation/modification dynamics of poly(-caprolactone) (PCL) was investigated in a thermogravimetric analyzer under non-isothermal and isothermal conditions. The time evolution of the molecular weight distribution during degradation was studied using gel permeation chromatography. Experimental molecular weight evolution and weight loss profile were modeled using continuous distribution kinetics. The degradation exhibited distinctly different behavior under non-isothermal and isothermal heating. Under non-isothermal heating, the mass of the polymer remained constant at initial stages with rapid degradation at longer times. The Friedman and Chang methods of analysis showed a 3-fold change (from 18 to 55–62 kcal mol−1) in the activation energy from low temperatures to high temperatures during degradation. This suggested the governing mechanism changes during degradation and was explained using two parallel mechanisms (random chain scission and specific chain end scission) without invoking the sequential reaction mechanisms. Under isothermal heating, the polymer degraded by pure unzipping of specific products from the chain end. 相似文献
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B.V. Subba Reddy Govindaraju Karthik Tamilselvan Rajasekaran Aneesh Antony B. Sridhar 《Tetrahedron letters》2012,53(19):2396-2401
A rhodium(II) catalyzed [4+2]/[2+2] cycloaddition reaction of N-protected isatin-3-arylimine with acylketene derived from α-diazocarbonyl compounds has been achieved for the first time for the preparation of a novel class of spiro(oxindolyl)oxazinone and spiro(oxindolyl)-β-lactam derivatives. 相似文献
7.
Pitchiah Esakki Karthik Chinnaiah Jeyabharathi Shanmugam Senthil Kumar Kanala Lakshmi Narasimha Phani 《Journal of Solid State Electrochemistry》2013,17(12):3055-3061
It is shown that the gold surface is catalytically deactivated and smoothened upon removal of the Prussian blue (PB)–gold nanocomposite formed on the gold surface. Atomic force microscopy proves surface smoothening after PB removal. The voltammetric responses of Ru(NH3)6Cl3 on the smoothened surface remain unaffected, but the reactions that involve multistep and inner-sphere electron transfer are affected on the smoothened surface as exemplified by hydroquinone, ferrous oxalate redox reactions, and oxygen reduction. These effects are attributed to catalytic deactivation as a consequence of removal of the active sites. Figure
It is shown that the gold surface is catalytically deactivated and smoothened upon removal of the Prussian blue (PB)–gold nanocomposite formed on the gold surface. Atomic force microscopy proves surface smoothening after PB removal. The voltammetric responses of Ru(NH3)6.Cl3 on smoothened surface remain unaffected, but the reactions that involve multistep and inner-sphere electron transfer are affected on the smoothened surface as exemplified by hydroquinone, ferrous oxalate redox reactions, and oxygen reduction. These effects are attributed to catalytic deactivation as a consequence of removal of the active sites. Graphical abstract shows the Au surface smoothening as a consequence of Prussian blue-gold nanocomposite (Au-PB) formation and removal 相似文献
8.
Electrochemical bromination of alkyl aromatic compounds by two-phase electrolysis yields the corresponding α, α-dibrominated products. The reaction has been carried out in a single-compartment electrochemical cell using aqueous sodium bromide (40–50%), containing a catalytic amount of HBr as electrolyte, and chloroform, containing an alkyl aromatic compound, as the organic phase with a Pt plate as anode at 10–15°C. Two-phase electrolysis results in high yields (70–90%) of dibromomethyl, bis(bromomethyl), and bis(dibromomethyl) arenes, depending upon the charge passed. 相似文献
9.
Mourad Benlamri Kyle M. Bothe Alex M. Ma Gem Shoute Amir Afshar Himani Sharma Arash Mohammadpour Manisha Gupta Kenneth C. Cadien Ying Y. Tsui Karthik Shankar Douglas W. Barlage 《固体物理学:研究快报》2014,8(10):871-875
A high effective electron mobility of 33 cm2 V–1 s–1 was achieved in solution‐processed undoped zinc oxide (ZnO) thin films. The introduction of silicon nitride (Si3N4) as growth substrate resulted in a mobility improvement by a factor of 2.5 with respect to the commonly used silicon oxide (SiO2). The solution‐processed ZnO thin films grown on Si3N4, prepared by low‐pressure chemical vapor deposition, revealed bigger grain sizes, lower strain and better crystalline quality in comparison to the films grown on thermal SiO2. These results show that the nucleation and growth mechanisms of solution‐processed films are substrate dependent and affect the final film structure accordingly. The substantial difference in electron mobilities suggests that, in addition to the grain morphology and crystalline structure effects, defect chemistry is a contributing factor that also depends on the particular substrate. In this respect, interface trap densities measured in high‐κ HfO2/ZnO MOSCAPs were about ten times lower in those fabricated on Si3N4 substrates. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)
10.
The motion of molecules across channels and pores is critically important for understanding mechanisms of many cellular processes.
Here we investigate the mechanism of interactions in the molecular transport through nanopores by analyzing exactly solvable
discrete stochastic models. According to this approach the channel transport is viewed as a set of chemical transitions between
discrete states. It is shown that the strength and spatial distribution of molecule/channel interactions can strongly modify
the particle current. Our analysis indicates that the most optimal transport is achieved when the binding sites are near the
entrance or exit of the pore depending on the sign of interaction potential. In addition, the role of intermolecular interactions
during the channel transport is studied, and it is argued that an increase in the flux can be observed for some optimal interaction
strength. The mechanisms of these phenomena are discussed. 相似文献