全文获取类型
收费全文 | 145篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
化学 | 134篇 |
力学 | 2篇 |
数学 | 8篇 |
物理学 | 8篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有152条查询结果,搜索用时 15 毫秒
91.
A method for spectral curve deconvolution is described, evaluated and applied to micellar systems. The technique is based on combination of H-point curve isolation method (HPCIM) and H-point standard addition method (HPSAM). HPCIM is used for extracting the spectrum of solute in micellar pseudophase and HPSAM is used for calculation of equilibrium concentrations of solute in aqueous phase for each sample. The outputs of procedure are spectrum of dye molecules in micellar pseudophase free from contribution of the dye in the aqueous phase, and partition coefficients of considered solutes between micelle and water phase. The effects of noise and extent of solute partitioning on the reliability of the method are evaluated using model data. The applications of the method to the study of interaction of two different solutes, m-cresol purple (m-CP) and Azure C with Brij-35 and 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA) with cetyltrimethylamonium bromide (CTAB) micellar systems are presented. 相似文献
92.
An underpotential deposition (UPD) replacement tactic was employed to design a Pd overlayer on gold (Au) nanoparticles electrodeposited on a carbon ionic liquid electrode (CILE). Pd/Au/CILE was applied as an amperometric sensor for the determination of formaldehyde in aqueous solutions. The sensor displayed two linear ranges from 15 µM–1.4 mM and 1.4–56.7 mM of formaldehyde. The limit of detection was 3 µM of formaldehyde and the sensitivity of the sensor was 2.35 µA mM?1, using the calibration graph in the lower range. The presence of 20 mM of formic acid and methanol and 10 mM ethanol did not interfere with the determination of formaldehyde solution. 相似文献
93.
Bita Baghernejad Majid M. Heravi Hossein A. Oskooie Nargess Poormohammad Maliheh Khorshidi Yahia Sh. Beheshtiha 《Molecular diversity》2011,15(1):245-248
Abstract
A simple and efficient synthesis of N-cyclohexyl-benzofuran derivatives was achieved via a one-pot three-component reaction of cyclohexylisocyanide, an aromatic aldehydes, and phenols in DMF for 10 h with good yields. 相似文献94.
Zareei Maliheh Yoozbashizadeh Hossein Madaah Hosseini Hamid Reza 《Journal of Thermal Analysis and Calorimetry》2019,135(2):1185-1196
Journal of Thermal Analysis and Calorimetry - Alumina nanofluids are one of the most useful nanofluids. In order to evaluate the colloidal behavior of nanoparticles in alumina/water nanofluid, the... 相似文献
95.
Jafari Adeleh Arabzadeh Mohammadi Seyed Mohammad Ali Farsangi Maliheh Maghfoori Naseriyeh Mohsen Hasanpour 《Nonlinear dynamics》2019,95(4):3249-3274
Nonlinear Dynamics - A new problem of observer-based fractional adaptive type-2 fuzzy backstepping control for a class of fractional-order MIMO nonlinear dynamic systems with dead-zone input... 相似文献
96.
The effect of imidazolium-based ionic liquids, ([C12mim][Cl] and [C8mim][Cl]), on the acid-base equilibria of two sulfonated indicators has been studied. The presence of ILs leads to decreased
pK
a values because of the stronger electrostatic interaction of cationic ILs with the basic forms of the indicators with more
negative charge. The longer alkyl side chain of [C12mim][Cl] compared to [C8mim][Cl] results in stronger hydrophobic interaction of this IL with the basic forms of the dyes leading to a more effective
decrease in the pK
a values. Also, the transition points and transition intervals of the acid-base titration curves of the indicators were affected
by the presence of ILs. It was found that the IL interaction with acid-base indicators also results in sharpening the acid-base
titration curves of the indicators. From these observations, it is concluded that the presence of ILs can tune the pK
a values of indicators. All the experiments were performed spectrophotometrically and the results were obtained using curve
fitting methods. 相似文献
97.
Maliheh Amini Moghaddam Petr Stloukal Pavel Kucharczyk Aneta Tow‐Swiatek Tomasz Garbacz Martina Pummerova Tomasz Klepka Vladimír Sedlaík 《先进技术聚合物》2019,30(8):2100-2108
This work investigates preparation by extrusion of microcellular antimicrobial polylactide (PLA) with an additive, the latter comprising 1% potassium aluminum sulfate dodecahydrate (ALUM), and 3% or 5% of a mixture of sodium hydrogen carbonate and sodium dihydrogen phosphate (1:1). Study was made as to the properties of the materials, their hydrolysis, release profiles, and antimicrobial properties in comparison with the pure polymer. Measuring the molecular weight of samples by gel permeation chromatography revealed that, during thermal processing, the molecular weight of the PLA prepared with additives mentiond above had reduced by approximately 43%. A mechanical test confirmed a decline in mechanical properties after processing as compared with the pure PLA. Release of the antimicrobial compound and the subsequent antimicrobial activity against Staphylococcus aureus and Escherichia coli was evaluated according to ISO 22196:2007. The release of ALUM from the microcellular specimens took place in two steps. During the first 10 days, the rate of release was extremely high in contrast with the remaining period. However, the release rate of the nonporous sample was seen to equal less than 1% in the first 10 days, a phenomenon probably arising through its less active surface. 相似文献
98.
Precise Design of Phosphorescent Molecular Butterflies with Tunable Photoinduced Structural Change and Dual Emission 下载免费PDF全文
Chenkun Zhou Yu Tian Dr. Zhao Yuan Dr. Mingu Han Jamie Wang Prof. Lei Zhu Maliheh Shaban Tameh Prof. Chen Huang Prof. Biwu Ma 《Angewandte Chemie (International ed. in English)》2015,54(33):9591-9595
Photoinduced structural change (PSC) is a fundamental excited‐state dynamic process in chemical and biological systems. However, precise control of PSC processes is very challenging, owing to the lack of guidelines for designing excited‐state potential energy surfaces (PESs). A series of rationally designed butterfly‐like phosphorescent binuclear platinum complexes that undergo controlled PSC by Pt–Pt distance shortening and exhibit tunable dual (greenish‐blue and red) emission are herein reported. Based on the Bell–Evans–Polanyi principle, it is demonstrated how the energy barrier of the PSC, which can be described as a chemical‐reaction‐like process between the two energy minima on the first triplet excited‐state PES, can be controlled by synthetic means. These results reveal a simple method to engineer the dual emission of molecular systems by manipulating PES to control PSC. 相似文献
99.
The kinetic methodology based on the difference of reaction rates, is based on the reaction between a common oxidizing agents such as tris(1,10-phenanthroline) and iron(III) complex (ferriin, [Fe (phen)3]3+) in the presence of citrate and spectrophotometrically, monitoring the changes of absorbance at the maximum wavelength of 511 nm. Experimental conditions such as pH, reagents and citrate concentrations were optimized, and the data obtained from the experiments were processed by several chemometric approaches, such as artificial neural network (ANN) and partial least squares (PLS). A set of synthetic mixtures of carbidopa (CD), levodopa (LD) and methyldopa (MD) was evaluated and the results obtained by the applications of these chemometric approaches were discussed and compared. It was found that the back propagation artificial neural network (BP-ANN) method afforded better precision relatively than those of radial basis function artificial neural networks (RBF-ANN) and PLS. The proposed method was also applied satisfactorily to the determination of carbidopa, levodopa and methyldopa in real samples. 相似文献
100.
A method for the determination of sulfide based on the addition reaction of sulfide with magenta at pH 7 and 25 degrees C is described. The decrease in absorbance of magenta at 540 nm, its lambda(max), over a fixed time is proportional to the concentration of sulfide over the range of 25-2500 ng ml(-1). The limit of detection was found to be 15 ng ml(-1). Ten replicate analysis of a sample solution containing 1.5 mug ml(-1) sulfide gave a relative standard deviation of 0.8%. The effects of various cations and anions on sulfide determination have been reported and procedures for removal of interferences have been described. 相似文献