全文获取类型
收费全文 | 205篇 |
免费 | 10篇 |
专业分类
化学 | 148篇 |
晶体学 | 3篇 |
力学 | 2篇 |
数学 | 29篇 |
物理学 | 33篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 18篇 |
2015年 | 5篇 |
2014年 | 15篇 |
2013年 | 32篇 |
2012年 | 8篇 |
2011年 | 15篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
排序方式: 共有215条查询结果,搜索用时 312 毫秒
51.
52.
Cemil Ibis Sibel Sahınler Ayla Senol Yavuz 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):492-502
Abstract Novel thio- and alkoxy-substituted benzoquinone derivatives were synthesized from the reactions of p-chloranil (1) and related nucleophiles in a sodium carbonate (Na2CO3) solution of acetonitrile or in chloroform with Et3N. The structures of novel compounds were characterized by using microanalysis, FTIR, 1H NMR, 13C NMR, MS, CV, and fluorescence spectroscopy. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.] 相似文献
53.
54.
Cemil Ibis Sibel Sahinler Ayla 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2350-2356
Abstract Novel O- S,O- S,S- N,N- and N,S-substituted naphthoquinone compounds were prepared by reaction of 2,3-dichloro-1,4-naphthoquinone and the corresponding nucleophiles in the presence of chloroform and triethylamine or ethanol solution of Na2CO3. The structures of the novel naphthoquinone compounds were characterized by micro analysis, FT-IR, UV/Vis, 1H NMR, 13C NMR, MS, and fluorescence spectroscopy. GRAPHICAL ABSTRACT 相似文献
55.
Sevinc Kurbanoglu Burcu Dogan‐Topal Bengi Uslu Alp Can Sibel A. Ozkan 《Electroanalysis》2013,25(6):1473-1482
The effect of surface modifications on the electrochemical behavior of the anticancer drug idarubicin was studied at multiwalled carbon nanotubes modified glassy carbon and edge plane pyrolytic graphite electrodes. The surface morphology of the modified electrodes was characterized by scanning electron microscopy. The modified electrodes were constructed for the determination of idarubicin using adsorptive stripping differential pulse voltammetry. The experimental parameters such as supporting electrolyte, pH, accumulation time and potential, amount of carbon nanotubes for the sensitive assay of idarubicin were studied as details. Under the optimized conditions, idarubicin gave a linear response in the range 9.36×10?8–1.87×10?6 M for modified glassy carbon and 9.36×10?8–9.36×10?7 M for modified edge plane pyrolytic graphite electrodes. The detection limits were found as 1.87×10?8 M and 3.75×10?8 M based on modified glassy carbon and edge plane pyrolytic graphite electrodes, respectively. Interfering species such as ascorbic acid, dopamine, and aspirin showed no interference with the selective determination of idarubicin. The analyzing method was fully validated and successfully applied for the determination of idarubicin in its pharmaceutical dosage form. The possible oxidation mechanism of idarubicin was also discussed. The results revealed that the modified electrodes showed an obvious electrocatalytic activity toward the oxidation of idarubicin by a remarkable enhancement in the current response compared with bare electrodes. 相似文献
56.
The novel substituted 2,3-dichloro-1,4-naphthoquinone derivatives were synthesized from the reactions of (1) and related nucleophilles in sodium carbonate (Na2CO3) solution of ethanol, chloroform with Et3N, or potassium carbonate (K2CO3) solution of acetonitrile. The structures of novel compounds were characterized by using microanalysis, Fourier transform–infrared, 1H NMR, 13C NMR, mass spectrometry, and cyclic voltammetry (CV).
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
57.
Effect of ultrasonic irradiation on crystallization kinetics of potassium dihydrogen phosphate 总被引:1,自引:0,他引:1
The ultrasound effect applied on potassium dihydrogen phosphate was investigated in a continuous crystallization system. The studied process variables were ultrasonic power (W) and residence time. The crystal size distributions of the final products obtained with and without ultrasonic power were determined and the data were evaluated by using modified form of Abegg, Stevens and Larson (ASL) model. The supersaturation limit decreased with ultrasonic waves and the crystal morphology was modified. The average crystal size decreased in the presence of ultrasonic power. An abrasive effect was observed at a high ultrasonic power input. 相似文献
58.
In this study we have employed two ionic liquids (ILs) as a new media for the analysis of aluminum in aqueous solutions by spectrofluorimetric method. ILs are liquid salts and they have no measurable vapor pressure up to their thermal decomposition point, >300 ??C. This lack of vapor pressure makes these materials highly attractive for many studies as they can be used as clean solvents. Besides they are promising environments for analysis purposes and optical sensor designs. The results revealed that absorption, excitation and emission spectra of the morin?CAl complex exhibited considerable changes in moieties. The morin?CAl complex was stable at aluminum concentrations below 9.1?mg?L?1 in 25% 1-butyl-3-methylimidazolium bromide (IL-I)-water binary mixtures. The higher concentrations of IL (>25% by volume) was not suitable for the complex formation thus in pure IL media the complex formation even at high aluminum concentrations was not observed. The complex stoichiometry ratio of aluminum:morin was 2:1 in IL-I-water binary mixtures. The linear concentration range was 0.045?C7.2?mg?L?1 with a correlation coefficient of r?=?0.9909. The detection limit was found to be 0.036?mg?L?1. Cu2+, Mn2+ and PO 4 3? ions exhibited less interfering effect in presence of IL-I and the tolerance limit of Cu enhanced 10 times when compared with ethanol. 相似文献
59.
Ersin Demir Recai Inam Sibel A. Ozkan Bengi Uslu 《Journal of Solid State Electrochemistry》2014,18(10):2709-2720
A sensitive and selective electroanalytical method for the determination of tadalafil (TAD) using adsorptive stripping square wave voltammetry at multiwalled carbon nanotube paste electrode (MWCNTPE) and modified TiO2-multiwalled carbon nanotube paste electrode (TiO2-MWCNTPE) was presented. The calibration curves were linear in the concentration range of 3.6–8.1 and 12.7–61.1 μM on MWCNTPE, 0.27–15.2 μM on TiO2-MWCNTPE. The recommended method was successfully applied to the determination of the drug in tablets and human serum samples with good recoveries. The selectivity of the proposed method was considered in the presence of Ca2+, K+, Na+, 2-mercapto benzimidazole, thiourea, and dopamine by means of recovery tests. Interfering agents did not show considerable effect on TAD determination. No electroactive interferences from the tablet excipients and endogenous substances from biological material were detected. The possible electrooxidation pathway and the number of transferred electrons were also investigated. 相似文献
60.
Periodica Mathematica Hungarica - Two new asymmetric generalizations of the Filbert and Lilbert matrices constructed by the products of two Fibonacci and Lucas numbers are considered, with... 相似文献