全文获取类型
收费全文 | 147篇 |
免费 | 12篇 |
国内免费 | 5篇 |
专业分类
化学 | 110篇 |
数学 | 10篇 |
物理学 | 44篇 |
出版年
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 22篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 16篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 15 毫秒
1.
Lal Sohan Arora Sanjiv Kumar Vinod Rani Shikha Sharma Chetan Kumar Parvin 《Journal of Thermal Analysis and Calorimetry》2018,132(3):1707-1716
Journal of Thermal Analysis and Calorimetry - The synthesis of Schiff bases of chitosan is performed by the reaction of chitosan with different heteroaryl aldehydes, i.e., furfuraldehyde,... 相似文献
2.
Formation of PdNiZn thin film at oil‐water interface: XPS study and application as Suzuki‐Miyaura catalyst
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nanosheet of PdNiZn and nanosphere of PdNiZn/reduced‐graphene oxide (RGO) with sub‐3 nm spheres have been successfully synthesized through a facile oil‐water interfacial strategy. The morphology and composition of the films were determined by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive analysis of X‐ray (EDAX) and elemental mapping. In the present study, we have developed a method to minimize the usage of precious Pd element. Due to the special structure and intermetallic synergies, the PdNiZn and PdNiZn/RGO nanoalloys exhibited enhanced catalytic activity and durability relative to Pd nanoparticles in Suzuki‐Miyaura C‐C cross‐coupling reaction. Compared to classical cross‐coupling reactions, this method has the advantages of a green solvent, short reaction times, low catalyst loading, high yields and reusability of the catalysts. 相似文献
3.
This paper presents a method for the construction of a graphene paste electrode (GPE) from reduced graphene oxide (RGO). The GPE was successfully used for the determination of medetomidine. The influence of some experimental variables such as pH, supporting electrolyte, scan rate, and possible interferences were studied. Differential pulse voltammetric (DPV) peak currents of medetomidine increased linearly with its concentration in the range from 0.009 to 2.5 µM. The limit of detection (LOD) and limit of quantitation (LOQ) values for the determination of medetomidine were 2.8 and 9.2 nM, respectively. Also, for the first time, the electroreduction behavior of medetomidine was investigated. 相似文献
4.
5.
Malek Taher Maghsoodlou Sayyed Mostafa Habibi Khorasani Nourollah Hazeri Mahmoud Nassiri Reza KaKaei Ghasem Marandi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):553-560
Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, in the presence of strong NH-acids, such as imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole, benzimidazole, and 5,6-dimethylbezimidazole. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon–carbon partial double bond resulting from the conjugation of the ylide moiety with the adjacent carbonyl group. 相似文献
6.
Malek Taher Maghsoodlou Nourollah Hazeri Sayyed Mostafa Habibi Khorasani Aqil Ghulame Shahzadeh Mahmoud Nassiri 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):913-919
Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of strong NH acids, such as indole and 2-methyl indole, 3-methyl indole, and 5-boromo indole. These stable ylides exist in a solution as a mixture of two geometrical isomers as a result of the restricted rotation around the carbon–carbon partial double bond resulting from the conjugation of the ylide moiety with the adjacent carbonyl group. 相似文献
7.
A simple and efficient method for the convenient synthesis of 2-arylbenzimidazole has been described on reaction with o-phenylenediamine and various aromatic aldehydes using cobalt(II) chloride hexahydrate as a catalyst. The method is cost-effective, high-yielding, clean, and selective. 相似文献
8.
Mohammad Mazloum-Ardakani Javad Safari Parvin Pourhakkak Mohammad Ali Sheikh-Mohseni 《International journal of environmental analytical chemistry》2013,93(14):1638-1649
A PVC (poly vinyl chloride) membrane electrode for lead ion based on 2-(((E)-2-((E)-1-(2-hydroxyphenyl)methyliden)hydrazono)metyl)phenol (HMHMP) as a membrane carrier was prepared. This electrode exhibited linear response with Nernstian slope of 29.2?±?0.2?mV per decade within the concentration range of 2.0?×?10?7–1.0?×?10?1?M lead ion. The limit of detection, as determined from the intersection of the extrapolated linear segments of the calibration plot, was 8.0?×?10?8 M. The electrode exhibited high selectivity for Pb (II). The response time of the electrode was about 5–10?s for different concentrations. The electrode is suitable for use in aqueous solutions in a pH range of 5.0–7.5. It was used as an indicator electrode in a titration of Pb (II) with chromate at constant pH. This electrode was used for the determination of lead in ore samples, and the results were in agreement with those obtained with an atomic absorption spectroscopy (AAS) method. Also lead selective electrode was used for monitoring of lead in spiked samples of the Zayanderud River and waste water by the potentiometry technique. 相似文献
9.
Ashwani Kumar Sahanaz Parvin Dr. Raj Kumar Das Prof. Sayan Bhattacharyya 《化学:亚洲杂志》2021,16(21):3444-3452
Metal-organic coordination polymers (CP) have attracted the scientific attention for electrochemical water oxidation as it has the similar coordination structure like natural photosynthetic coordinated complex. However, the harsh synthesis conditions and bulky nature pose a major challenge in the field of catalysis. Herein, 3–5 nm CP particles synthesized at room temperature using aqueous solutions of Ni2+/Cu2+ and 2,5-dihydroxyterepthalic acid as precursor were applied for alkaline water and urea electrolysis. The overpotential required is only 300 mV at 10 mA cm−2 by Nano-Ni CP for water oxidation, with turnover frequency (TOF) of 21.4 s−1 which is around 8 times higher than its bulk-counterpart. Overall water and urea splitting were achieved with Nano-Cu (−) ∥ Nano-Ni (+) couple on Ni foam at 1.69 and 1.52 V to achieve 10 mA cm−2, respectively. High electrochemical surface area (ECSA), high TOF, and enhanced mass diffusion are found to be the key parameters responsible for the state-of-the-art water and urea splitting performances of nano-CPs as compared to their bulk counterparts. 相似文献
10.
Encapsulation of Cu(II) complexes of methyl-2-(2-hydroxybenzylideneamino)-4,5,6,7-tetrahydrobenzo[b]-thiophene-3-carboxylate (HL1) and 2-ethyl-4-methyl 5-(2-hydroxybenzylideneamino)-3-methylthiophene-2,4-dicarboxylate (HL2) in the supercages of zeolite NaY was performed by the flexible ligand method. The neat and encapsulated complexes were characterized by physicochemical and spectroscopic methods and employed as catalysts for oxidation of benzyl alcohol and phenol. The encapsulated complexes were both more reactive and stable as catalysts than the corresponding free complexes. The encapsulated complexes could be reused several times. Complexes of HL2 were more reactive than those of HL1, probably due to the electron-withdrawing effect of the CO2Et group. 相似文献