全文获取类型
收费全文 | 93篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 38篇 |
晶体学 | 2篇 |
力学 | 2篇 |
数学 | 20篇 |
物理学 | 35篇 |
出版年
2021年 | 1篇 |
2020年 | 5篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有97条查询结果,搜索用时 15 毫秒
1.
ABSTRACT The asymmetric cross-aldol reaction of simple ketones (acetone, cyclohexanone) with isatin derivatives in the presence of crude extract from earthworms as green and effective biocatalyst proceeds easily in MeCN/H2O (1:1) as solvent to afford 3-hydroxy-2-oxindoles derivatives. Ten compounds were synthesized in high yields (62–88%) and moderate ee (29–42%). Structure of the synthesized compounds has been characterized on the basis of NMR spectra and CHN analysis. The ee of the obtained compounds was determined by chiral phase HPLC analysis. 相似文献
2.
Prof. Dr. Qian Miao Dr. Farzaneh Rouhani Dr. Hamed Moghanni-Bavil-Olyaei Dr. Kuan-Guan Liu Xue-Mei Gao Jing-Zhe Li Xiu-De Hu Prof. Dr. Zhi-Min Jin Prof. Mao-Lin Hu Prof. Ali Morsali 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(43):9518-9526
As redox-active based supercapacitors are known as highly desirable next-generation supercapacitor electrodes, the targeted design of two ferrocene-functionalized (Fc(COOH)2) clusters based on coinage metals, [(PPh3)2AgO2CFcCO2Ag(PPh3)2]2 ⋅ 7 CH3OH (SC1: super capacitor) and [(PPh3)3CuO2CFcCO2Cu(PPh3)3] ⋅ 3 CH3OH (SC2), is reported. Both structures are fully characterized by various techniques. The structures are utilized as energy storage electrode materials, giving 130 F g−1 and 210 F g−1 specific capacitance at 1.5 A g−1 in Na2SO4 electrolyte, respectively. The obtained results show that the presence of CuI instead of AgI improves the supercapacitive performance of the cluster. Further, to improve the conductivity, the PSC2 ([(PPh3)2CuO2CFcCO2]∞), a polymeric structure of SC2, was synthesized and used as an energy storage electrode. PSC2 displays high conductivity and gives 455 F g−1 capacitance at 3 A g−1. The PSC2 as a supercapacitor electrode presents a high power density (2416 W kg−1), high energy density (161 Wh kg−1), and long cycle life over 4000 cycles (93 %). These results could lead to the amplification of high-performance supercapacitors in new areas to develop real applications and stimulate the use of the targeted design of coordination polymers without hybridization or compositions with additive materials. 相似文献
3.
C Lanthony JM Ducéré MD Rouhani A Hemeryck A Estève C Rossi 《The Journal of chemical physics》2012,137(9):094707
We propose a barrierless mechanism for describing the oxidation of Al(111) in which oxygen atoms located on the outer surface extract aluminum atoms of the surface layers through local cooperation of other pre-adsorbed oxygen atoms. We show the details of this complex chemical process that kinetically competes with the non-destructive formation of an oxygen monolayer onto the Al surface, thus elucidating the initial aluminum oxidation regime. We demonstrate that further stripping of the complete surface Al layer is consistent with both (i) the formation of a defective alumina structure and (ii) an oxide capping layer preventing further oxidation at low temperature. 相似文献
4.
5.
Ali Ramazani Morteza Rouhani Aram Rezaei Nahid Shajari Ali Souldozi 《Helvetica chimica acta》2011,94(2):282-288
Reactions of biacetyl (=butane‐2,3‐dione) with (N‐isocyanimino)triphenylphosphorane in the presence of aromatic carboxylic acids proceed smoothly at room temperature and under neutral conditions to afford 3‐(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)‐3‐hydroxybutan‐2‐one derivatives in high yields. 相似文献
6.
We introduce the notion of almost expansive sequences and curves and study their ergodic and asymptotic properties in a Hilbert
space H. We apply our results to study the asymptotic behavior of solutions to the quasi-autonomous expansive type evolution system
(du/dt)(t) + f(t) ∈ Au(t) on [0, ∞). 相似文献
7.
M. Mohsenzadeh S. Rouhani M. V. Takook 《International Journal of Theoretical Physics》2009,48(3):755-762
The power spectrum of scalar field and space-time metric perturbations produced in the process of inflation of universe, have
been presented in this paper by an alternative approach to field quantization namely, Krein space quantization (Gazeau et
al. in Class. Quantum Gravity 17:1415, 2000; Takook in Int. J. Mod. Phys. E 11:509, 2002; Rouhani and Takook in ). Auxiliary negative norm states, the modes of which do not interact with the physical world, have been utilized in this
method. Presence of negative norm states play the role of an automatic renormalization device for the theory. 相似文献
8.
Novel PVC-based coated graphite electrode for selective determination of quinoline yellow 总被引:1,自引:0,他引:1
Novel coated graphite electrode (CGE) for the determination of quinoline yellow (QY), an artificial food colorant, was evaluated based on the use of tetraphenylphosponium-QY ion-pair complex as the electroactive substance. The electrode revealed linear emf-pQY response over wide concentration ranges (1.0 × 10?1 ~ 5.0 × 10?5 M) with a slope ?30.1 ± 0.2 mV decade?1 and a limit of detection of 4.0 × 10?5 M. The electrode showed good stability, reproducibility and fast response (<5 s). It can be used in wide pH range (4.7–10.7) and was successfully applied to determination of quinoline yellow in artificial mixtures and commercial soft drinks. The results obtained with the electrode were in good agreement with the value obtained by using HPLC measurements, as an official method. 相似文献
9.
The effective photoelastic constants of a superlattice composed of thin alternating layers of orthorhombic symmetry are calculated as functions of dielectric, elastic and photoelastic constants of the constituents. In a preliminary step to this calculation, we also obtain the effective dielectric tensor for any symmetry of the layers. It is shown that appropriate combinations of these effective constants are arithmetic averages of the corresponding quantities in the constituents, each layer having a weight equal to its relative thickness. 相似文献
10.
Ali Ramazani Amir Tofangchi Mahyari Morteza Rouhani Aram Rezaei 《Tetrahedron letters》2009,50(40):5625-5627
Reaction of an isocyanide with an iminium ion intermediate, formed by reaction between an electron-poor 2-hydroxybenzaldehyde derivative and a secondary amine in the presence of silica gel proceeds smoothly at room temperature to afford benzo[b]furan derivatives in high yields. 相似文献