全文获取类型
收费全文 | 122篇 |
免费 | 3篇 |
专业分类
化学 | 60篇 |
数学 | 28篇 |
物理学 | 37篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 16篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有125条查询结果,搜索用时 15 毫秒
11.
12.
Starting from known results, due to Y. Tian in [5], referring to the real matrix representations of the real quaternions, in this paper we will investigate the left and right real matrix representations for the complex quaternions and we will give some examples in the special case of the complex Fibonacci quaternions. 相似文献
13.
Vitalii S. Tkach Dmitrii S. Suslov Gennadii V. Ratovskii Tuczek Felix 《Journal of organometallic chemistry》2008,693(12):2069-2073
A series of palladium complexes of general formula [(Acac)PdL1L2]+A−, where L1, L2 = phosphines and A = BF4, CF3SO3, were synthesized. Preliminary studies show that the complexes are active in selective dimerization of styrene and addition polymerization of norbornene. 相似文献
14.
Russian Physics Journal - The effect of the scattering phase functions of sea water types by the Petzold classification on the characteristics of signals of an airborne lidar is investigated using... 相似文献
15.
16.
I. V. Shamanaev I. V. Deliy V. P. Pakharukova E. Yu. Gerasimov V. A. Rogov G. A. Bukhtiyarova 《Russian Chemical Bulletin》2015,64(10):2361-2370
The effect of the reduction conditions on the physicochemical and catalytic properties of Ni2P/SiO2 catalysts was studied. The catalysts were prepared by impregnating silica with a solution of nickel acetate and diammonium hydrogen phosphate followed by drying, calcination, and temperature-programmed reduction. The Ni2P/SiO2 catalysts were reduced prior to hydrodeoxygenation (HDO) of methyl palmitate in the catalytic reactor (in situ) at temperatures of 550, 600, and 650 °С for 3 h and at 600 °С for 1 and 6 h. The reduction temperature and reduction time were shown to affect the conversion of methyl palmitate, and the optimal reduction conditions of the Ni2P/SiO2 catalysts were found. The Ni2P/SiO2 catalyst synthesized according to a widely used preparation method, including steps of passivation and rereduction at 450 °С in addition to the reduction step, is inferior in activity to the samples prepared in situ. 相似文献
17.
A new approach to the investigation of the stability of nonlinear nonautonomous differential equations with impulse effects in critical cases is proposed. The approach is based on the direct method of Lyapunov with the use of piecewise differentiable functions. The sufficient conditions of the asymptotic stability of the critical position of equilibrium in one case are obtained. The case is analogous to Kamenkov’s critical case. 相似文献
18.
Nina E. Bogdanchikova Vitalii P. Petranovskii Roberto Machorro M. Yoshihiro Sugi Victor M. Soto G. Sergio Fuentes M. 《Applied Surface Science》1999,150(1-4):58-64
The stability and decay of silver clusters characterized by absorption bands 320 and 285 nm incorporated in mordenites with different SiO2/Al2O3 molar ratios were studied under ambient conditions. Significantly different rates of disappearance of these two bands were the basis for assigning them to different silver species. Oxidation converts the clusters peaking at 320 and 285 nm into other silver clusters characterized by absorption bands at 310 and 240 nm, respectively. The oxidation of silver clusters peaking at 285 nm is significantly faster than that at 320 nm. The stability of both original clusters decreases with acid site strength that, in its turn, depends on Si02/Al2O3 molar ratio. The minimum lifetime of clusters peaking at 320 and 285 nm equal to ca. 40 and 20 days, respectively, was observed for mordenite characterized by the strongest acid sites. For mordenites possessing weaker acid sites, the lifetime of these clusters is found to be more than 50 months. The oxidation of silver clusters is reversible, and re-reduced silver clusters were revealed to possess the same electron structure as original ones. 相似文献
19.
Oleg A. Drozhzhin Vitalii A. Shevchenko Zoia V. Bobyleva Anastasia M. Alekseeva Evgeny V. Antipov 《Molecules (Basel, Switzerland)》2022,27(11)
In the present work, we focus onthe experimental screening of selected electrolytes, which have been reported earlier in different works, as a good choice for high-voltage Li-ion batteries. Twenty-four solutions were studied by means of their high-voltage stability in lithium half-cells with idle electrode (C+PVDF) and the LiNi0.5Mn1.5O4-based composite as a positive electrode. Some of the solutions were based on the standard 1 M LiPF6 in EC:DMC:DEC = 1:1:1 with/without additives, such as fluoroethylene carbonate, lithium bis(oxalate) borate and lithium difluoro(oxalate)borate. More concentrated solutions of LiPF6 in EC:DMC:DEC = 1:1:1 were also studied. In addition, the solutions of LiBF4 and LiPF6 in various solvents, such as sulfolane, adiponitrile and tris(trimethylsilyl) phosphate, atdifferent concentrations were investigated. A complex study, including cyclic voltammetry, galvanostatic cycling, impedance spectroscopy and ex situ PXRD and EDX, was applied for the first time to such a wide range of electrolytesto provide an objective assessment of the stability of the systems under study. We observed a better anodic stability, including a slower capacity fading during the cycling and lower charge transfer resistance, for the concentrated electrolytes and sulfolane-based solutions. Among the studied electrolytes, the concentrated LiPF6 in EC:DEC:DMC = 1:1:1 performed the best, since it provided both low SEI resistance and stability of the LiNi0.5Mn1.5O4 cathode material. 相似文献
20.
V. S. Shamanaev 《Russian Physics Journal》2007,50(12):1178-1182
In the present paper, the feasibility is demonstrated of application in hydrooptics of the method that has long been developed
for atmospheric sensing and undecervedly forgotten. The range of lidar return signal variations is calculated versus the water
turbidity. Upgrade of the equipment allows a hypothesis about vertical homogeneity of water depth to be abandoned.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 9–13, December, 2007. 相似文献