全文获取类型
收费全文 | 310篇 |
免费 | 21篇 |
国内免费 | 5篇 |
专业分类
化学 | 204篇 |
晶体学 | 1篇 |
力学 | 3篇 |
综合类 | 1篇 |
数学 | 63篇 |
物理学 | 64篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 15篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 5篇 |
2016年 | 17篇 |
2015年 | 11篇 |
2014年 | 12篇 |
2013年 | 35篇 |
2012年 | 24篇 |
2011年 | 29篇 |
2010年 | 16篇 |
2009年 | 18篇 |
2008年 | 17篇 |
2007年 | 19篇 |
2006年 | 11篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有336条查询结果,搜索用时 15 毫秒
71.
In this article we consider a class of first order nonlinear integro-differential equations with delay. We propose new approach for investigating local and global existence of the solutions of its Cauchy problem. This approach gives new results. 相似文献
72.
We study the backward problem for non-linear (semilinear) parabolic partial differential equations in Hilbert spaces. The problem is severely ill-posed in the sense of Hadamard. Under a weak a priori assumption on the exact solution, we propose a new Fourier truncated regularization method for stabilising the ill-posed problem. In comparison with previous studies on solving the nonlinear backward problem, our method shows a significant improvement. 相似文献
73.
74.
Lanthanum cobaltite oxide, LaCoO3, was prepared by the evaporation technique and the amorphous metal complex method. Powders were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and surface area measurements. The effect of the synthesis route on the phase purity, particle size, surface area, and morphology of the powders was studied. A single perovskite phase was synthesized at 700°C using the amorphous metal complex route. However, the evaporation technique required higher temperature for LaCoO3 crystallization. Based on the characterization results, low temperature formation of LaCoO3 was attributed to the homogeneity of the precursors. Such behavior also results in different microstructures. Powder synthesized by the amorphous metal complex method exhibited the highest surface area and the lowest particle size. 相似文献
75.
S. Awang Kechil I. Hashim 《Communications in Nonlinear Science & Numerical Simulation》2009,14(4):1346-1354
In this paper, the steady two-dimensional laminar forced MHD Hiemenz flow against a flat plate with variable wall temperature in a porous medium which was solved numerically using the implicit finite-difference of Keller-box method [Yih KA. The effect of uniform suction/blowing on heat transfer of magnetohydrodynamic Hiemenz flow through porous media. Acta Mech 1998;130:147–58] is revisited. A simple analytic approach of the Adomian decomposition method (ADM) is employed to obtain an approximate analytical solution of the problem. The skin friction coefficient and the rate of heat transfer given by the ADM are in good agreement with the numerical solutions of the Keller-box method. 相似文献
76.
Mokhtar Kirane 《Nonlinear Analysis: Theory, Methods & Applications》2010,73(12):3723-235
We investigate the profile of the blowing-up solutions to the nonlinear nonlocal system (FDS):
77.
G. A. El-Shobaky Th. El-Nabarawy G. A. Fagal M. Mokhtar 《Journal of Thermal Analysis and Calorimetry》1996,46(5):1473-1481
V2O5/Al2O3 solids of varying compositions were prepared, dried at 100°C and calcined in air at 400–1000°C. The solid-solid interactions between the mixed oxides were investigated by means of DTA, TG and XRD techniques.The results revealed that ammonium metavanadate and aluminium hydroxide decomposed at 260 and 290°C, respectively, to yield an ammonium vanadium intermediate compound and Al2O3 as solids. The intermediate compound readily decomposed at 360°C to give V2O5.Solid V2O5 generally catalyses the crystallization of Al2O3 to an extent proportional to its amount present. The solid-solid interactions between Al2O3 and V2O3 to produce AlV2O4 and AlVO4 took place at 750 and 900°C. These solids decomposed entirely at 1000°C, producing V2O5 and alpha-corundum. The pure Al2O3 samples employed existed as amorphous solids even when heated in air at 750°C, but in the presence of V2O5 (7–18 wt.%) they crystallized to thetaalumina at 600°C. The pure solid alumina crystallized at 1000°C to a mixture of theta and kappa-alumina. In the presence of V2O5, alpha-corundum together with kappa and theta phases was obtained on heating at 900°C. 相似文献
78.
New selective and sensitive Spectrophotometric methods for quinone determination are described. Quinone samples are treated with either methanolic solution of rhodanine, fluorene in ammoniacal media or aqueous semicarbazide hydrochloride solution. Semicarbazide is the most sensitive reagent for the determination of 1,4-benzoquinone, 1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone. Quinones substituted with electron withdrawing groups are better determined using rhodanine. The average recovery is 99.1%, 98.7% and 99.2% using rhodanine, fluorene and semicarbazide as reagents, respectively. 相似文献
79.
Four kinds of polythiophenes have been doped with CH3SO3H in CHCl3 under air,oxygen,and nitrogen. In the doping of two types of poly(3-hexylthiophene)s,P3HexTh(Zn/Ni)and P3HexTh(Fe)with different contents of a head-to-tail unit,the p-doping occurs at a similar rate.The reaction between poly(3-dodecylthiophene),P3DodTh,and the acid takes place more rapidly.P3OBuTh with a butoxy substituent undergoes more facile p-doping and receives photochemical reaction with CHCl3,and this reaction obeys a pseudo-first-order rate law with a rate constant kobs of 1.42×10-5s-1at room tempera- ture. 相似文献
80.
Series Solution for Unsteady Boundary-Layer Flows Due to Impulsively Stretching Plate 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Seripah Awang Kechil Ishak Hashim 《中国物理快报》2007,24(1):139-142
The third-order nonlinear partial differential equation modelling the unsteady boundary-layer flows caused by an impulsively stretching fiat plate is solved by using the Adomian decomposition method (ADM). The ADM yields analytic solution in the form of a rapidly convergent infinite series with easily computable terms. The series solution using the ADM for the unsteady flows is presented for the first time. 相似文献