全文获取类型
收费全文 | 163篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
化学 | 96篇 |
晶体学 | 3篇 |
力学 | 11篇 |
数学 | 51篇 |
物理学 | 12篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 12篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 18篇 |
2012年 | 8篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有173条查询结果,搜索用时 15 毫秒
101.
102.
Different solvents including cyclohexane, dichloromethane, chloroform, toluene, 1-octanol, and methyl isobutyl ketone (MIBK) have been evaluated in extracting copper(II) from nitrate medium by salicylideneaniline. Extracted species differs from solvent to solvent: CuL2 in cyclohexane, toluene, 1-octanol, and methyl isobutyl ketone. However, in dichloromethane or chloroform, there are two complexes of the type CuL2 and CuL2(HL). The extraction constants and percentage of extraction (%E) are calculated for different solvents. Solvent played an important role in recovering copper(II) from the aqueous solution, thus affecting the extraction equilibrium and extraction efficiency. The nonpolar solvent showed better performance than the polar solvent. The maximum extraction efficiency was 85.75% at pH?=?4.5, which was from cyclohexane. 相似文献
103.
104.
N. I. Amel’kin 《Mechanics of Solids》2011,46(3):335-347
Equations of motion are obtained for a rigid body bearing N three-degree-of-freedom control momentum gyroscopes in gimbals and the entire set of steady motions in a homogeneous external
field is determined. The steady motion dependence on the magnitude of the system angular momentum is studied and a detailed
analysis of the secular stability is performed. 相似文献
105.
Any unitary irreducible representation π of a Lie group G defines a moment set Iπ, subset of the dual g? of the Lie algebra of G. Unfortunately, Iπ does not characterize π. If G is exponential, there exists an overgroup G+ of G, built using real-analytic functions on g?, and extensions π+ of any generic representation π to G+ such that Iπ+ characterizes π.In this paper, we prove that, for many different classes of group G, G admits a quadratic overgroup: such an overgroup is built with the only use of linear and quadratic functions. 相似文献
106.
V. V. Amel’kin A. F. Andreev I. V. Gaishun V. I. Gromak V. A. Il’in N. A. Izobov I. T. Kiguradze J. Llibre V. I. Mironenko V. A. Pliss V. G. Romanovskii N. Kh. Rozov A. P. Sadovskii K. R. Schneider I. N. Sergeev D. S. Shafer T. K. Shemyakina N. I. Vulpe A. Zegeling W. Zhang H. Żołądek 《Differential Equations》2011,47(10):1530-1539
107.
Choukchou-Braham Esma Benabadji Kamel Ismet Benkhaled Amel Sekkal Amina Rim Heddi Djawhar Djamaà Zoulikha 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):273-279
The removal of orange Telon from aqueous solutions by poly(N-octyl-4-vinylpyridiniumbromide) copolymer was investigated. Batch adsorption experiments were carried out to study the effect of experimental parameters on the orange Telon adsorption equilibrium. The adsorption characteristics of copolymer to ward orange Telon in dilute aqueous solution were followed using UV-Vis spectrophotometry. Adsorption equilibrium was reached within 60 min for 0.03 g of poly(4-vinylpyridine quaternized at 58%. The kinetic of adsorption is best described by a pseudo-second-order model. Results also showed that the equilibrium modeling of orange Telon removal process was described by Langmuir isotherms. The maximum adsorption capacity determined from the Langmuir isotherm was 76.4 mg g? 1. The study of the thermodynamic parameters showed that the adsorption of orange Telon on copolymer is an exothermic process and the randomness decreases at the solid-solution interface during the adsorption of dye on the copolymer. 相似文献
108.
A short sequence involving Rh(II) mediated carbene insertion followed by Lewis acid promoted reductive acetal cleavage with Et3SiH provides a stereoselective method for the construction of 2,3,5-trisubstituted tetrahydrofuran rings. 相似文献
109.
Riadh Ben Fatma Mejdi Azaïez Amel Ben Abda Nabil Gmati 《Comptes Rendus Mecanique》2007,335(12):787-792
This Note is dedicated to the numerical treatment of the ill-posed Cauchy–Helmholtz problem. Resorting to the domain decomposition tools, these missing boundary data are rephrased through an ‘interfacial’ equation. This equation is solved via a preconditioned Richardson algorithm with dynamic relaxation. The efficiency of the proposed method is illustrated by some numerical experiments. To cite this article: R. Ben Fatma et al., C. R. Mecanique 335 (2007). 相似文献
110.
N. I. Amel’kin 《Mechanics of Solids》2007,42(4):517-529
To study the stability of steady rotations of a control moment gyro system with internal dissipation, we use the Barbashin-Krasovskii theorem and the relation, established in [1], between the Lyapunov function and steady motions. Taking into account the special properties of the original problem, we reduce it to a lower-dimensional problem.We give a detailed presentation of an algorithm for analyzing the stability of steady motions of a gyrostat and use this algorithm to perform a complete study for two systems consisting, respectively, of one and two gyros whose gimbal axes are parallel to the principal axis of inertia of the system. Each steady motion is identified as either asymptotically stable or unstable. We find periodic motions that exist only in the presence of dynamic symmetry and which are regular precessions. For the system with two gyros, we prove the asymptotic stability of quiescent states and prove that in the angular momentum range where these states are defined the system does not have any other stable motions. 相似文献