全文获取类型
收费全文 | 157篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学 | 86篇 |
力学 | 10篇 |
数学 | 49篇 |
物理学 | 13篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 11篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有158条查询结果,搜索用时 16 毫秒
41.
42.
Messaoudi Abderrahim Errachid Mohammed Jbilou Khalide Sadok Hassane 《Numerical Algorithms》2019,80(1):253-278
Numerical Algorithms - Let x0,x1, ? , xn, be a set of n + 1 distinct real numbers (i.e., xm ≠ xj, for m ≠ j) and let ym,k, for m = 0, 1, ? , n, and k = 0, 1, ? , rm,... 相似文献
43.
Nacer Ferrah Omar Abderrahim Mohamed Amine Didi Didier Villemin 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(3):721-730
A novel sorbent resin consisting of a Phosphonic Acid grafted on Merrifield Resin (PA-MR) for the extraction of uranyl from
nitrate media is described. The sorption behaviour of uranyl cation on PA-MR was investigated using batch equilibrium technique.
The effects of parameters such as shaking speed, pH levels, contact time, metal concentrations, ionic strength and temperature
were reported. The results show that the sorption capacity increases with increasing both initial uranyl ion concentration
and temperature and decreases with increasing ionic strength. Therefore, the optimum condition for the present study should
be using 6.6 mg adsorbent per 1.0 mg uranyl in solution with pH 3.6 and shaking at 250 rpm for 180 min. The adsorption behavior
of the system was also investigated and found to be in line with Langmuir isotherm. The kinetic data was well described by
the pseudo second-order. Thermodynamics data leads to endothermic process ∆H = + 31.03 kJ−1 mol−1, ∆S = + 146.64 J mol−1 K−1 and ∆G = −11.96 kJ mol−1 at 20 K. ∆G decreased to negatives values with increasing temperature indicating that the process was more favoured at high temperature. 相似文献
44.
Abderrahim El Haib Ahmed Benharref Eric Manoury Martine Urrutigoïty Maryse Gouygou 《Tetrahedron: Asymmetry》2011,22(1):101-108
The acid-catalyzed rearrangement of two enantiomerically pure epoxides derived from sesquiterpernic himachalenes, which are the main components of the essential oil of the Atlas cedar, has been studied using various Lewis and Bronsted acids. Several new polycyclic compounds have been obtained with different selectivities depending upon the catalysts used and the reaction conditions, and were fully characterized by spectroscopic methods. Mechanisms to explain the formation of the different compounds observed in the reaction mixture have also been proposed. 相似文献
45.
Samira Idrissi Abderrahim Jabar Lahoucine Bahmad 《International journal of quantum chemistry》2024,124(2):e27341
In this paper, we study and discuss the structural, and electronic properties of the RbXF3 (X = Co, Mn, V or Fe) Perovskite Materials using the Density Functional Theory (DFT). Also, the origin of both semi-conductor (SM) and half-metallic (HM) characters have been outlined. The density functional theory (DFT) has been applied to illustrate the physical properties of the RbXF3 (X = Co, Mn, Fe or V) perovskite materials. The generalized gradient approximation introduced by Perdew–Burke and Ernzerhof (GGA-PBE) with Hubbard correction has been used for modeling the physical properties of the RbXF3 (X = Co, Mn, V or Fe) perovskite compounds. The total and partial densities of states of each solar perovskite RbVF3 (X = Co, Mn, Fe or V) material have been illustrated and discussed. In addition, the contribution of the different elements: Rb, Co, Mn, Fe, V and F, has been investigated revealing the most contributing ones in the valance and conduction bands. The magnetic behavior of the studied solar perovskites RbVF3 (X = Co, Mn, Fe or V) materials, has been outlined. It is found that the perovskites RbCoF3 and RbFeF3 are half-metallic, while the materials RbMnF3 and RbVF3 exhibit a semi-conductor behavior. 相似文献
46.
47.
N‐benzimidazol‐2‐yl imidate type 1 reacts with thiourea, carbon disulfide, cyanamide, and hydrazide to give, respectively, [1,2‐a] benzimidazolo‐1,3,5‐triazin‐2‐thione 2 , [1,2‐a] benzimidazolo‐1,3,5‐thiadiazin‐2‐thione 3 , [1,2‐a] benzimidazolo‐1,3,5‐triazin‐2‐amine 4 , and [1,2‐a] benzimidazol‐2‐yl amidrazone 5 with good yields. Structures elucidation of all newly synthesized heterocyclic compounds was based on the data of IR, 1H NMR, 13C NMR, elemental analysis, and MS of some products. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:279–283, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20618 相似文献
48.
49.
50.
The notion of graphical metric regularity is introduced and conditions ensuring this kind of regularity for systems of finite-dimensional multifunctions are given in terms of partial approximate subdifferentials. 相似文献