全文获取类型
收费全文 | 131篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
化学 | 57篇 |
晶体学 | 2篇 |
力学 | 5篇 |
数学 | 27篇 |
物理学 | 45篇 |
出版年
2022年 | 10篇 |
2021年 | 16篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 16篇 |
2015年 | 7篇 |
2014年 | 3篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 8篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
1995年 | 4篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 3篇 |
排序方式: 共有136条查询结果,搜索用时 15 毫秒
1.
Some new stabilisers having a chelating polymeric structure were synthesised and characterised, i.e., 8-hydroxyquinoline-formaldehyde chelating resins of Cd, Zn, and Pb. The efficiency of these new stabilisers was studied with respect to PVC. The stabilised PVC samples showed outstanding thermal stability as studied by thermogravimetric techniques, i.e., the percentage of HCl evolved reduced remarkably with increasing polymer decomposition temperature. 相似文献
2.
Phosphine Substituted Chelate Ligands. XVIII. Penta- and Tetracarbonylmetal Complexes of Chromium, Molybdenum, and Tungsten with Secondary and Tertiary Phosphinothioformamide Ligands Mono- and bidentately coordinated phosphinothioformamide complexes are obtained by photochemical substitution of the metal hexacarbonyls M(CO)6 (M ? Cr ( a ), Mo ( b ), W ( c )). The M(CO)5 · THF adducts react with secondary thioamides under exclusion of light to give the P-coordinate pentacarbonyl complexes [(CO)5MPPh2C(S)NHR1] (R1 ? Ph ( 1a – c ), Me ( 2a )). The photoreaction of M(CO)5 · THF with secondary and tertiary thioamides at low temperatures leads to the formation of the P, S-chelate complexes . The corresponding N-silylated complexes 6a – c (R1 ? Me3Si, R2 ? Ph) are obtained by direct photosubstitution of M(CO)6 in cyclohexane solution. The labile bis(thioformamide) complexes [(CO)4M(PPh2C(S)NHMe)2] ( 7a – c , cis-trans isomers) are synthesized in low yields according to the same procedure. The attempted alkylation of the chelate complexes 3a – c remains unsuccessful, whereas the secondary thioformamides react with n-BuLi/CH2Br2 to give the methylene bis(thioformirnidoesters) [Ph2PC(NR1)S]2CH2 (R1 ? Ph (8), Me ( 9 )) in quantitative yields. 相似文献
3.
Hasan M. El Ghanem Saa’Di Abdul Jawad Yazan A. Hussain Adnan S. Abu-Surrah 《Journal of Macromolecular Science: Physics》2014,53(5):878-892
Impedance spectroscopy was utilized to investigate the dielectric properties, ac conductivity and charge transport mechanisms in propylene-alt-CO/ethylene-alt-CO (EPEC) random terpolymer filled with multi-walled carbon nanotubes (MWCNT) as a function of nanofiller content, frequency, and temperature. Equivalent resistor-capacitor (RC) circuit models were proposed to describe the impedance characteristics of the unfilled terpolymer and the nanocomposite at different temperatures. For the nanocomposites, the ac conductivity tended to be frequency independent at low frequencies. At high frequencies, the ac conductivity increased with frequency. The dc conductivity (i.e., plateau of the ac conductivity at low frequencies) at room temperature increased from 10?9 (Ω·m)?1 for the unfilled polymer to l0?3 (Ω·m)?1 for the 6 wt% MWCNT/EPEC nanocomposite. At low temperatures, the equivalent RC model for EPEC-0 and EPEC-2 was found to consist of a parallel RC circuit. However, for 6 wt% MWCNT/EPEC nanocomposite, an RC model consisting of an R/constant phase element (CPE) circuit and a resistor in series was required to describe the impedance behavior of the nanocomposite. 相似文献
4.
Christopher M. Spillmann Jawad Naciri Mu‐San Chen Amritha Srinivasan Banahalli R. Ratna 《Liquid crystals》2013,40(4):373-380
In this report we demonstrate the ability to tune the physical properties of a liquid crystal elastomer (LCE) by varying the amount and type of crosslinking within the elastomer network. LCE films composed of a single mesogenic compound were capable of uniaxial contraction when thermally actuated through the nematic to isotropic phase of the material. We probed the physical properties of the LCE films while varying the amount and concentration of two crosslinking agents and measured actuation strains of 10–35%, elastic moduli of 3–14 MPa, and transition temperatures ranging between 75 and 60°C. The viscous losses of the elastomers and the estimated work capable of being produced by the films were also evaluated. The ability to tune the physical properties of the LCE films allows for a wide range of applications including robotics, microelectromechanical systems (MEMS), shape‐changing membranes, and/or microfluidics. 相似文献
5.
6.
7.
Iqbal Saeed Raza Aadil Butt Muhammad Fasih Uddin Mirza Jawad Iqbal Muhammad Ghafoor Salman El-Hajjar Mohammed 《Optical Review》2021,28(3):278-288
Optical Review - In this paper, we propose a full duplex architecture based on a hybrid link composed of free space optics (FSO) and multimode plastic optical fiber (MMPOF) for short-range wireless... 相似文献
8.
9.
Jawad Y. Abuhlail 《Applied Categorical Structures》2008,16(1-2):13-28
In this paper we introduce and investigate top (bi)comodules of corings, that can be considered as dual to top (bi)modules of rings. The fully coprime spectra of such (bi)comodules attains a Zariski topology, defined in a way dual to that of defining the Zariski topology on the prime spectra of (commutative) rings. We restrict
our attention in this paper to duo (bi)comodules (satisfying suitable conditions) and study the interplay between the coalgebraic
properties of such (bi)comodules and the introduced Zariski topology. In particular, we apply our results to introduce a Zariski
topology on the fully coprime spectrum of a given non-zero coring considered canonically as duo object in its category of
bicomodules.
Supported by King Fahd University of Petroleum & Minerals, Research Project # INT/296. 相似文献
10.
Khalid Bouras Abdelmonaim El Kaddouri Jawad H’michane Mohammed Moussa 《Rendiconti del Circolo Matematico di Palermo》2012,61(3):355-360
We characterize Banach lattices on which each positive operators is b-weakly compact and we derive some characterizations of KB-spaces. 相似文献