全文获取类型
收费全文 | 202篇 |
免费 | 11篇 |
专业分类
化学 | 117篇 |
晶体学 | 7篇 |
力学 | 7篇 |
数学 | 26篇 |
物理学 | 56篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 17篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 14篇 |
2008年 | 9篇 |
2007年 | 17篇 |
2006年 | 14篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有213条查询结果,搜索用时 15 毫秒
181.
182.
183.
184.
Alfiya Safiulina Nataliya Borisova Mikhail Grigoriev Dmitriy Baulin Vladimir Baulin Aslan Tsivadze 《Molecules (Basel, Switzerland)》2021,26(8)
With the aim to find new efficient extractants for recovery of f-block elements from processing wastes of different origin, we have compared a series of phosphoryl-containing podands, including (2-(diphenylphosphorylmethoxy)phenyl)diphenylphosphine oxide 1 and its analogues 5–7, where the ArP(O)Ph2 group of phosphine oxide type is replaced by phosphonic fragments. Quantum-chemical modelling of the structures of phosphoryl-containing podands 1 and 5–7 has been performed, which was later confirmed by the data of X-ray diffraction. The features of extraction of nitric acid, as well as U(VI), Th(IV), Nd(III), and Ho(III) with compounds 1 and 5–7 from nitric acid media into 1,2-dichloroethane have been studied. The compositions of extracted complexes have been determined. 相似文献
185.
The stability problem of low-speed plane Couette-Poiseuille flow of air under heat transfer effects is solved numerically
using the linear stability theory. Stability equations obtained from two-dimensional equations of motion and their boundary
conditions result in an eigenvalue problem that is solved using an efficient shoot-search technique. Variable fluid properties
are accounted for both in the basic flow and the perturbation (stability) equations. A parametric study is performed in order
to assess the roles of moving wall velocity and heat transfer. It is found that the moving wall velocity and the location
of the critical layers play decisive roles in the instability mechanism. The flow becomes unconditionally stable whenever
the moving wall velocity exceeds half of the maximum velocity in the channel. With wall heating and Mach number effects included,
the flow is stabilized. 相似文献
186.
Photocatalytic Hydrogen Evolution by Oleic Acid‐Capped CdS,CdSe, and CdS0.75Se0.25 Alloy Nanocrystals
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Emre Aslan Okan Birinci Abdalaziz Aljabour Faruk Özel Ilker Akın Dr. Imren Hatay Patir Dr. Mahmut Kus Prof. Dr. Mustafa Ersoz 《Chemphyschem》2014,15(13):2668-2671
Photocatalytic generation of hydrogen by using oleic acid‐capped CdS, CdSe, and CdS0.75Se0.25 alloy nanocrystals (quantum dots) has been investigated under visible‐light irradiation by employing Na2S and Na2SO3 as hole scavengers. Highly photostable CdS0.75Se0.25 alloy nanocrystals gave the highest hydrogen evolution rate (1466 μmol h?1 g?1), which was about three times higher than that of CdS and seven times higher than that of CdSe. 相似文献
187.
In the present study, Pt4(CH)n (1 ≤ n ≤ 7) and Pt4(benzene)2 metalorganic complexes have been investigated by performing density functional theory within spin polarized local density approximation, generalized gradient approximation and hybrid exchange correlation functionals in terms of the geometric properties, stability and energetics, electronic properties and chemical reactivity indexes. Locally stable isomers are distinguished from transition states by vibrational frequency analysis. Our calculations indicate that Pt4(CH)4 and Pt4benzene metal hydrocarbon complexes are the most stable structures among the studied species. 相似文献
188.
Binding and distribution properties of trimethoprim (TMP) in the presence of various anionic surfactants; sodium octyl sulfate (C8SO4Na), sodium decyl sulfate (C10SO4Na), sodium lauryl sulfate (C12SO4Na), and sodium tetradecyl sulfate (C14SO4Na) has been studied by conductivity, spectrophotometry and surface tension measurements. The surface properties of anionic surfactants, that is, maximum surface excess concentration (Γ max ) and minimum area per surfactant molecule (A min ) at the air/water interface have been evaluated in the absence and presence of TMP using Gibbs adsorption isotherm. From conductivity data the ionization degree and counterion binding parameter have been obtained. Spectrophotometric experiments were used to determine binding constants of TMP to anionic micelles. With the increasing alkyl chain of surfactants, the interaction becomes stronger, which shows the importance of hydrophobic forces and incorporation of TMP molecules to the pure micelles of anionic surfactants increased. The results obtained from the surface tension and conductometric studies have been correlated with those obtained from the spectroscopic studies and binding tendency of TMP to anionic micelles followed the order as: C14SO4Na > C12SO4Na > C10SO4Na > C8SO4Na. From these results, the study of the interaction TMP in different anionic micellar solutions provided information about the characteristics of binding properties of poorly soluble drugs. 相似文献
189.
Pınar Esra Erden Nazife Aslan Alev Doğan Esin Canel Esma Kiliç 《Journal of solution chemistry》2014,43(6):1156-1166
Stoichiometric protonation constants (log10 K 1 and log10 K 2) of some aliphatic dipeptides (Gly–Tyr, Gly–Phe, Gly–Val, Gly–Leu, Gly–Thr, Gly–Met and Gly–Pro) were determined potentiometrically in 20, 40, and 60 % (v/v) 1,4-dioxane–water and dimethyl sulfoxide–water mixtures at 25.0 (±0.1) °C with an ionic strength of 0.10 mol·L?1 sodium chloride. The protonation constants were calculated with the computer program PKAS and selection of the best fit chemical models is based on the statistical parameters. The effects of solvent composition on these protonation constants are discussed to determine the factors which control these processes. It has been observed that, while the correlation between log10 K 1 and log10 K 2 with the percentages of dimethyl sulfoxide in the dimethyl sulfoxide–water mixtures are not linear, these values linearly increase as the concentration of 1,4-dioxane increases in the solvent mixtures. 相似文献
190.