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排序方式: 共有114条查询结果,搜索用时 31 毫秒
1.
A. Kirstin Sockwell Prof. Dr. Modi Wetzler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(10):2380-2388
The promise of polyhydroxamic acid ligands for the selective chelation of the f-block elements is becoming increasingly more apparent. The initial studies of polyhydroxamic acid siderophores showed the formation of highly stable complexes with PuIV, but a higher preference for FeIII hindered effective applications. The development of synthetic routes toward highly pure and customizable ligands containing multiple hydroxamic acids allowed for the growth of new classes of compounds. Although the first round of these ligands focused on the incorporation of siderophore-like frameworks, the new synthetic strategies led to small molecules of various frameworks and even resins for applications in the field of f-block element separations and biological desorption. Unfortunately, a lack of consistent stability-constant data makes direct comparisons across this body of work difficult. More studies into the stability constants and separations of the f-block elements in a variety of pH ranges is necessary to truly realize the potential for polyhydroxamic acid ligands. 相似文献
2.
Laurence Muhr Steve Pontvianne Katalin Selmeczi Cdric Paris Sandrine Boschi‐Muller Laetitia Canabady‐Rochelle 《Journal of separation science》2020,43(11):2031-2041
Some metal‐chelating peptides have antioxidant properties, with potential nutrition, health, and cosmetics applications. This study aimed to simulate their separation on immobilized metal ion affinity chromatography from their affinity constant for immobilized metal ion determined in surface plasmon resonance, both technics are based on peptide‐metal ion interactions. In our approach, first, the affinity constant of synthetic peptides was determined by surface plasmon resonance and used as input data to numerically simulate the chromatographic separation with a transport‐dispersive model based on Langmuir adsorption isotherm. Then, chromatographic separation was applied on the same peptides to determine their retention time and compare this experimental tR with the simulated tR obtained from simulation from surface plasmon resonance data. For the investigated peptides, the relative values of tR were comparable. Hence, our study demonstrated the pertinence of such numerical simulation correlating immobilized metal ion affinity chromatography and surface plasmon resonance. 相似文献
3.
Dr. Dorian Didier Dr. Pierre‐Olivier Delaye Marwan Simaan Biana Island Dr. Guillaume Eppe Dr. Hendrik Eijsberg Amir Kleiner Prof. Dr. Paul Knochel Prof. Dr. Ilan Marek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):1038-1048
The copper‐catalyzed carbomagnesiation reaction of cyclopropenyl esters 1 leads to various substituted cyclopropanes species 3 in good yields with very high diastereoselectivities. The reaction proceeds through a syn‐chelated carbomagnesiation reaction and could be extended to various cyclopropenylmethyl ester derivatives 5 . The potential of this approach was illustrated by the preparation of two consecutive all‐carbon quaternary stereocenters. However, the carbometalation reaction needs to be performed at temperature ranging from ?35 to ?20 °C to avoid subsequent fragmentation reaction into stereodefined β,γ‐nonconjugated unsaturated esters 4 . Alternatively, the carbocupration reaction with organocopper species could also be performed to leads to configurationally stable cyclopropyl copper species 2[Cu] . Additionally, when the Lewis acid character of the copper center is decreased (i.e., RCuCNLi), the reaction proceed with an anti‐selectivity. The diastereodivergent behavior of these organometallic species is of synthetic interest, since both diastereomers syn‐ 3 and anti‐ 3 can be obtained, at will, from the same precursor cyclopropenyl esters 1 . 相似文献
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Abstract The binding of pyrenesulfonic acid and pyrenebutyric acid to poly(vinyl benzyl trimethylammonium) chloride was investigated by UV and fluorescence spectroscopy. It was found that the binding constant was 7.5 × 104 and 3.5 × 104M?1, respectively. The addition of the polyelectrolyte quenches the fluorescence of the pyrene group, and at the same time the typical excimer emission appears. This emission originates in pre-formed ground state aggregates of the pyrene derivatives incorporated into the polyion domain. Similar effects were observed when anionic polyelectrolytes, poly(styrene sulfonic), and poly(vinyl sulfonic) acids were added to cationic pyrene derivatives. The binding constants depend on the length of the aliphatic sidechain of the derivatives. 相似文献
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讨论了近 10年来发展较为活跃的螯合离子色谱 (CIC)的原理及其系统组成和分析流程 ,高效螯合离子色谱(HPCIC)的原理 ,高效螯合固定相的类型、应用范围及优缺点等 ,其中包括化学键合、永久涂敷或动态涂敷的高效螯合固定相 , 5 3篇。 相似文献
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Superparamagnetic magnetite nanoparticles were synthesized induced by chitosan hydrogel under ambient conditions via iron ions assembly, and the inducing effect of chitosan hydrogel was discussed. Results of X‐ray diffraction and transmission electron microscopy indicate that the nanoparticles were inverse cubic spinel structure magnetite with diameter about 16 nm, and the superparamagnetic nanoparticles with narrow size distribution dispersed uniformly in chitosan. The magnetization measurements indicated that the nanoparticles showed the typical superparamagnetic behavior. The crystallinity, morphology, and magnetic properties of magnetite nanoparticles were remarkably influenced by the pH values of iron ion solutions. The interaction between magnetite and chitosan was illustrated by FT‐IR and thermogravimetric analysis, which concluded that the magnetite nanoparticles were coated by a chitosan layer via the amino groups of chitosan. The chitosan hydrogel assisted in the synthesis of superparamagnetic magnetite nanoparticles through chelation by amino groups. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
Audrey Devatine Jean Paul Canselier Nadine Gabas Joël Jaud 《Journal of chemical crystallography》2003,33(2):85-90
The new crystal and molecular structures of a less common hydrated calcium L(–)-malate (calcium (2S) 2-hydroxybutanedioate trihydrate) Ca(C4H4O5)3H2O, are reported. X-ray crystallographic data are as follows: a = 6.6460(3) Å, b = 8.3795(3) Å, c = 8.2707(4) Å, = 112.640(2)°, V = 425.1(4) Å3, space group P21 (No. 4), Z = 2, D
calc = 1.767 g cm–3. The calcium ion coordination number is seven. One of the three water molecules present in the unit cell is less strongly bound, only interacting with a calcium ion. In aqueous or hydroalcoholic solution, both di- and trihydrated species crystallize simultaneously. 相似文献