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排序方式: 共有293条查询结果,搜索用时 140 毫秒
191.
C Deville A Spyratou P Aguirre-Etcheverry C Besnard AF Williams 《Inorganic chemistry》2012,51(16):8667-8669
Quadruple helical structures are assembled around a tetranuclear cubane structure using four chiral tridentate ligands and two ligands coordinating diagonally across a face. Stereoselectivity in the complex formation is observed. 相似文献
192.
Beata A. Butruk Paulina A. Ziętek Tomasz Ciach 《Central European Journal of Chemistry》2011,9(6):1039-1045
The aim of this study was to develop a method of manufacturing versatile hydrophobic coatings for polymers. Authors present
a simple technique of polyurethane (PU) surface modification with covalently attached silicones (PDMS) or fluorocarbons (PFC).
Diisocyanates were applied as linker molecules. The obtained coatings were characterized using spectroscopic analysis (FTIR),
scanning acoustic microscopy (SAM) and water contact angle measurements. FTIR analysis revealed high efficiency of grafting
reaction. The results of contact angle measurement indicated significant increase of hydrophobicity — from 66° (unmodified
PU) to 113° (PU grafted with PDMS) and 118° (PU grafted with PFC). Acoustic microscopy analysis confirmed satisfactory homogeneity
and smoothness of the fabricated layers. In vitro cell tests revealed non-adherent properties of the surfaces. Both, MTT assay
and fluorescence staining confirmed non-cytotoxicity of the coatings, which makes them potential candidates for use in biomedical
applications.
相似文献
193.
García JJ Zerecero-Silva P Reyes-Rios G Crestani MG Arévalo A Barrios-Francisco R 《Chemical communications (Cambridge, England)》2011,47(36):10121-10123
Nickel(0) catalysts were used to produce substituted imidazoles in good to high yields using benzonitrile, p-substituted benzonitriles and 4-cyanopyridine as starting materials. 相似文献
194.
Adriana Pajares Mabel Bregliani M. Paulina Montaña Susana Criado Walter Massad José Gianotti Isela Gutiérrez Norman A. García 《Journal of photochemistry and photobiology. A, Chemistry》2010,209(2-3):89-94
Within the frame of possible precursory photoreactions in the generation of humic substances, the visible-light promoted interaction between riboflavin (Rf), a native photosensitizer in aqueous systems, and gallic acid (GA), a polyphenol naturally formed after lignin degradation, was investigated. A systematic kinetic and mechanistic study was conducted under aerobic conditions in aqueous media, through visible-light continuous photolysis, polarographic detection of oxygen uptake, stationary and time resolved fluorescence spectroscopy, time resolved near-IR phosphorescence detection and laser flash photolysis techniques. GA is degraded relatively fast in pH 7 aqueous solutions, where singlet molecular oxygen (O2(1Δg)), superoxide radical anion (O2?) and hydrogen peroxide (H2O2) – all three species photogenerated from triplet excited Rf – participate in the photoprocess. The general conclusion is that in natural waters GA can undergo spontaneous phototodegradation under environmental conditions. Radical species generated in the presence of Rf can participate in condensation or polymerization reactions promoting the natural synthesis of humic products. 相似文献
195.
Technologies Employed in the Treatment of Water Contaminated with Glyphosate: A Review 总被引:1,自引:0,他引:1
Patricio J. Espinoza-Montero Carolina Vega-Verduga Paulina Alulema-Pullupaxi Lenys Fernndez Jose L. Paz 《Molecules (Basel, Switzerland)》2020,25(23)
Glyphosate [N-(phosphonomethyl)-glycine] is a herbicide with several commercial formulations that are used generally in agriculture for the control of various weeds. It is the most used pesticide in the world and comprises multiple constituents (coadjutants, salts, and others) that help to effectively reach the action’s mechanism in plants. Due to its extensive and inadequate use, this herbicide has been frequently detected in water, principally in surface and groundwater nearest to agricultural areas. Its presence in the aquatic environment poses chronic and remote hazards to human health and the environment. Therefore, it becomes necessary to develop treatment processes to remediate aquatic environments polluted with glyphosate, its metabolites, and/or coadjutants. This review is focused on conventional and non-conventional water treatment processes developed for water polluted with glyphosate herbicide; it describes the fundamental mechanism of water treatment processes and their applications are summarized. It addressed biological processes (bacterial and fungi degradation), physicochemical processes (adsorption, membrane filtration), advanced oxidation processes—AOPs (photocatalysis, electrochemical oxidation, photo-electrocatalysis, among others) and combined water treatment processes. Finally, the main operating parameters and the effectiveness of treatment processes are analyzed, ending with an analysis of the challenges in this field of research. 相似文献
196.
197.
Reaction Mechanism in Ionic Liquids: Kinetics and Mechanism of the Aminolysis of 4‐Nitrophenyl Acetate
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Paulina Pavez Daniela Millán Mabel Rojas Javiera I. Morales José G. Santos 《国际化学动力学杂志》2016,48(6):337-343
In this work, we report a kinetic study of the reactions of the title compound with secondary alicyclic amines at different temperatures in acetonitrile and several ionic liquids (ILs). From this study, we have described that the reactions in MeCN and in the studied ILs occur by a concerted mechanism and that the activation parameters are sensitive to the structural properties of the ILs. The pKa values of all amines used in both MeCN and ILs were determined. 相似文献
198.
199.
200.
Olimpo García-Beltrán Natalia MenaEdwin G. Pérez Bruce K. Cassels Marco T. Nuñez Francisca WerlingerDaniel Zavala Margarita E. Aliaga Paulina Pavez 《Tetrahedron letters》2011,52(49):6606-6609
Two fluorescence probes for the detection of cysteine (Cys), glutathione (GSH) and other biothiols, such as homocysteine (Hcy) and cysteinyl-glycine (Cys-Gly), were developed. These molecular probes are coumarin-based derivatives containing a chalcone-like moiety that reacts with biothiols through a Michael addition reaction, leading to strong fluorescence enhancements. The reactivity of the tested biothiols toward both probes (ChC1 and ChC2) follows the order Cys > GSH > Hcy > Cys-Gly, ChC1 being less reactive than ChC2. Possible interference with other amino acids was assessed. ChC1 and ChC2 display a highly selective fluorescence enhancement with thiols, allowing these probes to be used for fluorimetric thiol determination in SH-SY5Y cells. 相似文献