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71.
Zofia Rzączyńska Anna Danczowska-Burdon Justyna Sienkiewicz-Gromiuk 《Journal of Thermal Analysis and Calorimetry》2010,101(2):671-677
Pyridine-2,5-dicarboxylic acid, known as isocinchomeric acid is one of six isomers containing two carboxylic groups. Light
lanthanide (III) complexes with pyridine-2,5-dicarboxylic acid with general formula Ln2L3·nH2O, where n = 8, 9, were obtained. Their thermal and spectroscopic properties were studied. Sodium salt was obtained as Na2L·H2O. Hydrated complexes of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) are stable to 313–333 K, whereas
Na2L·H2O is stable to about 333 K. Dehydration process for all compounds runs in one stage, next they decompose into appropriate
lanthanide oxalates, oxocarbonates carbonates and finally to metal oxides. Bands of νCOOH vibrations at 1736 and 1728 cm−1 disappear on complex spectra and νas and νs of COO− groups appear thus indicating that complexation process took place. 相似文献
72.
1-Hydroxyphosphonate 1 in the presence of triethylamine in acetonitrile solution undergoes irreversible rearrangement to phosphate 2 and reversible retro-phospho-aldol (retro-Abramov) reaction. The X-ray structures for 1 and 2 revealed that the phosphonate-phosphate rearrangement occurs with retention of configuration at the phosphorus atom. 相似文献
73.
Justyna Jarczyk 《Nonlinear Analysis: Theory, Methods & Applications》2010,72(5):2608-96
Let I⊂R be a non-trivial interval, s:I→(0,∞) be a function, and let φ,ψ be real continuous strictly monotonic functions defined on I. We consider the equation
74.
Justyna Kosakowska 《数学学报(英文版)》2008,24(10):1687-1702
In the present paper we describe a specialization of prinjective Ringel-Hall algebra to 1, for prinjective modules over incidence algebras of posets of finite prinjective type, by generators and relations. This gives us a generalisation of Serre relations for semisimple Lie algebras. Connections of prinjective Ringel-Hall algebras with classical Lie algebras are also discussed. 相似文献
75.
tert‐Butyl(tert‐butoxy)zinc Hydroxides: Hybrid Models for Single‐Source Precursors of ZnO Nanocrystals
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Kamil Sokołowski Dr. Iwona Justyniak Dr. Wojciech Bury Dr. Justyna Grzonka Prof. Zbigniew Kaszkur Łukasz Mąkolski Michał Dutkiewicz Agnieszka Lewalska Elżbieta Krajewska Dominik Kubicki Dr. Katarzyna Wójcik Prof. Krzysztof J. Kurzydłowski Prof. Janusz Lewiński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5488-5495
Alkylzinc alkoxides, [RZnOR′]4, have received much attention as efficient precursors of ZnO nanocrystals (NCs), and their “Zn4O4” heterocubane core has been regarded as a “preorganized ZnO”. A comprehensive investigation of the synthesis and characterization of a new family of tert‐butyl(tert‐butoxy)zinc hydroxides, [(tBu)4Zn4(μ3‐OtBu)x(μ3‐OH)4?x], as model single‐source precursors of ZnO NCs is reported. The direct reaction between well‐defined [tBuZnOH]6 ( 16 ) and [tBuZnOtBu]4 ( 24 ) in various molar ratios allows the isolation of new mixed cubane aggregates as crystalline solids in a high yield: [(tBu)4Zn4(μ3‐OtBu)3(μ3‐OH)] ( 3 ), [(tBu)4Zn4(μ3‐OtBu)2(μ3‐OH)2] ( 4 ), [(tBu)4Zn4(μ3‐OtBu)(μ3‐OH)3] ( 5 ). The resulting products were characterized in solution by 1H NMR and IR spectroscopy, and in the solid state by single‐crystal X‐ray diffraction. The thermal transformations of 2 – 5 were monitored by in situ variable‐temperature powder X‐ray diffraction and thermogravimetric measurements. The investigation showed that the Zn?OH groups appeared to be a desirable feature for the solid‐state synthesis of ZnO NCs that significantly decreased the decomposition temperature of crystalline precursors 3 – 5 . 相似文献
76.
77.
Guzow K Rzeska A Mrozek J Karolczak J Majewski R Szabelski M Ossowski T Wiczk W 《Photochemistry and photobiology》2005,81(3):697-704
Photophysical properties of tyrosine and its derivatives with free and blocked functional groups were studied by steady state and time-resolved fluorescence spectroscopy and global analysis in organic solvents, such as methanol, 2-propanol, tetrahydrofuran (THF), and dimethylsulfoxide (DMSO). The mono-exponential fluorescence intensity decays were observed for all tyrosine derivatives in THF and DMSO solutions, whereas in alcohols some derivatives have bi-exponential decays. The rotamer population calculated from 1H nuclear magnetic resonance spectroscopy in DMSO does not correspond to the pre-exponential factors obtained from fluorescence spectroscopy. Moreover in the case of DMSO, the strong interaction of this solvent with the hydroxyl group of the fluorophore's phenol ring causes substantial changes in the fluorescence and nonradiative rate constants of tyrosine derivatives compared with those of tyrosine with a blocked hydroxyl group, Tyr(Me). The steady state and time-resolved fluorescence measurements in pure organic solvents and water-organic solvent mixtures indicate that the fluorescence quenching of the phenol chromophore of tyrosine by an acetyl or amide group or both depends on the polarity of the solvent used as well as the ability of the solvent to form hydrogen bonds with functional groups of tyrosine. 相似文献
78.
Katarzyna Sukowska-Ziaja Gokhan Zengin Agnieszka Gunia-Krzyak Justyna Popi Agnieszka Szewczyk Magdalena Jaszek Jerzy Rogalski Boena Muszyska 《Molecules (Basel, Switzerland)》2022,27(1)
Fungal mycelium cultures are an alternative to natural sources in order to obtain valuable research materials. They also enable constant control and adaptation of the process, thereby leading to increased biomass growth and accumulation of bioactive metabolites. The present study aims to assess the biosynthetic potential of mycelial cultures of six Ganoderma species: G. adspersum, G. applanatum, G. carnosum, G. lucidum, G. pfeifferi, and G. resinaceum. The presence of phenolic acids, amino acids, indole compounds, sterols, and kojic acid in biomass extracts was determined by HPLC. The antioxidant and cytotoxic activities of the extracts and their effects on the inhibition of selected enzymes (tyrosinase and acetylcholinesterase) were also evaluated. The total content of phenolic acids in the extracts ranged from 5.8 (G. carnosum) to 114.07 mg/100 g dry weight (d.w.) (G. pfeifferi). The total content of indole compounds in the extracts ranged from 3.03 (G. carnosum) to 11.56 mg/100 g d.w. (G. lucidum) and that of ergosterol ranged from 28.15 (G. applanatum) to 74.78 mg/100 g d.w. (G. adspersum). Kojic acid was found in the extracts of G. applanatum and G. lucidum. The tested extracts showed significant antioxidant activity. The results suggest that the analyzed mycelial cultures are promising candidates for the development of new dietary supplements or pharmaceutical preparations. 相似文献
79.
Adam Bieniek Jan Epsztajn Justyna A Kowalska Zbigniew Malinowski 《Tetrahedron letters》2001,42(52):9293-9295
The transformation of the benzanilides 1 into 4-arylisochroman-3-acetic acids 8 applying the following sequence of reactions is described. At first, the 3-arylphthalides 3 were obtained via metallation [n-BuLi] of benzanilides 1 and subsequent treatment of the generated bis-lithiated anilides 2 with aromatic aldehydes. Next, the 3-arylphthalides 3 were reduced [LiBH4] to phthalanes 5 and then, via reductive metallation [Li/C10H8] and reaction of the generated bis-lithiated species 6 with dimethylformamide, 3-hydroxy-4-arylisochromans 7 were produced. In the final step the isochromans 7 were treated with 1-methoxy-1-trimethylsilyloxyethene in the presence of titanium tetrachloride and furnished 4-arylisochromans-3-acetic acid methyl esters 8 as trans stereoisomers (Ψ-e/e). 相似文献
80.
Waldemar Tejchman Przemysaw Koodziej Justyna Kalinowska-Tucik Wojciech Nitek Grzegorz uchowski Anna Bogucka-Kocka Ewa esawska 《Molecules (Basel, Switzerland)》2022,27(7)
The treatment of parasitic infections requires the application of chemotherapy. In view of increasing resistance to currently in-use drugs, there is a constant need to search for new compounds with anthelmintic activity. A series of 16 cinnamylidene derivatives of rhodanine, including newly synthesized methoxy derivatives (1–11) and previously obtained chloro, nitro, and diethylamine derivatives (12–16), was investigated towards anthelmintic activity. Compounds (1–16) were evaluated against free-living nematodes of the genus Rhabditis sp. In the tested group of rhodanine derivatives, only compound 2 shows very high biological activity (LC50 = 0.93 µg/µL), which is higher than the reference drug albendazole (LC50 = 19.24 µg/µL). Crystal structures of two compounds, active 2 and inactive 4, were determined by the X-ray diffraction method to compare molecular geometry and search for differences responsible for observed biological activity/inactivity. Molecular modelling and selected physicochemical properties prediction were performed to assess the potential mechanism of action and applied in the search for an explanation as to why amongst all similar compounds only one is active. We can conclude that the tested compound 2 can be further investigated as a potential anthelmintic drug. 相似文献