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91.
Gorkem Yilmaz Muhammet U. Kahveci Yusuf Yagci 《Macromolecular rapid communications》2011,32(23):1906-1909
Current preparation methods for hydrogels based on redox or photopolymerization of water soluble monomers are simple to use, and flexible, but have the drawback of requiring additional modification steps for tuning or introducing properties for specific purposes. We have devised a simple and rapid synthetic strategy to prepare hydrogels possessing reactive sites to incorporate any molecules of interest by “Click Chemistry”. The strategy is based on the use of propargyl acrylamide (PAm) as comonomer together with acrylamide (AAm) and N,N′‐methylene bisacrylamide (BAAm) as crosslinker in photoinitiated polymerization. With the selective reactivity of photochemically generated free radicals towards acrylic function of PAm, hydrogels with clickable acetylene groups can be prepared in one pot, one step manner. Based on the acetylene functionality, any molecule possessing azide groups can be conjugated onto hydrogel by “Click Chemistry” as demonstrated on the example of fluoroscent azide functional pyrene. 相似文献
92.
We demonstrate here the rational design of a conformationally flexible C2-symmetric iodosylarene 8g based on secondary n-σ∗ or hydrogen-bonding interactions as a chiral catalyst for the enantioselective Kita oxidative spirolactonization of 1-naphthol derivatives 5. Iodosylarenes 8 were generated in situ from iodoarenes 7 and mCPBA as a co-oxidant. Furthermore, epoxyspirolactone 15 was obtained by the one-pot oxidation of 5 with mCBPA in the presence of 7g. Thus, the enantioselective oxidation of 5 to 6 and the successive enantio- and diastereo-selective oxidation of 5 to 15 proceeded in good yields when we controlled the amount of mCPBA. 相似文献
93.
Abdulhadi Baykal Hüseyin Kavas Zehra Durmu? Mine Demir Sinan Kazan Ramazan Topkaya Muhammet S. Toprak 《Central European Journal of Chemistry》2010,8(3):633-638
We report on the synthesis of Mn3O4 nanoparticles (NPs) using a novel sonochemical method without requiring any pH adjustment. Synthesized material was identified
as tetragonal hausmannite crystal structure model of Mn3O4 from XRD analysis. Crystallite size was estimated from x-ray line profile fitting to be 17±5 nm. FTIR analysis revealed stretching
vibrations of metal ions in tetrahedral and octahedral coordination confirming the crystal structure. TEM analysis revealed
a dominantly cubic morphology of NPs with an average size of ∼20 nm. Magnetic evaluation revealed a blocking temperature,
T
B of 40 K above which the material behaves paramagnetic. Asymmetric coercive field is attributed to the interaction between
ferromagnetic Mn3O4 and antiferromagnetic Mn oxide at the surface of nanoparticles.
相似文献
94.
95.
A tridentate bisbenzimidazole-pyridine ligand (L-C5) with two pentyl side-units and its metal complexes with Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ metal ions were synthesized and characterized. The structures of the ligand (L-C5) and its five coordinate [Mn(L-C5)Cl2] were elucidated by single crystal X-ray diffraction studies. The absorption and photoluminescence properties of the compounds were studied in solution media. The ligand is highly fluorescent, and binding of the metal ions to the ligand has caused significant changes in the emission band (shift or quenching). Moreover, the effect of aggregation on UV–Vis. absorption and emission properties was examined in MeOH-water mixtures. The ligand was found to show aggregation-induced quenching in the MeOH-water mixture. The ligand was also screened for its colorimetric and fluorometric sensing ability of several metal ions [Na+, K+, Mg2+, Al3+, Ca2+, Mn2+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Hg2+, Pb2+]. The ligand showed selective sensing ability towards Zn2+, and the limit of detection was calculated as 3.09 × 10−7 m . The ligand also showed a distinguishable color change in the presence of Fe2+ under daylight. 相似文献
96.
97.
AbstractA new series of water-compatible proline catalysts (4–6) derived from calixarene bearing a hydrophobic nature have been synthesised. It was found that the compound 4 was a highly efficient organocatalyst for aldol reactions occurred in the water. Under optimised reaction conditions, high yields (up to 82%), good enantioselectivities (ee up to 81%) and high diastereoselectivities (dr up to 91:9) were obtained. 相似文献
98.
99.
Muhammet Y?ld?r?mYa?ar Dürüst 《Tetrahedron》2011,67(18):3209-3215
1,3-Dipolar cycloaddition of in situ generated C,N-diaryl nitrilimines to 2-methyl-2-vinyl oxirane gives rise to the regioselective formation of novel 5-(2-methyloxiranyl)-4,5-dihydropyrazole derivatives in moderate to good yields. The structures and stereochemistries of the new cycloadducts were confirmed by spectroscopic/physical methods including X-ray diffraction data. 相似文献
100.
Several 6-substituted-8-nitrothiazolo[3,2-c]pyrimidine derivatives have been obtained very efficiently by a multicomponent cyclisation of 2-(nitromethylene)thiazolidine, formaldehyde and various aliphatic or aromatic amines in water, using both microwave irradiation and conventional heating. Reaction yields were considerably higher and the reaction times very much reduced using microwave heating when compared to conventional heating, resulting in the definition of a rapid and efficient synthetic protocol. 相似文献