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101.
Hitoshi Okuda Ryota Seto Yasuhito Koyama Toshikazu Takata 《Journal of polymer science. Part A, Polymer chemistry》2010,48(19):4192-4199
Poly(arylene thioether)s ( PTEs ) containing 9,9′‐spirobifluorene moieties were synthesized in high yields from 9,9′‐spirobifluorene‐2,2′‐bis(N,N‐dimethylcarbamothioate) 4 as the masked dithiol and various difluoroarenes as electrophilic monomers. All PTEs showed high thermal stability: The 10% weight loss temperature as evaluated by thermogravimetric analysis was over 470 °C under both nitrogen and air atmospheres. The glass transition temperature estimated by DSC was in the range 210–270 °C. The PTEs showed high solubility in ordinary organic solvents, such as CHCl3, NMP, and THF. Most PTEs exhibited remarkably high refractive indices ranging from 1.69 to 1.73 at 587.6 nm, whereas no or little birefringence was observed for the PTEs . © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4192–4199, 2010 相似文献
102.
103.
Ohsumi M Hazama M Fukaminato T Irie M 《Chemical communications (Cambridge, England)》2008,(28):3281-3283
Photochromism of a symmetric diarylmaleimide derivative, having two thiophene rings (1), and a non-symmetric derivative having a S,S-dioxide thiophene ring and a thiophene ring (2) as the aryl moieties, was studied in various solvents. The photocyclization quantum yield of gradually decreased with increasing the solvent polarity and the reaction was not observed in polar solvents, such as ethanol and acetonitrile; on the other hand, such a strong solvent dependence of the photocyclization reaction was not observed for ; the different behavior is attributed to the weaker electron donating ability of the S,S-dioxide thiophene ring. 相似文献
104.
Prof. Dr. Toshikazu Takata Prof. Dr. Koji Yamamoto Kazuki Higuchi Dr. Masahiro Ogawa Ayumi Kawasaki Shunya Mizuno Hikaru Iwasaki Masaki Nagashima Prof. Dr. Yoshihiro Hayashi Prof. Dr. Susumu Kawauchi Prof. Dr. Kazuko Nakazono Prof. Dr. Yasuhito Koyama 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303494
Post-synthesis modification of polymers streamlines the synthesis of functionalized polymers, but is often incomplete due to the negative polymer effects. Developing efficient polymer reactions in artificial systems thus represents a long-standing objective in the fields of polymer and material science. Here, we show unprecedented macrocycle-metal-complex-catalyzed systems for efficient polymer reaction that result in 100 % transformation of the main chain functional groups presumably via a processive mode reaction. The complete polymer reactions were confirmed in not only intramolecular reaction (hydroamination) but also intermolecular reaction (hydrosilylation) by using Pd- and Pt-macrocycle-catalyzed systems. The most fascinating feature of the both reactions is that higher-molecular-weight polymers reach completion faster. Various studies suggested that the reactions occur in the catalyst cavity via the formation of a supramolecular complex between the macrocycle catalyst and polymer substrate like pseudorotaxane, which should be of characteristic of the efficient polymer reactions progressing in a processive mode. 相似文献
105.
Fumio Hamazu Sumio Akashi Tatsuya Koizumi Toshikazu Takata Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1991,29(11):1675-1680
Three benzyl p-hydroxyphenyl methylsulfonium salts with different counter anions were synthesized as novel latent thermal initiators. Syntheses of the sulfonium salts ( 2 ) were performed by the reaction of p-hydroxyphenyl methyl sulfide with benzyl chloride followed by exchange of the counter anion (Cl?) with SbF?6 ( 2a ), PF?6 ( 2b ), or BF?4 ( 2c ). In the bulk polymerization of glycidyl phenyl ether (PGE) with 2 , initiator activity of the sulfonium salts was evaluated by comparison with that of benzyl tetramethylenesulfonium hexafluoroantimonate ( 1 , R = H). Among the initiators, 2a showed the highest activity, and was much more active than 1 (R = H). Since the polymerization of PGE with 2a proceeded efficiently at more than 80°C but not at all at less than 60°C, 2a was suggested to be a good latent thermal initiator. 相似文献
106.
Surasak Seesukphronrarak Shinichi Kawasaki Kana Kobori Toshikazu Takata 《Journal of polymer science. Part A, Polymer chemistry》2007,45(14):3073-3082
Several poly(arylene thioether)s ( PTEs ) containing a fluorene moiety were synthesized by the polycondensation of masked dithiols such as 9,9‐bis(4‐(N,N‐dimethyl‐S‐carbamoyl)phenyl)fluorene and various difluoroarenes. All PTEs were obtained in quantitative yields. The PTEs showed good thermal stability: the 10% weight loss temperature was over 480 °C under both nitrogen and air atmosphere by TGA, and glass temperature was within a range of 204–275 °C by DSC. Most PTEs exhibited remarkably high refractive index values in a range of 1.66–1.72 at 589 nm, whereas they had a very low degree of birefringence properties. Furthermore, the PTEs showed high solubility in ordinary organic solvents such as chloroform, N‐methylpyrrolidone, and tetrahydrofuran. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3073–3082, 2007 相似文献
107.
108.
Organic sulfur compounds such as disulfide, thiolsulfinate, thiolsulfonate, thiol, sodium thiolate, and sodium sultinale were readily oxidized to both sulfinic and sulfonic acids with superoxide anion generated from potassium superoxide and 18-crown-6-ether under mild conditions. However, both sulfide and sulfoxide did not react with superoxide anion, O2-. Although thiol was easily oxidized to disulfide with O2? at room temperature, it was oxidized further with O2? at 60° to the corresponding sulfinic and sulfonic acids. Symmetrical disulfide was obtained in the reaction of unsymmetrical thiolsulfinate or thiolsulfonate along with both sulfinic and sulfonic acids. Most reactive was thiolsulfinate which reacted at lower temperature ranging between ?40 and 0° to afford the products within 30 min. Relative reactivities fall in the following order: thiolsulfinate > thiolsulfonate > disulfide ? sodium thiolate ? sodium sulfinate. Polar solvents such as pyridine and acetonitrile were more effective than such a less polar solvent as benzene in the oxidation of the substrate, and increased amount of the crown ether shortened the reaction time. Nucleophilic attack of O2? and electron transfer processes are believed to be involved in these oxidations. 相似文献
109.
Intramolecular 1,3-dipolar cycloaddition of 2-phenoxybenzonitrile N-oxides to benzene rings, accompanied by dearomatization, formed the corresponding isoxazolines in high yields. The X-ray single-crystal structure analysis revealed that the reaction formed the cis-adduct as a single isomer. The substituents on the benzene rings markedly affected the reaction rate, yield, and structure of the final product. 相似文献
110.
T Fukushima S Horike H Kobayashi M Tsujimoto S Isoda ML Foo Y Kubota M Takata S Kitagawa 《Journal of the American Chemical Society》2012,134(32):13341-13347
The mesoscale design of domain assembly is crucial for controlling the bulk properties of solids. Herein, we propose a modular design of domain assembly in porous coordination polymer crystals via exquisite control of the kinetics of the crystal formation process. Employing precursors of comparable chemical reactivity affords the preparation of homogeneous solid-solution type crystals. Employing precursors of distinct chemical reactivity affords the preparation of heterogeneous phase separated crystals. We have utilized this reactivity-directed crystallization process for the facile synthesis of mesoscale architecture which are either solid-solution or phase-separated type crystals. This approach can be also adapted to ternary phase-separated type crystals from one-pot reaction. Phase-separated type frameworks possess unique gas adsorption properties that are not observed in single-phasic compounds. The results shed light on the importance of crystal formation kinetics for control of mesoscale domains in order to create porous solids with unique cooperative functionality. 相似文献