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排序方式: 共有106条查询结果,搜索用时 31 毫秒
21.
Aidan H. Coffey Pilsun Yoo Dong Hee Kim Akriti Dr. Matthias Zeller Sona Avetian Prof. Libai Huang Prof. Peilin Liao Prof. Letian Dou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6599-6607
Two-dimensional (2D) organic-inorganic hybrid materials are currently of great interest for applications in electronics and optoelectronics. Here, the synthesis and optical properties of a new type of halide-organothiolate-mixed 2D hybrid material, Pb2X(S-C6H5)3, are reported, in which X is a halide (I, Br, or Cl). Different from conventional lead-based 2D layered materials, these compounds feature unusual five-coordinated lead centers with a stereochemically active electron lone pair on the lead atoms and four-coordinated iodine atoms. The Pb2X(S-C6H5)3 materials feature an indirect bandgap, strongly emissive long-lived self-trap states, and an extremely large Stokes shift. Interestingly, the optical bandgap of the materials can be tuned through variation of the halides; however, the photoluminescence is less sensitive to the composition and is more likely dominated by lead-sulfur lattice interactions or the lead lone-pair electrons. Our results support that a halide–organothiolate mixed anion hybrid structure offers a unique platform for discovering new exciting 2D electronic materials. 相似文献
22.
Adsorption of cetyltrimethylammonium (CTA) and cetylpyridinium (CP) onto Na-rich montmorillonite (MMT) was studied. For this purpose, the adsorption isotherms of CTA and CP, along with desorption curves of metal cations (Na+, K+, Ca2+, Mg2+), were obtained by means of capillary isotachophoresis and atomic absorption spectrometry. Infrared, X-ray diffraction pattern, specific surface area, porosity, and moisture adsorption measurements of montmorillonite revealed that CTA and CP were adsorbed in monolayer arrangements. CTA is assumed to be attached to the negatively charged MMT surface mainly by electrostatic forces. On the other hand, CP, adsorbed in higher amounts, can be additionally bound via other interactions of pyridinium rings, such as induced and pi-pi interactions. By the surfactant adsorption, the montmorillonite surface became hydrophobic and its micro- and mesopores were significantly diminished. Using scanning electron microscopy, aggregation of such organically modified MMT particles was observed. 相似文献
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Vojtech Adam Pavel Hanustiak Sona Krizkova Miroslava Beklova Josef Zehnalek Libuse Trnkova Ales Horna Bernd Sures Rene Kizek 《Electroanalysis》2007,19(18):1909-1914
In this paper we proposed a palladium(II) biosensor. The biosensor is based on determining of interactions between palladium(II) and metallothionein modified hanging mercury drop electrode by means of differential pulse voltammetry. We studied influence of two supporting electrolytes (potassium or sodium chloride) on the signals of the biosensor. Based on the results obtained we found potassium chloride (0.05 M) as the most suitable supporting electrolyte to determine palladium(II). The detection limit of the biosensor for palladium ions was evaluated as 100 nM with RSD about 10%. Moreover, we utilized the biosensor for measurement of the target molecule in the presence of human blood serum and human urine. 相似文献
24.
Electrophoretically mediated microanalysis (EMMA) was applied for the study of kinetic parameters of the bisubstrate enzymatic reaction of rhodanese. The Michaelis constants (K(m)) for both substrates and the effect of temperature on rhodanese reaction were evaluated by means of the combination of the EMMA methodology with a partial filling technique. In this setup, the part of the capillary is filled with the buffer best for the enzymatic reaction whereas, the rest of the capillary is filled with the background electrolyte optimal for separation of substrates and products. The enzymatic reaction was performed in 25 mM N-(2-hydroxymethyl)piperazine-2'-(2-ethanesulfonic acid) (HEPES) buffer (pH 8.5) while the low pH background electrolyte 100 mM beta-alanine-HCl (pH 3.5) was used for separation of substrates and products that are the inorganic anions. The estimated value of K(m) for thiosulfate of 1.30 x 10(-2) M was consistent with previously published values; the K(m) for cyanide of 7.6 x 10(-3) M was determined for the first time. In addition, the type of kinetic mechanism of enzymatic reaction was also elucidated. The finding of the double displacement (ping-pong) mechanism is in accordance with previous literature data. Also, the experimentally determined temperature optimum of the rhodanese-catalyzed reaction around 20-25 degrees C agreed with literature values. 相似文献
25.
Rudolph D. Deanin Carol M. Barry Somsak Woramongconchai Sona C. Parikh 《Macromolecular Symposia》1998,135(1):55-62
Mixed plastics from junked autos were homogenized by milling or extrusion, modified by addition of low-molecular-weight low-melt-viscosity polymers, and processed by compression or injection molding. Properties were comparable with high-density polyethylene and common building panel materials. 相似文献
26.
Stuart J. Rowan Phiriyatorn Suwanmala Sona Sivakova 《Journal of polymer science. Part A, Polymer chemistry》2003,41(22):3589-3596
Supramolecular polymerization, that is, the self-assembly of polymer-like materials through the utilization of the noncovalent bond, has been a developing area of research over the last decade. In this article, we report the synthesis of nucleobase-terminated (N6-anisoyl-adenine and thymine) low-molecular-weight poly(tetrahydrofuran) macromonomers (<2000 g mol−1). The adenine-derived supramolecular telechelic polymer self-assembled in the solid state to yield materials with film- and fiber-forming capabilities. This material was thermally reversible and exhibited a ceiling temperature, above which a drop in viscosity was observed and fibers could no longer be obtained. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3589–3596, 2003 相似文献
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