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291.
To improve the separation of monosulfate glycosaminoglycan disaccharide isomers by microchip electrophoresis, we found that addition of 1,4-dioxane (DO) dramatically improved analyte resolution, probably due to solvation effects. Methylcellulose (MC) was tested for the ability to suppress EOF and analyte adsorption to the chip. To improve analyte resolution, buffer pH, beta-CD, and DO were systematically investigated. Fast separation was achieved by increasing the electric field strength, and field-amplified sample stacking occurred with increasing buffer concentrations. Therefore, based on our findings, we describe an efficient method for the separation of monosulfate and trisulfate unsaturated disaccharides (DeltaDi-UA2S, DeltaDi-4S, DeltaDi-6S, and DeltaDi-triS) derivatized with 2-aminoacridone hydrochloride. A mixture of monosulfate disaccharide isomers (DeltaDi-UA2S, DeltaDi-4S, and DeltaDi-6S) was baseline-separated within 75 s on a poly(methyl methacrylate) chip using a mixed buffer (DO/running buffer 57:43 v:v), 0.5% MC, pH 6.81, with an E(sep) of 558 V/cm. The theoretical plate was in the range of 5 x 10(5) to 1 x 10(6) m-1. 相似文献
292.
We describe a microchip electrophoresis (MCE) method for the assay of unsaturated disaccharides of chondroitin sulfates, dermatan sulfates, and hyaluronic acid (HA). Poly(vinyl alcohol) (PVA) could be irreversibly adsorbed onto poly(methyl methacrylate) (PMMA) substrates and this approach was applicable for dynamic coating. The characteristics of the PMMA surface with PVA coating were evaluated in terms of the wettability, EOF, and adsorption of 2-aminoacridone (AMAC)-labeled disaccharide. The water contact angle decreased from 73 degrees on a pristine PMMA surface to 37.5 degrees on a PVA-coated surface, indicating that the PVA coating increased hydrophilicity. EOF was reduced approximately twofold and was relatively stable. Scanning electron microscopy and fluorescence microscopy images showed that adsorption of AMAC-labeled disaccharides was dramatically suppressed. Using the PVA coating, baseline separation of two pairs of glycosaminoglycan (GAG) disaccharide isomers, DeltaDi-diS(B)/DeltaDi-diS(D) and DeltaDi-0S/DeltaDi-HA, was achieved in Tris-borate buffer within 130 s by MCE. 相似文献
293.
A dynamic coating using methylcellulose (MC) and a nonionic detergent (polysorbate 20) was developed, which controlled protein adsorption onto the surface of microchannels on a microchip made of poly(methyl methacrylate) (PMMA). Optimum concentration of polysorbate 20 in combination with the range of MC concentrations controlled the protein adsorption onto the microchannel surface, and increased the solubility of the protein samples while facilitating the injection of high concentrations of MC solutions into the microchannels. Higher concentrations of nonionic detergent increased the EOF mobility as opposed to the electrophoretic mobility and caused the electrophoresis to fail. Nondenaturing microchip electrophoresis of protein samples with molecular masses ranging from 20 to 100 kDa were completed in 100 s. Also, successful separation of a BSA sample and its complex with anti-BSA mAb ( 220 kDa) was achieved on a PMMA microchip. The separation exhibited high reproducibility in both migration time (RSD = 1%) and peak area (RSD = 10-15%). 相似文献
294.
Hyoe Hatakeyama Yoshinobu Izuta Ken Kobashigawa Shigeo Hirose Tatsuko Hatakeyama 《Macromolecular Symposia》1998,130(1):127-138
Polyurethane (PU) sheets were prepared from glucose-, fructose-and sucrose-based polycaprolactones (PCL). The obtained saccharide-based PCL's were characterized by gel permeation chromatography, Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The glass transition temperature, thermal degradation temperature, tensile strength, elongation and Young's modulus of the PU sheets were measured. The obtained results suggest that the molecular motion of PU's is enhanced with increasing fraction of PCL chains in PU molecules, and that at the same time the saccharide components act as hard segments. 相似文献
295.
Aiko Nakano Atsuhiro Osuka Iwao Yamazaki Tomoko Yamazaki Yoshinobu Nishimura 《Angewandte Chemie (International ed. in English)》1998,37(21):3023-3027
Up to 14 porphyrin rings are present in the title compounds 1 , which are readily available with high regioselectivity from linear nickel–zinc porphyrins. Upon irradiation with light a rapid energy transfer from the peripheral porphyrin rings to the diporphyrin core takes place. 相似文献
296.
Kohji Ohno Yoshinobu Tsujii Takeshi Fukuda 《Journal of polymer science. Part A, Polymer chemistry》1998,36(14):2473-2481
Controlled free radical polymerization of sugar-carrying methacrylate, 3-O-methacryloyl-1,2 : 5,6-di-O-isopropylidene-d-glucofuranose (MAIpGlc) was achieved by the atom transfer radical polymerization (ATRP) technique with an alkyl halide/copper-complex system in veratrole at 80°C. The time–conversion first-order plot was linear and the number-average molecular weight increased in direct proportion to the ratio of the monomer conversion to the initial initiator concentration, providing PMAIpGlc with a low polydispersity. The sequential addition of the two monomers styrene (S) and MAIpGlc afforded a block copolymer of the type PS-b-PMAIpGlc. The acidolysis of the homo- and block copolymers gave well-defined glucose-carrying water-soluble polymers PMAGlc and PS-b-PMAGlc, respectively. The amphiphilic PS-b-PMAGlc block copolymer exhibited a microdomain surface morphology with spherical PS domains in a PMAGlc matrix. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2473–2481, 1998 相似文献
297.
Yoshinobu Inouye Yoshiko Sakaino 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):884-887
Red non‐solvate crystals of the title compound from ethanol, C23H19N3O4, orange solvate crystals from tert‐butanol, C23H19N3O4·C4H10O, yellow solvate crystals from dioxane–water, C23H19N3O4·0.5C4H8O2, and intense yellow solvate crystals from benzene–N,N′‐dimethylformamide, C23H19N3O4·C6H6, differ from each other in their molecular conformation and hydrogen‐bonding scheme. The bathochromic shifts of the crystal color are explained by the molecular planarity and charge‐transfer effect among the imidazole molecules. 相似文献
298.
Yoshinobu Inouye 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):e361-e362
The reduction of (1R,8R,11R)‐3,3,11‐trimethyl‐6,6‐ethylenedioxybicyclo[6.3.0]undecan‐2‐one, C16H26O3, (I), gave exclusively an alcohol, C16H28O3, (II). The stereochemistry of the hydroxyl group in (II) was shown as R. The conformation around the eight‐membered carbocycle in (I) differs markedly from that in (II). 相似文献
299.
Yasutomo Kajikawa 《哲学杂志》2020,100(15):2018-2039
ABSTRACT The temperature dependence of the reduced activation energy w?=?ε/kBT of the conductivity σ has been utilised for determining the impurity conduction mechanism in doped semiconductors in many studies. Herein, the formula for deconvoluting w when plural conduction mechanisms appear is used to confirm the analysis of the data of the Hall-effect measurements on Al-doped n-ZnSe samples. The analysis is performed on the basis of an impurity-Hubbard-band model which includes ε 2 conduction in the top Hubbard band as well as ε 3 and Efros-Shklovskii (ES) variable-range hopping (VRH) conduction processes in the bottom Hubbard band. As the result of the analysis, transitions among the three hopping conduction mechanisms of ε 2, ε 3, and ES VRH are clearly shown in the temperature dependence of w as well as in that of the Hall mobility, which are hardly noticed in the temperature dependence of σ. In addition, the power-law exponent of the prefactor of ES VRH conductivity is determined through the fit to the temperature dependence of w to show that it decreases from ~ 1.5 to ~ 0 with increasing net donor concentration. 相似文献
300.
The light-addressable potentiometric sensor (LAPS) represents a versatile platform for chemical and biosensing. Thanks to the light addressability, the flat sensor surface of a LAPS can be flexibly divided into areas or pixels, each functioning as an independent sensor that can be modified with various sensing materials for measuring different ions or molecules. Since it first appeared in the late 1980s, it has been applied to various cells and biological samples, driven by technological developments. In this short review, the principles of a LAPS and its variants are briefly described focusing on recent trends and applications to cells and biosensing. 相似文献