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61.
For a noncommutative configuration space whose coordinate algebra is the universal enveloping algebra of a finite-dimensional Lie algebra, it is known how to introduce an extension playing the role of the corresponding noncommutative phase space, namely by adding the commuting deformed derivatives in a consistent and nontrivial way; therefore, obtaining certain deformed Heisenberg algebra. This algebra has been studied in physical contexts, mainly in the case of the kappa-Minkowski space-time. Here, we equip the entire phase space algebra with a coproduct, so that it becomes an instance of a completed variant of a Hopf algebroid over a noncommutative base, where the base is the enveloping algebra. 相似文献
62.
Vladislava Mičková Silvia Ružičková Dagmar Remeteiová Martina Laubertová Marianna Dorková 《Chemical Papers》2018,72(5):1231-1238
Sampling is the most important procedure in arriving at the value of an electronic scrap. Inappropriate sampling makes other procedures, including assaying, valueless, as the sample must really represent the electronic scrap from which it was taken. The aim of this study was to develop the procedure to investigate the composition of heterogeneous printed circuit boards (PCBs) material and to show its applicability as well as its related limitations. The contents of Cu, Pb, Ni, and Zn in PCBs from wasted mobile phones were determined. Mixtures of aqua regia, hydrogen peroxide and hydrofluoric acid were applied to sample digestion. Open and closed vessel wet digestion with or without heating and microwave-assisted one was realized. For these purposes different sample amounts (0.2, 0.4, and 0.5 g) were applied and on the basis of calculated relative standard deviation values (RSD), the precision of repeated the most effective digestion was evaluated. The microwave-assisted wet digestion and mixture of aqua regia and hydrogen peroxide was found as the most effective one of the compared mixtures and applied conditions. A sample amount of 0.5 g was found as the most suitable. RSD values confirm the importance of electronic waste material sample preparation. 相似文献
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64.
Yoshiki Chujo Akio Naka Martina Krämer Kazuki Sada Takeo Saegusa 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):1213-1223
Abstract This paper describes the synthesis of various star-shaped polymers by means of complexation of bipyridyl-terminated polyoxyethylene with Ru(II) ion. Three kinds of bipyridyl-terminated polyoxyethylenes of different molecular weights were prepared from the corresponding polyoxyethylene monomethyl ethers with narrow molecular weight distributions. Bipyridyl was found to be introduced quantitatively at the end of the polymers based on the results of UV spectra. The formation of a star-shaped polymer was carried out by the reaction of RuCl3 with three equivalents of bipyridyl-terminated polyoxyethylene. The UV spectrum of the star-shaped polymer obtained supported the formation of a typical Ru(II) tris(bipyridyl) complex. From the results of GPC, the star-shaped polymer obtained had a higher molecular weight than the pre-polymer and showed a narrow molecular weight distribution. In the case of a Ni(II) or a Co(II) complex, however, the star-shaped polymer was found to be dissociated into three linear prepolymers under the conditions of GPC measurement. 相似文献
65.
Kathrin Schreglmann Martina Hoeche Sibylle Steinbeiss Sandra Reinnicke Martin Elsner 《Analytical and bioanalytical chemistry》2013,405(9):2857-2867
Environmental degradation of organic micropollutants is difficult to monitor due to their diffuse and ubiquitous input. Current approaches—concentration measurements over time, or daughter-to-parent compound ratios—may fall short, because they do not consider dilution, compound-specific sorption characteristics or alternative degradation pathways. Compound-specific isotope analysis (CSIA) offers an alternative approach based on evidence from isotope values. Until now, however, the relatively high limits for precise isotope analysis by gas chromatography—isotope ratio mass spectrometry (GC-IRMS) have impeded CSIA of sub-microgram-per-liter scale micropollutant concentrations in field samples. This study presents the first measurements of C and N isotope ratios of the herbicide atrazine and its metabolite desethylatrazine at concentrations of 100 to 1,000 ng/L in natural groundwater samples. Solid-phase extraction and preparative HPLC were tested and validated for preconcentration and cleanup of groundwater samples of up to 10 L without bias by isotope effects. Matrix interferences after solid-phase extraction could be greatly reduced by a preparative HPLC cleanup step prior to GC-IRMS analysis. Sensitivity was increased by a factor of 6 to 8 by changing the injection method from large-volume to cold-on-column injection on the GC-IRMS system. Carbon and nitrogen isotope values of field samples showed no obvious correlation with concentrations or desethylatrazine-to-atrazine ratios. Contrary to expectations, however, δ 13 C values of desethylatrazine were consistently less negative than those of atrazine from the same sites. Potentially, this line of evidence may contain information about further desethylatrazine degradation. In such a case, the common practice of using desethylatrazine-to-atrazine ratios would underestimate natural atrazine degradation. 相似文献
66.
Portable chemiluminescence multiplex biosensor for quantitative detection of three B19 DNA genotypes
Mara Mirasoli Francesca Bonvicini Luisa Stella Dolci Martina Zangheri Giorgio Gallinella Aldo Roda 《Analytical and bioanalytical chemistry》2013,405(2-3):1139-1143
A miniaturized multiplex biosensor exploiting a microfluidic oligonucleotide array and chemiluminescence (CL) lensless imaging detection has been developed for parvovirus B19 genotyping. The portable device consists of a reaction chip, comprising a glass slide arrayed with three B19 genotype-specific probes and coupled with a polydimethylsiloxane microfluidic layer, and a charge-coupled device camera modified for lensless CL imaging. Immobilized probes were used in DNA hybridization reactions with biotin-labeled targets, and then hybrids were measured by means of an avidin-horseradish peroxidase (HRP) conjugate and CL detection. All hybridization assay procedures have been optimized to be performed at room temperature through the microfluidic elements of the reaction chip, with sample and reagents delivery via capillary force exploiting adsorbent pads to drive fluids along the microchannels. The biosensor enabled multiplex detection of all B19 genotypes, with detectability down to 80 pmol?L?1 for all B19 genotype oligonucleotides and 650 pmol?L?1 for the amplified product of B19 genotype 1, which is comparable with that obtained in traditional PCR-ELISA formats and with notably shorter assay time (30 min vs. 2 h). The specificity of the assay has been evaluated by performing DNA–DNA hybridization reactions among sequences with different degrees of homology, and no cross hybridizations among B19 genotypes have been observed. The clinical applicability has been demonstrated by assaying amplified products obtained from B19 reference serum samples, with results completely consistent with the reference PCR-ELISA method. The next crucial step will be integration in the biosensor of a miniaturized PCR system for DNA amplification and for heat treatment of amplified products. Figure
A portable multiplex biosensor was developed for detection and genotyping of parvovirus B19 DNA, exploiting lensless CL imaging. The reaction chip is composed of a polydimethylsiloxane microfluidic layer coupled with a glass slide on which oligonucleotide probes specific for three different B19 genotypes are covalently immobilized in a 3?×?3 array. The reaction chip was used in hybridization reactions with biotin-labeled targets and then hybrids were then detected by means of an avidin-HRP conjugate, upon addition of a CL substrate for HRP 相似文献
67.
Sven Zukunft Martina Sorgenfrei Cornelia Prehn Gabriele Möller Jerzy Adamski 《Chromatographia》2013,76(19-20):1295-1305
Dried blood spot (DBS) samples are already successfully used in newborn screening and pharmacological analyses. The application of DBS matrix to further metabolomic methods will considerably extend the analytical options for the diagnostics of metabolic diseases. We present an MS/MS based method for the simultaneous extraction and quantification of 188 metabolites from dried blood spots. We provide a sensitive and reproducible method that adapts the AbsoluteIDQ? p180 kit of Biocrates to the DBS matrix for the quantification of metabolites of different substance classes including amino acids, biogenic amines, free carnitine, acylcarnitines, hexoses, glycerophospholipids, lysophosphatidylcholines, phosphatidylcholines, and sphingolipids. 相似文献
68.
Rolf Carlson Alexandre Descomps Alemayehu Mekonnen Andreas Westerlund Martina Havelkova 《合成通讯》2013,43(19):2939-2945
A convenient procedure for the synthesis of 1-bromo-3-buten-2-one, 4, from commercially available 2-ethyl-2-methyl-1,3-dioxolane, 1, is described. The procedure involves three reaction steps: (1) The acetal 1 is converted to 2-(1-bromoethyl)-2-bromomethyl-1,3-dioxolane, 2, by reacting 1 with elemental bromine in dichloromethane to yield 98% of 2. (2) Dehydrobromination of 2 with potassium tert-butoxide in tetrahydrofuran gives 2-bromomethyl-2-vinyl-1,3-dioxolane, 3, in 84–93% yield. (3) Removal of the acetal protection from 3 by formolysis for 6–10 h afforded 1-bromo-3-buten-2-one, 4, in 85–94% yield. A more rapid method is acid hydrolysis of 3 under microwave activation (100 °C, 8–10 min), by which 4 was obtained in 75% yield. Full experimental details are given.
69.
70.
Martina Mazzoni Lorenzo Franco Alberta Ferrarini Carlo Corvaja Giovanni Zordan Gianfranco Scorrano 《Liquid crystals》2013,40(2):203-208
A nitroxide [60]fullerene adduct containing a pyrrolidine-1-oxyl group has been synthesized. Its orientational order in the nematic phase of the liquid crystal solvent 4,4′-azoxyanisole (PAA) has been measured from the variation of the EPR spectral parameters on passing from the isotropic to the nematic phase. Highly resolved EPR lines allow for precise evaluation of the shifts of the g, a N and a H values. Since the g and the hyperfine tensors are known, the order matrix could be obtained. This is compared with the one calculated with a theoretical model based on short range solute-solvent interactions, which predicts a considerable degree of orientation of the molecular axes, despite the almost spherical shape of the molecule. The agreement with experimental findings is quite good and it is further improved if a bent structure of the pyrrolidine ring is taken into account. 相似文献