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Fabio Mazzotti Leonardo Di Donna Hicham Benabdelkamel Bartolo Gabriele Anna Napoli Giovanni Sindona 《Journal of mass spectrometry : JMS》2010,45(4):358-363
Pterostilbene (trans‐3,5‐dimethoxy‐4‐hydroxystilbene) is an active component found in several plant species, exhibiting important pharmacological properties. A new and reliable method of assaying this phyto compound in various matrices is presented; the assay is based on (1) the selectivity of liquid chromatography (LC) hyphenated with electrospray ionisation (ESI), (2) the specificity of a two‐step mass spectrometric analysis (MS/MS) and (3) the accuracy of the isotope dilution method. The labelled analogue may be conveniently synthesised in a few steps. The sensitivity of the method is confirmed by the very low limit of detection (LOD) and limit of quantitation (LOQ) values achieved in the assay of pterostilbene in two distinct fortified matrices, and is further supported by the observed accuracy values. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Bruno M. Soares Ederson R. Pereira Juliana V. Maciel Augusto A. Vieira Fabio A. Duarte 《Journal of separation science》2013,36(20):3411-3418
This work reports the development of a dispersive liquid – liquid microextraction method for the simultaneous extraction, preconcentration, and derivatization of Hg2+ and CH3Hg+ species from water samples for further determination by GC – MS. Some parameters of the proposed method, such as volume and type of disperser and extraction solvent, and Na[B(C6H5)4] concentration were investigated using response surface methodology. Suitable recoveries were obtained using 80 μL C2Cl4 (as extraction solvent), 1000 μL ethanol (as disperser solvent), and 300 μL 2.1 mmol/L Na[B(C6H5)4] (as derivatizing agent). Accuracy was evaluated in terms of recovery and ranged from 87 to 99% with RSD values <7%. In addition, a certified reference material of water (NIST 1641d) was analyzed and agreed with the certified value about 107% (for Hg2+), with RSD values <8.5%. LODs were 0.3 and 0.2 μg/L, with enrichment factors of 112 and 115 for Hg2+ and CH3Hg+, respectively. The optimized method was applied for the determination of Hg2+ and CH3Hg+ in tap, well, and lake water samples. 相似文献
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Fátima Milhano Santos Augusto Quaresma Pedro Rui Filipe Soares Rita Martins Maria João Bonifácio João António Queiroz Luís António Passarinha 《Journal of separation science》2013,36(11):1693-1702
Despite of membrane catechol‐O‐methyltransferase (MBCOMT, EC 2.1.1.6) physiological importance on catecholamines’ O‐methylation, no studies allowed their total isolation. Therefore, for the first time, we compare the performance of three hydrophobic adsorbents (butyl‐, epoxy‐, and octyl‐Sepharose) in purification of recombinant human COMT (hMBCOMT) from crude Brevibacillus choshinensis cell lysates to develop a sustainable chromatographic process. Hydrophobic matrices were evaluated in terms of selectivity and hMBCOMT's binding and elution conditions. Results show that hMBCOMT's adsorption was promoted on octyl and butyl at ≤375 mM NaH2PO4, while on epoxy higher concentrations (>850 mM) were required. Additionally, hMBCOMT's elution was promoted on epoxy, butyl, and octyl using respectively 0.1–0.5, 0.25–1, and 1% of Triton X‐100. On butyl media, a stepwise strategy using 375 and 0 mM NaH2PO4, followed by three elution steps at 0.25, 0.7 and 1% Triton X‐100, allowed selective hMBCOMT isolation. In conclusion, significant amounts of MBCOMT were purified with high selectivity on a single chromatography procedure, despite its elution occurs on multiple peaks. Although successful applications of hydrophobic interaction chromatography in purification of membrane proteins are uncommon, we proved that traditional hydrophobic matrices can open a promising unexplored field to fulfill specific requirements for kinetic and pharmacological trials. 相似文献
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Antonella Battisti Silvio Panettieri Gerardo Abbandonato Emanuela Jacchetti Francesco Cardarelli Giovanni Signore Fabio Beltram Ranieri Bizzarri 《Analytical and bioanalytical chemistry》2013,405(19):6223-6233
The arsenal of fluorescent probes tailored to functional imaging of cells is rapidly growing and benefits from recent developments in imaging strategies. Here, we present a new molecular rotor, which displays strong absorption in the green region of the spectrum, very little solvatochromism, and strong emission sensitivity to local viscosity. The emission increase is paralleled by an increase in emission lifetime. Owing to its concentration-independent nature, fluorescence lifetime is particularly suitable to image environmental properties, such as viscosity, at the intracellular level. Accordingly, we demonstrate that intracellular viscosity measurements can be efficiently carried out by lifetime imaging with our probe and phasor analysis, an efficient method for measuring lifetime-related properties (e.g., bionalyte concentration or local physicochemical features) in living cells. Notably, we show that it is possible to monitor the partition of our probe into different intracellular regions/organelles and to follow mitochondrial de-energization upon oxidative stress. 相似文献
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Barbara Bojko Krzysztof Gorynski German Augusto Gomez-Rios Jan Matthias Knaak Tiago Machuca Vinzent Nikolaus Spetzler Erasmus Cudjoe Michael Hsin Marcelo Cypel Markus Selzner Mingyao Liu Shaf Keshavjee Janusz Pawliszyn 《Analytica chimica acta》2013
Metabolomics and biomarkers discovery are an integral part of bioanalysis. However, untargeted tissue analysis remains as the bottleneck of such studies due to the invasiveness of sample collection, as well as the laborious and time-consuming sample preparation protocols. In the current study, technology integrating in vivo sampling, sample preparation and global extraction of metabolites – solid phase microextraction was presented and evaluated during liver and lung transplantation in pig model. Sampling approaches, including selection of the probe, transportation, storage conditions and analyte coverage were discussed. The applicability of the method for metabolomics studies was demonstrated during lung transplantation experiments. 相似文献
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Sabina Strano-Rossi Erika Castrignanò Luca Anzillotti Sara Odoardi Fabio De-Giorgio Ana Bermejo Vincenzo L. Pascali 《Analytica chimica acta》2013
A method for the screening of various anabolic steroids and their esters in human hair, based on liquid-chromatography–high resolution mass spectrometry using an Exactive benchtop Orbitrap mass spectrometer, has been set up and validated. This method involved methanolic incubation of 30 mg of hair and analysis of the relevant extract in HPLC using a C18 column. The mass detector, with nominal resolving power of 100,000, operated in full scan mode in APCI under positive ionization mode. Analytes were identified by exact mass, correspondence of isotopic cluster and retention times. 相似文献
120.
(S)-β-Bisabolene, (S)-1, was synthetized by a synthetic route in which (S)-4-methyl-3-cyclohexene carboxylic acid, (S)-10, which was the key intermediate, was prepared via a highly diastereoselective TiCl4-catalyzed Diels-Alder reaction between isoprene and the acrylate of commercial (R)-pantolactone, followed by hydrolysis. Compound (S)-10 was then converted into ketone (S)-13 using two different procedures. The best one of these, as regards the degree of stereospecificity, involved the reaction of (S)-10 with 2 equiv of 4-methyl-3-penten-1-yllithium, 14, in the presence of CeCl3, and gave (S)-13 having ca. 84% ee. The Zr-promoted methylenation of this ketone afforded highly enantiomerically enriched (S)-1. 相似文献