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111.
A novel method for the manufacturing of microchips for on-chip combinations of electrochemistry (EC) and sheathless electrospray ionisation mass spectrometry (ESI-MS) is described. The technique, which does not require access to clean-room facilities, is based on the incorporation of an array of gold microcoil electrodes into a poly(dimethylsiloxane)(PDMS) microflow channel equipped with an integrated graphite based sheathless ESI emitter. Electrochemical measurements, which were employed to determine the electroactive area of the electrodes and to test the microchips, show that the manufacturing process was reproducible and that the important interelectrode distance in the electrochemical cell could to be adequately controlled. The EC-ESI-MS device was evaluated based on the ESI-MS detection of the oxidation products of dopamine. The results demonstrate that the present on-chip approach enables full potentiostatic control of the electrochemical cell and the attainment of very short transfer times between the electrochemical cell and the electrospray emitter. The transfer times were 0.6 and 1.2 s for flow rates of 1.0 and 0.5 microL min(-1), respectively, while the electrochemical conversion efficiency of the electrochemical cell was found to be 30% at a flow rate of 0.5 microL min(-1). To decouple the electrochemical cell from the ESI-MS high voltage and to increase the user-friendliness, the on-line electrochemistry-ESI-MS experiments were performed using a wireless Bluetooth battery-powered instrument with the chip floating at the potential induced by the ESI high voltage. The described on-chip EC-ESI-MS device can be used for fundamental electrochemical investigations as well as for applications based on the use of electrochemically controlled sample pretreatment, preconcentration and ionisation steps prior to ESI-MS. 相似文献
112.
Debugging Eukaryotic Genetic Code Expansion for Site‐Specific Click‐PAINT Super‐Resolution Microscopy
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Dr. Ivana Nikić Gemma Estrada Girona Jun Hee Kang Giulia Paci Sofya Mikhaleva Christine Koehler Dr. Nataliia V. Shymanska Camilla Ventura Santos Daniel Spitz Dr. Edward A. Lemke 《Angewandte Chemie (International ed. in English)》2016,55(52):16172-16176
Super‐resolution microscopy (SRM) greatly benefits from the ability to install small photostable fluorescent labels into proteins. Genetic code expansion (GCE) technology addresses this demand, allowing the introduction of small labeling sites, in the form of uniquely reactive noncanonical amino acids (ncAAs), at any residue in a target protein. However, low incorporation efficiency of ncAAs and high background fluorescence limit its current SRM applications. Redirecting the subcellular localization of the pyrrolysine‐based GCE system for click chemistry, combined with DNA‐PAINT microscopy, enables the visualization of even low‐abundance proteins inside mammalian cells. This approach links a versatile, biocompatible, and potentially unbleachable labeling method with residue‐specific precision. Moreover, our reengineered GCE system eliminates untargeted background fluorescence and substantially boosts the expression yield, which is of general interest for enhanced protein engineering in eukaryotes using GCE. 相似文献
113.
Magi E Liscio C Pistarino E Santamaria B Di Carro M Tiso M Scaloni A Renzone G Cosulich ME 《Analytical and bioanalytical chemistry》2008,391(2):671-678
An interdisciplinary approach was employed to monitor the concentration and the effects of butyltin compounds in mussels (Mytilus galloprovincialis). Tissues from animals exposed to a marine area (Vado Ligure harbour) with a high concentration of tributyltin (TBT) were
analysed and compared with control samples. TBT concentrations were measured by gas chromatography–mass spectrometry and the
protein pattern in gill tissues was studied by proteomic analysis. Several proteomic signatures associated with contaminant
exposure were observed; spots that were significantly increased in all contaminated samples were identified by mass spectrometry
as fragments of β-tubulin. The degradation of β-tubulin was then confirmed by western blot analysis with specific anti-β-tubulin
antibody. The effects observed on mussel gills after exposure in the TBT-polluted area are discussed. 相似文献
114.
Hydrogen‐Borrowing and Interrupted‐Hydrogen‐Borrowing Reactions of Ketones and Methanol Catalyzed by Iridium
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Di Shen Darren L. Poole Camilla C. Shotton Anne F. Kornahrens Dr. Mark P. Healy Prof. Timothy J. Donohoe 《Angewandte Chemie (International ed. in English)》2015,54(5):1642-1645
Reported herein is the use of catalytic [{Ir(cod)Cl}2] to facilitate hydrogen‐borrowing reactions of ketone enolates with methanol at 65 °C. An oxygen atmosphere accelerates the process, and when combined with the use of a bulky monodentate phosphine ligand, interrupts the catalytic cycle by preventing enone reduction. Subsequent addition of pro‐nucleophiles to the reaction mixture allowed a one‐pot methylenation/conjugate addition protocol to be developed, which greatly expands the range of products that can be made by this methodology. 相似文献
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Krissina Camilla Molinari Washington Luiz Esteves Magalhães Agnieszka Pawlicka 《Molecular Crystals and Liquid Crystals》2019,693(1):18-29
AbstractA proximate analysis by using multiple linear regressions was used for the first time to analyze torrefied Pinus taeda L. pellets. The result, obtained from three fitted equations: HHV = 0.3921?×?FC + 0.1578?×?VM (statistical R2 = 99.91%), FC = 39.4886 – 0.1042×T – 0.5640×t?+?0.0027×(T?×?t) (statistical R2 = 75.05%), and VM = 0.3402×T?+?1.4262×t – 0.0061×(T?×?t) (statistical R2 = 99.75%), indicated that the torrefaction of the pellets increased their high heating value (HHV) and fixed carbon (FC) and decreased the volatile matters (VM). These equations fitted the results better than equations published elsewhere. 相似文献
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