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141.
Solid‐Phase Parallel Synthesis of Functionalised Medium‐to‐Large Cyclic Peptidomimetics through Three‐Component Coupling Driven by Aziridine Aldehyde Dimers
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Dr. Adam P. Treder Dr. Jennifer L. Hickey Marie‐Claude J. Tremblay Dr. Serge Zaretsky Dr. Conor C. G. Scully Dr. John Mancuso Annie Doucet Prof. Andrei K. Yudin Prof. Eric Marsault 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9249-9255
The first solid‐phase parallel synthesis of macrocyclic peptides using three‐component coupling driven by aziridine aldehyde dimers is described. The method supports the synthesis of 9‐ to 18‐membered aziridine‐containing macrocycles, which are then functionalized by nucleophilic opening of the aziridine ring. This constitutes a robust approach for the rapid parallel synthesis of macrocyclic peptides. 相似文献
142.
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143.
Conor Pranckevicius Liu Liu Prof. Dr. Guy Bertrand Prof. Dr. Douglas W. Stephan 《Angewandte Chemie (International ed. in English)》2016,55(18):5536-5540
The first carbodicarbene stabilized by flanking cyclopropenylidenes is reported. Tetraphenylcarbodicyclopropenylidene ( 2 ) is accessed by deprotonation of the corresponding triafulvene cyclopropenium salt, and has been spectroscopically characterized in [D8]THF solution at ?60 °C. Main‐group and transition‐metal complexes of 2 have been accessed, and have revealed the high sigma donating ability, and exclusive η1 binding of this neutral all carbon ligand. Variable temperature NMR spectroscopy studies reveal varying degrees of free rotation in the flanking cyclopropenylidene groups of 2 in its coordination compounds. 相似文献
144.
By exploiting its ability to play sounds, a mobile phone with suitable software installed can serve the basic functions of a potentiostat in controlling an applied potential to oxidise ECL-active molecules, while the resultant photonic signal is monitored using the camera in video mode. In combination with paper microfluidic sensors this opens significant new possibilities for low-cost, instrument-free sensing. 相似文献
145.
Thomas Adam John McAughey Conor McGrath Christoph Mocker Ralf Zimmermann 《Analytical and bioanalytical chemistry》2009,394(4):1193-1203
This paper describes the combined set-up of on-line chemical analysis of gas phase by single-photon ionisation/resonance enhanced
multiphoton ionisation–time-of-flight mass spectrometry (SPI/REMPI-TOFMS) and on-line particle size analysis by differential
electrical mobility particle spectrometry (DMS 500) for the investigation of fresh cigarette mainstream smoke. SPI is well
suited for the investigation of a great variety of organic species, whereas REMPI is highly sensitive for aromatic compounds.
Gas phase measurements of filtered and unfiltered smoke are possible with the SPI/REMPI-TOFMS in order to determine the influence
of the presence of particles on the chemical composition of the gas phase. Initial results are shown for the characterisation
and comparison of three pure Virginia tobacco research cigarettes having filter ventilations of 0%, i.e. no filter ventilation,
35% and 70% ventilation. The three cigarette types are smoked under two different smoking regimes, a standard regime using
puff parameters equivalent to the conventional International Standard Organisation regime and a more intense smoking regime.
For the gas phase, qualitative puff-by-puff resolved yields of three selected compounds (acetaldehyde, phenol and styrene)
are shown and compared. For particulate matter, particle number, count median diameter and total surface area are illustrated
on a puff-by-puff basis. Yields of the chemicals analysed, puff number and surface area are in good agreement with the intensity
of the smoking regime and the dilution of smoke by filter ventilation. However, gaseous compounds are influenced differently,
depending whether an absolute particle filter is present or not, i.e. they can be totally removed (phenol), partially removed
(styrene) or not affected (acetaldehyde). For particle analysis, the count median diameter decreases from puff to puff and
is strongly dependent on the smoking regime and ventilation rate. Thereby, 0% ventilated cigarettes smoked under the intense
regime result in the smallest count median diameters of ca. 180 nm, whereas 70% ventilated cigarettes smoked with a standard
regime lead to the largest values of up to 280 nm. As particle diameter increases, particle number decreases as a consequence
of increasing time for particle coagulation. 相似文献
146.
Clark IP George MW Greetham GM Harvey EC Long C Manton JC McArdle H Pryce MT 《The journal of physical chemistry. A》2012,116(3):962-969
The photochemistry of (η(6)-anisole)Cr(CO)(3) and (η(6)-thioanisole)Cr(CO)(3) was investigated by picosecond time-resolved infrared spectroscopy in n-heptane solution at 298 K. Two independent excited states are populated following 400 nm excitation of each of these complexes. An excited state with some metal-to-CO charge-transfer character is responsible for the CO-loss process, which is slow compared to CO-loss from Cr(CO)(6). Observed first order rate constants of 1.8 × 10(10) s(-1) and 2.5 × 10(10) s(-1) were obtained for the anisole and thioanisole complexes, respectively. The second excited state has metal-to-arene charge transfer character and results in a haptotropic shift of the thioanisole ligand. DFT calculations characterized the excited states involved and the nature of the haptotropic shift intermediate observed for the thioanisole species. 相似文献
147.
Long C 《The journal of physical chemistry. A》2012,116(25):6845-6850
The potential energy profiles of the optically accessible excited states of two model (η(6)-arene)Cr(CO)(3) systems were explored using Time-Dependent Density Functional Theory. Two photochemical reactions were investigated, CO-loss and the haptotropic or ring-slip of the arene ligand. In both cases the photochemical reaction requires the surmounting of a small thermal barrier in the lowest energy excited state. In the case of (η(6)-benzene)Cr(CO)(3) only one excited state is populated following 400 nm excitation and this leads to the release of CO. The calculated energy barrier to this process is 13 kJ mol(-1). In the case of (η(6)-thiophenol)Cr(CO)(3) two excited states are accessible one leading to CO-loss while the other results in the ring-slip process. The calculated barrier to the ring-slip process is 11 kJ mol(-1). The calculations are consistent with the results of picosecond time-resolved infrared studies. 相似文献
148.
Rivadehi S Reid EF Hogan CF Bhosale SV Langford SJ 《Organic & biomolecular chemistry》2012,10(4):705-709
A chemosensor bearing dipyrrolyl motifs as recognition sites and a tetrathiafulvalene redox tag has been evaluated as an optical and redox sensor for a series of anions (F(-), Cl(-), Br(-), HSO(4)(-), CH(3)COO(-), and H(2)PO(4)(-)) in DCM solution. The receptor shows specific optical signaling for fluoride but little electrochemical effect in solution. The solid-state performance of the sensor leads to measurable changes in water. Design implications towards better systems based on these results and other examples are discussed. 相似文献
149.
Zammit EM Barbante GJ Carlson B Doeven EH Barnett NW Hogan CF Richter MM Francis PS 《The Analyst》2012,137(12):2766-2769
The reaction of various [Os(L)(2)(L')](2+) complexes (where L and L' are phenanthroline, diphosphine or diarsine ligands) and organic reducing agents after chemical or electrochemical oxidation of the reactants produces an emission of light corresponding to MLCT transitions. In certain instances, the emission was greater than that of [Ru(bipy)(3)](2+), but the relative signals were dependent on many factors, including reagent concentration, mode of oxidation, reducing agent and the sensitivity of the photodetector over the wavelength range. 相似文献
150.