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231.
The mechanisms of the reduction of four isoelectronic heteroallenes (CS(2), COS, PhN(3), and PhNCO) by trivalent uranium complex (MeC(5)H(4))(3)U were determined by using DFT methods. The experimental formation of either the bimetallic CS(2) and the PhNCO uranium(IV) adducts or the bimetallic sulfide complex (COS) and the monometallic uranium(V) phenylimide complex (PhN(3)) were rationalized. The formation of the products was explained by a unique reaction mechanism with a uranium(IV)-bridged heteroallene intermediate. 相似文献
232.
Revel S Doudet L Alonso L Coleman AW Shahgaldian P 《Chemical communications (Cambridge, England)》2012,48(1):73-75
para-Hexanoylcalix[4, 6 or 8]arenes have been used as surface acoustic wave sensor capture layers showing a high efficiency for the detection of linear alcohols, with high reproducibility and rapid response times. 相似文献
233.
R Labruère A Alouane T Le Saux I Aujard P Pelupessy A Gautier S Dubruille F Schmidt L Jullien 《Angewandte Chemie (International ed. in English)》2012,51(37):9344-9347
Dual photoliberation: A caged, branched, self-immolative spacer (see scheme, gray box) was designed to rapidly and simultaneously release a desired compound (green) and a fluorophore?(red) upon photoactivation. Careful kinetic analysis of the disassembly of the spacer shows that it occurs on the shortest time scale reported to date. 相似文献
234.
Ludovic Chahen 《Journal of organometallic chemistry》2006,691(20):4257-4264
The square-planar palladium complexes trans-[PdCl2(PPh2-CH2-2,4,6-C6H2Me3)2] (1) and trans-[PdCl2(η2-PPh2-CH2-2,4,6-C6HMe3-CH2-2,4,6-C6HMe3-CH2-PPh2)] (2) have been synthesized from [PdCl2(cod)] (cod = 1,5-cyclooctadiene) and the corresponding new phosphine or diphosphine ligands. The single-crystal X-ray structure analysis reveals for both complexes a trans arrangement of the two chlorine and of the two phosphorus atoms. In both cases, ortho-metallation leading to palladacycles is not possible, since all ortho positions in the benzylic rings of 1 and 2 are blocked by methyl substituents. Both complexes are found to catalyze Suzuki cross-coupling reactions of deactivated and even bulky arene substrates. 相似文献
235.
An important feature of experimental science is that data of various kinds is being produced at an unprecedented rate. This is mainly due to the development of new instrumental concepts and experimental methodologies. It is also clear that the nature of acquired data is significantly different. Indeed in every areas of science, data take the form of always bigger tables, where all but a few of the columns (i.e. variables) turn out to be irrelevant to the questions of interest, and further that we do not necessary know which coordinates are the interesting ones. Big data in our lab of biology, analytical chemistry or physical chemistry is a future that might be closer than any of us suppose. It is in this sense that new tools have to be developed in order to explore and valorize such data sets. Topological data analysis (TDA) is one of these. It was developed recently by topologists who discovered that topological concept could be useful for data analysis. The main objective of this paper is to answer the question why topology is well suited for the analysis of big data set in many areas and even more efficient than conventional data analysis methods. Raman analysis of single bacteria should be providing a good opportunity to demonstrate the potential of TDA for the exploration of various spectroscopic data sets considering different experimental conditions (with high noise level, with/without spectral preprocessing, with wavelength shift, with different spectral resolution, with missing data). 相似文献
236.
237.
Yuriy Shpinov Antoine Schlichter Dr. Philippe Pelupessy Dr. Thomas Le Saux Prof. Ludovic Jullien Dr. Beatrice Adelizzi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(28):e202200497
Donor-acceptor Stenhouse adducts (DASAs) are reversibly photoswitchable dyes, which are able to interconvert between a red/NIR absorbing triene-like state and a colorless cyclic state. Although optically attractive for multiple applications, their low solubility and lack of photoswitching in water impede their use in aqueous environments. We developed water-soluble DASAs based on indoline as donor and methyl, or trifluoromethyl, pyrazolone-based acceptors. In acetonitrile, photophysical analysis and photochemical studies, accounted with a three-state kinetic model, confirmed the reversible photoswitching mechanism previously proposed. In water, the colorless cyclic state is a thermodynamic sink at neutral pH values. In contrast, in acidic conditions, we observed a fast scrambling of DASAs’ end-group resulting in the in situ formation of Stenhouse salts (StS), which are in turn capable of reversible photoswitching. We believe that this unexpected result is of interest not only for the future design of DASAs with improved stability, but also for further development and applications of StS as photoswitchable probes. 相似文献
238.
Martin Gillard Guillaume Piraux Martin Daenen Michaël Abraham Dr. Ludovic Troian-Gautier Dr. Laure Bar Hugues Bonnet Prof. Frédérique Loiseau Dr. Hélène Jamet Dr. Jérôme Dejeu Prof. Eric Defrancq Prof. Benjamin Elias 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202202251
Photosensitizers that gather high photo-oxidizing power and strong visible-light absorption are of great interest in the development of new photo-chemotherapeutics. Indeed, such compounds constitute attractive candidates for the design of type I photosensitizers that are not dependent on the presence of oxygen. In this paper, we report on the synthesis and studies of new ruthenium(II) complexes that display strong visible-light absorption and can oxidize guanine residues under visible-light irradiation, as evidenced by nanosecond transient absorption spectroscopy. The reported compounds also tightly bind to G-quadruplex DNA structures from the human telomeric sequence (TTAGGG repeat). The kinetic and thermodynamic parameters of the interaction of these Ru(II) complexes with G-quadruplex and duplex DNA were studied thanks to luminescence titrations and bio-layer interferometry measurements, which revealed higher affinities towards the non-canonical G-quadruplex architecture. Docking experiments and non-covalent ionic analysis allowed us to gain information on the mode and the strength of the interaction of the compounds towards G-quadruplex and duplex DNA. The different studies emphasize the substantial influence of the position and the number of non-chelating nitrogen atoms on the interaction with both types of DNA secondary structures. 相似文献
239.
Aline Gardez Ghassen Saidani Ludovic Biennier Robert Georges Edouard Hugo Vijayanand Chandrasekaran Vivien Roussel Bertrand Rowe K. P. J. Reddy E. Arunan 《国际化学动力学杂志》2012,44(11):753-766
More than 70 molecules of varied nature have been identified in the envelopes of carbon‐rich stars through their spectral fingerprints in the microwave or far infrared regions. Many of them are carbon chain molecules and radicals, and a significant number are unique to the circumstellar medium. The determination of relevant laboratory kinetics data is critical to keep up with the development of the high spectral and spatial resolution observations and of the refinement of chemical models. Neutral–neutral reactions of the CN radical with unsaturated hydrocarbons could be a dominant route in the formation of cyanopolyynes, even at low temperatures and deserve a detailed laboratory investigation. The approach we have developed aims to bridge the temperature gap between resistively heated flow tubes and shock tubes. The present kinetic measurements are obtained using a new reactor combining a high‐enthalpy source with a flow tube and a pulsed laser photolysis–laser‐induced fluorescence system to probe the undergoing chemical reactions. The high‐enthalpy flow tube has been used to measure the rate constant of the reaction of the CN radical with propane (C3H8), propene (C3H6), allene (C3H4), 1,3‐butadiene (1,3‐C4H6), and 1‐butyne (C4H6) over a temperature range extending from 300 to 1200 K. All studied reactions of CN with unsaturated hydrocarbons are rapid, with rate coefficients greater than 10?10 cm3 · molecule?1 · s?1 and exhibit slight negative temperature dependence above room temperature. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 753–766, 2012 相似文献
240.
Ludovic Castro Stéphanie Labouille Doug R. Kindra Dr. Joseph W. Ziller Dr. Francois Nief Prof. Dr. William J. Evans Prof. Dr. Laurent Maron 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7886-7895
Reaction mechanisms for the oxidative reactions of CO2 and COS with [(C5Me5)2Sm] have been investigated by means of DFT methods. The experimental formation of oxalate and dithiocarbonate complexes is explained. Their formation involve the samarium(III) bimetallic complexes [(C5Me5)2Sm‐CO2‐Sm(C5Me5)2] and [(C5Me5)2Sm‐COS‐Sm(C5Me5)2] as intermediates, respectively, ruling out radical coupling for the formation of the oxalate complex. 相似文献