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231.
Late‐Stage Isotopic Carbon Labeling of Pharmaceutically Relevant Cyclic Ureas Directly from CO2
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Antonio Del Vecchio Dr. Fabien Caillé Dr. Arnaud Chevalier Olivier Loreau Kaisa Horkka Prof. Dr. Christer Halldin Dr. Magnus Schou Dr. Nathalie Camus Dr. Pascal Kessler Dr. Bertrand Kuhnast Dr. Frédéric Taran Dr. Davide Audisio 《Angewandte Chemie (International ed. in English)》2018,57(31):9744-9748
A robust, click‐chemistry‐inspired procedure for radiolabeling of cyclic ureas was developed. This protocol, suitable for all carbon isotopes (11C, 13C, 14C), is based on the direct functionalization of carbon dioxide: the universal building block for carbon radiolabeling. The strategy is operationally simple and reproducible in different radiochemistry centers, exhibits remarkably wide substrate scope with short reaction times, and demonstrates superior reactivity as compared to previously reported systems. With this procedure, a variety of pharmaceuticals and an unprotected peptide were labeled with high radiochemical efficiency. 相似文献
232.
Dr. Maria F. Espada Soukaina Bennaamane Dr. Qian Liao Dr. Nathalie Saffon‐Merceron Dr. Stéphane Massou Dr. Eric Clot Dr. Noel Nebra Dr. Marie Fustier‐Boutignon Dr. Nicolas Mézailles 《Angewandte Chemie (International ed. in English)》2018,57(39):12865-12868
Intermolecular, stepwise functionalization by BH bonds of a (triphosphine)MoIV–nitrido complex generated by N2 splitting is reported. The imido–hydride and di‐hydride–amido MoIV complexes have been isolated and characterized. Addition of PinBH to the [Mo(H)2(N(BPin)2)]+ complex at room temperature results in the liberation of borylamines from the metal center. 相似文献
233.
Reversible CO2 Addition to a Si=O Bond and Synthesis of a Persistent SiO2–CO2 Cycloadduct Stabilized by a Lewis Donor–Acceptor Ligand
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Dr. Ricardo Rodriguez Dr. Isabel Alvarado‐Beltran Jérémy Saouli Dr. Nathalie Saffon‐Merceron Dr. Antoine Baceiredo Prof. Vicenç Branchadell Dr. Tsuyoshi Kato 《Angewandte Chemie (International ed. in English)》2018,57(10):2635-2638
The donor‐stabilized sila‐β‐lactone 1 reacts with CO2 via a remarkable reversible [2+2]‐cycloaddition reaction to form the spiro‐cyclic silicon carbonate derivative 2 . Furthermore, photolysis of 2 under pressure of CO2 affords the first persistent SiO2–CO2 cycloadduct 3 , presenting a Si2O4‐like structure, which is stabilized by a Lewis donor–acceptor type ligand. As predicted by theoretical calculations, in marked contrast to the thermodynamically stable SiO2 dimer, the SiO2–CO2 mixed cycloadduct 3 is labile and readily releases CO2. 相似文献
234.
Enrique Sentandreu Manuel D. Peris-Díaz Shannon R. Sweeney Jennifer Chiou Nathalie Muñoz Stefano Tiziani 《Chromatographia》2018,81(7):981-994
Leukemia cell and melanoma tumor tissue extracts were studied for small (mostly m/z?<?250) polar metabolites by LC-ESI-HRMSn analysis powered by a hybrid Quadrupole-Orbitrap. MS data were simultaneously acquired in fast polarity switching mode operating in MS1 and MS/MS (All Ion Fragmentation, AIF) full-scan analyses at high mass resolution. Positive metabolite assignments were achieved by AIF analysis considering at least two characteristic transitions. Targeted metabolite profiling was achieved by the relative quantification of 18 metabolites through spiking of their respective deuterated counterparts. Manual data processing of MS1 and AIF scans were compared for the accurate determination of natural metabolites and their deuterated analogs by chromatographic alignment and peak area integration. Evaluation of manual and automated (MetaboList R package) AIF data processing yielded comparable results. The versatility of AIF analysis also enabled the untargeted metabolite profiling of leukemia and melanoma samples in which 22 and 53 compounds were, respectively, identified outside those studied by labeling. The main limitation of this method was that low abundance metabolites with scan rates below 8 scans/peak could not be accurately quantified by AIF analysis. The combination of AIF analysis with MetaboList R package represents an opportunity to move towards automated, faster, and more global metabolomics approaches supported by an entirely flexible open source data processing platform freely available from Comprehensive R Archive Network (CRAN, https://CRAN.R-project.org/package=MetaboList). 相似文献
235.
The first vinylmercury hydrides, and among them the parent compound, have been prepared by a chemoselective reduction of the corresponding vinylmercury chlorides with tributylstannane in the presence of a radical inhibitor. These hydrides have been characterized on the basis of their spectral data ((1)H, (13)C, and (199)Hg NMR spectroscopy and mass spectrometry). The photoelectron spectra of the ethenylmercury hydride displays bands at 9.79, 10.13, 11.41, and 13.20 eV. On the basis of photoelectron spectra and ab initio quantum chemical calculations some (d-p)pi interaction between the vinyl pi-system and the mercury d-orbitals could be concluded. Vinylmercury hydrides have been condensed and then revaporized in vacuum at low temperature, but they exhibit a very low stability at room temperature even diluted in toluene (tau(1/2) approximately 1 min); elemental mercury and the corresponding divinylmercury were formed under these conditions. 相似文献
236.
Nathalie Guihéry 《Theoretical chemistry accounts》2006,116(4-5):576-586
Correlated ab initio calculations have been performed on the [Re2OCl10]3− anion. The calculated spectrum does not respect the intervals given by the usually accepted double exchange Hamiltonian. Surprisingly enough the ground-state happens to be of intermediate spin multiplicity (i.e. a quartet) at any level of correlation treatment. A model that combines the Anderson and Hasegawa method and the usually used double exchange one rationalizes the spectrum calculated both by a configuration interaction restricted to the open shell molecular orbitals and at a more correlated level of calculation. An alternative analysis of the double exchange phenomenon, based on a molecular orbital language, is presented. The specific effects of the electronic correlation brought by extended active space and by a difference dedicated configuration interaction are also analyzed. 相似文献
237.
Mellot-Draznieks C Serre C Surblé S Audebrand N Férey G 《Journal of the American Chemical Society》2005,127(46):16273-16278
Using a combination of simulations and powder diffraction, we report here the study of the very large swelling of a three-dimensional nanoporous iron(III) carboxylate (MIL-88) which exhibits almost a reversible doubling (approximately 85%) of its cell volume while fully retaining its open-framework topology. The crystal structure of the open form of MIL-88 has been successfully refined and indicates that atomic displacements larger than 4 angstroms are observed when water or various alcohols are adsorbed in the porous structure, revealing an unusually flexible crystallized framework. X-ray thermodiffractometry shows that only a displacive transition occurs during the swelling phenomenon, ruling out any bond breaking. 相似文献
238.
Goudreau N Brochu C Cameron DR Duceppe JS Faucher AM Ferland JM Grand-Maître C Poirier M Simoneau B Tsantrizos YS 《The Journal of organic chemistry》2004,69(19):6185-6201
The virally encoded NS3 protease is essential to the life cycle of the hepatitis C virus (HCV), an important human pathogen causing chronic hepatitis, cirrhosis of the liver, and hepatocellular carcinoma. The design and synthesis of 15-membered ring beta-strand mimics which are capable of inhibiting the interactions between the HCV NS3 protease enzyme and its polyprotein substrate will be described. The binding interactions between a macrocyclic ligand and the enzyme were explored by NMR and molecular dynamics, and a model of the ligand/enzyme complex was developed. 相似文献
239.
Seifallah Abid Yohan Gisbert Mitsuru Kojima Nathalie Saffon-Merceron Jrme Cuny Claire Kammerer Gwnaël Rapenne 《Chemical science》2021,12(13):4709
Mastering intermolecular gearing is crucial for the emergence of complex functional nanoscale machineries. However, achieving correlated motion within trains of molecular gears remains highly challenging, due to the multiple degrees of freedom of each cogwheel. In this context, we designed and synthesised a series of star-shaped organometallic molecular gears incorporating a hydrotris(indazolyl)borate anchor to prevent diffusion on the surface, a central ruthenium atom as a fixed rotation axis, and an azimuthal pentaporphyrinic cyclopentadienyl cogwheel specifically labelled to monitor its motion by non-time-resolved Scanning Tunneling Microscopy (STM). Desymmetrisation of the cogwheels was first achieved sterically, i.e. by introducing one tooth longer than the other four. For optimal mechanical interactions, chemical labelling was also investigated as a preferential way to induce local contrast in STM images, and the electronic properties of one single paddle were modulated by varying the porphyrinic scaffold or the nature of the central metal. To reach such a structural diversity, our modular synthetic approach relied on sequential cross-coupling reactions on a penta(p-halogenophenyl)cyclopentadienyl ruthenium(ii) key building block, bearing a single pre-activated p-iodophenyl group. Chemoselective Sonogashira or more challenging Suzuki–Miyaura reactions allowed the controlled introduction of the tagged porphyrinic tooth, and the subsequent four-fold cross-couplings yielded the prototypes of pentaporphyrinic molecular gears for on-surface studies, incorporating desymmetrised cogwheels over 5 nm in diameter.Star-shaped cogwheel prototypes incorporating one sterically- or chemically-labelled porphyrinic paddle were designed and synthesised with the aim of achieving intermolecular gearing on surfaces. 相似文献
240.
Ferlay S Holakovsky R Hosseini MW Planeix JM Kyritsakas N 《Chemical communications (Cambridge, England)》2003,(11):1224-1225
The co-crystallisation of [Fe(CN)5NO]2- and cyclic achiral 1(2+) and chiral 2(2+) or 3(2+) bisamidinium tectons leads in the crystalline phase to the formation of 1-D H-bonded achiral and chiral molecular networks respectively. In all cases, the network is formed by mutual bridging of the anionic and cationic units through a chelate mode of H-bonding. 相似文献