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431.
Emilie Bigorgne Laurent Foucaud Céline Caillet Laure Giambérini Johanne Nahmani Fabien Thomas Fran?ois Rodius 《Journal of nanoparticle research》2012,14(7):1-17
An in vitro approach using c?lomocytes of Eisenia fetida was investigated to evaluate toxicity of TiO2 nanoparticles. C?lomocytes were exposed to well-dispersed suspension of small aggregates (130?nm) of TiO2 nanoparticles (1?C25???g/ml) during 4, 12 and 24?h. Intracellular localisation suggested that the main route of uptake was endocytosis. Cellular responses showed that TiO2 nanoparticles were not cytotoxic and had no effect on phagocytosis at any of the four concentrations for each time tested. Concerning molecular responses, an increase of fetidin and metallothionein mRNA expression was observed starting from 4?h of exposure. In contrast, expression of coelomic cytolytic factor mRNA decreased for 10 and 25???g/ml after 4?h. Superoxide dismutase, catalase and glutathione-S-transferase expression were not modified suggesting that oxidative stress was not induced by TiO2 in our experimental conditions. This in vitro approach showed that TiO2 nanoparticles were taken up by c?lomocytes and they could modify the molecular response of immune and detoxification system. 相似文献
432.
Thibault Dutronc Priv.‐Doz. Dr. Emmanuel Terazzi Dr. Laure Guénée Kerry‐Lee Buchwalder Dr. Sébastien Floquet Prof. Dr. Claude Piguet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(4):1385-1391
This work illustrates how enthalpy and entropy changes responsible for successive phase transitions of cyanobiphenyl‐based liquid crystals can be combined to give cohesive free energy densities. These new parameters are able to rationalize and quantify the demixing of the melting and clearing processes that occur in thermotropic liquid crystals. Minor structural variations at the molecular level can be understood as pressure increments that alter either the melting or clearing temperatures in a predictable way. This assessment of microsegregation operating in amphiphilic molecules paves the way for the chemical programming of the domain of existence of liquid‐crystalline phases. 相似文献
433.
Highly Fluorinated Tris(indazolyl)borate Silylamido Complexes of the Heavier Alkaline Earth Metals: Synthesis,Characterization, and Efficient Catalytic Intramolecular Hydroamination 下载免费PDF全文
Nuria Romero Sorin‐Claudiu Roşca Dr. Yann Sarazin Prof. Jean‐François Carpentier Dr. Laure Vendier Sonia Mallet‐Ladeira Dr. Chiara Dinoi Prof. Michel Etienne 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(10):4115-4125
Heteroleptic silylamido complexes of the heavier alkaline earth elements calcium and strontium containing the highly fluorinated 3‐phenyl hydrotris(indazolyl)borate {F12‐Tp4Bo, 3Ph}? ligand have been synthesized by using salt metathesis reactions. The homoleptic precursors [Ae{N(SiMe3)2}2] (Ae=Ca, Sr) were treated with [Tl(F12‐Tp4Bo, 3Ph)] in pentane to form the corresponding heteroleptic complexes [(F12‐Tp4Bo, 3Ph)Ae{N(SiMe3)2}] (Ae=Ca ( 1 ); Sr ( 3 )). Compounds 1 and 3 are inert towards intermolecular redistribution. The molecular structures of 1 and 3 have been determined by using X‐ray diffraction. Compound 3 exhibits a Sr ??? MeSi agostic distortion. The synthesis of the homoleptic THF‐free compound [Ca{N(SiMe2H)2}2] ( 4 ) by transamination reaction between [Ca{N(SiMe3)2}2] and HN(SiMe2H)2 is also reported. This precursor constitutes a convenient starting material for the subsequent preparation of the THF‐free complex [(F12‐Tp4Bo, 3Ph)Ca{N(SiMe2H)2}] ( 5 ). Compound 5 is stabilized in the solid state by a Ca???β‐Si?H agostic interaction. Complexes 1 and 3 have been used as precatalysts for the intramolecular hydroamination of 2,2‐dimethylpent‐4‐en‐1‐amine. Compound 1 is highly active, converting completely 200 equivalents of aminoalkene in 16 min with 0.50 mol % catalyst loading at 25 °C. 相似文献
434.
435.
Laure Biniek Christos L. Chochos Nicolas Leclerc Olivier Boyron Sadiara Fall Patrick Lévèque Thomas Heiser 《Journal of polymer science. Part A, Polymer chemistry》2012,50(9):1861-1868
It has been shown recently, that the presence of alkyl side chains at the 3‐positions on the thiophene rings placed next to 2,1,3‐benzothiadiazole core in the backbone of several conjugated polymers results in severe steric hindrance and prevents efficient planarity of the thiophene‐2,1,3‐benzothiadiazole‐thiophene (TBzT) segment. Both properties have a strong influence on the optoelectronic properties of the polymer and need to be considered when the polymer is to be used for organic electronics applications. In this work, we modified a previously synthesized oligothiophene copolymer, consisting of two 3,4′‐dialkyl‐2,2′‐bithiophene units attached to a 2,1,3‐benzothiadiazole unit (TBzT segment) and a thieno[3,2‐b]thiophene unit, by optimizing the lateral alkyl side chains following a density functional theory investigation. It is demonstrated that eliminating the alkyl side chains from the 3‐positions of the TBzT segment and anchoring them onto the thieno[3,2‐b]thiophene, using an efficient synthesis of the 3,6‐dihexylthieno[3,2‐b]thiophene unit, allows us to reduce the energy band gap. In addition, the chemical modification leads to a better charge transport and to an enhanced photovoltaic efficiency of polymer/fullerene blends. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
436.
Helical,Axial, and Central Chirality Combined in a Single Cage: Synthesis,Absolute Configuration,and Recognition Properties 下载免费PDF全文
Dawei Zhang Jean‐Christophe Mulatier Dr. James Robert Cochrane Dr. Laure Guy Prof. Guohua Gao Dr. Jean‐Pierre Dutasta Prof. Alexandre Martinez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8038-8042
The synthesis of eight enantiopure molecular cages (four diastereomeric pairs of enantiomers) comprising a helically chiral cyclotriveratrylene (CTV) unit, three axially chiral binaphthol linkages, and three centrally asymmetric carbon atoms of a trialkanolamine core, is described. These new cages constitute a novel family of hemicryptophanes, which combine three classes of chirality. Their absolute configuration was successfully assigned by a chemical correlation method to overcome the signals overlap in the ECD spectra of the binaphtol and CTV units. Stereoselective recognition of glucose and mannose derivatives was investigated with these new chiral cages. Excellent enantio‐ and diastereoselectivity were reached, since in some cases, both exclusive enantio‐ and diastereo‐discrimination have been observed. In addition, compared with the most relevant hemicryptophanes, these new cages also exhibit improved binding affinities. 相似文献
437.
Thierry Bodineau Isabelle Gallagher Laure Saint-Raymond Sergio Simonella 《纯数学与应用数学通讯》2023,76(12):3852-3911
It has been known since Lanford that the dynamics of a hard-sphere gas is described in the low density limit by the Boltzmann equation, at least for short times. The classical strategy of proof fails for longer times, even close to equilibrium. In this paper, we introduce a weak convergence method coupled with a sampling argument to prove that the covariance of the fluctuation field around equilibrium is governed by the linearized Boltzmann equation globally in time (including in diffusive regimes). This method is much more robust and simpler than the one devised in Bodineau et al which was specific to the 2D case. 相似文献
438.
NMR Fingerprints of the Drug‐like Natural‐Product Space Identify Iotrochotazine A: A Chemical Probe to Study Parkinson’s Disease 下载免费PDF全文
Dr. Tanja Grkovic Dr. Rebecca H. Pouwer Marie‐Laure Vial Luca Gambini Alba Noël Dr. John N. A. Hooper Dr. Stephen A. Wood Dr. George D. Mellick Prof. Dr. Ronald J. Quinn 《Angewandte Chemie (International ed. in English)》2014,53(24):6070-6074
The NMR spectrum of a mixture of small molecules is a fingerprint of all of its components. Herein, we present an NMR fingerprint method that takes advantage of the fact that fractions contain simplified NMR profiles, with minimal signal overlap, to allow the identification of unique spectral patterns. The approach is exemplified in the identification of a novel natural product, iotrochotazine A ( 1 ), sourced from an Australian marine sponge Iotrochota sp. Compound 1 was used as a chemical probe in a phenotypic assay panel based on human olfactory neurosphere‐derived cells (hONS) from idiopathic Parkinson’s disease patients. Compound 1 at 1 μM was not cytotoxic but specifically affected the morphology and cellular distribution of lysosomes and early endosomes. 相似文献
439.
Back Cover: Large Zero‐Field Splittings of the Ground Spin State Arising from Antisymmetric Exchange Effects in Heterometallic Triangles (Angew. Chem. Int. Ed. 21/2014) 下载免费PDF全文
440.
Dr. Anne‐Laure Fameau Adrian Carl Dr. Arnaud Saint‐Jalmes Dr. Regine von Klitzing 《Chemphyschem》2015,16(1):66-75
Remarkable properties have emerged recently for aqueous foams, including ultrastability and responsiveness. Responsive aqueous foams refer to foams for which the stability can be switched between stable and unstable states with a change in environment or with external stimuli. Responsive foams have been obtained from various foam stabilizers, such as surfactants, proteins, polymers, and particles, and with various stimuli. Different strategies have been developed to design this type of soft material. We briefly review the two main approaches used to obtain responsive foams. The first approach is based on the responsiveness of the interfacial layer surrounding the gas bubbles, which leads to responsive foams. The second approach is based on modifications that occur in the aqueous phase inside the foam liquid channels to tune the foam stability. We will highlight the most sophisticated approaches, which use light, temperature, and magnetic fields and lead to switchable foam stability. 相似文献