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Dr. Jamie A. Leitch Tatiana Rogova Prof. Dr. Fernanda Duarte Prof. Dr. Darren J. Dixon 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(10):4150-4159
The construction of diverse sp3-rich skeletal ring systems is of importance to drug discovery programmes and natural product synthesis. Herein, we report the photocatalytic construction of 2,7-diazabicyclo[3.2.1]octanes (bridged 1,3-diazepanes) via a reductive diversion of the Minisci reaction. The fused tricyclic product is proposed to form via radical addition to the C4 position of 4-substituted quinoline substrates, with subsequent Hantzsch ester-promoted reduction to a dihydropyridine intermediate which undergoes in situ two-electron ring closure to form the bridged diazepane architecture. A wide scope of N-arylimine and quinoline derivatives was demonstrated and good efficiency was observed in the construction of sterically congested all-carbon quaternary centers. Computational and experimental mechanistic studies provided insights into the reaction mechanism and observed regioselectivity/diastereoselectivity. 相似文献
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Research into new reversible hydrogen storage materials has the potential to help accelerate the transition to a hydrogen economy. The discovery of an efficient and cost-effective method of safely storing hydrogen would revolutionise its use as a sustainable energy carrier. Accurately measuring storage capacities – particularly of novel nanomaterials – has however proved challenging, and progress is being hindered by ongoing problems with reproducibility. Various metal and complex hydrides are being investigated, together with nanoporous adsorbents such as carbons, metal-organic frameworks and microporous organic polymers. The hydrogen storage properties of these materials are commonly determined using either the manometric (or Sieverts) technique or gravimetric methods, but both approaches are prone to significant error, if not performed with great care. Although commercial manometric and gravimetric instruments are widely available, they must be operated with an awareness of the limits of their applicability and the error sources inherent to the measurement techniques. This article therefore describes the measurement of hydrogen sorption and covers the required experimental procedures, aspects of troubleshooting and recommended reporting guidelines, with a view of helping improve reproducibility in experimental hydrogen storage material research. 相似文献
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Dr. Carmen Martin Dr. Katharina Kastner Dr. Jamie M. Cameron Elizabeth Hampson Dr. Jesum Alves Fernandes Dr. Emma K. Gibson Dr. Darren A. Walsh Dr. Victor Sans Dr. Graham N. Newton 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(34):14437-14441
We report the design and preparation of multifunctional hybrid nanomaterials through the stabilization of gold nanoparticles with thiol-functionalised hybrid organic–inorganic polyoxometalates (POMs). The covalent attachment of the hybrid POM forms new nanocomposites that are stable at temperatures and pH values which destroy analogous electrostatically functionalised nanocomposites. Photoelectrochemical analysis revealed the unique photochemical and redox properties of these systems. 相似文献
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Mary S. Collins Trevor A. Shear Elizabeth K. Smith Dr. S. Michael Strain Dr. Lev N. Zakharov Prof. Dr. Darren W. Johnson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(58):13290-13293
An unusual trithioorthoformate-capped cyclophane cage was assembled via antimony-activated iodine oxidation of thiols as confirmed by 1H-NMR spectroscopy and X-ray crystallography. The disulfide bridges can undergo desulfurization with hexamethylphosphorous triamide (HMPT) at ambient temperature to capture a trithioether cyclophane cage capped by the trithioorthoformate. In both cages a methine proton points directly into the small cavity. This unexpected structure is hypothesized to have formed as a result of haloform insertion during oxidation. 相似文献
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Jonathan C. Golec Eve M. Carter John W. Ward William G. Whittingham Luis Simón Robert S. Paton Darren J. Dixon 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(40):17570-17575
A bifunctional iminophosphorane (BIMP)-catalysed enantioselective synthesis of α,β-unsaturated cyclohexenones through a facially selective 1,3-prototropic shift of β,γ-unsaturated prochiral isomers, under mild reaction conditions and in short reaction times, on a range of structurally diverse substrates, is reported. α,β-Unsaturated cyclohexenone products primed for downstream derivatisation were obtained in high yields (up to 99 %) and consistently high enantioselectivity (up to 99 % ee). Computational studies into the reaction mechanism and origins of enantioselectivity, including multivariate linear regression of TS energy, were carried out and the obtained data were found to be in good agreement with experimental findings. 相似文献
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Chiral non-racemic analogues of cyclam were prepared via reaction of (1R, 2R)-cyclohexane-1,2-diamine with appropriately substituted malonyl dichlorides. Larger macrocycles are formed as by-products in some cases. All new macrocycles were characterised by X-ray crystallography. 相似文献
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