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61.
Dye ST Annis J Becker-Szendy R Bratton CB Casper D Claus R Crouch M Errede S Gajewski W Goldhaber M Haines TJ Jones TW Kielczewska D Kropp WR Learned JG LoSecco JM McGrew C Matthews J Mudan MS Price LR Reines F Schultz J Seidel S Sinclair D Sobel HW Stone JL Sulak LR Svoboda R Thornton G van der Velde JC 《Physical review letters》1989,62(18):2069-2072
62.
Dr. Marlene Bruce Dr. Martin Papke Dr. Andreas W. Ehlers Manuela Weber Prof. Dr. Dieter Lentz Dr. Nicolas Mézailles Prof. Dr. J. Chris Slootweg Prof. Dr. Christian Müller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(63):14332-14340
The [4+2] cycloaddition of 2-(2′-pyridyl)-4,6-diphenyl-λ3-phosphinine with the highly reactive dienophile hexafluoro-2-butyne has been studied and the first pyridyl-functionalized 1-phosphabarrelene was obtained and structurally characterized. Although monodentate CF3-1-phosphabarrelenes show only a poor coordination ability, the chelating nature of the novel P,N-hybrid ligand gives access to various transition-metal complexes. Upon irradiation with UV light, the pyridyl-functionalized 1-phosphabarrelene undergoes a rather selective di-π-methane rearrangement in the coordination sphere of the metal center, leading to the formation of a complex based on a hitherto unknown pyridyl-functionalized 5-phosphasemibullvalene derivative. DFT calculations provide first insights into the mechanism of this reaction. 相似文献
63.
Dr. Devin H. A. Boom Dr. Andrew R. Jupp Prof. Dr. J. Chris Slootweg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(39):9133-9152
Amine–boranes have gained a lot of attention due to their potential as hydrogen storage materials and their capacity to act as precursors for transfer hydrogenation. Therefore, a lot of effort has gone into the development of suitable transition- and main-group metal catalysts for the dehydrogenation of amine–boranes. During the past decade, new systems started to emerge solely based on p-block elements that promote the dehydrogenation of amine–boranes through hydrogen-transfer reactions, polymerization initiation, and main-group catalysis. In this review, we highlight the development of these p-block based systems for stoichiometric and catalytic amine–borane dehydrogenation and discuss the underlying mechanisms. 相似文献
64.
65.
Flip Holtrop Dr. Andrew R. Jupp Nicolaas P. van Leest Maximilian Paradiz Dominguez Dr. René M. Williams Prof. Dr. Albert M. Brouwer Prof. Dr. Bas de Bruin Dr. Andreas W. Ehlers Prof. Dr. J. Chris Slootweg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(41):9005-9011
Archetypal phosphine/borane frustrated Lewis pairs (FLPs) are famed for their ability to activate small molecules. The mechanism is generally believed to involve two-electron processes. However, the detection of radical intermediates indicates that single-electron transfer (SET) generating frustrated radical pairs could also play an important role. These highly reactive radical species typically have significantly higher energy than the FLP, which prompted this investigation into their formation. Herein, we provide evidence that the classical phosphine/borane combinations PMes3/B(C6F5)3 and PtBu3/B(C6F5)3 both form an electron donor–acceptor (charge-transfer) complex that undergoes visible-light-induced SET to form the corresponding highly reactive radical-ion pairs. Subsequently, we show that by tuning the properties of the Lewis acid/base pair, the energy required for SET can be reduced to become thermally accessible. 相似文献
66.
Tetiana Krachko Volodymyr Lyaskovskyy Martin Lutz Koop Lammertsma J. Chris Slootweg 《无机化学与普通化学杂志》2017,643(14):916-921
Recently, Brønsted acids, such as phosphoric acids, carboxylic acids, and triflic acid, were found to catalyze the reduction of phosphine oxides to the corresponding phosphines. In this study, we fully characterize the HCl, HOTf, and Me2SiHOTf adducts of triphenylphosphine oxide and find that the thermally stable adduct Ph3POH+OTf– is efficiently converted into triphenylphosphine at 100 °C in the presence of readily available hydrosiloxanes. Under the same reaction conditions, also Ph3POSiMe2H+OTf– selectively affords triphenylphosphine indicating that silylated phosphine oxides are likely intermediates in this process. 相似文献
67.
Terence Davis Matthew C Dix Michal J Rokicki Amy JC Brook Caroline S Widdowson David Kipling Mark C Bagley 《Chemistry Central journal》2011,5(1):1-5
To develop more potent small molecules with enhanced free radical scavenger properties, a series of N-substituted isatin derivatives was synthesized, and the cytoprotective effect on the apoptosis of PC12 cells induced by H2O2 was screened. All these compounds were found to be active, and N-ethyl isatin was found with the most potent activity of 69.7% protective effect on PC12 cells. Structure-activity relationship analyses showed the bioactivity of N-alkyl isatins decline as the increasing of the chain of the alkyl group, furthermore odd-even effect was found in the activity, which is interesting for further investigation. 相似文献
68.
Devin H. A. Boom Ewoud J. J. de Boed Emmanuel Nicolas Martin Nieger Andreas W. Ehlers Andrew R. Jupp J. Chris Slootweg 《无机化学与普通化学杂志》2020,646(13):586-592
The reaction of the intramolecular frustrated Lewis pair (FLP) tBu2PCH2BPh2 with the amine-boranes NH3 · BH3 and Me2NH · BH3 leads to the formation of the corresponding FLP-H2 adducts as well as novel five-membered heterocycles that result from capturing the in situ formed amino-borane by a second equivalent of FLP. The sterically more demanding tBu2PCH2BMes2 does not form such a five-membered heterocycle when reacted with Me2NH · BH3 and its H2 adduct liberates dihydrogen at elevated temperatures, promoting the metal-free catalytic dehydrogenation of amine-boranes. 相似文献
69.
J Chris Slootweg Andreas W. Ehlers Koop Lammertsma 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4-5):803-807
In analogy with the valence isomerism of the hydrocarbons bicyclobutane, 1,3-butadiene and cyclobutene, the rearrangements for 2-phospha-4-sila-bicyclo[1.1.0]butane were studied at the B3LYP/6-311+G** level of theory. The monocyclic 1,2-dihydro-1,2-phosphasilete is shown to be the thermodynamically preferred product, in contrast to the isomerism of the hydrocarbons that favors the 1,3-butadiene structure. 相似文献