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201.
A new class of hemilabile unsymmetrical 2-(1-arylimino)-6-(pyzazol-1-yl)pyridine ligands and their ruthenium(II) and nickel(II) NNN complexes were synthesized. The Ru(II) complex catalysts have been fully characterized and exhibited good to excellent catalytic activity in the transfer hydrogenation (TH) of ketones in refluxing 2-propanol. These results have demonstrated rare examples of active ruthenium(II) NNN complex catalysts that do not feature a N-H functionality for TH of ketones. 相似文献
202.
203.
204.
Twelve OCO bisacetamide ligands 4aa-4dc were synthesized after condensation of isophenylenediamines 1a-1d and anhydride/acyl chlorides. The corresponding Pd(II)–OCO–H(5aa-5ac), Pd(II)–OCO–Me(5ba-5bc), Pd(II)–OCO–OMe(5ca-5?cc), Pd(II)–OCO–NO2(5da-5dc) pincer complexes were prepared via C-H activation of precursors and Pd(OAc)2, and characterized by IR, 1H NMR, 13C NMR and elemental analysis. The α-arylation of ketones and aryl bromides catalyzed by 5 under low catalyst loadings (0.1?mol%) show that 5da exhibits the highest catalytic activity, resulting in a 98% isolated yield. 相似文献
205.
Leo A. Paquette 《Angewandte Chemie (International ed. in English)》1990,29(6):609-626
Convergency is a highly serviceable aspect of organic synthesis, particularly when its application is accompanied by high levels of chirality transfer and regiocontrol. A reaction that is notably well suited to these objectives is the oxy-Cope rearrangement. In addition, the benefits that can accrue from suitable condensation of β γ-unsaturated ketones with a vinyl organometallic and subsequent [3,3] sigmatropic shift are substantive enhancement in structural complexity and the ability to generate a myriad of polycyclic frameworks. Another profitable feature is the complementary regeneration of the carbonyl group in a new structural context. In view of the pivotal role played by the carbonyl functionality in synthetic transformations, reacquisition of such a reaction site translates into heightened chemical versatility. The trajectories followed by vinyl organometallics as they engage in 1,2 addition to ketones are gradually being understood. Proper diastereoselective control of this bond-making process, when coupled with full awareness of the chair or boat topography adopted during the ensuing oxy-Cope electronic reorganization, provides for exciting new strategy-level dimensions not often available in other contexts. The use of this two-step sequence as a prelude to a third chemical event clearly serves to expand the possibilities for molecular construction still more. While a considerable amount of the work to date has focused on the preparation of rather elaborate carbocyclic molecules, principally with a view to gaining access to complex natural products, the possibilities for heterocyclic synthesis are currently being accorded increased attention. 相似文献
206.
Sergiy M. Kovalenko Valentyn P. Chernykh Volodymyr M. Baumer Svitlana S. Kovalenko 《Monatshefte für Chemie / Chemical Monthly》2002,133(5):673-678
Summary. The condensation of salicylaldehyde, 1-methyl-4-piperidone, and methylamine has been studied as a model reaction. It was
found that at a molar ratio of salicylaldehyde: 1-methyl-4-piperidone = 2:1 and an excess of methylamine the previously unknown
heterocyclic compound 2-(3,6,13-trimethyl-1,2,3,4,4a,5,6,7-octahydro-7,12a-epiminopyrido[4,3-b][1,5]benzoxazocin-5-yl)-phenol was formed; its structure was elucidated by spectroscopic methods and X-ray analysis. A reaction
pathway for this new multi-component condensation is suggested and discussed.
Received August 20, 2001. Accepted (revised) November 15, 2001 相似文献
207.
208.
Gang Xu Jian Ping Wu Xin Miao Ai Li Rong Yang College of Material Science Chemical Engineering Zhejiang University Hangzhou PR China 《中国化学快报》2007,18(6):643-646
Microwave-assisted Kornblum oxidation is proved to be an effective way to obtain aldehyde and ketones from their corresponding chlorides. Under microwave irradiation, not only the reaction time was greatly decreased, due to avoiding the by-product, the yield was increased. It is noteworthy that the scope of the method was broadly expanded. 相似文献
209.
2-Aminobenzyl alcohol reacts with an array of ketones in dioxane at 100 °C in the presence of a catalytic amount of CuCl2 along with KOH under O2 atmosphere to afford the corresponding quinolines in good yields. 2-Aminobenzyl alcohol is also oxidatively coupled and cyclized with various aldehydes by step-by-step procedure, an initial treatment of 2-aminobenzyl alcohol in the presence of CuCl2 and KOH in dioxane under O2 atmosphere and subsequent addition of aldehyde to the mixture followed by stirring under argon atmosphere, to give 3-substituted quinolines in moderate to good yields. 相似文献
210.
Cultures of the myxobacterium Chondromyces crocatus on agar plates were analysed by closed-loop-stripping analysis or solid phase micro extraction. The odour profiles consist mainly of pyrazines, sesquiterpenoids and some aromatic compounds, summing up to more than 50 components. Several new pyrazines as 2-(1-hydroxy-1-methylethyl)-3-methoxypyrazine (9), 2-(1-hydroxy-1-methylpropyl)-3-methoxypyrazine (10), and 2-(1-hydroxy-2-methylpropyl)-3-methoxypyrazine (11) were identified besides several known pyrazines. A major pyrazine occurring in most samples was 2,5-bis-(1-methylethyl)pyrazine (3). While the well known sesquiterpenoid geosmin (1) was present in low amounts, the related compound (1(10)E,5E)-germacradien-11-ol (21) was identified in most samples in larger quantities. Other prominent sesquiterpenoids not reported before from microorganisms were (6S,10S)-6,10-dimethylbicyclo[4.4.0]dec-1-en-3-one (16), which was accompanied by smaller amounts of several derivatives. The biosynthesis of these compounds is discussed in relation to the recently proposed biosynthetic pathways to 1 and 21. 相似文献