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151.
This study presents the use of quaternary ammonium bromides as additives in N-methylformamide (NMF) for the separation and quantification of chelating agents as copper complexes by capillary zone electrophoresis (CZE). The new quaternary ammonium bromides were synthesized in our laboratory and used for the first time for CZE applications performed in NMF media. The methods were developed and optimized for determination of six chelating agents (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA), nitrilotriacetic acid (NTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. Among the tested electrolyte additives in NMF media (pHapp 10.2) dimethyldioctylammonium bromide (DMDOAB), dimethyldinonylammonium bromide (DMDNAB) and dimethyldidecylammonium bromide (DMDDAB), at a concentration of 20 mmol L−1 improved the separation of the copper complexes. The optimized methods require only 12 min for one analysis, and the detection limits for copper complexes of DMDNAB, the best-performing additive, were ≤24 μmol L−1. Relative standard deviations (R.S.D.) for migration times were ≤2.5, ≤2.1, ≤3.1% and for peak areas, ≤3.1, ≤3.0, ≤3.2% for DMDOAB, DMDNAB and DMDDAB used as additives, respectively. All three methods were successfully applied to the analysis of natural and wastewater samples. No matrix effects from these samples were observed. The interaction between quaternary ammonium bromides and copper complexes is discussed. 相似文献
152.
Incorporation of a hemilabile amino group with a bulky, electron-rich phosphorus ligand led to a reversal in the order of aryl bromide reactivity in Pd-catalysed aryl amination reactions. 相似文献
153.
Ramakrishnan Chidambaram 《Tetrahedron letters》2004,45(7):1441-1444
Conditions that ensure a more reproducible Pd(0)-mediated procedure to convert aryl bromides to aryl cyanides have been developed that entail the use of zinc dust to keep the Pd in the zero oxidation state and zinc acetate to ensure high catalytic activity. This procedure is applicable to a wide range of substrates and obviates the need for stringent removal of oxygen from the reaction medium. 相似文献
154.
Amongindiumhandes,thestructuralchemistryofthebromidesisrichest.Whilethefirststudycantracebacktothebeginningofthecentury',thebinaryphasediagramhasonlyrecentlybeencompleted'-'duetotheunusualinstabilityofthiscompoundslikeInBr,In5Br=,InZBr3,In.Br7andIner,.Accordingtotheexperiment,thebinaryindiumbromidesareverysensitivetotheair,light,humidityandmechanicalstress.Theoriginoftheunusualinstabilityofthecompoundscreatedgreatinterestamongthetheoreticalchemists.Theresultsbasedonthesemi-empiricalquantU… 相似文献
155.
Oxygen transfer from sulfoxide: formation of aromatic aldehydes from dihalomethylarenes 总被引:1,自引:0,他引:1
The conversion of dihalomethylarenes to the corresponding aldehydes is accomplished conveniently by using sulfoxides as the oxygen donor under neutral conditions. 相似文献
156.
Araceli Núñez 《Tetrahedron》2004,60(29):6217-6224
Tris(trimethylsilyl)silane (TTMSS) and azabisisobutyronitrile (AIBN) promoted the intermolecular arylation of aryl and heteroaryl bromides onto aromatic solvents under thermal conditions via a radical pathway. 相似文献
157.
Synthesis of Quinazolines and Tetrahydroquinazolines: Copper‐Catalyzed Tandem Reactions of 2‐Bromobenzyl Bromides with Aldehydes and Aqueous Ammonia or Amines
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Prof. Xuesen Fan Bin Li Dr. Shenghai Guo Yuanyuan Wang Prof. Xinying Zhang 《化学:亚洲杂志》2014,9(3):739-743
An efficient synthesis of diversely substituted quinazolines and 1,2,3,4‐tetrahydroquinazolines through copper‐catalyzed tandem reactions of the readily available 2‐bromobenzyl bromides, aldehydes, and aqueous ammonia or amines has been developed. By using ammonia and simple aliphatic amines as the nitrogen source, the present method provides a versatile and practical protocol for the synthesis of quinazolines and 1,2,3,4‐tetrahydroquinazolines. 相似文献
158.
A variety of aryl sulfides were synthesized by aryl bromides with thiols, with PEG400 and nickel as catalysts under basic conditions in the absence of solvents. This article reported an easy and convenient method for formation of aryl‐sulfur bonds. 相似文献
159.
《合成通讯》2013,43(20):3615-3620
Abstract Tertiary-β-bromo alcohols, derived from simple monoterpenes and olefins, react with BF3.OEt2 in refluxing benzene in 1–2 h to afford the corresponding allylic/secondary bromides in 45–90% yield. In case of substrates containing olefinic or hydroxyl groups, formation of cyclic ethers was observed. 相似文献
160.
A simple and efficient electrocatalytic carboxylation of arylic bromides has been developed using silver as cathode and magnesium as anode in N,N-dimethylformamide (DMF) under mild conditions. The influences of some key factors (such as the nature of cathode material, current density, and temperature) on this reaction were investigated. The investigations were extended to other arylic bromides under the optimized conditions, and the corresponding carboxylic acids were obtained in moderate to good yields (30–78%). The electrochemical behavior was studied at different electrodes (Ag, Cu, Ni, and Ti) by cyclic voltammetry, which showed significant electrocatalytic effect of the silver electrode toward the reductive carboxylation of arylic bromides. 相似文献