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81.
A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium(Ⅳ) bromate (TNCB) supported on NaHSO4.H2O under solvent-free conditions is reported. 相似文献
82.
Zi-Bo Li 《Tetrahedron letters》2005,46(13):2223-2226
The BINOL-salen compound (S)-5c in combination with Ti(OiPr)4 is found to catalyze the addition of TMSCN to aldehydes to form chiral cyanohydrins with very good enantioselectivity (75-85% ee). The reactions are carried out in one-pot at room temperature without the need to isolate the chiral Lewis acid catalyst. 相似文献
83.
三甲硅基醚的断裂研究 总被引:1,自引:0,他引:1
Sommer等[1]首次应用(Me3SiO)2SO2向醇羟基引人三甲硅基(TMS)以保护羟基以来,已发展出很多方便有效的向醇羟基引人TMS保护基团的方法[2].通常,立体阻碍越小的醇,其羟基越容易被硅基化,而且该TMS保护基团也就越容易在酸或碱性条件下被水解脱除[2]我们在天然产物PrehisPanolone的合成中[3],羟基r-丁烯酸内酯2是一个关键的中间体.如何脱除前体三甲硅基醚的r-丁烯酸内酯1中的TMS保护基团是一个关键的问题.我们采用四了基氟化铵(TBAF)[4](A)、酸性水解[5](B)、碱性醇解[6](C)和三氟化硼乙醚溶液(BF3-Et2O)[7]… 相似文献
84.
Carine Duhayon Yves Canac Laurent Dubrulle Carine Maaliki Remi Chauvin 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(3):198-202
Electrostatic interactions between localized integral charges make the stability and structure of highly charged small and rigid organics intriguing. Can σ/π‐electron delocalization compensate reduced conformational freedom by lowering the repulsion between identical charges? The crystal structure of the title salt, C14H16N42+·2CF3SO3−, (2), is described and compared with that of the 2,2′′‐bis(diphenylphosphanyl) derivative, (4). The conformations of the dications and their interactions with neighbouring trifluoromethanesulfonate anions are first analyzed from the standpoint of formal electrostatic effects. Neither cation exhibits any geometrical strain induced by the intrinsic repulsion between the positive charges. In contrast, the relative orientation of the imidazolium rings [i.e. anti for (2) and syn for (4)] is controlled by different configurations of the interactions with the closest trifluoromethanesulfonate anions. The long‐range arrangement is also found to be specific: beyond the formal electrostatic packing, C—H…O and C—H…F contacts have no definite `hydrogen‐bond' character but allow the delineation of layers, which are either pleated or flat in the packing of (2) or (4), respectively. 相似文献
85.
A. R. Hajipour S. E. Mallakpour I. Mohammadpoor-baltork H. Adibi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):155-163
Abstract Benzyltriphenylphosphonium peroxomonosulfate (BnPh3P+HSO5 ?) (1) is used as a new reagent for oxidative deprotection of trimethylsilyl and tetrahydropyranyl ethers and ethylene acetals to afford carbonyl compounds in refluxing acetonitrile in the presence of bismuth chloride. 相似文献
86.
A simple and efficient method has been developed for the synthesis ofα-amino nitriles from aldehydes,amines and trimethylsilyl cyanide(Me3SiCN) in the presence of a catalytic amount of cyanuric acid at room temperature. 相似文献
87.
88.
Binaphthophospholes 1 are the starting compounds for the synthesis of chiral phosphine oxides 3 or phosphines 4 via reaction of phospholium salts 2 with nucleophiles. The binaphthyl residue acts as a stereochemical probe for monitoring the integrity of the phosphorus stereocenter. 相似文献
89.
Reactions of 3-tributylstannyl-2-(trimethylsilymethyl)propene with acid chlorides or aldehydes proceed smoothly without any catalytic activation to afford allylsilanes bearing various functionalities. 相似文献
90.
Beatrice Kern Hannes Vitze Michael Bolte Matthias Wagner Hans‐Wolfram Lerner 《无机化学与普通化学杂志》2008,634(11):1830-1832
The lithium silanolate LiOSiMe3 is accessible from the reaction of Me3SiOSiMe3 with LiMe in tetrahydrofuran. Single crystals of [Li7(OSiMe3)7(THF)] were obtained from toluene at 25 °C. The structure of [Li7(OSiMe3)7(THF)] (C2/c) features a capped trigonal antiprismatic arrangement of seven Li atoms. The Li atoms in [Li7(OSiMe3)7(THF)] are μ3‐bridged by seven O atoms of the silanolate ligand. 相似文献