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101.
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103.
A new strategy for solid phase synthesis of a secondary amide library using sulfonamide linker via radical traceless cleavage is reported. Polystyrylsulfonyl chloride (1) reacted with primary amines to afford polystyryl-supported N-alkyl sulfonamides (2), which were acylated with acid chlorides and followed by radical cleavage with TiCl4/Zn to afford secondary amides. It was interestingly found that the products released from acyl alkanesulfonamide resins are closely dependent on the substituents of benzene rings of alkyl or acyl groups on the resins. When the substituent on benzene ring of N-benzyl group of sulfonamides is an electron rich MeO-group, the products released from sulfonamide resins are dependent on the substitution position on benzene ring: para-MeO- to yield 1,2-bis (p-methoxylphenyl)ethane and N-p-methoxylbenzyl benzamide (30:1); ortho-MeO- to give 1,2-bis (o-methoxylphenyl)ethane and N-o-methoxylbenzyl benzamide (1:15); and meta-MeO- only to release N-m-methoxylbenzyl benzamide. Neither N-benzoyl sulfonamide resins on benzene ring with electron-drawing para-O2N-, nor the one with electron-donating para-H2N- could release any amide product, while the N-benzoyl sulfonamide resins on benzene ring with para-acetamido group released para-acetamidobenzamides. The conjugation effect to stabilize the radical groups in the radical cleaving process was observed. 相似文献
104.
105.
An operationally simple and high yielding procedure has been developed for the preparation of nitriles from aldoximes and primary amides using bromodimethylsulfonium bromide (BDMS) as a novel and efficient reagent in the absence of any added base or catalyst. The optimal protocol is applicable to access a wide range of cyano compounds including aromatic, heterocyclic, and aliphatic species. The conversion of aldoximes to nitriles takes place at room temperature in acetonitrile, whereas acetonitrile at reflux temperature is required for rapid conversion in the case of primary amides. 相似文献
106.
Korepin A. G. Galkin P. V. Glushakova N. M. Lagodzinskaya G. V. Loginova M. V. Lodygina V. P. Eremenko L. T. 《Russian Chemical Bulletin》2001,50(1):104-109
A new version of the Mannich reaction involving amino alcohols (3-aminopropan-1-ol and aminoethanol) was developed. These compounds react with formaldehyde and CH or NH acids to give N-substituted tetrahydro-1,3-oxazines or oxazolidines. 相似文献
107.
108.
109.
V. Renugopalakrishnan G. Madrid G. Cuevas A. T. Hagler 《Journal of Chemical Sciences》2000,112(1):35-42
Density functional theory was applied to the calculation of molecular structures of N-methyl formamide (NMF), N,N-dimethyl
formamide (DMF), and N,N-dimethyl acetamide (DMA). DFT calculations on NMF, DMF, and DMA were performed using a combination
of the local functional of Vosko, Wilk, and Nusair (VWN) with the nonlocal exchange functional of Becke and the nonlocal correlational
functional of Lee, Yang, and Parr (BLYP). The adiabatic connection method (ACM) of Becke has also been used, for the first
time, for the calculation of molecular structures of NMF, DMF, and DMA. The calculated molecular structures are in excellent
agreement with the experimental geometries of NMF and DMA derived from gas-phase electron-diffraction studies. Sparse experimental
data on the gas-phase geometry of DMF reported in the literature compares well with the DFT results on DMF. DFT emerges as
a powerful method to calculate molecular structures. 相似文献
110.
Jacqueline Jiménez Mildred López Vladimir Carranza Angel Mendoza Jenaro Varela Estibaliz Sansinenea Aurelio Ortiz 《Tetrahedron letters》2017,58(3):235-239
An alternative methodology for the synthesis of chiral 3-(p-tolyl) butanoic acids is presented. This was accomplished through the diastereoselective hydrogenation reaction of different chiral N-3-(p-tolyl) but-2-enamides, using Pd/C in EtOH, to produce the corresponding chiral N-3-(p-tolyl) butanamides with high chemical yields and moderate diastereomeric ratios. Removal of the chiral auxiliary from N-3-(p-tolyl) butanamides gave the respective enantiomerically pure acids. 相似文献