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41.
Wenbo Liu Dr. Peichen Tang Yi Zheng Dr. Yun-Lai Ren Xinzhe Tian Wankai An Prof. Xianfu Zheng Yinggang Guo Zhenpeng Shen 《化学:亚洲杂志》2021,16(21):3509-3513
Nitrogen transfer from cyanide anion to an aldehyde is emerging as a promising method for the synthesis of aromatic nitriles. However, this method still suffers from a disadvantage that a use of stoichiometric Cu(II) or Cu(I) salts is required to enable the reaction. As we report herein, we overcame this drawback and developed a catalytic method for nitrogen transfer from cyanide anion to an alcohol via the complete cleavage of the C≡N triple bond using phen/Cu2O as the catalyst. The present condition allowed a series of benzyl alcohols to be smoothly converted into aromatic nitriles in moderate to high yields. In addition, the present method could be extended to the conversion of cinnamic alcohol to 3-phenylacrylonitrile. 相似文献
42.
Debayan Roy Dr. Beeraiah Baire 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4009-4015
Design and development of a domino cyclative approach for the synthesis of new polycyclic γ-butenolides from β-aryl-Z-enoate propargylic alcohols, through the interception of an intermediate of the Z-enoate-assisted Meyer–Schuster rearrangement, has been reported. A systematic NMR analysis of various derivatives of this class revealed and supported the potential atropisomerism associated with them. These molecules represent first examples of butenolide ring-based atropisomeric compounds in organic chemistry. The synthetic process involves a synchronous construction of both rings with concurrent creation of the potential stereogenic rotational axis. 相似文献
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45.
Hiroki Kiyama Tsubasa Inokuma Yusuke Kuroda Yousuke Yamaoka Kiyosei Takasu Ken-ichi Yamada 《Tetrahedron letters》2019,60(2):175-177
A new catalytic method for separating enantiomers of racemic compounds is proposed. Catalytic asymmetric addition of racemic trans-2-substituted cyclohexanols to imines provided diastereomeric mixtures of aminals, and the subsequent separation of the enantiomers by silica-gel column chromatography and the hydrolysis of the aminals produced the alcohols in an optically active form. 相似文献
46.
Jeaphianne P. M. van Rijn Andrés M. Escorcia Walter Thiel 《Journal of computational chemistry》2019,40(21):1902-1910
Combined quantum mechanics/molecular mechanics (QM/MM) calculations were used to investigate the reaction mechanism of taxadiene synthase (TXS). TXS catalyzes the cyclization of geranylgeranyl diphosphate (GGPP) to taxadiene (T) and four minor cyclic products. All these products originate from the deprotonation of carbocation intermediates. The reaction profiles for the conversion of GGPP to T as well as to minor products were calculated for different configurations of relevant TXS carbocation complexes. The QM region was treated at the M06-2X/TZVP level, while the CHARMM27 force field was used to describe the MM region. The QM/MM calculations suggest a reaction pathway for the conversion of GGPP to T, which slightly differs from previous proposals regarding the number of reaction steps and the conformation of the carbocations. The QM/MM results also indicate that the formation of minor products via water-assisted deprotonation of the carbocations is highly exothermic, by about −7 to −23 kcal/mol. Curiously, however, the computed barriers and reaction energies indicate that the formation of some of the minor products is more facile than the formation of T. Thus, the present QM/MM calculations provide detailed insights into possible reaction pathways and into the origin of the promiscuity of TXS, but they do not reproduce the product distribution observed experimentally. © 2019 Wiley Periodicals, Inc. 相似文献
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48.
Babasaheb P. Bandgar Vibhav S. Sadavarte Sampada V. Bettigeri 《Monatshefte für Chemie / Chemical Monthly》2002,133(3):345-348
Summary. Benzylic alcohols are selectively converted into their corresponding iodides using KI/H2SO4 supported on natural kaolinitic clay and microwaves.
Received August 20, 2001. Accepted (revised) September 18, 2001 相似文献
49.
Vinogradov M. G. Gorshkova L. S. Chel'tsova G. V. Kurilov D. V. Ferapontov V. A. Shishk O. V. Heise G. L. 《Russian Chemical Bulletin》2003,52(8):1841-1846
An improved procedure was developed for asymmetric reduction of acetophenone and propiophenone by the chiral reagent NaAl(IPTOLate)H2. This procedure is based on isolation of the chiral alcohol that formed as a crystalline host—guest complex with the IPTOL ligand. The enantiomeric enrichment of the product was as high as 97% ee. The ability of IPTOL and its analogs to form host—guest complexes with a number of ether-type solvents, 1-phenylethanol, and 1-phenylpropan-1-ol as well as thermal stabilities of IPTOL-containing complexes with these alcohols were studied. 相似文献
50.
I. M. Skvortsov 《Chemistry of Heterocyclic Compounds》2003,39(4):493-503
Data have been summarized of several studies on the separation of isomeric pyrrolizidine alcohols by GLC using liquid polar stationary phases. It was shown that the order of emergence of isomers from the chromatographic column is determined to a significant extent by competition of intermolecular hydrogen bonds formed in the sorbate-sorbent systems and intramolecular hydrogen bonds in the molecules of the same pyrrolizidine alcohols. The preference for one or other type of hydrogen bond depends on the stereochemistry of the pyrrolizidine alcohols. Analysis of the geometric conditions for the formation of intramolecular hydrogen bonds in the investigated compounds in conjunction with chromatographic resolution data enables their configurations to be assigned. The anomalously short retention times of highly strained 5-hydroxyalkyl-3-methylpyrrolizidines are explained by the existence in them of a bicyclic conformation predominantly with a trans linkage and with f avora ble geometric conditions for forming intramolecular hydrogen bonds in them. 相似文献