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排序方式: 共有299条查询结果,搜索用时 18 毫秒
31.
Yu. M. Volovenko V. V. Ivanov A. O. Pushechnikov 《Chemistry of Heterocyclic Compounds》2002,38(2):213-218
Bromination of 1-oxo(imino, amino)benzo[4,5]imidazo[1,2-a]pyridines gave the corresponding 2-bromo derivatives. Acylation using the Vilsmeier complex in acetic anhydride gave the N-formyl and N-acetyl derivatives. The reaction of the amine with the Vilsmeier complex, acetyl acetone, ethyl acetoacetate, and 2,5-dimethoxytetrahydrofuran occurs at the amino group. 相似文献
32.
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34.
Emil Byström Anna Nordborg Fredrik Limé Ngoc Phuoc Dinh Knut Irgum 《Journal of separation science》2010,33(11):1563-1570
A combined surface activation and “grafting to” strategy was developed to convert divinylbenzene particles into weak cation exchangers suitable for protein separation. The initial activation step was based on plasma modification with bromoform, which rendered the particles amenable to further reaction with nucleophiles by introducing Br to a surface content of 11.2 atom‐%, as determined by X‐ray photoelectron spectroscopy. Grafting of thiol‐terminated glydicyl methacrylate telomers to freshly plasma activated surfaces was accomplished without the use of added initiator, and the grafting was verified both by reduction in bromine content and the appearance of sulfur‐carbon linkages, showing that the surface grafts were covalently bonded. Following grafting the attached glydicyl methacrylate telomer tentacles were further modified by a two‐step procedure involving hydrolysis to 2,3‐hydroxypropyl groups and conversion of hydroxyl groups to carboxylate functionality by succinic anhydride. The final material was capable of baseline separating four model proteins in 3 min by gradient cation exchange chromatography in a fully aqueous eluent. 相似文献
35.
Various cycloalkanes and straight‐chain alkanes were efficiently brominated with an aqueous HBr‐H2O2 system. This oxidative brominating process was promoted by catalysis and irradiation with light. The cycloalkanes were converted to the corresponding bromo‐cycloalkanes in moderate yields and the straight‐chain alkanes produced dominantly secondary bromides. This simple but effective bromination method of alkanes is characterized by high atom efficiency, inexpensive reagents and the absence of organic waste, which make it a good alternative to the existing method for C? H activation through bromination. 相似文献
36.
Reaction of substituted benzene rings with N‐bromophthalimide, under neutral conditions, gave the corresponding bromo derivatives with a preference for the formation of the para bromo isomer over the ortho isomer. The simple work‐up procedure minimizes loss of product and the yields are good. 相似文献
37.
The behavior of (pyrrol-1-yl)furazans in electrophilic substitution reactions (halogenation, nitration, and acylation) was
studied. The presence of the furazan ring substantially did not affect the regioselectivity of the reactions but it prevented
replacement of all the hydrogen atoms in the pyrrole ring by electrophiles.
Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1516–1520, August, 2007. 相似文献
38.
A. A. Tikhonov A. A. Vasil’ev M. V. Chirskaya M. I. Struchkova N. L. Merkulova S. G. Zlotin 《Russian Chemical Bulletin》2007,56(1):122-129
Dehydrobromination of vicinal dibromoalkanes in systems comprising 1,2-dimethoxy-ethane, N-butyl-N′-methylimidazolium tetrafluoroborate (or tetrabutylammonium bromide), and a base with subsequent palladium-catalyzed cross-coupling
of the thus formed bromoalkenes with arylboronic acids furnished substituted styrenes.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 116–123, January, 2007. 相似文献
39.
The reactions of acylimines of hexafluoroacetone with 1,3-C,N-binucleophiles giving rise to fluorine-containing 1,4-dihydropyrimidines,
including fused compounds, were studied.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 706–709, April, 2006. 相似文献
40.
Dr. Qingzhen Yu Le'an Hu Yue Wang Shasha Zheng Prof. Dr. Jianhui Huang 《Angewandte Chemie (International ed. in English)》2015,54(50):15284-15288
A Ru‐catalyzed direct C? H activation/meta‐bromination of arenes bearing pyridyl, pyrimidyl, and pyrazolyl directing groups has been developed. A series of bromo aryl pyridines and pyrimidines have been synthesized, and further coupling reactions have also been demonstrated for a number of representative functionalized arenes. Preliminary mechanistic studies have revealed that this reaction may proceed through radical‐mediated bromination when NBS is utilized as the bromine source. This type of transformation has opened up a new direction for the radical non‐ipso functionalization of metal with regard to future C? H activation development that would allow the remote functionalization of aromatic systems. 相似文献