全文获取类型
收费全文 | 293篇 |
免费 | 0篇 |
专业分类
化学 | 243篇 |
力学 | 1篇 |
数学 | 2篇 |
物理学 | 47篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 12篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2002年 | 9篇 |
2001年 | 2篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 16篇 |
1985年 | 11篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1967年 | 1篇 |
1965年 | 3篇 |
排序方式: 共有293条查询结果,搜索用时 707 毫秒
1.
N. A. Klyuev R. A. Khmel'nitskii G. A. Mal'tseva L. N. Zhukauskaite A. N. Kost 《Chemistry of Heterocyclic Compounds》1973,9(7):895-900
The mass spectra of the following methyl-substituted hydroxyquinolines have been studied in the range of energies of the ionizing electrons of 15–50 eV: 2-hydroxy-4-methylquinoline, 6-hydroxy-2-methylquinoline, 6-hydroxy-4-methylquinoline, 8-hydroxy-2-methylquinoline, 8-hydroxy-4-methylquinoline, 2,6-dihydroxy-4-methylquinoline, and 4,6-dihydroxy-2-methylquinoline. It has been shown that the processes of dissociative ionization for the series of compounds investigated take place exclusively from the keto forms of the molecular ions. The stability to electron impact is determined largely by the degree of enolization of the structures considered. The values of the selective decomposition are given and a scheme is proposed for the identification of the isomeric methyl-substituted hydroxyquinolines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 972–978, July, 1973. 相似文献
2.
V. N. Charushin G. M. Petrova G. G. Aleksandrov L. G. Egorova A. I. Chernishev E. O. Sidorov N. A. Klyuev O. N. Chupakhin 《Chemistry of Heterocyclic Compounds》1987,23(4):426-435
Dibenzo[d,k]-1,3,6,10-tetraazatetracyclo[7.3.1.02,7.06,13]trideca-4,11-dienes undergo addition reactions at the C(2) carbon atom with alcohols and thiols, accompanied by cleavage of the C-N bond of the imidazoline ring, to generate diquinoxalino[1,2-a2,3-d]pyrrole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 513–522, April, 1987. 相似文献
3.
V. P. Kruglenko N. S. Patalakha P. B. Kurapov N. A. Klyuev V. A. Idzikovskii I. I. Grandberg M. V. Povstyanoi 《Chemistry of Heterocyclic Compounds》1985,21(5):587-593
The synthesis has been effected of new representatives of the imidazo[1,2-b]-1,2,4-triazepin-4-ones (-thiones). It has been shown with the aid of IR and UV spectroscopic and mass spectrometric methods that the lactam (thione) form is the predominant one for the compounds synthesized.For Communication 11, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 694–699, May, 1985. 相似文献
4.
5.
V. A. Zyryanov N. A. Klyuev V. L. Rusinov I. Ya. Postovskii A. B. Belikov L. F. Lusev 《Chemistry of Heterocyclic Compounds》1980,16(4):437-442
Depending on the reaction conditions, the nitration of 1-phenyl-5-styryltetrazole (I) with nitric acid and nitrating mixture give 1-(4-nitrophenyl)-5-styryltetrazole, 1-(4-nitrophenyl)-5-(4-nitrostyryltetrazole), and 1-(2,4-dinitrophenyl)-5-(4-nitrostyryl) tetrazole. The structures of the compounds obtained have been established by an analysis of their mass spectra and of the mass spectra of model compounds. The positions and sequences of entry of the nitro groups have been determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 558–563, April, 1980. 相似文献
6.
V. A. Zamureenko N. A. Klyuev B. V. Bocharov V. S. Kabanov A. M. Zakharov 《Chemistry of Natural Compounds》1990,25(5):549-551
The composition of the essential oil of wild bergamot bee balm introduced into the Krasnodarsk Krai has been analyzed by chromatomass spectrometry. The essential oil contains 34 components of which the main ones are -pinene (3.5%), -pinene (2.9%), -terpinene (1.7%), p-cymene (32.5), an aliphatic aldehyde (6.3%), sabinene hydrate (1.9%), -caryophyllene (1.1%), the methyl ether of carvacrol (5.5%), citronellyl acetate (1.6%), thymol (12.6%), and carvacrol (24.0%). The compounds were identified on the basis of their mass-spectrometric characteristics and arithmetical retention indices.A. N. Severtsov Institute of Animal Evolutionary Morphology and Ecology, Academy of Sciences of the USSR, Moscow. All-Union Scientific-Research Institute of Drugs, Moscow. Translated from Khimiya Prirodnykh Soedinenii, Vol. 5, pp. 646–649, September–October, 1989. 相似文献
7.
V. P. Kruglenko V. A. Idzikovskii N. A. Klyuev M. V. Povstyanoi 《Chemistry of Heterocyclic Compounds》1988,24(3):317-320
A number of new 4-imino-substituted 2-methyl-7,8-diphenyl-5H-imidazo[1,2-b]-1,2,4-triazepines were synthesized by replacing the S atom in 2-methyl-7,8-diphenyl-5H-imidazo[1,2-b]-1,2,4-triazepine-4-thione by the action of nitrogen-containing nucleophiles. It is shown that the imine form is characteristic for the synthesized compounds.See [1] for communication 18.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 386–389, March, 1988. 相似文献
8.
N. A. Klyuev 《Journal of Analytical Chemistry》2002,57(6):462-479
The review is devoted to the use of mass spectrometry and chromatography–mass spectrometry in various areas of pharmaceutical chemistry. The role of the above techniques in the structural identification of impurities in drug preparations and in the determination of the biotransformation behavior of pharmaceuticals in human and animal bodies is shown. The inactivation of drugs under the action of external factors (oxidation by atmospheric oxygen and the effects of moisture, heat, and light) is illustrated. The use of various ionization techniques and the spectra of metastable ions for determining the structures of components of biologically active substances are exemplified. 相似文献
9.
T. L. Pilicheva V. L. Rusinov O. N. Chupakhin N. A. Klyuev G. G. Aleksandrov S. E. Esipov 《Chemistry of Heterocyclic Compounds》1986,22(11):1250-1255
Non-charge-activated 6-nitroazolo[1,5-a]pyrimidines have been reacted with indoles, and the effects of substituents in the azole moiety of the substrate molecule have been examined.For communication 5, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenni, No. 11, 1544–1549, November, 1986. 相似文献
10.
V. L. Rusinov E. N. Ulomskii N. A. Klyuev V. M. Orlov S. V. Shorshnev O. N. Chupakhin 《Chemistry of Heterocyclic Compounds》1992,28(11):1331-1334
Prototropic reactions of 6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[5,1-c][1,2,4]triazines is tautomeric as established from photoionization results. The ratios of the tautomers in the gas phase and in solution have been determined by mass and 13C NMR spectroscopy.For Communication 18 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1555–1559, November, 1992. 相似文献