全文获取类型
收费全文 | 346篇 |
免费 | 1篇 |
专业分类
化学 | 135篇 |
晶体学 | 3篇 |
力学 | 3篇 |
数学 | 6篇 |
物理学 | 200篇 |
出版年
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 11篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2014年 | 9篇 |
2013年 | 17篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 17篇 |
2007年 | 12篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 10篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有347条查询结果,搜索用时 15 毫秒
11.
A. B. Zolotoi S. V. Konovalikhin N. M. Sergeev A. V. Buevich P. N. Lukin A. N. Lyshchikov M. Yu. Skvortsova S. P. Zil'berg O. E. Nasakin 《Journal of Structural Chemistry》1990,31(3):464-471
For communication 13, see [1]. 相似文献
12.
A. B. Zolotoi S. V. Konovalikhin P. M. Lukin O. A. D'yachenko S. P. Zil'berg O. E. Nasakin 《Chemistry of Heterocyclic Compounds》1988,24(10):1166-1171
The Michael condensation of 1,1,2,2-tetracyanoethane with 3-methyl-4-benzylideneisoxazolin-5-one having the Z configuration leads to a heterocyclic spiran with retention of the cis orientation of the phenyl and keto groups. The deviations of the series of bond angles of the spiran from the standard values, the abnormal lengths of the C-C bonds adjacent to the gem-dicyano group, and the appearance of nonbonding >C=O(...)CN interactions and conjugation effects in the enaminonitrile fragment are discussed.For Communication 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1404–1410, October, 1988. 相似文献
13.
Ya. S. Kayukov P. M. Lukin O. E. Nasakin V. N. Khrustalev V. N. Nesterov M. Yu. Antipin V. V. Sheverdov 《Chemistry of Heterocyclic Compounds》1997,33(4):423-425
It has been established by x-ray structural analysis that on reacting 4-oxoalkane-1,1,2,2-tetracarbonitriles with aldehydes
6-imino-2,7-dioxabicyclo[3.2.1]octane-4,4,5-tricarbonitriles are formed and not 3-imino-2,6-dioxabicyclo[2,2,2] octane-4,8,8-tricarbonitriles
as has been proposed.
Chuvash State University, Cheboksary 428015. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 497–499,
April, 1997. 相似文献
14.
Conclusions On the basis of measurements of values of in liquid hydrocarbons, it has been shown that the path length before localization of a photoliberated electron increases with increasing mobility of the excess electron, from approximately 40 Å (methylcyclohexane) to 200 Å (isooctane). In a liquid with10–2 cm2/V·sec (methylcyclohexane, hexane), the localization takes place before or immediately after thermalization of the electron. In a liquid with>10–1 cm2/V·sec, the electron passes through the main part of its path before localization, being in thermal equilibrium with the medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2198–2203, October, 1985. 相似文献
15.
A. B. Zolotoi P. M. Lukin S. V. Konovalikhin M. Yu. Skvortsova O. E. Nasakin L. O. Atovmyan 《Chemistry of Heterocyclic Compounds》1991,27(4):413-419
The problems of the structure—property interrelationship of 3-imino-2-oxabicyclo[2.2.1]heptane derivatives are discussed on the basis of x-ray diffraction studies (XDS). A pathway for the formation of the bicyclic compounds is proposed, and the realization of spirans in the reaction of sym-tetracyanoethane with conjugated cyclic systems containing s-cis C=C and C=O fragments is substantiated. The factors responsible for the syn orientation of the oxygen atom and the N-substituent of the imino group are analyzed. It is shown that a change in the steric hindrance in the bicyclic compounds leads to a change in the conformation of the latter. The reasons for the shortening of the Csp3-Csp3, Csp3-Csp and C=N exo bonds and the correlation of the XDS and IR spectroscopic data are examined. From the XDS data for N-bromo-substituted imines, a model for Br+...NC electrophilic attack was proposedCommunication 16 from the series Chemistry of 1,1,2,2-tetracyanoethane. See [1] for Communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 519–526, April, 1991. 相似文献
16.
17.
Physics of Atomic Nuclei - In this paper, the analysis of the relation between the multiplication factor of neutrons of the multiplying system measured in critical experiments and the system... 相似文献
18.
N. F. Morozov D. A. Indeitsev A. V. Lukin I. A. Popov O. V. Privalova D. Yu. Skubov L. V. Shtukin 《Doklady Physics》2016,61(11):562-566
Branching of equilibria of a system of three parallel conducting nano/microlayers, which is used to detect changes in the external and internal mechanical and electric characteristics (for example, conductivity, tension force, and gap between layers), has been investigated. A change in the physical parameters may cause asymmetric bending of the outer layers and deformation of the formerly neutral middle layer. By changing the current in one of the outer layers slowly, their initial symmetry (neutrality of the inner layer) can be restored and the change that occurred in the parameters can be determined. 相似文献
19.
Highly Efficient One‐Pot Preparation of 1,2,4‐Oxadiazoles in the Presence of Diazabicycloundecene 下载免费PDF全文
New highly efficient method for the cyclization of acylamidoximes in the presence of diazabicycloundecene was developed and incorporated into a general and practical one‐pot synthesis of 1,2,4‐oxadiazoles (11 examples, 85–97% yields). 相似文献
20.
Artem Cherepakha Vladimir O. Kovtunenko Andrey Tolmachev Oleg Lukin 《Journal of heterocyclic chemistry》2013,50(5):1071-1077
A set of synthetic procedures was developed to yield functionalized pyrido‐, pyrimido‐, and thiazo‐annulated thiadiazine‐1,1‐dioxides on a preparative scale. In all cases the thiadiazine‐1,1‐dioxide ring closure was carried out through a reaction of hetaryl‐sulfonyl chlorides with amidines under mild noncatalytic conditions. In the case of 2‐chloropyridine‐3‐sulfonyl chloride derivatives and 2,4‐dichlorothiazole‐5‐sulfonyl chloride open‐chain sulfonylated amidine intermediates were isolated and then subjected to the cyclization step. The reaction with 2,4‐dichloropyrimidine‐5‐sulfonyl chloride gave rise to the corresponding thiadiazine‐1,1‐dioxides in one‐pot. Similarly, a reaction of 2‐chloropyridine‐3‐sulfonamide with lactime ethers proceeded in one‐pot readily giving the corresponding thiadiazine‐1,1‐dioxides. Remaining chlorine atoms on the prepared hetaryl‐annulated benzothiadiazine‐1,1‐dioxides readily undergo aromatic nucleophilic displacement reactions serving thus as additional variation points for the design of biologically potent compounds. 相似文献