全文获取类型
收费全文 | 3065篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
化学 | 1126篇 |
晶体学 | 29篇 |
力学 | 116篇 |
数学 | 265篇 |
物理学 | 1542篇 |
出版年
2022年 | 26篇 |
2021年 | 47篇 |
2020年 | 43篇 |
2019年 | 75篇 |
2018年 | 100篇 |
2017年 | 82篇 |
2016年 | 95篇 |
2015年 | 40篇 |
2014年 | 83篇 |
2013年 | 150篇 |
2012年 | 90篇 |
2011年 | 141篇 |
2010年 | 96篇 |
2009年 | 102篇 |
2008年 | 108篇 |
2007年 | 135篇 |
2006年 | 100篇 |
2005年 | 73篇 |
2004年 | 72篇 |
2003年 | 77篇 |
2002年 | 75篇 |
2001年 | 66篇 |
2000年 | 62篇 |
1999年 | 53篇 |
1998年 | 52篇 |
1997年 | 46篇 |
1996年 | 47篇 |
1994年 | 26篇 |
1993年 | 24篇 |
1992年 | 26篇 |
1991年 | 27篇 |
1990年 | 32篇 |
1989年 | 37篇 |
1988年 | 34篇 |
1987年 | 26篇 |
1986年 | 29篇 |
1985年 | 34篇 |
1984年 | 40篇 |
1983年 | 31篇 |
1982年 | 37篇 |
1981年 | 33篇 |
1980年 | 23篇 |
1979年 | 38篇 |
1977年 | 38篇 |
1976年 | 30篇 |
1975年 | 22篇 |
1973年 | 28篇 |
1972年 | 27篇 |
1971年 | 29篇 |
1970年 | 25篇 |
排序方式: 共有3078条查询结果,搜索用时 171 毫秒
71.
V. A. Petrov V. K. Kunanets K. N. Makarov L. S. German 《Russian Chemical Bulletin》1989,38(3):572-575
Conclusions When perfluorinated tertiary cyclic amines containing a substituent at the nitrogen atom are heated with antimony pentafluoride, they isomerize to the corresponding azomethines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 646–649, March, 1989. 相似文献
72.
B. A. Vigante M. I. Terekhova Ya. Ya. Ozols E. S. Petrov G. Ya. Dubur 《Chemistry of Heterocyclic Compounds》1989,25(9):1028-1031
The patterns governing the dependence of NH-acidity on the presence of -, - and -substituents in the 1,4-dihydropyridine ring and on their nature have been established by comparison of the pKa values of monocyclic 1,4-dihydropyridines and 4,5-dihydroindenopyridines. Additional data were obtained on the influence of the the electronic effects of sulfur-containing substitutents on the reaction center in the dihydropyridine molecules.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1228–1231, September, 1989. 相似文献
73.
Sadykov R. A. Samokhina M. G. Petrov P. N. Paramonov E. A. Dzhemilev U. M. 《Russian Journal of Applied Chemistry》2004,77(7):1130-1135
Transformations of inert cyclohexane into dimethyldecalins under mild conditions in the presence of a simple catalytic system consisting of aluminum metal and halomethanes were studied. 相似文献
74.
Kovaleva E. G. Molochnikov L. S. Kharchuk V. G. Kuznetsova O. V. Shishmakov A. B. Yanchenko M. Yu. Buldakova L. Yu. Zhdanov I. N. Mikushina Yu. V. Petrov L. A. 《Kinetics and Catalysis》2004,45(5):752-758
The distribution of Cu2+ ions in ZrO2 and sulfated ZrO2 hydrogel phases was studied by EPR spectroscopy and voltammetry. The formation of the following three types of copper structures was observed: mononuclear Cu2+ complexes (A), magnetic associates (B), and Cu2+ compounds (C) that gave no EPR signals under the conditions used in the spectroscopic measurements. The specific catalytic activity of various Cu2+ compounds in the liquid-phase reaction of 2,3,5-trimethyl-1,4-hydroquinone oxidation was determined. The copper complexes C were found to exhibit the highest catalytic activity. 相似文献
75.
V. L. Sukhorukov I. D. Petrov V. F. Demekhin V. F. Volko 《Russian Physics Journal》1984,27(9):743-748
Calculations have been performed on the integral shapes of the K
lines, which are long-wave satellites of the K
1 lines, for Cl, Ti, and Fe, where allowance has been made for interference between states in the 2p–1 and 3p–2p configurations. The calculations show that these satellites represent short-wave branches of the K lines strengthened by the 3p-1s transition with simultaneous M electron ejection. The strong interference between the amplitudes of these processes in the final state means that it is in principle quite impossible to speak of the intensities of the K
satellites without stating how they are isolated from the measured spectrum.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 34–39, September, 1984. 相似文献
76.
Sharutin V. V. Sharutina O. K. Senchurin V. S. Egorova I. V. Ivanenko T. K. Petrov B. I. 《Russian Journal of General Chemistry》2003,73(2):202-203
Pentaphenylantimony and -phosphorus react with arylmercury chlorides in toluene at room temperature to give diaryl derivatives of mercury in yields of up to 95%. The reactions of pentaphenylantimony and -phosphorus with silicon and tin halides involve arylation of the latter in yields of up to 79%. The products of the reaction of pentaphenylphosphorus with triphenylbismuth dihalides are tetraphenylphosphorus halides, triphenylbismuth, and halobenzene. 相似文献
77.
L. E. Ermakova A. N. Momotova L. R. Gudkin Yu. Yu. Petrov M. P. Sidorova 《Colloid Journal》2007,69(1):75-81
The electrokinetic potentials of silicon and titanium aeroxides and the adsorption of potential-determining ions on them are measured as functions of pH in 10?3-1 M NaCl solutions. The positions of the points of zero charge and the isoelectric points are determined. The adsorption of a cationic dye, oxazine 1, from aqueous solutions free of background electrolytes and in the presence of 10?2 M NaCl is measured for both the oxides. The effect of the adsorption of the specifically sorbed cation on the electrokinetic behavior of the tested aeroxides is analyzed. 相似文献
78.
D. M. Roitershtein K. A. Lyssenko P. A. Belyakov M. Yu. Antipin E. S. Petrov 《Russian Chemical Bulletin》1997,46(9):1590-1594
The reaction of the cyclopentadienyllutetium anthracenide, C5H5Lu(C14H10)2−(THF)2 (1), with azobenzene yielded the [C5H5(THF)Lu(μ−η2:η2−PhN—NPh)]2(THF)2 (2) binuclear complex. The structure of the reaction product was established by X-ray structural analysis. The dynamic behavior
of complex2 in a THF-d8 solution was studied by1H NMR spectroscopy in the temperature range of 265–330 K.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1667–1671, September, 1997. 相似文献
79.
Pashkevich D. S. Mukhortov D. A. Petrov V. B. Alekseev Yu. I. Asovich V. S. Barabanov V. G. 《Russian Journal of Applied Chemistry》2004,77(1):92-97
Formation of high-temperature inverse wave of the filtration combustion of graphite fixed bed in fluorine was studied. Scientific principles of the industrial process of the tetrafluoromethane synthesis from graphite and fluorine were developed. 相似文献
80.
Cycloadducts of hexafluorothioacetone (HFTA) were prepared in high yield by a CsF catalyzed reaction between readily available 2,2,4,4-tetrakis-(trifluoromethyl)-1,3-dithietane (as a source of HFTA) with conjugated electron-rich hydrocarbon dienes, such as cyclopentadiene, 2,3-dimethylbuta-1,3-diene, cyclohexa-1,3-diene or (1Z,3Z)-cyclohepta-1,3-diene. Cyclohexa-1,4- and (1Z,5Z)-cycloocta-1,5-dienes, also undergo the reaction with in situ generated HFTA, but form the products of insertion of HFTA into the C-H bond of the diene as a result of ene-reaction. The highly selective reaction of HFTA with (1Z,3Z,5Z)-cyclohepta-1,3,5-triene and (1Z,3Z,5Z,7Z)-cycloocta-1,3,5,7-tetraene leads to the formation of cycloadducts derived from exclusive addition of thioacetone to the corresponding bicyclic isomers—bicyclo[4.1.0]hepta-2,4-diene or bicyclo[4.2.0]octa-2,4,7-triene, respectively. The corresponding cycloadducts of HFTA with 2,3-dimethylbutadiene-1,3-cyclohexa-1,3-cyclohexa-1,4-dienes and (1Z,3Z,5Z)-cyclohepta-1,3,5-triene were also prepared by direct reaction of sulfur/hexafluoropropene/KF and the corresponding hydrocarbon substrate at 35-45 °C in DMF. 相似文献