全文获取类型
收费全文 | 361篇 |
免费 | 0篇 |
专业分类
化学 | 194篇 |
晶体学 | 5篇 |
力学 | 2篇 |
数学 | 40篇 |
物理学 | 120篇 |
出版年
2021年 | 5篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 16篇 |
2009年 | 18篇 |
2008年 | 4篇 |
2007年 | 14篇 |
2006年 | 5篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 4篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 9篇 |
1971年 | 9篇 |
1970年 | 5篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 8篇 |
1966年 | 5篇 |
1965年 | 6篇 |
1964年 | 3篇 |
1961年 | 3篇 |
1960年 | 3篇 |
1959年 | 3篇 |
排序方式: 共有361条查询结果,搜索用时 15 毫秒
81.
Yuldashev M. P. Batirov É. Kh. Vdovin A. D. Malikov V. M. Yagudaev M. R. 《Chemistry of Natural Compounds》1989,25(3):303-308
From the epigeal part ofThermopsis alterniflora Rgl.et Schmalh. (Fabaceae), in addition to formononetin, ononin, cynaroside, and rothindin, two new acylated flavone glycosides have been isolated and, on the basis of chemical transformations and spectral characteristics, their structures have been established as 4,5,7-trihydroxy-3-methoxyflavone 7-O-(6-O-crotonoyl--D-glucopyranoside) and 4,5,7-trihydroxyflavone 7-O-(6-O-crotonoyl--D-glucopyranoside).Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 352–359, May–June, 1989. 相似文献
82.
N. S. Nametkin V. M. Vdovin E. Sh. Finkel'shtein A. M. Popov A. V. Egorov 《Russian Chemical Bulletin》1973,22(12):2742-2743
Conclusions The hydrogenolysis of spiro[2,3]hexane on Pt/kieselguhr at 100° in a flow system proceeds selectively, with a cleavage of the cyclopropane C-C bond furthest away from the quaternary carbon atom, and leads to the formation of gem-dimethylcyclobutane. At 140–150° the direction of the reaction changes toward the predominant formation of ethylcyclobutane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2806–2807, December, 1973. 相似文献
83.
84.
B. L. Kuzin N. M. Bogdanovich D. I. Bronin I. Yu. Yaroslavtsev G. K. Vdovin Yu. A. Kotov A. V. Bagazeev A. I. Medvedev A. M. Murzakaev O. P. Timoshenkova A. K. Stol’ts 《Russian Journal of Electrochemistry》2007,43(8):920-928
The electric and electrochemical characteristics of cathodes made of La0.6Sr0.4Fe0.8Co0.2O3?δ (LSFC) and intended for fuel cells with electrolytes based on ceric oxide are studied. Adding cupric oxide into the LSFC cathode is shown to exert a favorable effect of the properties of the LSFC-CuO/SDC electrode system, where SDC stands for the CeO2-Sm2O3 electrolyte. The effect produced by cupric oxide when added in the form of nanopowder is perceptibly greater than in the case of micropowdered CuO. Adding a mere 0.5 wt % of nanopowdered CuO reduces the LSFC cathode resistance nearly tenfold. The cathode’s adhesion to the electrolyte substantially improves as well, which makes it possible to lower the cathode’s firing temperature by 100°C. The maximum of electrochemical activity is intrinsic to cathodes containing 2 wt % CuO, with the caking temperature of 1000°C. According to a 2011-h life test of the LSFC-SDC composite cathodes containing nanopowdered CuO, temporal stability of their electrochemical characteristics improves with the SDC content. The time dependences of the polarization resistance of cathodes containing 40–50 wt % SDC look like decaying exponential curves. The steady-state polarization resistance, calculated on the basis of this, is equal to 0.1–0.2 ohm cm2. At an overvoltage of less than 100 mV, the cathodes may provide for a current density of 0.5–1.0 A cm?2. 相似文献
85.
Khanin Yu. N. Vdovin E. E. Grigor’ev M. V. Makarovsky O. Alhazmi Manal Morozov S. V. Mishchenko A. Novoselov K. S. 《JETP Letters》2019,109(7):482-489
JETP Letters - The evolution of the manifestation of levels of defects in h-BN in tunneling through graphene/h-BN/graphene heterostructures with various degrees of perfection, from completely... 相似文献
86.
87.
88.
N. M. Bogdanovich D. I. Bronin G. K. Vdovin I. Yu. Yaroslavtsev B. L. Kuzin 《Russian Journal of Electrochemistry》2009,45(4):456-464
The sintering features, electroconductivity, and electrochemical characteristics of bilayer electrodes with functional composite
layers based on La(Sr)MnO3 (LSM) and La(Sr)Fe(Co)O3 with LSM collector layer and Bi(Y)O1.5 (YDB) electrolyte additive in contact with Ce (Sm)O2(SDC), La(Sr)Ga(Mg)O3, and Zr(Sc)O2 electrolytes were studied. YDB additive to the electrode collector layer was shown to produce a positive effect to the properties
of the studied electrode systems. The maximum electrochemical activity and electroconductivity was observed for the electrodes
with 5 wt % of YDB electrolyte additive in the collector layer. Thus, electroconductivity of electrodes is almost doubled
and 100 mV cathode overvoltage current density is increased by 30% at the temperatures of 800 to 900°C and up to 10-fold at
650 to 700°C. The collector layer sintering temperature of bilayer electrodes can be reduced from 1150 to 1000°C without loss
of electrochemical activity. The service life tests (about 1200 h) of composite electrodes with LSM2-SDC functional layer
and 90% LSM2 + 10% YDB collector layer in contact with SDC electrolyte showed the time dependences of polarization resistance
tending to saturation and described with damped exponent.
Original Russian Text ? N.M. Bogdanovich, D.I. Bronin, G.K. Vdovin, I.Yu. Yaroslavtsev, B.L. Kuzin, 2009, published in Elektrokhimiya,
2009, Vol. 45, No. 4, pp. 486–494. 相似文献
89.
Vdovin A Sepioł J Urbańska N Pietraszkiewicz M Mordziński A Waluk J 《Journal of the American Chemical Society》2006,128(8):2577-2586
Laser-induced fluorescence and dispersed fluorescence spectra measured in supersonic jets for 9,10,19,20-tetra-n-methylporphycene and 9,10,19,20-tetra-n-propylporphycene reveal, for both compounds, the presence of two different species which are assigned to trans and cis tautomeric forms. Doublet splitting of lines is observed, disappearing upon deuteration of the inner nitrogen atoms. This finding is interpreted as an indication of double hydrogen tunneling. The values of tunneling splitting are obtained for both ground and lowest singlet excited states. The splitting is similar for cis and trans forms, and the barrier for tautomerization is larger in the excited state. Due to the coupling of hydrogen motion with rotation of alkyl substituents, tautomerization occurs in an asymmetric double minimum potential, with the ordering of energy minima reversed upon excitation. The second singlet excited state is found to lie very close to S(1), thus facilitating an efficient radiationless depopulation. 相似文献
90.
G. V. Vdovin I. R. Guralnik O. A. Zayakin N. A. Klimov S. P. Kotova M. Yu. Loktev A. F. Naumov V. V. Patlan S. A. Samagin 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(1):71-77
The results of the development of modal liquid crystal wavefront correctors are reviewed. The modal principle of control is described. Characteristics and examples of application of electrically and optically controlled lenses and multichannel correctors with a tunable response function in different systems are reported. 相似文献