全文获取类型
收费全文 | 325篇 |
免费 | 0篇 |
专业分类
化学 | 218篇 |
晶体学 | 3篇 |
力学 | 3篇 |
数学 | 11篇 |
物理学 | 90篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 4篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 11篇 |
2011年 | 16篇 |
2010年 | 8篇 |
2009年 | 13篇 |
2008年 | 20篇 |
2007年 | 14篇 |
2006年 | 17篇 |
2005年 | 9篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1993年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有325条查询结果,搜索用时 15 毫秒
41.
E. A. Rychagova L. V. Kalakutskaya S. N. Titova G. A. Domrachev S. Yu. Ketkov 《Russian Chemical Bulletin》2011,60(9):1888-1898
New soluble fullerene derivatives But n C60 were synthesized by the reaction of C60M n (THF) x (M = Li, Na; n = 4, 6, 8, 10, 12) with tert-butyl bromide ButBr. The thus obtained compounds were characterized by spectroscopic methods (IR and NMR spectroscopy), mass spectrometry (MALDI), elemental analysis, and quantum chemical calculations. HPLC was used for chromatographic separation of the products of the reaction of C60Na n (THF) x (n = 4, 6, 8, 12) with ButBr. It was found that But 4C60 and But 6C60 decompose on the column. A complex of physicochemical methods of analysis was used for establishing compositions of individual fractions of chromatographic separation of But 4C60. The structure of one of the components was determined as 1-tert-butyl-1,2-dihydrofullerene 1,2-ButC60H. 相似文献
42.
K. V. Titova V. P. Nikol’skaya V. V. Buyanov O. B. Pudova G. P. Karzhavina O. A. Zharkova 《Russian Journal of Applied Chemistry》2011,84(1):167-169
Tetraalkylammonium chlorides peroxosolvates (CH3)4NCl·H2O2 and (C2H5)4NCl·H2O2 were synthesized. The composition of the solvates was proved by chemical analysis; their X-ray patterns, IR spectra, and thermograms were obtained. The solubility of the solvates in water and their stability in aqueous solutions were investigated. 相似文献
43.
A. V. Velikorodov O. Yu. Poddubnyi O. O. Krivosheev O. L. Titova 《Russian Journal of Organic Chemistry》2011,47(3):402-404
1,3-Dipolar cycloaddition of methyl 4-[2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)acetyl]phenylcarbamate to non-stabilized azomethine ylides generated by decarboxylation of α-amino acid (sarcosine and proline) adducts with ketones (isatin and ninhydrin) occurred regioselectively with formation of the corresponding spiro compounds having a carbamate moiety. 相似文献
44.
Quantum chemical calculations were carried out to study the reaction of Al atom in the ground electronic state with H(2)O molecule. Examination of the potential energy surface revealed that the Al + H(2)O → AlO + H(2) reaction must be treated as a complex process involving two steps: Al + H(2)O → AlOH + H and AlOH + H → AlO + H(2). Activation barriers for these elementary reaction channels were calculated at B3LYP/6-311+G(3df,2p), CBS-QB3, and G3 levels of theory, and appropriate rate constants were estimated by using a canonical variational theory. Theoretical analysis exhibited that the rate constant for the Al + H(2)O → products reaction measured by McClean et al. must be associated with the Al + H(2)O → AlOH + H reaction path only. The process of direct HAlOH formation was found to be negligible at a pressure smaller than 100 atm. 相似文献
45.
T. N. Titova 《Journal of Applied Mathematics and Mechanics》1981,45(6):773-777
A method of finding the generating function of a canonical transformation reducing a quadratic Hamltonian and the corresponding Hamiltonian matrix to some normal form, is obtained. The problem of reducing a fourth order Hamiltonian matrix to its normal form is solved as an example. 相似文献
46.
47.
48.
Yu. N. Matyushin T. S. Kon'kova K. V. Titova E. N. Loginova A. B. Vorob'ev Yu. A. Lebedev 《Russian Chemical Bulletin》1981,30(10):1972-1973
Conclusions We determined the enthalpies of solution (5.53 ± 0.03 kcal/mole) and formation (21.7 ± 0.28 kcal/mole) of dimethyltriazanium chloride.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2392–2394, October, 1981. 相似文献
49.
50.
The rotational hysteresis loss in Y3Fe5O12 single crystals is found to increase with the field up to 2.5–3 kOe at all temperatures between –183 and 250 ° C, this being followed by a fall, a further peak at 8–10 kOe, and a slow fall, with some residual effect even at 20 kOe. This loss is sensitive to heat treatment; annealing for 2 hr at 275 ° C greatly reduces the loss at –183 ° C and halves the main (second) peak at 20 ° C. These anomalies do not occur in ferrites with the spinel structure. The first anistropy constant is slightly reduced at all temperatures as a result of annealing. 相似文献