全文获取类型
收费全文 | 428125篇 |
免费 | 4749篇 |
国内免费 | 1430篇 |
专业分类
化学 | 234875篇 |
晶体学 | 6250篇 |
力学 | 17839篇 |
综合类 | 10篇 |
数学 | 48223篇 |
物理学 | 127107篇 |
出版年
2020年 | 2992篇 |
2019年 | 3038篇 |
2018年 | 3429篇 |
2017年 | 3373篇 |
2016年 | 5997篇 |
2015年 | 4513篇 |
2014年 | 6351篇 |
2013年 | 18783篇 |
2012年 | 14409篇 |
2011年 | 17710篇 |
2010年 | 11505篇 |
2009年 | 11555篇 |
2008年 | 16576篇 |
2007年 | 16625篇 |
2006年 | 16131篇 |
2005年 | 14746篇 |
2004年 | 13275篇 |
2003年 | 11914篇 |
2002年 | 11695篇 |
2001年 | 13986篇 |
2000年 | 10587篇 |
1999年 | 8361篇 |
1998年 | 6424篇 |
1997年 | 6369篇 |
1996年 | 6330篇 |
1995年 | 5795篇 |
1994年 | 5539篇 |
1993年 | 5279篇 |
1992年 | 6141篇 |
1991年 | 6080篇 |
1990年 | 5732篇 |
1989年 | 5511篇 |
1988年 | 5734篇 |
1987年 | 5455篇 |
1986年 | 5161篇 |
1985年 | 7177篇 |
1984年 | 7277篇 |
1983年 | 5926篇 |
1982年 | 6259篇 |
1981年 | 6151篇 |
1980年 | 5902篇 |
1979年 | 6291篇 |
1978年 | 6365篇 |
1977年 | 6319篇 |
1976年 | 6208篇 |
1975年 | 6008篇 |
1974年 | 5854篇 |
1973年 | 6033篇 |
1972年 | 3642篇 |
1971年 | 2736篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
892.
893.
Smirnov Yu. N. Komarov B. A. Kushch P. P. Ponomareva T. I. Lantsov V. M. 《Russian Journal of Applied Chemistry》2002,75(2):265-275
To control the structural contributions of the polycondensation and polymerization curing of epoxy resins, the curing kinetics of the composites diepoxide-tertiary amine and diepoxide-(primary + tertiary) amines is studied by the isothermal calorimetry. 相似文献
894.
This paper concerns with three series of experiments about dimethylsulfide gas phase oxidation, carried out at increasing NOx level (< 20 ppb, 1 ppm, 10 ppm) to show the relation between the amounts of nitrogen oxides and the molar yields of sulfur containing products. DMSO, DMSO2, HCHO, HCOOH and SO2 were found as main reaction products. From these experiments and from preceding studies, a sensitive decrease in the quantity of total sulfur products in aerosol phase is underlined. This result derives from the reaction of NOx with CH3S(O)O2 and CH3S(O)OO radicals, which leads to stable intermediates as methylsulphonylperoxynitrate, MSPN, with a characteristic PAN-like structure. 相似文献
895.
896.
V. A. Kaganovskii T. F. Makovskaya V. M. Chertov 《Theoretical and Experimental Chemistry》1994,30(2):78-80
A study has been made of the effect of combining tetraethoxysilane hydrolysis and polycondensation catalysts operating by different mechanisms on the texture parameters of synthesized silica gels. The effect of hydrothermal treatment of a fluorine-containing silica hydrogel on the thermal stability of the xerogel texture was demonstrated.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 30, No. 2, pp. 95–98, March–April, 1994. 相似文献
897.
898.
899.
N. A. Davidenko Yu. P. Get’manchuk M. A. Zabolotnyi T. G. Zabolotnaya L. P. Linets E. V. Mokrinskaya V. A. Pavlov S. L. Studzinskii N. G. Chuprina 《High Energy Chemistry》2006,40(6):410-416
The effect of doping with CdS nanoparticles of recording medium films for the thermoplastic holographic recording process, which are based on photosemiconductors (oligomers and cooligomers of glycidylcarbazole) and a dielectric (a styrene copolymer with octyl methacrylate) containing a photoconductivity sensitizer, on their photosensitivity was studied. The enhancement of photosensitivity of films by doping with nanoparticles is associated with the appearance of an additional channel for transport of electrons generated from sensitizer molecules. A difference in informational properties between the oligomer and the polymer films was revealed. 相似文献
900.
T. T. Kucherenko P. V. Muzyka É. B. Rusanov A. N. Chernega V. A. Kovtunenko A. K. Tyltin F. S. Babichev 《Chemistry of Heterocyclic Compounds》1992,28(5):515-518
An unusual path for the reaction of 2-aryl-1-dimethylamino-2H-isoindoles with N-R-maleimides, leading to the imides of l,2-dihydronaphthalene-2,3-dicarboxylic adds, was established by x-ray crystallographic analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 614–618, May, 1992 相似文献