全文获取类型
收费全文 | 222399篇 |
免费 | 2371篇 |
国内免费 | 273篇 |
专业分类
化学 | 115854篇 |
晶体学 | 2850篇 |
力学 | 10110篇 |
综合类 | 8篇 |
数学 | 29318篇 |
物理学 | 66903篇 |
出版年
2021年 | 2153篇 |
2020年 | 2488篇 |
2019年 | 2873篇 |
2018年 | 4308篇 |
2017年 | 4368篇 |
2016年 | 5788篇 |
2015年 | 3201篇 |
2014年 | 4872篇 |
2013年 | 9927篇 |
2012年 | 8264篇 |
2011年 | 9115篇 |
2010年 | 7190篇 |
2009年 | 7042篇 |
2008年 | 8561篇 |
2007年 | 8321篇 |
2006年 | 7402篇 |
2005年 | 6836篇 |
2004年 | 6403篇 |
2003年 | 5683篇 |
2002年 | 5650篇 |
2001年 | 5826篇 |
2000年 | 4535篇 |
1999年 | 3427篇 |
1998年 | 3058篇 |
1997年 | 2851篇 |
1996年 | 2777篇 |
1995年 | 2417篇 |
1994年 | 2449篇 |
1993年 | 2450篇 |
1992年 | 2505篇 |
1991年 | 2739篇 |
1990年 | 2693篇 |
1989年 | 2707篇 |
1988年 | 2600篇 |
1987年 | 2592篇 |
1986年 | 2414篇 |
1985年 | 3051篇 |
1984年 | 3041篇 |
1983年 | 2599篇 |
1982年 | 2671篇 |
1981年 | 2578篇 |
1980年 | 2330篇 |
1979年 | 2635篇 |
1978年 | 2792篇 |
1977年 | 2875篇 |
1976年 | 2966篇 |
1975年 | 2752篇 |
1974年 | 2693篇 |
1973年 | 2864篇 |
1972年 | 2287篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
941.
942.
I. L. Nizhnik 《Ukrainian Mathematical Journal》1998,50(11):1789-1791
We investigate a nonlinear chain of two Chua oscillators and its stable solutions.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 11, pp. 1567–1569, November, 1998. 相似文献
943.
I.G. Kalinina K.Z. Gumargalieva Yu.A. Shlyapnikov 《Polymer Degradation and Stability》1993,40(3):411-416
p-Toluensulfonic acid retards oxidation of polyethylene and, to a greater extent, of polyethylene-poly-p-methylstyrene blends. The real antioxidant is p-cresol, formed by p-toluensulfonic acid transformation in oxidizing polyethylene and, in blends, through peroxidation and subsequent acid-catalyzed decomposition of hydroperoxides of poly-p-methylstyrene. 相似文献
944.
945.
946.
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, p. 2899, December, 1991. 相似文献
947.
Boundary value problems are formulated concerning characteristic oscillations relative to capillary-sound equilibrium forms and theorems are established concerning properties of spectra of these problems; theorems are also presented concerning stability of the indicated forms of equilibrium.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 3, pp. 359–364, March, 1991. 相似文献
948.
Alexeff I. Rader M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1992,20(6):669-671
In multimegavolt electrostatic generators, the accidental sparkover discharges change in character as the voltage and stored energy increase. The usual forked, unidirectional discharges are replaced by complex discharges containing numerous closed loops. It is suggested that this is an example of the formation of closed-current loops that generate magnetic fields in astrophysics 相似文献
949.
V. D. Levchenko A. I. Morozov A. S. Sigov 《Journal of Experimental and Theoretical Physics》2002,94(5):985-991
Multilayer ferromagnet-layered antiferromagnet (Fe/Cr) structures frustrated because of roughness of interlayer boundaries were studied by mathematical modeling methods. The phase diagram of a three-layer system (plotted as film thickness versus the degree of roughness of the interfaces) was obtained, and the order parameter distributions in each phase were determined. The character of phase transitions in this system was studied. The applicability range of the Slonczewski magnetic proximity model was determined. 相似文献
950.
R. Kimmich F. Klammler V. D. Skirda I. A. Serebrennikova A. I. Maklakov N. Fatkullin 《Applied magnetic resonance》1993,4(4):425-440
Geometrical restrictions of water diffusion in different aqueous protein systems were studied using two versions of the NMR field gradient technique. The samples were aqueous systems of bovine serum albumin, gelatin and horse myoglobin at concentrations ranging from diluted solutions to almost dry powders being only partly hydrated. Hydrated protein aerogels were produced by the aid of a special preparation procedure and studied in addition. The experiments referred to the, temperature and concentration dependences of the water diffusion coefficient above and below the free-water freezing temperature. The diffusion coefficient within clusters of overlapping hydration shells is reduced by one order of magnitude compared with that of bulk water. Geometrical restrictions manifest themselves (a) by the obstruction effect observed at low protein concentrations, (b) by the topologically two-dimensional diffusion in the network of overlapping hydration shells, (c) by the percolation threshold appearing at about 15%b.w. water and (d) by the anomalous diffusion behaviour concluded from the protein aerogel study. 相似文献