全文获取类型
收费全文 | 215439篇 |
免费 | 1565篇 |
国内免费 | 627篇 |
专业分类
化学 | 117925篇 |
晶体学 | 3270篇 |
力学 | 8349篇 |
综合类 | 6篇 |
数学 | 23305篇 |
物理学 | 64776篇 |
出版年
2020年 | 1970篇 |
2019年 | 2263篇 |
2018年 | 3206篇 |
2017年 | 3113篇 |
2016年 | 4267篇 |
2015年 | 2371篇 |
2014年 | 3818篇 |
2013年 | 9260篇 |
2012年 | 6891篇 |
2011年 | 8435篇 |
2010年 | 6071篇 |
2009年 | 5921篇 |
2008年 | 8137篇 |
2007年 | 8206篇 |
2006年 | 7630篇 |
2005年 | 6936篇 |
2004年 | 6166篇 |
2003年 | 5641篇 |
2002年 | 5497篇 |
2001年 | 5939篇 |
2000年 | 4684篇 |
1999年 | 3470篇 |
1998年 | 3007篇 |
1997年 | 3033篇 |
1996年 | 2823篇 |
1995年 | 2319篇 |
1994年 | 2419篇 |
1993年 | 2450篇 |
1992年 | 2595篇 |
1991年 | 2657篇 |
1990年 | 2559篇 |
1989年 | 2533篇 |
1988年 | 2463篇 |
1987年 | 2434篇 |
1986年 | 2357篇 |
1985年 | 3037篇 |
1984年 | 3194篇 |
1983年 | 2559篇 |
1982年 | 2827篇 |
1981年 | 2703篇 |
1980年 | 2503篇 |
1979年 | 2718篇 |
1978年 | 2833篇 |
1977年 | 2856篇 |
1976年 | 2832篇 |
1975年 | 2687篇 |
1974年 | 2665篇 |
1973年 | 2810篇 |
1972年 | 1875篇 |
1967年 | 1830篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
E. J. S. Lage 《Physica A》1987,140(3):629-636
We study critical dynamics of general q-state Potts models on d-dimensional hypercubic lattices. The master equation is formulated according to a theory recently presented by the author. A simple bond moving technique, followed by decimation, is used to obtain the dynamical exponents. Although this approximation yields poor results for the static exponents, the dynamic behaviour is closer to Monte Carlo simulations. We compare our results with those obtained with a different formulation of dynamics. A final discussion is included. 相似文献
113.
S. E. Bogushevich V. N. Makatun A. K. Potapovich I. I. Ugolev 《Journal of Applied Spectroscopy》1991,55(4):1016-1020
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 613–618, October, 1991. 相似文献
114.
E. N. Dovbnya 《Journal of Mathematical Sciences》1991,57(1):2903-2905
The behavior of the edges of cuts in shallow shells with the symmetric combined action of tension and flexure is investigated. For shells of different curvature with one and two parallel or collinear cuts, the load region in which there is no contact of the cut edges in the course of shell deformation is determined.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 19, pp. 98–100, 1988. 相似文献
115.
116.
117.
Results of an experimental observation of the voltage oscillations associated with a discrete tunneling of holes in porous silicon at room temperature are presented. The noise characteristics of diode structures with a porous silicon interlayer formed on heavily boron-doped silicon single crystals are studied. Peaks of excessive noise are observed at frequencies of ~1 MHz, at which single-electron oscillations should be expected. The peak noise power is found to increase with current according to the ~2.5 power law and, at a current density of 0.15 A/cm2, to exceed the noise power of the receiver by three to four orders of magnitude. The complex shape of the noise spectrum and its extension to the higher frequency region with increasing current are explained by the three-dimensionality of the system of nanometer-sized silicon grains embedded in insulating silicon dioxide of porous silicon. 相似文献
118.
119.
The present paper deals with the well-posedness and regularity of one class of one-dimensional time-dependent boundary-value problems with global boundary conditions on the entire time interval. We establish conditions for the well-posedness of boundary-value problems for partial differential equations in the class of bounded differentiable functions. A criterion for the regularity of the problem under consideration is also obtained. 相似文献
120.
Binding energy spectra of the valence electrons of the open shell molecule NO have been obtained up to 55 eV at azimuthal angles of 0° and 7° using binary (e, 2e) spectroscopy at an impact energy of 1200 eV. The momentum distribution has been obtained for the least tightly bound (unpaired) electron, removal of which leads to formation of the X 1Σ+ ground state of NO+. Momentum distributions have also been measured at 21.0 and 40.5 eV. The measured momentum distributions are compared with several literature wavefunctions of varying complexity. They are found to be in excellent agreement with those calculated using the natural spin orbital wavefunctions of Kouba and Ohrn. 相似文献