全文获取类型
收费全文 | 82836篇 |
免费 | 467篇 |
国内免费 | 412篇 |
专业分类
化学 | 27473篇 |
晶体学 | 828篇 |
力学 | 6930篇 |
数学 | 32656篇 |
物理学 | 15828篇 |
出版年
2020年 | 50篇 |
2019年 | 50篇 |
2018年 | 10471篇 |
2017年 | 10279篇 |
2016年 | 6156篇 |
2015年 | 914篇 |
2014年 | 390篇 |
2013年 | 586篇 |
2012年 | 3954篇 |
2011年 | 10714篇 |
2010年 | 5760篇 |
2009年 | 6162篇 |
2008年 | 6770篇 |
2007年 | 8954篇 |
2006年 | 427篇 |
2005年 | 1529篇 |
2004年 | 1745篇 |
2003年 | 2169篇 |
2002年 | 1220篇 |
2001年 | 354篇 |
2000年 | 405篇 |
1999年 | 215篇 |
1998年 | 252篇 |
1997年 | 217篇 |
1996年 | 276篇 |
1995年 | 191篇 |
1994年 | 159篇 |
1993年 | 180篇 |
1992年 | 134篇 |
1991年 | 132篇 |
1990年 | 110篇 |
1989年 | 122篇 |
1988年 | 116篇 |
1987年 | 111篇 |
1986年 | 101篇 |
1985年 | 137篇 |
1984年 | 133篇 |
1983年 | 112篇 |
1982年 | 120篇 |
1981年 | 107篇 |
1980年 | 123篇 |
1979年 | 114篇 |
1978年 | 96篇 |
1977年 | 78篇 |
1976年 | 65篇 |
1975年 | 67篇 |
1974年 | 71篇 |
1973年 | 64篇 |
1972年 | 51篇 |
1914年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Mathieu Boiret Anna de Juan Nathalie Gorretta Yves-Michel Ginot Jean-Michel Roger 《Analytica chimica acta》2015
Raman chemical imaging provides chemical and spatial information about pharmaceutical drug product. By using resolution methods on acquired spectra, the objective is to calculate pure spectra and distribution maps of image compounds. With multivariate curve resolution-alternating least squares, constraints are used to improve the performance of the resolution and to decrease the ambiguity linked to the final solution. Non negativity and spatial local rank constraints have been identified as the most powerful constraints to be used. 相似文献
3.
4.
5.
S. V. Panin I. V. Vlasov V. P. Sergeev B. B. Ovechkin P. O. Marushchak Sunder Ramasubbu P. S. Lyubutin V. V. Titkov 《Physical Mesomechanics》2015,18(3):261-272
The structure and properties of 12Cr1MoV steel irradiated with a zirconium ion beam were studied by optical microscopy, scanning electron microscopy, and micro- and nanoindentation. It is shown that the modification covers the entire cross-section of the irradiated specimens to a depth of 1 mm. The data on irradiation-induced structural changes are used to interpret the changes in mechanical properties of the irradiated specimens under static and cyclic loading. Particular attention is given to analysis of strain estimation by the digital image correlation method. 相似文献
6.
He Haidong Yang Haifeng Zhou Longpeng Chen Tianchi 《Journal of Russian Laser Research》2015,36(3):292-299
Ni–Co alloys have a wide range of applications in various fields owning to their excellent physical, chemical, and mechanical properties. In this paper, we prepare Ni–Co alloy coatings on 316L stain steel surfaces by electroplating. We present a novel approach utilizing a nanosecond laser to induce microtextures on Ni–Co alloy coatings. We study experimentally the effects of laser power and scanning rate on the surface morphologies of Ni–Co alloy coatings. The results indicate that the shape and size of induced microtextures can be controlled by the laser power and scanning rate. The size of grains increases with increase in the work current of the laser (WCL) at a certain scanning rate. With the WCL constant, the size of grains decreases with increase in scanning rate while their average height increases. It is a simple and easily-controlled method for the fabrication of microstructures on Ni–Co alloy coatings, which has promising applications in investigations of the properties of microtextured surfaces, such as friction, adhesion, and wetting. 相似文献
7.
8.
9.