全文获取类型
收费全文 | 24258篇 |
免费 | 3922篇 |
国内免费 | 2642篇 |
专业分类
化学 | 16987篇 |
晶体学 | 299篇 |
力学 | 1443篇 |
综合类 | 240篇 |
数学 | 2681篇 |
物理学 | 9172篇 |
出版年
2024年 | 78篇 |
2023年 | 507篇 |
2022年 | 824篇 |
2021年 | 832篇 |
2020年 | 990篇 |
2019年 | 908篇 |
2018年 | 758篇 |
2017年 | 730篇 |
2016年 | 1110篇 |
2015年 | 1049篇 |
2014年 | 1300篇 |
2013年 | 1684篇 |
2012年 | 2081篇 |
2011年 | 2085篇 |
2010年 | 1431篇 |
2009年 | 1370篇 |
2008年 | 1539篇 |
2007年 | 1405篇 |
2006年 | 1348篇 |
2005年 | 1092篇 |
2004年 | 875篇 |
2003年 | 727篇 |
2002年 | 625篇 |
2001年 | 523篇 |
2000年 | 512篇 |
1999年 | 591篇 |
1998年 | 490篇 |
1997年 | 430篇 |
1996年 | 438篇 |
1995年 | 387篇 |
1994年 | 361篇 |
1993年 | 325篇 |
1992年 | 270篇 |
1991年 | 229篇 |
1990年 | 239篇 |
1989年 | 161篇 |
1988年 | 119篇 |
1987年 | 84篇 |
1986年 | 97篇 |
1985年 | 65篇 |
1984年 | 37篇 |
1983年 | 39篇 |
1982年 | 37篇 |
1981年 | 21篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1976年 | 1篇 |
1957年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Kangli Min Fengzhen Huang Xiaomei Lu Yi Kan Junting Zhang Song Peng Yaoyang Liu Jie Su Chao Zhang Zijian Liu Jinsong Zhu 《Solid State Communications》2012,152(4):304-306
KNb0.95Co0.05O3 (KN–Co) ceramic was prepared via a solid-state reaction method, and the effect of cobalt dopant on the structural, electric, and magnetic properties was studied. The KN–Co ceramic with polycrystalline perovskite structure exhibited ferromagnetic and ferroelectric properties simultaneously at room temperature, and the coupling of them was confirmed by a large magnetocapacitance effect (about 13%) near the Curie temperature. The possible causes for the magnetism and magnetoelectric properties are discussed. 相似文献
992.
993.
994.
Pollutants release is highly consistent with suspended sediment concentration (SSC) in water column, especially during re-suspension and transport events. The present research focuses on pollutant dynamic release from re-suspended sediment, especially the vertical distribution relationship between them. The sediment erosion experiments on a series of uniform flow are conducted in a circulate flume. Reactive tracer (phosphorus) is used as the contaminant in fine-grained sediments to identify the release characteristic length and time. Experimental results show that the flow condition near-bed depends on the sediment surface roughness. The region with high turbulent intensities corresponds to a high concentration sediment layer. In addition, the SSC decreases with the distance, water depth, and particle grain size. The sediment in a smaller grain size takes much more time to reach equilibrium concentration. Total phosphorus (TP) concentration changes along the water depth as SSC in the initial re-suspension stage, appearing in two obvious concentration regimes: the upper low-concentration layer and the high-concentration near-bottom layer. This layered phenomenon remains for about 3 hours until SSC distri- bution tends to be uniform. Longitudinal desorption plays an important role in long-way transport to reduce the amount of suspended sediment in water column. 相似文献
995.
996.
997.
998.
999.
1000.