全文获取类型
收费全文 | 171篇 |
免费 | 4篇 |
专业分类
林业 | 22篇 |
农学 | 5篇 |
基础科学 | 1篇 |
41篇 | |
综合类 | 30篇 |
农作物 | 12篇 |
水产渔业 | 21篇 |
畜牧兽医 | 30篇 |
园艺 | 5篇 |
植物保护 | 8篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 9篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 14篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 5篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 12篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1974年 | 2篇 |
1938年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有175条查询结果,搜索用时 187 毫秒
171.
Niessing J Ebisch B Schmidt KE Niessing M Singer W Galuske RA 《Science (New York, N.Y.)》2005,309(5736):948-951
Functional imaging methods monitor neural activity by measuring hemodynamic signals. These are more closely related to local field potentials (LFPs) than to action potentials. We simultaneously recorded electrical and hemodynamic responses in the cat visual cortex. Increasing stimulus strength enhanced spiking activity, high-frequency LFP oscillations, and hemodynamic responses. With constant stimulus intensity, the hemodynamic response fluctuated; these fluctuations were only loosely related to action potential frequency but tightly correlated to the power of LFP oscillations in the gamma range. These oscillations increase with the synchrony of synaptic events, which suggests a close correlation between hemodynamic responses and neuronal synchronization. 相似文献
172.
Boris AV Kovaleva NN Dolgov OV Holden T Lin CT Keimer B Bernhard C 《Science (New York, N.Y.)》2004,304(5671):708-710
The temperature-dependent redistribution of the spectral weight of the CuO2 plane-derived conduction band of the YBa2Cu3O6.9 high-temperature superconductor (superconducting transition temperature = 92.7 kelvin) was studied with wide-band (0.01- to 5.6-electron volt) spectroscopic ellipsometry. A superconductivity-induced transfer of the spectral weight involving a high-energy scale in excess of 1 electron volt was observed. Correspondingly, the charge carrier spectral weight was shown to decrease in the superconducting state. The ellipsometric data also provide detailed information about the evolution of the optical self-energy in the normal and superconducting states. 相似文献
173.
Spatial distribution of the parent materials, color, clay-eluviated horizon thickness, textural profile type, presence and position of the ferruginous nodules and ferricretes in the profile are analyzed at a small scale using the thematic information content of the published 1:200,000 soil map of Benin. Analyses indicate that there is a regional differentiation of the soil cover which is first drawn on that of the geological provinces, sedimentary basins, great morpho-structural units, and then determined by the factors that control the preservation or the transformation and erosion of an ancient lateritic mantle. These factors are directly influenced by differential changes of the local base levels. 相似文献
174.