全文获取类型
收费全文 | 187篇 |
免费 | 11篇 |
专业分类
林业 | 3篇 |
农学 | 3篇 |
48篇 | |
综合类 | 53篇 |
农作物 | 7篇 |
畜牧兽医 | 77篇 |
园艺 | 2篇 |
植物保护 | 5篇 |
出版年
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2013年 | 8篇 |
2012年 | 8篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 2篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1996年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1966年 | 2篇 |
1947年 | 1篇 |
1945年 | 3篇 |
1944年 | 1篇 |
1941年 | 2篇 |
1939年 | 1篇 |
1938年 | 1篇 |
1935年 | 1篇 |
1933年 | 1篇 |
1929年 | 2篇 |
1927年 | 1篇 |
1923年 | 1篇 |
1920年 | 1篇 |
1917年 | 2篇 |
1915年 | 1篇 |
1913年 | 1篇 |
1912年 | 2篇 |
1911年 | 3篇 |
1906年 | 1篇 |
排序方式: 共有198条查询结果,搜索用时 15 毫秒
1.
2.
Raymond J. C. Cannon 《Pest management science》1993,37(4):331-335
Bacillus thuringiensis (Bt)-based insecticide products constitute the overwhelming majority of biopesticides but, despite having been commercially available for over 30 years, they have made little impact (<1%) on the crop-protection market as a whole. This has been largely due to poor cost-performance factors relative to synthetic organic pesticides. However, recent biotechnological advances—including genetic modification—combined with a variety of emerging opportunities, have created the prospect of the commercialisation of a new range of highly effective Bt-based biopesticides. Bioencapsulation of single-gene products—delta-endotoxins from selected Bt isolates—in killed Pseudomonad cells (Mycogen Corporation's ‘CellCap’ technology), offers a flexible delivery system with enhanced persistence. This versatile approach selects only the most appropriate biotoxins, which can be used to target a number of pest species. It is anticipated that Bt-based pesticides will continue to fill an increasing number of gaps in the panoply of synthetic crop-protection chemicals. Genetically modified products offer advantages in terms of efficacy, flexibility and safety but public concerns regarding perceived risks need to be addressed. 相似文献
3.
This case report documents an unusual tracheal foreign body (a moth) in Congo African grey parrot (Psittacus erithacus erithacus). Gross postmortem signs and histopathology results are presented. A discussion of the peculiar avian anatomy that may have contributed to the aspiration of the moth is provided. 相似文献
4.
5.
6.
7.
8.
9.
Leinekugel X Khazipov R Cannon R Hirase H Ben-Ari Y Buzsáki G 《Science (New York, N.Y.)》2002,296(5575):2049-2052
The behavior of immature cortical networks in vivo remains largely unknown. Using multisite extracellular and patch-clamp recordings, we observed recurrent bursts of synchronized neuronal activity lasting 0.5 to 3 seconds that occurred spontaneously in the hippocampus of freely moving and anesthetized rat pups. The influence of slow rhythms (0.33 and 0.1 hertz) and the contribution of both gamma-aminobutyric acid A-mediated and glutamate receptor-mediated synaptic signals in the generation of hippocampal bursts was reminiscent of giant depolarizing potentials observed in vitro. This earliest pattern, which diversifies during the second postnatal week, could provide correlated activity for immature neurons and may underlie activity-dependent maturation of the hippocampal network. 相似文献
10.
Cannon RH 《Science (New York, N.Y.)》1976,191(4226):424