全文获取类型
收费全文 | 771篇 |
免费 | 61篇 |
国内免费 | 21篇 |
专业分类
林业 | 46篇 |
农学 | 20篇 |
基础科学 | 42篇 |
94篇 | |
综合类 | 146篇 |
农作物 | 53篇 |
水产渔业 | 33篇 |
畜牧兽医 | 340篇 |
园艺 | 26篇 |
植物保护 | 53篇 |
出版年
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 22篇 |
2019年 | 22篇 |
2018年 | 16篇 |
2017年 | 18篇 |
2016年 | 35篇 |
2015年 | 27篇 |
2014年 | 26篇 |
2013年 | 41篇 |
2012年 | 26篇 |
2011年 | 34篇 |
2010年 | 35篇 |
2009年 | 43篇 |
2008年 | 37篇 |
2007年 | 37篇 |
2006年 | 48篇 |
2005年 | 36篇 |
2004年 | 29篇 |
2003年 | 26篇 |
2002年 | 37篇 |
2001年 | 10篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 4篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1973年 | 4篇 |
1928年 | 4篇 |
1925年 | 6篇 |
1924年 | 6篇 |
1899年 | 4篇 |
排序方式: 共有853条查询结果,搜索用时 15 毫秒
1.
AM Mwanza A Madej H Kindahl N Lundeheim & S Einarsson 《Reproduction in domestic animals》2001,36(3-4):157-161
The effects of lipopolysaccharide ( Escherichia coli , O55:B5), administered 18 h after ovulation in the second oestrus after weaning on the hormonal profiles in 14 Swedish cross-bred (Landrace × Yorkshire) multiparous sows were studied. The endotoxin group (E-group) sows were administered with 300 ng/kg of lipopolysaccharide (LPS) whereas the control group (C-group) sows were administered 5 ml of saline intravenously via an indwelling jugular cannula. Blood samples for hormonal analyses were collected from all sows until slaughter. In the E-group, progesterone, cortisol and prostaglandin F2α metabolite levels increased significantly (p < 0.05) following LPS compared with the C-group. It can be concluded from this study that apart from elevating cortisol and prostaglandin F2α metabolite, LPS also elevates progesterone levels. 相似文献
2.
3.
4.
5.
6.
7.
8.
The potential of mini-ridging for controlling intrarow weeds: estimating minimum lethal burial depth
Charles N. Merfield Jacquelyn R. Bennett Nadine A. Berry Arthur Bluon Dean M. O’Connell Simon Hodge 《Weed Research》2020,60(5):353-362
Weed management using synthetic herbicides is undergoing a global decline, necessitating a re-evaluation of existing control measures and the development of novel weed management tools. ‘Mini-ridging’ is a non-discriminatory, physical weeding method that functions by burying weeds in the intrarow with a laterally shifted ridge of soil. In glasshouse trials using potted plants, we found that plant recovery after soil application was influenced by plant size, which in turn was influenced by plant species, developmental stage and/or age. The likelihood of plant recovery after soil application was negatively related to the depth of soil applied: very few plants survived total coverage by soil but, conversely, survival could be substantial if some parts of the plants were not covered. The results suggest that burial under a depth of 6 cm of soil would eliminate most plants regardless of species or growth stage. Larger plants would require the application of a greater total depth of soil to achieve this 6 cm of soil cover, and weed management would, therefore, tend to be more successful and more practical if weeds were targeted when still small. This research demonstrates the potential of plant burial as a simple and reliable means of non-chemical weed management, and re-emphasises that, for weed control to be effective, the applied soil layer must cover the whole plant. 相似文献
9.
柑橘是是广西的重要果树品种,在水果产业中占有重要地位。通过对广西柑橘业的现状剖析,从自然资源、品种资源、社会资源、季节、成本、质量、区位等方面提出广西发展柑橘的优势,并对这些优势的利用及实现措施进行探讨,将有利于做强做大广西的柑橘产业。 相似文献
10.