全文获取类型
收费全文 | 3050篇 |
免费 | 76篇 |
国内免费 | 149篇 |
专业分类
林业 | 203篇 |
农学 | 152篇 |
基础科学 | 192篇 |
151篇 | |
综合类 | 1238篇 |
农作物 | 100篇 |
水产渔业 | 84篇 |
畜牧兽医 | 775篇 |
园艺 | 286篇 |
植物保护 | 94篇 |
出版年
2024年 | 16篇 |
2023年 | 42篇 |
2022年 | 56篇 |
2021年 | 78篇 |
2020年 | 89篇 |
2019年 | 133篇 |
2018年 | 145篇 |
2017年 | 91篇 |
2016年 | 118篇 |
2015年 | 89篇 |
2014年 | 156篇 |
2013年 | 168篇 |
2012年 | 186篇 |
2011年 | 185篇 |
2010年 | 230篇 |
2009年 | 194篇 |
2008年 | 171篇 |
2007年 | 206篇 |
2006年 | 161篇 |
2005年 | 129篇 |
2004年 | 113篇 |
2003年 | 129篇 |
2002年 | 90篇 |
2001年 | 77篇 |
2000年 | 52篇 |
1999年 | 50篇 |
1998年 | 19篇 |
1997年 | 16篇 |
1996年 | 19篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 12篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有3275条查询结果,搜索用时 15 毫秒
61.
问:我是一名农民工,每年初,我们县的许多农民都与本地的建筑公司签订劳动合同,然后由建筑公司派往全国各地施工。近几年,陆续有一些同乡因工受伤。由于各地赔偿标准不同,大家对应该在哪里解 相似文献
62.
63.
64.
油松毛虫是太岳山林局段峪河林场主要林业有害生物之一,通常发生快,危害严重。笔者介绍了段峪河林场油松毛虫的发生与危害现状,结合林场的自然地理环境,从行政保障和技术防治2方面提出了有效的预防和防治措施,并着重介绍了人工释放赤眼蜂的防治效果,旨在为油松毛虫的有效预防和防治提供依据。 相似文献
65.
新疆天山东部国有林区位于自治区首府乌鲁木齐东西两翼工农业经济发达地区,即天山北坡经济带,东西长约1 000多公里,南北宽约250多公里,横跨新疆哈密、昌吉、乌鲁木齐、塔城4个地州(市)和13个县市(区)。林区面积为265.29万hm2,其中林业用地面积84.85万hm2,非林业用地面积180.44万hm2,活立木蓄积5 254.5×104 m3。 相似文献
66.
This research aimed to identify a suitable planting pattern for oilseed flax production in a dry-farming region. A long-term field experiment was started in 2012 with a 4-year crop rotation cycle,designed to measure the effects on flax crop performance of previous crop,and various patterns of flax planting interval within the four-year rotation,compared with continuous flax cropping. Crop parameters measured included plant height,stem diameter,dry matter accumulation and distribution,and the experiment included six different crop rotation patterns:Flax→flax →flax→flax[(F)FFF];Flax→wheat→potato→flax[(F)WPF];Flax→potato→flax→wheat[(F)PFW];Flax→ flax→wheat→potato[(F)FWP];Flax→wheat→flax→potato[(F)WFP]and flax→wheat→potato→wheat[(F)WPW]. Results for the ninth year showed significantly increased grain yield(29. 89%-109. 57%)in crop rotation treatments compared with continuous cropping of oilseed flax. The ranking of the six tested rotations for yield was:(F)WPW>(F)FWP>(F)WFP>(F)PFW>(F)WPF>(F)FFF. The grain yield of oilseed flax was significantly affected by previous crop,frequency and years interval of flax cropping and number of years of continuous flax cropping. Yield was increased by 54. 45%-59. 29% under wheat stubble and potato stubble compared with oilseed flax stubble,and increased by 30. 66% and 109. 57%,respectively,under 50% and 25% frequencies,compared with 100% frequency. The grain yield of oilseed flax under two-year continuous cropping was higher by 29. 89% than four-year continuous cropping,and increased with increase in years interval between flax crops. Correlation analysis identified a significantly positive correlation between oilseed flax grain yield and effective capsule number,branch number and 1000-seed weight. The effective capsule number,branch number and 1000-seed weight of oilseed flax under rotation treatment were increased by 35. 88%-108. 91%,15. 47%-46. 19% and 14. 61%-16. 34%,respectively(P<0. 05),compared with continuous cropping. In addition,the high grain yield of oilseed flax was accompanied by an increase in plant height,stem diameter and dry matter accumulation and these increases were,respectively,5. 11%-42. 24%,2. 77%-39. 92% and 31. 25%-117. 89% under the rotation regimes,compared with continuous cropping. Reduction in the number of years of continuous cropping years,change of crop stubble,decreased flax planting frequency and increased of interval between flax crops also improved flax crop performance. In summary,crop rotation improved the vigor of oilseed flax,resulting in greater plant height and stem diameter,improved dry matter accumulation and distribution,leading to increased branch number,effective capsule number and 1000-seed weight,and increase in the crop yield of oilseed flax. The results indicated that a multiple-crop rotation pattern was an effective way to avoid the yield reduction caused by continuous cropping in oilseed flax. The rotation: Flax→wheat→potato→wheat performed best among those tested and can be recommended as an appropriate cropping rotation for oilseed flax production in the dry region of northwest China. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved. 相似文献
67.
68.
69.
梨果套袋后的主要病害有褐斑病、黑斑病、黑星病、轮纹病、炭疽病等;害虫主要有黄粉蚜、康氏粉蚧、梨木虱、红蜘蛛、梨网蝽、食心虫、二斑叶蝉等,应采取综合措施进行防治。 相似文献
70.