全文获取类型
收费全文 | 5124篇 |
免费 | 153篇 |
国内免费 | 160篇 |
专业分类
林业 | 540篇 |
农学 | 199篇 |
基础科学 | 332篇 |
237篇 | |
综合类 | 2792篇 |
农作物 | 448篇 |
水产渔业 | 63篇 |
畜牧兽医 | 367篇 |
园艺 | 324篇 |
植物保护 | 135篇 |
出版年
2024年 | 24篇 |
2023年 | 42篇 |
2022年 | 52篇 |
2021年 | 78篇 |
2020年 | 76篇 |
2019年 | 96篇 |
2018年 | 46篇 |
2017年 | 93篇 |
2016年 | 166篇 |
2015年 | 169篇 |
2014年 | 314篇 |
2013年 | 296篇 |
2012年 | 288篇 |
2011年 | 444篇 |
2010年 | 408篇 |
2009年 | 387篇 |
2008年 | 374篇 |
2007年 | 363篇 |
2006年 | 317篇 |
2005年 | 229篇 |
2004年 | 143篇 |
2003年 | 132篇 |
2002年 | 131篇 |
2001年 | 103篇 |
2000年 | 105篇 |
1999年 | 79篇 |
1998年 | 77篇 |
1997年 | 57篇 |
1996年 | 55篇 |
1995年 | 63篇 |
1994年 | 43篇 |
1993年 | 45篇 |
1992年 | 47篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 15篇 |
1988年 | 21篇 |
1987年 | 8篇 |
1986年 | 3篇 |
排序方式: 共有5437条查询结果,搜索用时 8 毫秒
1.
[目的]评价宁南霉素、艾德拉和碧护3种药剂混合使用防治番茄黄花曲叶病毒病的效果。[方法]通过田间试验研究8%宁南霉素、艾德拉绿(花、果)与碧护组成的药剂对番茄黄化曲叶病毒病的防治效果。[结果]8%宁南霉素、艾德拉绿(花、果)与碧护组成的试验药剂对番茄黄化曲叶病毒病具有很好的田间防治效果,第3次施药后10、20、30 d防效均在82%以上,与对照药剂番茄黄化曲叶病毒灵差异达极显著水平,且其产量比清水对照增加25 747.5 kg/hm~2,保产率为103.90%。[结论]宁南霉素、艾德拉和碧护混合使用对番茄黄花曲叶病毒病具有较好的防治效果,为番茄黄花曲叶病毒病的有效防治提供了理论依据。 相似文献
2.
落叶松红腹叶蜂的防治技术 总被引:1,自引:0,他引:1
本文描述了落叶松红腹叶蜂的管理和防治技术.管理技术包括:(1)提高测报水平;(2)制定和应用防治指标;(3)制定防治计划和开展防治措施。防治技术包括:(1)采取营林措施,使郁闭度保持0.7;(2)用壮苗造林,并适地适树;(3)利用天敌开展生物防治,还可以采用化学药物防治措施。 相似文献
3.
4.
5.
6.
沙棘红缘天牛综合防治 总被引:2,自引:0,他引:2
1987~1990年,对沙棘毁灭性害虫红缘天牛发生特点及防治技术进行研究,提出了从加强沙棘园综合管理,提高树势入手,结合成虫期喷雾,幼虫为害期注射的综合防治措施,防效达95%左右,同时可兼治蚜虫、木虱、茶翅蝽等多种害虫。 相似文献
7.
Dietary protein for young grazing sheep: Interactions with gastrointestinal parasitism 总被引:1,自引:0,他引:1
Effects of protein supplementation and of nematode control on production responses in young grazing sheep and on nematode population dynamics were assessed. Young Merino wether sheep (n = 270) were allocated to one of three supplementation (Su) treatments and one of three regimes of nematode control (drench, Dr) in a factorial design. Each of the nine treatments was replicated three times in a randomised complete block. Animals received no supplement (SuO) or were given supplements at a level equivalent to 200 g day−1, fed three times a week. The supplements contained 25% lucerne meal with either 75% sunflower meal (Su1) or 75% formaldehyde-treated sunflower meal (Su2). Nematode control regimes were: not drenched unless survival of individual animals was threatened (DrO); drenched according to a strategic drenching programme (Dr1); treatment with a controlled-release albendazole capsule (Dr2). Infections with Haemonchus contortus were suppressed by use of closantel. Due to drought conditions and lack of pasture growth, lucerne hay was fed to all sheep from Week 14 onwards (350 g per head per day, fed twice a week). Supplementation reduced the need for ‘survival drenching’ in Dr0 sheep considerably. Live-weight gain was increased significantly by supplementation with Su1 or Su2 during the 36-week experiment. Undrenched animals given Su1 or Su2 tended to grow faster than unsupplemented animals in the Dr1 and Dr2 groups. Greasy wool production and fibre diameter were increased by supplementation and anthelmintic treatment. Faecal worm egg counts (FEC) in undrenched sheep were significantly lower for Su1 and Su2 sheep than for Su0 sheep. There were no effects of supplementation on FEC in Dr1 or Dr2 sheep. Worm burden was generally unaffected by supplementation, while the drenching treatments Dr1 and Dr2 reduced worm burden at Week 16 and to a lesser extent at Week 27. Trichostrongylus colubriformis was the predominant nematode species, with smaller numbers of Nematodirus spp., Trichostrongylus vitrinus, Trichostrongylus axei and Ostertagia circumcincta also present. It was concluded that supplementary feeding with protein meal substantially reduced production losses attributable to nematode infections in young grazing sheep. This appears to be due to an enhanced resilience of the host, rather than any major changes in development of protective immunity. 相似文献
8.
9.
瓜类作物细菌性果实腐斑病(BFB)防治研究概述 总被引:8,自引:1,他引:8
瓜类细菌性果实腐斑病(BFB)是近年来威胁全球瓜类作物的严重病害。它主要通过种子带菌传播,寄主以西瓜、甜瓜为主,近年有向其他瓜类(南瓜)和蔬菜(番茄)等蔓延的趋势。其防治应分阶段,在种子田、育苗床和生产瓜田按要求进行,只有这样才能达到综合防治的效果。 相似文献
10.