首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   501篇
  免费   17篇
  国内免费   26篇
林业   22篇
农学   52篇
基础科学   8篇
  48篇
综合类   204篇
农作物   112篇
畜牧兽医   8篇
园艺   15篇
植物保护   75篇
  2023年   5篇
  2022年   4篇
  2021年   12篇
  2020年   4篇
  2019年   7篇
  2018年   11篇
  2017年   17篇
  2016年   20篇
  2015年   11篇
  2014年   29篇
  2013年   27篇
  2012年   24篇
  2011年   52篇
  2010年   38篇
  2009年   35篇
  2008年   37篇
  2007年   45篇
  2006年   40篇
  2005年   18篇
  2004年   17篇
  2003年   16篇
  2002年   13篇
  2001年   10篇
  2000年   9篇
  1999年   7篇
  1998年   7篇
  1997年   5篇
  1996年   4篇
  1995年   2篇
  1994年   3篇
  1993年   3篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1973年   1篇
排序方式: 共有544条查询结果,搜索用时 15 毫秒
91.
High herbicide levels can be localized on or near seed of acetolactate synthase (ALS) resistant maize (Zea mays). The magnesium salt of imazapyr was optimal for seed dressings (drenching, priming, and coating), for preventing field damage from parasitic Striga hermonthica (witchweed) in three seasons. Striga emerged on untreated maize from 6 to 12 weeks after planting. There was almost no Striga emergence for 3 months on imazapyr-dressed homozygous ALS-R 3245IR maize seeds. Occasional Striga that emerged and flowered formed no seed by harvest. Dust or polyvinylpyrrolidone adhesive coatings were safer in maize and as effective in Striga control as priming. Seed dressing coupled with pulling Striga escapes reduces infestation and can be used to deplete the Striga seed bank until genetic crop resistance becomes available.  相似文献   
92.
综述了除草剂安全剂对作物中参与除草剂解毒作用的酶以及作为除草剂作用靶标位点酶水平与活性的影响。安全剂能增强细胞色素P450酶系统活性,诱导P450在除草剂降解中的作用;增加作物体内谷胱甘肽的含量,从而促进除草剂与谷胱甘肽的轭合而发挥解毒作用;降低由于除草剂对乙酰乳酸合成酶的抑制作用而引起的植物毒性等。  相似文献   
93.
为筛选安全有效的蓖麻田间除草剂,选用4种除草剂对蓖麻田间杂草防效进行了田间试验研究。结果表明:除草效果最好的处理为氟乐灵1800g/hm2+扑草净2250g/hm2、氟乐灵1800g/hm2+甲乙莠6000g/hm2,对蓖麻基本没有药害。  相似文献   
94.
除草剂对亚麻幼苗生化指标影响   总被引:4,自引:0,他引:4  
通过对都尔、精稳杀得、绿黄隆、二甲四氯处理的亚麻幼苗生化指标的测定,明确了这四种除草剂对亚麻幼苗的蛋白质、核酸、DNA及其酶的活性的影响。与此同时通过IAA、GA含量的测定明确这四种除草剂对亚麻生长发育及产量影响的机理。  相似文献   
95.
Lolium multiflorum Lam. (annual ryegrass) is used extensively as a forage crop and seed is produced in several areas worldwide. Seed production has been shown to be commercially possible in Atlantic Canada but improved weed control is needed. Studies were conducted in two provinces (Prince Edward Island and New Brunswick) to determine the effects of the herbicides bentazon, bromoxynil/MCPA, dicamba/MCPA, thifensulfuron/tribenuron, 2,4-D and MCPA on weed control, L. multiflorum growth, seed yields and seed germination in 1998 and 1999. The herbicides MCPA, dicamba/MCPA and bromoxynil/MCPA as evaluated in these experiments provided acceptable control of the broad-leaved weeds present and had no effect on seed yield or seed germination. Although the thifensulfuron/tribenuron caused early foliar injury, the plants recovered and it provided excellent weed control. None of the herbicides affected seed germination. MCPA, dicamba/MCPA and bromoxynil/MCPA could be used to provide control of broad-leaved weeds and thifensulfuron/tribenuron could be used if growers were willing to accept some early injury and possible yield loss to obtain the improved weed control.  相似文献   
96.
草克星(NC-311)是日本日产株式会社新开发的磺酰脲类除草剂,具有用量低,杀草谱广,高效和安全的特点。为了评价草克星对稻田杂草的防除效果和对水稻的安全性,我们于1990年进行了田间小区试验和植物生长箱模拟试验。材料和方法植物生长箱模拟试验在中国水稻研究所进行。设备为LH-200-RD植物生长箱,温度25℃,光照强度为2800 lux,光照时间10 h/d。盆栽用13×13×8 cm塑料方盆,重复3次。  相似文献   
97.
In recent years flaxleaf fleabane has become a widespread and difficult-to-control weed in no-tilled fallowed fields, where weeds are controlled by applications of glyphosate, in annual cropping systems of north-east Australia. Fifty-two populations, collected in a national survey from agricultural and non-agricultural areas, were tested in two glyphosate dose-response pot experiments. In two subsequent pot experiments, a sub-set of these populations was tested with a field rate of glyphosate when weeds of two ages were grown at different soil moistures. In the first and second experiments, most populations collected from chemical fallowed or cropped fields in north-east Australia had GR50 (estimated dose for 50% biomass reduction) values three to six times greater than the susceptible populations, indicating low levels of glyphosate resistance. Several populations from roadsides adjacent to chemical fallowed or cropped fields also had higher GR50 values, indicating movement of seeds from resistant plants. In the third experiment, weed biomass of all populations from chemical fallowed or cropped fields was 70-98% of unsprayed compared to 2-3% for the susceptible populations, irrespective of weed age or soil moisture. In the fourth experiment which treated older weeds, the response of several resistant populations to glyphosate was unaffected by differences in weed age and soil moisture, whereas the biomass of the other resistant populations was greater following spraying of older and/or moisture stressed plants compared with smaller non-stressed plants. Thus, exclusive reliance on glyphosate for fallow weed control in this region has resulted in the evolution of resistance in flaxleaf fleabane populations in a cropping system with annual non-transgenic crops. Prolific production of windborne seeds, combined with poor control associated with spraying large moisture-stressed weeds, is likely to have contributed also to flaxleaf fleabane becoming such a problem weed.  相似文献   
98.
Greenhouse and field experiments were conducted to evaluate the efficacy of various combinations of imazethapyr (0, 23, 46, and 70 g ai/ha) with glyphosate (0, 210, 420, 630, and 840 g ae/ha) on Setaria faberi, Amaranthus rudis, Abutilon theophrasti, and Ipomoea hederacea control. Additivity was the most frequently observed interaction and no synergistic interaction occurred throughout this study. The combination of imazethapyr with glyphosate at 210 g/ha caused an antagonistic response on Setaria faberi. Glyphosate at 420 g/ha with or without imazethapyr provided at least 95% control of Setaria faberi. The interaction between glyphosate and imazethapyr was additive on Amaranthus rudis control. Eight of the twenty-one herbicide combinations were antagonistic on Abutilon theophrasti control. Antagonistic interactions occurred when 46 or 70 g/ha of imazethapyr was added to 420 or 630 g/ha of glyphosate; while no antagonistic interactions were noted when glyphosate rate was 840 g/ha. The interactions on Ipomoea hederacea control were additive when the glyphosate rate was at least 420 g/ha. Glyphosate at 210 g/ha plus imazethapyr at 46 or 70 g/ha caused antagonistic interactions on Ipomoea hederacea control. Weed control tended to be more variable when the glyphosate rate was 210 g/ha and the imazethapyr rate was 46 or 70 g/ha. In general, the addition of imazethapyr to low rates of glyphosate improved control of Amaranthus rudis and Ipomoea hederacea and did not improve control of Setaria faberi and Abutilon theophrasti.  相似文献   
99.
大豆抗除草剂资源筛选   总被引:1,自引:0,他引:1  
通过三年的大田和分栽试验,研究了2000多份大豆对绿黄隆和阿特拉津的抗性反应。结果表明,不同大豆对绿黄隆的抗性反应差异较大,多数材料抗性很差,没有发现具有高度抗性,可用于理论研究或育种实践的材料,不同大豆对阿特拉津的抗性在苗期存在差异,但绝大多数材料在第一复叶未展开前即死掉,仅有极少数材料能结荚,而荚又很少。用常规方法筛选抗绿黄隆的材料是有希望的,筛选抗阿特拉津的材料及为困难。  相似文献   
100.
荔枝草农用活性初步研究   总被引:2,自引:0,他引:2  
研究了荔枝草乙醇提取物及其萃取物的抑菌、除草活性。结果表明,荔枝草乙醇提取物对27种供试病原真菌均有一定抑制作用。乙醇提取物在浓度为0.03g/mL(以干材料计)时,对苹果腐烂病菌、葡萄白腐病菌、瓜果腐霉病菌的抑制率分别达到89.09%、91.12%、92.59%;荔枝草乙醇提取物的乙酸乙酯萃取物对苹果腐烂病菌、葡萄白腐病菌、瓜果腐霉病菌抑制效果最好,其EC50分别为0.24、0.29、0.12mg/mL;荔枝草乙醇提取物对几种杂草也有很好的抑制效果,在浓度为0.2g/mL时,对生菜、反枝苋、黄瓜的抑制率分别为93.65%、92.76%和97.57%。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号