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   363篇
  免费   20篇
  国内免费   8篇
林业   2篇
农学   60篇
基础科学   4篇
  68篇
综合类   146篇
农作物   14篇
水产渔业   4篇
畜牧兽医   6篇
园艺   63篇
植物保护   24篇
  2024年   2篇
  2023年   1篇
  2022年   7篇
  2021年   10篇
  2020年   11篇
  2019年   13篇
  2018年   9篇
  2017年   15篇
  2016年   19篇
  2015年   13篇
  2014年   15篇
  2013年   27篇
  2012年   29篇
  2011年   30篇
  2010年   12篇
  2009年   18篇
  2008年   14篇
  2007年   32篇
  2006年   17篇
  2005年   8篇
  2004年   12篇
  2003年   9篇
  2002年   4篇
  2001年   7篇
  2000年   8篇
  1999年   3篇
  1998年   3篇
  1997年   5篇
  1996年   4篇
  1995年   5篇
  1994年   3篇
  1993年   5篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1984年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
排序方式: 共有391条查询结果,搜索用时 15 毫秒
21.
Field experiments were conducted at the Crop Research and Seed Multiplication Farm of Burdwan University, Burdwan, West Bengal, India, to evaluate the influence of integrated nutrient management on soil physicochemical properties in a mustard (Brassica campestris cv. ‘B9’) cropping system. The experiment was conducted during the winter seasons of 2011–2012 and 2012–2013 in old alluvial soil (pH 6–7). Seven different doses of biofertilizers (Azotobacter and phosphate solubilizing bacteria (PSB)), vermicomposts, organic (cow dung), and chemical fertilizers were applied on mustard in both the experimental seasons. The results indicated an improvement in soil quality by increasing soil porosity and water holding capacity significantly, as well as gradual build-up of the soil micronutrient status after harvesting of the crop. Dual applications of biofertilizers and vermicomposts have contributed significantly to higher soil organic matter, available nitrogen (N), phosphorus (P), and potassium (K) contents as well as micronutrient availability of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) and subsequently increased the soil health.  相似文献   
22.
23.
王慧超  李昌满  徐亚丽 《安徽农业科学》2011,(13):8159+8162-8159,8162
[目的]分析聚乙二醇(PEG)浸老化种子对茎瘤芥幼苗株高的影响。[方法]使用不同浓度PEG 6000(5%、10%、15%、20%、25%、30%、35%),以不同处理时间(4、8、12、16、20、24 h)浸茎瘤芥老化种子后,测量其幼苗株高。[结果]与对照相比,5%、10%、15%、20%、25%、30%PEG 6000以不同处理时间,浸茎瘤芥老化种子后,其幼苗株高均显著增加(P〈0.05)。[结论]25%PEG 6000浸茎瘤芥老化种子12 h,其幼苗株高最高。  相似文献   
24.
Information on biofumigant-green manure vegetative biomass, nutrient, and glucosinolate content sensitivity to phosphorus (P) is lacking for species used in potato and sugarbeet production. Therefore, available P effects on field-grown condiment yellow mustard (Sinapis alba, cv. IdaGold) and oilseed radish (Raphanus sativa, cv. Colonel) were evaluated (2001–03). Low soil P was generally more limiting to radish foliage P concentrations or uptake than to the mustard, suggesting inherent differences in their ability to access and accumulate P. While radish P and S concentrations increased with higher P, concentrations in mustard were either unaffected or reduced. Foliage P concentrations were more closely related to biomass of radish (r2 = 0.46) than mustard (r2 = 0.11). Mustard exceeded radish in biomass and S accumulation. Phosphorus effects on glucosinolates producing ionic or isothiocyanates were relatively insignificant. These biofumigants differ appreciably in their ability to access and accumulate P, but P effects on nutrient content or glucosinolates were minor.  相似文献   
25.
为研究紫外处理和热激处理对芥菜芽苗生理生化及其褪黑素富集的调控机制,本试验以芥菜籽粒为试材,研究经紫外处理和热激处理芥菜芽苗的主要生理生化指标及褪黑素合成关键酶基因表达情况。结果表明,经紫外处理和热激处理后,发芽期间,芥菜芽苗的芽长显著低于对照组(CK),可溶性蛋白含量和总抗氧化能力均显著高于CK(P<0.05),在观察时间点(4 和7 d),热激处理发芽4 d的芥菜芽苗褪黑素含量最高,分别是CK和紫外处理的2.89和2.47倍。发芽期间,紫外处理和热激处理各关键酶基因表达量存在显著差异,热激处理4 d时芥菜芽苗TDC2、T5H2及SNAT4的表达量较CK均显著上调,而SNAT2及ASMT3的表达量显著下调(P<0.05)。本研究表明热激处理可作为芥菜芽苗富集褪黑素的有效手段。  相似文献   
26.
Abstract

Potherb mustard (Brassica rapa var. nipposinica) and tomato plants (scion, ‘CF Momotaro haruka’; rootstock, ‘Dokutar K’; Solanum lycopersicum) were cultured in hydroponic medium containing cesium-137 (137Cs) at three different concentrations (0.03, 0.13 and 1.03 Bq L?1), and uptake of 137C into the plants was determined. When the 137Cs radioactivity concentration in the medium was 1.03 Bq L?1, the 137Cs radioactivity concentrations in the edible portions of the plants were 4.80 Bq kg?1 fresh weight for the potherb mustard plants and 3.60 Bq kg?1 fresh weight for the tomato plants. In both species, the 137Cs radioactivity concentration in the edible portions decreased with decreasing 137Cs radioactivity concentration in the culture medium. When the 137Cs radioactivity concentration in the medium was 0.03 Bq L?1, a concentration observed in many streams and in tap water in Fukushima Prefecture after the accident at the Fukushima Daiichi Nuclear Power Plant, the 137Cs radioactivity concentrations in the edible portions of the plants were 0.50 and 0.15 Bq kg?1 fresh weight for potherb mustard and tomato plants, respectively. These values are less than the Japanese allowable limit for radiocesium in food. For both species, the transfer factors for 137Cs uptake from the culture media to the edible portions and the average transfer rates over the cultivation period were calculated.  相似文献   
27.
Field trials were conducted for two consecutive years during the rabi season in sandy loam soils of Jammu (north India) under rainfed conditions to study the effect of gypsum and pyrite for sulfur (S) nutrition on the oil content, S uptake, and yield of Indian mustard. Application of S through gypsum or pyrite either in natural or ground form increased S content, uptake, oil content, and yield of mustard significantly over the control. Among the different treatments, S application at 50 kg S ha?1 of ground gypsum (GM2S2) recorded the significantly highest mean seed yield of 20.30 and 18.01 q ha?1, which lead to an increase of 30 and 29.8% in the first and second year, respectively, over the control. For the duration of the experiment, it was observed that 25 kg S ha?1 was the optimum dose, preferably of ground gypsum, for mustard crops under rainfed conditions.  相似文献   
28.
A field experiment was conducted during the (rabi) seasons of 2009–2010 and 2010–2011 at the research farm, Department of Agronomy, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, to find out the suitable row ratio of Indian mustard (Brassica juncea L.) intercropping with wheat (1:9, 2:9, 1:6, 2:6) and lentil (1:4, 1:5, 2:4, 2:5) row ratios, respectively. The highest yield attributes of mustard were recorded with mustard + lentil (2:5), which was significantly superior to mustard + wheat (1:9) and mustard + lentil (1:5). Maximum seed yield and stover yield of mustard was recorded with mustard + lentil (2:4), which was being significant over other row ratios of mustard + wheat (1:6, 1:9, 2:9) but was at par with mustard + lentil (1:5) and mustard + wheat (2:6) row ratios. Mustard equivalent yield (3128 kg ha?1) recorded under intercropping of mustard with wheat in 1:9 row ratio was significantly higher than sole cropping of mustard, wheat, and lentil, and other remaining intercropping systems. Intercropping of mustard with wheat in 1:9 row ratio showed the highest land equivalent ratio (1.51), aggressivity index (+0.15), net return (60,468 Rs ha?1), and benefit:cost ratio (4.3) among all other intercropping treatments.  相似文献   
29.
茎瘤芥新品种涪杂1号的选育   总被引:6,自引:1,他引:6  
涪杂1号茎瘤芥母本是胞质雄性不育系96118-3A,父本是优良的茎瘤芥自交系920154。该一代杂种从出苗至现蕾150~155 d(天),属中熟类型。瘤茎近圆球形,加工性能好,品质优,适于四川盆地茎瘤芥产区种植,一般每667 m2产量2 500—3 000 kg,最高可达4 000 kg。  相似文献   
30.
芥蓝是我国的特产蔬菜,主要食用肥嫩的花苔和嫩叶,茎叶、根等被当作废弃物腐烂于菜地而污染环境。利用物理、化学、生物等技术,可以从芥蓝废弃物中制备聚羟基烷酸脂、乳酸及其衍生物、芥蓝纸、膳食纤维、乙醇、沼气、有机肥、饲料和生物滤床滤料等。芥蓝废弃物的综合开发利用可提高经济效益,是芥蓝生产和加工的重要发展趋势。  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