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   123篇
  免费   15篇
林业   4篇
农学   17篇
基础科学   5篇
  35篇
综合类   14篇
农作物   19篇
水产渔业   2篇
畜牧兽医   28篇
园艺   3篇
植物保护   11篇
  2023年   1篇
  2022年   6篇
  2021年   8篇
  2020年   7篇
  2019年   8篇
  2018年   12篇
  2017年   14篇
  2016年   10篇
  2015年   9篇
  2014年   1篇
  2013年   15篇
  2012年   7篇
  2011年   7篇
  2010年   7篇
  2009年   3篇
  2008年   8篇
  2007年   2篇
  2006年   1篇
  2003年   1篇
  1999年   3篇
  1996年   1篇
  1993年   1篇
  1984年   2篇
  1982年   1篇
  1972年   2篇
  1942年   1篇
排序方式: 共有138条查询结果,搜索用时 31 毫秒
61.
【目的】研究种源、产地和环境因子对尖果沙枣、沙枣和东方沙枣的产胶率和胶多糖含量的影响。【方法】对新疆不同居群药用资源沙枣实地考察,收集沙枣胶,测算产胶率,提取沙枣胶中多糖并计算含量。【结果】不同基源的沙枣其产胶率和多糖含量统计上无显著差异(P>0.05,P=0.173);产地与产胶率相关性显著(尖果沙枣P=0.003、东方沙枣P=0.019、沙枣P=0.011),即低纬度地区产胶率高于高纬度地区,而产地与胶多糖含量差异不显著(P=0.051);生态因子海拔、无霜期、年均温和年积温与产胶率相关性显著,即海拔越低,无霜期越长,年均温和年积温越高,产胶率越高(P<0.05),而多糖含量与生态因子无显著相关(P值均>0.05)。【结论】在海拔较低的平原和天山以东、以南地区种植沙枣以推广沙枣胶产业。  相似文献   
62.
In this research work, multifunctional cotton fabric comprising of UV protection, superhydrophobicity and antibacterial activity has been developed using facile pad-dry-cure method. In the first step, the concentration of repellent chemical has been optimized. Then, formulations containing nanoparticles of ZnO or TiO2 along with optimized concentration of repellent chemical and organic-inorganic binder have been applied to cotton fabric followed by the evaluation of functional properties. The surface morphology and elemental composition of treated fabric has been characterized through SEM and EDX, respectively. The treated samples have shown promising UV protection, superhydrophobicity and antibacterial properties durable upto 20 washing cycles.  相似文献   
63.
Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water(hydropriming), Ca Cl2(2.2%, osmopriming), moringa leaf extracts(MLE 3.3%, osmopriming) and salicylic acid(SA, 50 mg L–1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in early planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyll contents followed by osmopriming with Ca Cl2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed priming; however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.  相似文献   
64.
Direct seeded rice is promising alternative to traditional transplanting, but requires appropriate crop and water management to maintain yield performance and achieve high water productivity. Present study evaluated the effect of seed priming and irrigation on crop establishment, tillering, agronomic traits, paddy yield, grain quality and water productivity of direct seeded rice in alternate wetting and drying(DSR-AWD) in comparison with direct seeded rice at field capacity(DSRFC). Seed priming treatments were osmo-priming with KCl(2.2%), Ca Cl2(2.2%) and moringa leaf extracts(MLE, 3.3%) including hydro-priming as control. Among the treatments, seed osmo-primed with MLE emerged earlier and had higher final emergence, followed by osmo-priming with Ca Cl2. Tillering emergence rate and number of tillers per plant were the highest for seed priming with Ca Cl2 in DSRAWD. Total productive and non-productive tillers, panicle length, biological and grain yields, harvest index were highest for seed priming with MLE or Ca Cl2 in DSR-AWD. Similarly, grain quality, estimated in terms of normal grains, abortive and chalky grains, was also the highest in DSR-AWD with MLE osmo-priming. Benefit cost ratio and water productivity was also the highest in DSR-AWD for seed priming with MLE. In conclusion, seed priming with MLE or Ca Cl2 can be successfully employed to improve the direct seeded rice performance when practiced with alternate wetting and drying irrigation.  相似文献   
65.
The bioavailability and interactive effects of calcium, iron and zinc fortified whole wheat flour chapattis on female Sprague–Dawley albino rats were determined. The whole wheat flour was fortified with CaCO3, FeSO4 and ZnSO4 at 1000, 40 and 20 mg/kg, respectively and fed to 64 female Sprague–Dawley rats for 4 weeks. Retention of Ca, Fe and Zn was determined in plasma, femur and liver tissues. Ca levels in plasma and liver did not alter significantly while the Ca retention in femur changed significantly with the change in fortificants. The calcium retention was higher in the femur of rats fed on the diet supplemented with Ca + Zn (221 ± 13.61 mg/g) than the rats fed on the diet supplemented with Ca + Fe (219 ± 18.92 mg/g). The iron in plasma, liver and femur ranged from 2.19 ± 0.11 to 2.77 ± 0.10 μg/ml, 203.5 ± 13.24 to 251.5 ± 17.19 μg/g and 43.5 ± 1.05 to 52 ± 2.07 μg/g while zinc content ranged from 1.31 ± 0.089 to 1.55 ± 0.114 μg/ml, 89.5 ± 3.41 to 132 ± 6.10 μg/g and 175 ± 8.29 to 191 ± 10.85 μg/g, respectively. The minerals interacted with each other resulting in decrease of bioavailability among each other. The absorption was higher in the rats fed on fortified diet than those fed on unfortified chapatti diet. Hence, it is concluded that fortification of whole wheat flour is feasible to overcome the Ca, Fe and Zn malnutrition in the vulnerable groups.  相似文献   
66.
ABSTRACT

This study was conducted to evaluate influence of zinc (Zn) application on productivity, grain biofortification and grain quality of wheat planted under plough tillage (PT) and zero tillage (ZT) systems. Zn was delivered as soil application (10 kg ha?1), foliage spray (0.025 M) and seed priming (0.5 M) in wheat planted under PT and ZT systems. ZT had higher total soil porosity, total soil organic matter, soil organic carbon and soil microbial biomass carbon than PT. Zn application, by either method, improved grain yield, grain Zn and grain quality in both tillage systems. The grain Zn concentration was 72% and 59% higher with soil-applied Zn in ZT wheat during 2016–2017 and 2017–2018, respectively, compared with no Zn. However, Zn seed priming was the most effective in improving wheat grain yield in both tillage systems. Foliage and Zn soil application were better in improving the indices of Zn use efficiency of Zn. In conclusion, Zn seed priming was the most effective method in improving the wheat grain yield, whereas soil Zn application in ZT and foliar applications in PT were the most effective for grain Zn biofortification. However, Zn soil application was the most cost-effective method of Zn application.  相似文献   
67.
Boron (B) is one of the essential micronutrients having a specific role, particularly during reproductive phase, in rice. In a previous experiment on aerobic rice, panicle sterility was noted as one of the major challenges. This experiment was conducted to evaluate the influence of soil-applied B on tillering, panicle sterility, water relations, and grain enrichment in fine-grain aromatic rice cultivars ‘Super Basmati’ and ‘Shaheen Basmati’. Boron was soil applied at 0.50, 0.75, 1, 1.25, and 1.50 kg ha?1 while the control treatment did not receive B. Rate of leaf emergence and elongation and tiller appearance were significantly improved by B application. Likewise, B application also improved the leaf chlorophyll contents and water relations in both rice cultivars. Substantial improvement in kernel yield and yield contributing traits was also observed by B application owing to decrease in panicle sterility. A linear increase in leaf and kernel B contents was observed with increase in B application rate. However, the range for an optimum B application rate is very narrow and increase of B application beyond 1 kg ha?1 was toxic. In conclusion, soil application of B is an effective way to decrease panicle sterility and increase the kernel yield and grain B enrichment in rice.  相似文献   
68.
Biochemical changes in wheat grains stored at 10, 25 and 45 °C for six months were studied. A significant decrease in pH and an increase in titratable acidity was observed during storage of wheat grains at 25 °C and 45 °C. Moisture contents of wheat grains decreased by 15% at 25 °C and 26% at 45 °C during six months of storage. A significant decrease in water soluble amylose (20–28%) along with an increase in insoluble amylose contents (7.6–17%) were observed during storage at 25 and 45 °C. Amylase activity of the samples showed a decrease as the storage progressed. Total soluble sugars increased by 9% at 10 °C and 12% at 25 °C; a 37% decrease was observed after six months storage at 45 °C. Total available lysine decreased by 18.0% and 22.6% at 25 and 45 °C, respectively, after six months storage. In vitro protein digestibility of wheat grains decreased by 5.00% at 25 °C and 10.28% at 45 °C during six months of storage. However, no significant biochemical changes occurred during storage at 10 °C.  相似文献   
69.
The livestock ration formulation problem is postulated within the framework of multiple-criteria decision-making techniques. This exercise is motivated by the fact that the ordinary least-cost approach can, and does, generate solutions that either cannot be implemented or supply nutritionally undesirable levels of various nutrients. This originates from using cost as the criterion for selecting the ingredients of the diet. But in fact, diet formulation problems involve several criteria and should, therefore, be solved using techniques designed for modelling such problems. This paper is an attempt at introducing these techniques to agricultural systems modellers and then demonstrating their use in livestock ration formulation. The multiple-criteria decision-making techniques covered include goal programming and its variants such as weighted and lexicographic approaches and multiple-objective programming.  相似文献   
70.
该试验研究了膳食菊糖和蔗糖对鸡消化道菌群发酵的影响。选择80只1日龄肉仔鸡分为4组,分别饲喂基础日粮;基础日粮+4%蔗糖+1%菊糖;基础日粮+蔗糖;基础日粮+菊糖。饲养35d后屠宰,测定消化道不同部位的pH值、乳酸、氨、短链不饱和脂肪酸(SCFA)和生物胺的含量。统计分析表明肉仔鸡的终末体重和肝脏、胰脏、嗉囊、肌胃和小肠重没有差异。  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