全文获取类型
收费全文 | 88篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
农学 | 4篇 |
10篇 | |
综合类 | 10篇 |
农作物 | 40篇 |
水产渔业 | 6篇 |
畜牧兽医 | 18篇 |
园艺 | 7篇 |
植物保护 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2017年 | 3篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 11篇 |
2010年 | 1篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1991年 | 2篇 |
排序方式: 共有96条查询结果,搜索用时 330 毫秒
41.
S. Pereira-Lorenzo A.M. Ramos-Cabrer M.B. Díaz-Hernández M. Ciordia-Ara D. Ríos-Mesa 《Scientia Horticulturae》2006
Chestnut cultivation and production in Spain has employed grafted seedlings from selected local cultivars. Previously, we have characterised the Spanish cultivars by morphological and molecular markers. We are presenting in this paper the proximate analysis and mineral content for the main Spanish cultivars. A total of 131 samples were collected from 47 cultivars in six important Spanish chestnut production regions; located in the North such as Asturias, Castilla-León (El Bierzo) and Galicia; in the Central such as Extremadura and in the South such as Andalucía; as well as the Canary Islands, the southermost part of Spain near to North Africa. High variability in chemical composition between cultivars and regions corresponded to the high genetic variability between cultivars. Correlations with environmental parameters were low, indicating that differences found between regions were probably reflecting the differences between cultivars. In Central and Southern Spain, some cultivars presented lowest moisture content due to the low summer rainfall in these regions. Differences in starch and total sugar contents were high and were negatively correlated with each other. There was no negative correlation between nut size and total sugar content. Lowest values of fibre content and ease of digestibility were found in cultivars from Galicia and Extremadura. No significant differences in Fe, Zn and Cu were found although Zn content is twice the value reported for European chestnuts. This work would be a valuable reference to chestnut quality for the food processing industry, nutritionists, breeders and growers alike. 相似文献
42.
Ahmed A Anjum FM Ur Rehman S Randhawa MA Farooq U 《Plant foods for human nutrition (Dordrecht, Netherlands)》2008,63(1):7-13
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
43.
M. A. Amaro Lopez G. Zurera Cosano R. Moreno Rojas R. M. García-Gimeno 《Plant foods for human nutrition (Dordrecht, Netherlands)》1996,49(1):13-26
The essential elements: calcium (Ca), magnesium (Mg), sodium (Na) potassium (K) and phosphorus (P) were analyzed in fresh asparagus to determine the effect of the ripening of the asparagus on the mineral content. Asparagus samples were classified in two groups by diameter (<11 mm and >14 mm). Asparagus from a sample group with the same diameter were divided into two portions (apical and basal) according to distance from the tip. The concentrations of calcium, magnesium and phosphorus increased with the ripening process of the asparagus while the content of sodium decreased when the white asparagus turned into a green ripening state. No significant differences were established for potassium. The green ripening state was the group with the greater concentration of calcium, magnesium and phosphorus. Statistically significant differences (p<0.001) were observed between portions of asparagus (tip and rest of stem) in the contents of the five mineral elements analyzed. The levels of mineral elements investigated increased notably in the tip of the asparagus with the exception of sodium and potassium of which the levels in the apical portion decreased or hardly modified. The variance analyses determined statistically significant differences (p<0.001) in the concentration of magnesium, sodium and phosphorus between asparagus diameters (<11 and >14 mm) and no significant differences (p>0.05) were found for calcium and potassium. The mean element levels were (mg/kg dry weight): Ca=3240±1186; Mg=1818±490; Na=368±86; K=37297±4167 and P=6809±2491. 相似文献
44.
土壤矿物质吸附砷的研究进展 总被引:24,自引:1,他引:24
砷是一种有毒的重金属元素,由于自然和人为的原因,世界上的许多国家存在砷污染问题,因此有关砷污染的研究与控制日益受到人们的关注。本文介绍了土壤砷污染的产生原因及污染状况,重点集中在探讨土壤中的各种矿物质对砷吸附行为的作用机理。这些矿物质包括铁铝氧化物和氢氧化物、锰氧化物、黏土矿物和碳酸盐类。关于砷在各类矿物质上的吸附机理,普遍接受的观点认为:砷氧阴离子与矿物质的表面发生了配位体交换过程并通过共价键的作用,形成了表面配位体。表面配位体以内层双齿双核鳌合形式为主,受矿物质的种类、pH值和氧化还原电位等因素的影响,外层吸附和其他鳌合状态可能存在。砷在土壤矿物质上的吸附效果强烈依赖于体系的pH值,这与吸附的理论模型和数学计算结果相一致。矿物质的种类、组成、结晶状态和表面积等影响了砷的吸附过程和吸附效果。土壤中存在的各种阴阳离子通过与砷阴离子竞争吸附位而影响砷在矿物质上的吸附。 相似文献
45.
Effects of dietary supplements on the availability of minerals in fish meal; preliminary observations 总被引:5,自引:0,他引:5
Shozo H. Sugiura Faye M. Dong Ronald W. Hardy 《Aquaculture (Amsterdam, Netherlands)》1998,160(3-4):283-303
Preliminary studies were conducted to determine if several feed supplements with the potential to improve dietary mineral availabilities in fish meal had any measurable effect in fish feeds. In the first study with rainbow trout, 11 supplements were tested: citric acid; sodium citrate; potassium chloride; sodium chloride; histamine dihydrochloride; EDTA disodium salt; sodium bicarbonate; a mixture of amino acids; ascorbic acid; a mixture of inositol and choline; and cholecalciferol. Apparent availability of calcium, phosphorus, magnesium, sodium, iron, manganese and strontium in fish meal-based diets was determined using both yttrium oxide (Y2O3) and chromium oxide (Cr2O3) as inert dietary markers. Apparent availability was expressed as the fractional net absorption (%) of minerals from diets. After a 7-day acclimation period with test diets, fecal samples were collected for five consecutive days using passive collection systems. Apparent availability of calcium, phosphorus, magnesium, iron, manganese and strontium was increased by citric acid supplementation. Apparent availability of manganese also was increased by EDTA and sodium citrate. The other supplements had no measurable effect on the apparent availability of minerals in fish meal. In the second study, the effect of supplemental citric acid was further investigated using monogastric (rainbow trout) and agastric fish (goldfish). Fish were fed for 5 weeks (rainbow trout) or 3 weeks (goldfish) with fish meal-based diets containing either 0% (control), 2% or 5% citric acid on a dry basis. Feces were collected by settling and by stripping. Apparent availabilities of calcium and phosphorus were greatly affected by citric acid supplementation in rainbow trout but not in goldfish. Phosphorus levels in feces of fish fed a diet with 5% citric acid were approximately half of that of fish fed the control diet (0% citric acid) in the rainbow trout trial. This pattern was consistent during the 5-week feeding trial. A dietary supplement of citric acid as high as 5% did not reduce feed intake or appetite of rainbow trout. Conversely, this level of dietary acidification led to a marked reduction of feed intake in goldfish. Dietary supplementation of citric acid at 2% level did not reduce feed intake of goldfish; however, this level of dietary acidification had little effect on the apparent availability of major minerals in fish meal-based diet. Levels of non-fecal excretion of calcium and phosphorus, inorganic phosphorus in urine, and citric acid in feces were increased in rainbow trout fed 5% citric acid. The pH values of the feces and urine were decreased in rainbow trout fed citric acid. Plasma bicarbonate, plasma calcium and phosphorus, and blood pH of rainbow trout tended to increase by a 5% dietary supplementation of citric acid. The soluble inorganic phosphorus content increased in the diets and decreased in the feces of rainbow trout by supplementing the diet with 5% citric acid. Feces samples of rainbow trout collected by stripping provided similar availability values to data collected by settling for most elements except sodium, which had negative values in all dietary treatments. 相似文献
46.
Chemical composition of grape canes 总被引:1,自引:0,他引:1
Emine Sema Çetin Duygu AltinözEcehan Tarçan Nilgün Göktürk Baydar 《Industrial Crops and Products》2011,34(1):994-998
In this study, chemical composition of canes which were sampled from ten different grape cultivars was investigated. For the determination of total phenolics, total flavanols and total flavonol contents, canes were analyzed spectrophotometrically. The phenolic compositions of the canes, including caffeic acid, catechin, p-coumaric acid, epicatechin, gallic acid, luteolin and trans-resveratrol were detected by HPLC. The anthron method was used for the determination of total carbohydrate content. The minerals such as K, P, Ca, Fe, Mg and Zn were determined by ICP-OES. All the parameters investigated in this study significantly changed depending on the cultivar. The results showed that grape canes as agricultural wastes from commercial viticultural activities represent a potentially important source of phenolics, minerals, carbohydrates and proteins. Therefore the grape canes may be used as an easily accessible source of natural antioxidants and food supplement. 相似文献
47.
土壤矿物风化过程中释放的盐基离子(BC)与硅(Si)的比值(BC︰Si)是定量评估土壤矿物风化对土壤酸化过程缓冲作用的基础,是准确估算当前环境下土壤酸化速率的依据。本研究以云母片岩、片麻岩和安山岩3种母质发育的湿润雏形土为研究对象,测定了其土壤物理、化学和矿物学性质。通过洗脱实验除去土壤交换性盐基以消除土壤胶体吸附的交换性盐基离子对矿物风化计量关系的影响,再利用模拟酸雨淋溶实验,采用Batch方法获取3种不同母质发育土壤的盐基离子和硅的释放量,进一步估算BC︰Si值。结果表明,由于母岩不同,土壤黏粒、pH、有机质、交换性盐基(K+、Na+、Ca2+和Mg2+)、阳离子交换量(CEC)和土壤矿物含量存在差异。在模拟酸雨淋溶实验条件下,未洗脱盐基土壤的BC︰Si值为洗脱盐基土壤的3倍以上,因此只有洗脱土壤交换性盐基才能获得来自风化过程的BC︰Si值。同一母质发育土壤的腐殖质表层(Ah)BC︰Si最小,母质层(C)最大。不同母质发育土壤的BC︰Si值表现为:片麻岩>云母片岩>安山岩,土壤中斜长... 相似文献
48.
黑龙江省不同类型土壤微量元素含量及对稻米品质的影响 总被引:5,自引:0,他引:5
采用单因素方法研究黑龙江省不同类型土壤铜、锰、铁、锌微量元素含量与稻米子粒铜、锰、铁、锌微量元素的关系及其对稻米品质的影响。结果表明,不同类型土壤铜含量顺序为白浆土>黑土>草甸土>盐碱土,锰和铁的含量顺序与铜一致,锌的含量则是黑土>白浆土>草甸土>盐碱土。土壤中的铜、锰、铁、锌含量与水稻子粒中各微量元素含量达极显著正相关;水稻子粒中铜、锰、铁、锌含量高,稻米整精米率、长宽比和食味评分降低,蛋白质含量和垩白粒率升高;各微量元素对于稻米出糙率和直链淀粉含量的影响不一致,子粒中铜、锰、铁含量高,稻米出糙率高,锌含量与稻米出糙率则相反,各微量元素对于稻米的出糙率影响不大,铜和锌含量低,锰和铁含量高,稻米的直链淀粉含量高,子粒中各微量元素与稻米品质指标的关系间接反映出各类土壤微量元素含量与稻米品质指标的关系。 相似文献
49.
The effect of replacing wheat flour by infrared stabilized rice bran (SRB) at the levels of 2.5, 5.0 and 10.0% on the content of thiamine, riboflavin, niacin, pyridoxamine, pyridoxine, minerals and phytic acid in white wheat, wheat bran, and whole grain wheat breads was investigated. The incorporation of SRB significantly increased the amount of the noted B vitamins, especially niacin, in all bread types (p < 0.05). Zinc, iron, potassium and phosphorus levels of the breads increased gradually and significantly with the inclusion of SRB (p < 0.05). Moreover, phytic acid content of the breads increased proportional to the SRB substitution dose (p < 0.05). 相似文献
50.
【目的】为了更好地开发利用洋葱的食用价值和保健功能提供依据。【方法】以河北、山东、昆明、甘肃4个产地的白皮洋葱和紫皮洋葱为研究对象,对其基本营养成分、矿物质成分、氨基酸成分进行分析比较,明确其差异性,可为深入研究洋葱的品质评价和资源开发利用提供基础资料。【结果】河北产地紫皮洋葱的基本营养物质含量、矿物质含量最高,氨基酸含量仅次于山东产地紫皮洋葱。【结论】河北产地紫皮洋葱可作为高值化开发利用的理想资源。 相似文献