全文获取类型
收费全文 | 183篇 |
免费 | 1篇 |
专业分类
林业 | 15篇 |
农学 | 8篇 |
基础科学 | 2篇 |
33篇 | |
综合类 | 15篇 |
农作物 | 14篇 |
水产渔业 | 13篇 |
畜牧兽医 | 39篇 |
园艺 | 25篇 |
植物保护 | 20篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 2篇 |
2014年 | 12篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 14篇 |
2010年 | 15篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1996年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有184条查询结果,搜索用时 422 毫秒
121.
Yusuf Kurt Santiago C. González-Martínez Ricardo Alía Kani Isik 《Annals of Forest Science》2012,69(3):345-351
Context
Turkish red pine (Pinus brutia Ten.) is widespread in the eastern Mediterranean Basin. In the late 1970s, four common gardens were established along steep altitudinal transects extending from the coast to about 1,200 m in the Taurus Mountains (Antalya, Turkey). 相似文献122.
Zeynel Abidin Kus Bunyamin Demir Ikbal Eski Feyza Gurbuz Sezai Ercisli 《Erwerbs-Obstbau》2017,59(4):291-299
The consumer acceptance and the quality standard of agricultural products such as apple are determined mostly by their colour. Colour is measured with a colorimeter and quantified using the C.I.E. L*, a*, b* colour space system. It is used commonly by researchers for the classification and identification of apple fruit. To the best of our knowledge, the present study is the first study investigating the prediction of some colour properties of six apple varieties through artificial neural networks (ANN). The apple varieties are ‘Amasya’, ‘Starking’, ‘Granny Smith’, ‘Pink Lady’, ‘Golden Delicious’, ‘Arapk?z?’ and the colour properties are L* (lightness), a* (redness), b* (yellowness), C* (chroma), h* (hue angle), CI (chroma index). General Regression Neural Networks (GRNN) and Adaptive Neuro Fuzzy Interface System (ANFIS) structures were employed to predict the colour properties. According to the experimental and simulation results, the proposed ANFIS predictor had a superior performance in prediction of these colour parameters. 相似文献
123.
Farmer perception of soil erosion and investment in soil conservation measures: emerging evidence from northern Taraba State,Nigeria 下载免费PDF全文
To combat soil erosion in the northern part of Taraba State, Nigeria, farmers are of major importance. Their perceptions vitally influence the levels of support and investment associated with solving problems of soil erosion through adoption of practices that are alternative to those in current use, including approaches focused on soil conservation. The objective of this study was to evaluate how farmer perceptions of soil erosion influence their investments in soil conservation, particularly soil or stone bunds, their applications of organic amendments and inorganic fertilizers and other soil conservation practices. In the study area, we undertook a field plot experiment and carried out a survey, using open‐ and closed‐ended questions. Water erosion and depletion of fertility were taken as the main indicators of soil erosion. The results of the experiment showed that farmers were aware of and perceived both indicators as having increased over the past decade. Farmer investments in water erosion control (3.7 US$/ha) and the prevention of soil fertility depletion (37.8 US$/ha) in the study area were found to be limited. The results also showed that awareness of water erosion was only marginally correlated with investment in water erosion control (χ2 = 4.906, P = 0.09) and not associated with investments in soil fertility control measures (χ2 = 0.175, P = 0.92). Those farmers who identified depletion of soil fertility as a problem, based on erosion, were not significantly more likely to make greater investments in soil conservation (χ2 = 0.947, P = 0.62) but did invest more in fertility measures (χ2 = 3.199, P = 0.20). Hence, further research is needed to determine other factors that may influence farmer investment in soil conservation, especially factors related to socio‐economic characteristics of farm households, institutional and technological innovations and field characteristics that were not addressed in this study. 相似文献
124.
An alternative approach to application of chitosan based on layer by layer (LbL) assembled technique is studied in this paper. For this aim, chitosan (CHT) was used as a bio-based cationic polyelectrolyte and pentasodium tripolyphosphate (TPP) and poly(sodium 4-styrene sulfonate) (PSS) were selected as anionic polyelectrolyte. TPP/CHT and PSS/CHT based bilayers were fabricated on the cationized woven cotton fabrics via layer-by-layer self-assembly technique. The characterization of coatings on the fabric surface in terms of surface appearance, atomal content, and chemical bondings were made in detail through SEM, XPS, and FTIR-ATR analysis. Also, the antibacterial activity, air permeability, and water contact angle were measured. Surface analyses demonstrate the interaction between TPP, PSS and chitosan separately. XPS spectra also showed the existence of LbL deposition over cotton substrates in terms of both elemental composition and the presence of different types of bondings on the fabric surface. The antibacterial activity analysis revealed that the modified cotton fabric with the addition of CHT/TPP and CHT/PSS bilayers could increase the degree of inhibition on K. pneumanie and S. aureus bacteria. 相似文献
125.
Tropical Animal Health and Production - The objective of this study was to determine the effect of supplementations of Leucaena leucocephala or Gliricidia sepium by goats fed old Panicum maximum... 相似文献
126.
127.
128.
Major flavonoids in grape seeds and skins: antioxidant capacity of catechin, epicatechin, and gallic acid 总被引:1,自引:0,他引:1
Grape seeds and skins are good sources of phytochemicals such as gallic acid, catechin, and epicatechin and are suitable raw materials for the production of antioxidative dietary supplements. The differences in levels of the major monomeric flavanols and phenolic acids in seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were determined, and the antioxidant activities of these components were assessed. The contribution of the major monomeric flavonols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, monomeric catechin, and epicatechin concentrations were 99, 12, and 96 mg/100 g of dry matter (dm) in Muscadine seeds, 15, 358, and 421 mg/100 g of dm in Chardonnay seeds, and 10, 127, and 115 mg/100 g of dm in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than in seeds. These three major phenolic constituents of grape seeds contributed <26% to the antioxidant capacity measured as ORAC on the basis of the corrected concentrations of gallic acid, catechin, and epicatechin in grape byproducts. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric, or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds. 相似文献
129.
Hayrettin Kuşçu Ahmet Turhan Neşe Özmen Pınar Aydınol Ali O. Demir 《Archives of Agronomy and Soil Science》2016,62(10):1396-1410
The main objective of this investigation was to evaluate the response of red pepper grown in a subhumid climate to different irrigation and nitrogen levels. Open-field trials were conducted in the Marmara Region, Turkey. Plants were subjected to three water levels [full irrigation (FI) = 100% crop evapotranspiration (ETc) and two deficit irrigations (DIs)= 66 and 33% ETc restoration] and four levels of N (0, 80, 160, and 240 kg N ha?1) during the 2012, 2013, and 2014 growing seasons. A split-plot experimental design was used. The highest values of biomass and marketable yield (MY) were observed under FI. DI significantly increased the fruit soluble solids content. The biomass yield, MY, and fruit weight significantly improved with increasing nitrogen levels. The 240 kg N ha?1 treatment under FI provided the maximum net income. Increasing N supply under DI conditions enhanced the water-use efficiency based on both biomass yield and MY. These results indicate that with respect to the yield, the net income, and the water productivity of red pepper, the FI with a nitrogen supply of 160–240 kg ha?1 is recommended for drip irrigated and N-fertigated red pepper under subhumid climate conditions. 相似文献
130.
In this study, the polyphenol oxidase (PPO) of artichoke (Cynara scolymus L.) was first purified by a combination of (NH(4))(2)SO(4) precipitation, dialysis, and a Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity column. At the end of purification, 43-fold purification was achieved. The purified enzyme migrated as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Polyacrylamide gel electrophoresis indicated that PPO had a 57 kDa molecular mass. Second, the contents of total phenolic and protein of artichoke head extracts were determined. The total phenolic content of artichoke head was determined spectrophotometrically according to the Folin-Ciocalteu procedure and was found to be 425 mg 100 g(-1) on a fresh weight basis. Protein content was determined according to Bradford method. Third, the effects of substrate specificity, pH, temperature, and heat inactivation were investigated on the activity of PPO purified from artichoke. The enzyme showed activity to 4-methylcatechol, pyrogallol, catechol, and L-dopa. No activity was detected toward L-tyrosine, resorsinol, and p-cresol. According to V(max)/K(m) values, 4-methylcatechol (1393 EU min(-1) mM(-1)) was the best substrate, followed by pyrogallol (1220 EU min(-1) mM(-1)), catechol (697 EU min(-1) mM(-1)), and L-dopa (102 EU min(-1) mM(-1)). The optimum pH values for PPO were 5.0, 8.0, and 7.0 using 4-methylcatechol, pyrogallol, and catechol as substrate, respectively. It was found that optimum temperatures were dependent on the substrates studied. The enzyme activity decreased due to heat denaturation of the enzyme with increasing temperature and inactivation time for 4-methylcatechol and pyrogallol substrates. However, all inactivation experiments for catechol showed that the activity of artichoke PPO increased with mild heating, reached a maximum, and then decreased with time. Finally, inhibition of artichoke PPO was investigated with inhibitors such as L-cysteine, EDTA, ascorbic acid, gallic acid, d,L-dithiothreitol, tropolone, glutathione, sodium azide, benzoic acid, salicylic acid, and 4-aminobenzoic acid using 4-methylcatechol, pyrogallol, and catechol as substrate. The presence of EDTA, 4-aminobenzoic acid, salicylic acid, gallic acid, and benzoic acid did not cause the inhibition of artichoke PPO. A competitive-type inhibition was obtained with sodium azide, L-cysteine, and d,L-dithiothreitol inhibitors using 4-methylcatechol as substrate; with L-cysteine, tropolone, d,L-dithiothreitol, ascorbic acid, and sodium azide inhibitors using pyrogallol as substrate; and with L-cysteine, tropolone, d,L-dithiotreitol, and ascorbic acid inhibitors using catechol as a substrate. A mixed-type inhibition was obtained with glutathione inhibitor using 4-methylcatechol as a substrate. A noncompetitive inhibition was obtained with tropolone and ascorbic acid inhibitors using 4-methylcatechol as substrate, with glutathione inhibitor using pyrogallol as substrate, and with glutathione and sodium azide inhibitors using catechol as substrate. From these results, it can be said that the most effective inhibitor for artichoke PPO is tropolone. Furthermore, it was found that the type of inhibition depended on the origin of the PPO studied and also on the substrate used. 相似文献