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   58篇
  免费   1篇
林业   1篇
农学   1篇
  17篇
综合类   1篇
农作物   2篇
水产渔业   6篇
畜牧兽医   26篇
园艺   1篇
植物保护   4篇
  2023年   2篇
  2022年   1篇
  2021年   1篇
  2020年   3篇
  2019年   3篇
  2018年   1篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2013年   6篇
  2012年   2篇
  2011年   9篇
  2010年   2篇
  2009年   1篇
  2008年   2篇
  2007年   9篇
  2006年   2篇
  2005年   3篇
  2004年   4篇
  2002年   1篇
  1995年   1篇
  1988年   1篇
排序方式: 共有59条查询结果,搜索用时 31 毫秒
51.
Phenols present in olive oil may contribute to the health effects of the Mediterranean lifestyle. Olive oil antioxidants increase the resistance of low-density lipoproteins (LDL) against oxidation in vitro, but human intervention studies have failed to demonstrate similar consistent effects. To better mimic the in vivo situation, plasma was incubated with either individual olive oil phenols or olive oil extracts with different phenolic compositions, and LDL was subsequently isolated and challenged for its resistance to oxidation. The results show that the ortho-dihydroxy phenols (hydroxytyrosol and oleuropein-aglycone) are more efficient than their mono-hydroxy counterparts (tyrosol and ligstroside-aglycone) in increasing the resistance of LDL to oxidation. However, the concentration of antioxidants required to inhibit LDL oxidation when added to whole plasma was substantially higher as compared to previous data where antioxidants are directly added to isolated LDL. In conclusion, this study supports the hypothesis that extra virgin olive oil phenols protect LDL in plasma against oxidation. The explanation that in vitro studies show protective effects in contrast to the lack of effect in the majority of human studies may be that the dose of the phenols and thus their plasma concentration in humans was too low to influence ex vivo LDL oxidizability. Further studies are required to gain a better understanding of the potential health benefits that extra virgin olive oil may provide.  相似文献   
52.
53.
The reproductive success of marine ectotherms is especially vulnerable in warming oceans due to alterations in adult physiology, as well as embryonic and larval survival prospects. These vital responses may, however, differ considerably across the species' geographical distribution. Here we investigated the life history, focusing on reproductive ecology, of three spatially distant populations (stocks) of Atlantic cod (Gadus morhua, Gadidae) (50–80° N), in the Irish/Celtic Seas-English Channel Complex, North and Barents Seas, under past and projected climate. First, experimental tracking of spawning behaviour evidenced that the ovulation cycle is highly distressed at ≥9.6 (±0.25)°C (Tup). This knife-edge threshold resulted in erratic spawning frequencies, whereas vitellogenin sequestration remained unaffected, indicating endocrine rather than aerobic scope constraints. Cod in the Celtic Sea-English Channel are, therefore, expected to show critical stock depensation over the next decades as spawning grounds warm above Tup, with Irish Sea cod subsequently at risk. Second, in the relatively cooler North Sea, the northward retraction of Calanus finmarchicus (Calanidae) and Para-Pseudocalanus spp. (Clausocalanidae) (1958–2017) limit cod larvae feeding opportunities, particularly in the southernmost subarea. However, the contrasting increase in Calanus helgolandicus (Calanidae) does not counteract this negative effect, likely because cod larvae hatch ahead of its abundance peaks. Overfishing again comes as a twin effect. Third, in the still relatively cold Barents Sea, the sustainably harvested cod benefit from improved food conditions in the recent ice-free polar region but at the energetic cost of lengthier and faster spawning migrations. Consequently, under climate change local stocks are stressed by different mechanistic factors of varying management severity.  相似文献   
54.
A high‐amylose, non‐floury corn, a floury corn, and a 1:1 blend were made into masa and then tortillas. The masa flour made with the high‐amylose corn had a greater amount of resistant starch (RS 28.8%) and a greater amount of total dietary fiber (TDF 42.1%) than that with the floury corn (RS 2.9%, TDF 9.6%), producing a high‐fiber tortilla. The masa was evaluated for pasting properties using a Rapid ViscoAnalyser (RVA). The high‐amylose masa slurry gelatinized little at 95°C. The floury masa had the greatest peak viscosity, whereas the 1:1 blend was intermediate in value. Sensory evaluations of the tortillas for the textural attributes showed the floury tortillas to be chewier, more rollable, and grittier than the high‐amylose tortillas, whereas the blend tortillas were intermediate for most attributes. The cutting force of the high‐amylose tortillas, measured on a texture analyzer, was very low; the blend and floury tortillas required more force. Chewiness was correlated to rollability (r = 0.99, P = 0.05). The %RS and %TDF were correlated to rollability (r = –0.99), and cutting force (r = 0.99). The floury and blend tortillas had firm textures expected of desirable tortillas, whereas the high‐amylose tortillas broke under little force, and would not roll. The high‐amylose tortillas had high amounts of RS and TDF but poor texture. The blend tortillas retained most floury tortilla textural properties, making them suitable products for consumer use.  相似文献   
55.
Twelve healthy approximately 3-yr-old captive-born 4.5-9 kg American alligators (Alligator mississipiensis) each had bronchoscopy and tracheal washes performed four times during a 10-mo period to evaluate seasonal respiratory microbiology and cytology. Cytologic evaluation of most samples showed a small amount of mucus and low numbers of ciliated columnar epithelium, cubodial epithelium, and keratinized squamous cells. No bacteria or parasites were observed, and there was no seasonal variation in the cytology. No significant bacterial or fungal growth was identified in any season. Hematology performed in the spring and fall evaluations showed seasonal variation in the red blood cell count, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin concentration, eosinophil count, and thrombocyte count. The lower respiratory tract (at the tracheal level) of healthy subadult alligators appears to be sterile, and cytology is similar to that described in domestic mammals.  相似文献   
56.
A 6-wk-old tiger (Panthera tigris) was evaluated for severe skin lacerations from an adult tiger attack. A caudal superficial epigastric skin flap was surgically placed to cover a defect that could not be closed over the hind limb; however, the skin flap did not adhere well to the granulation tissue over a period of 1 mo. The granulation bed matured and deteriorated. A subatmospheric pressure technique (vacuum-assisted closure, V.A.C. Therapy, Kinetic Concepts Inc., San Antonio, Texas 78219, USA) was utilized, and flap adherence occurred after 4 wk. This technique should be considered when dealing with severe or chronic wounds in tractable animals.  相似文献   
57.
58.
Under the assumption that milk yield may be reduced in herds with impaired welfare, the present study aimed at investigating whether milk yield could be used as a reliable indicator of welfare. In 125 commercial French dairy herds, the association between the welfare of the herd (evaluated using the Welfare Quality assessment protocol) and cow milk yield was investigated using linear mixed models. Positive associations were identified between milk yield and low aggressions between cows and good emotional state of the herd but there was a negative association with good health assessed through the occurrence of diseases and injuries. These opposite associations resulted in no association with the overall welfare of the herd. Milk yield should not therefore be used as an indicator of overall welfare.  相似文献   
59.
The aim of this paper is to study the role of Al- and H-ions, base cation deficiency and N-nutrition as solely NH4 in disturbing plant growth on acid soils. Effects of these factors on growth of the forest grass Bromus benekenii were studied experimentally and in the field and compared to other deciduous forest plants. Bromus benekenii is most frequent at pH >4.5 (soil solution) and absent at pH 3.8. In a pot experiment using an acid soil of pH 3.3, raised by steps to pH 5.2 by carbonate addition, growth of Bromus benekenii and nine other species (out of 17) was limited at pH <4.1. Toxicity of H-ions to Bromus benekenii was confirmed in a solution experiment at pH ≤4.2. Al-toxicity occurred at low Al-concentrations (20 μM) in Bromus benekenii and nine other tested species. Base cation (Ca+Mg) mitigation of Al-toxicity was found in a factorial solution experiment. Our experiments also indicate that H- and Al-ions interact in a way that makes combined treatments equally toxic as concentrations of H-or Al-ions alone. Incubation experiments showed that soil nitrification is retarded in acid soils. This may affect Bromus benekenii as it was most demanding on NO3-availability out of 15 species in a solution experiment. Only 50% growth was attained in a NH4- as compared to a NH4+NO3-treatment. Comparing experimental results with field data, we conclude that H- and Al-toxicity and unfavourable N-nutrition (as solely NH4) to a similar extent may explain the acidifuge behaviour of field layer plants.  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