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   124篇
  免费   5篇
林业   9篇
农学   1篇
基础科学   1篇
  19篇
综合类   8篇
农作物   5篇
水产渔业   14篇
畜牧兽医   47篇
园艺   10篇
植物保护   15篇
  2023年   1篇
  2021年   2篇
  2020年   2篇
  2019年   8篇
  2018年   7篇
  2017年   2篇
  2016年   2篇
  2015年   3篇
  2014年   5篇
  2013年   14篇
  2012年   11篇
  2011年   9篇
  2010年   8篇
  2009年   7篇
  2008年   4篇
  2007年   4篇
  2006年   6篇
  2005年   2篇
  2004年   10篇
  2003年   7篇
  2002年   8篇
  2001年   2篇
  1999年   3篇
  1996年   1篇
  1980年   1篇
排序方式: 共有129条查询结果,搜索用时 122 毫秒
1.
Standard limb, six lead (I, II, III, aVR, aVL, and aVF) electrocardiograms (ECGs) were recorded in 10 awake mature rock partridges (Alectoris graeca) and 10 chukar partridges (Alectoris chukar). Durations and amplitudes of P and T waves and QRS complexes, durations of P-Q and Q-T intervals, and mean heart rates were calculated from the lead II ECGs. All observable P and T waves were negative in aVR and aVL, whereas they were positive in all remaining leads. The most frequent forms of QRS complex were r-s (r-S) and q-r (q-R). A Q wave was observed in all aVR and aVL leads in both species. Chukar partridges had significantly higher amplitudes of P and T waves and QRS complexes than rock partridges. Mean heart rates were 310+/-15 beats/min and 317+/-19 beats/min for chukar partridges and rock partridges, respectively. Mean electrical axes, calculated from leads II and III, were -99+/-6.3 degrees and -95+/-1.7 degrees for chukar partridges and rock partridges, respectively. Clear ECGs were easily obtainable without anesthesia or sedation.  相似文献   
2.
This study was conducted in order to determine the prevalence and fertility of hydatid cysts in sheep in Kirikkale, Turkey. A total of 3.2% of 553 lambs and 50.9% of 1320 adults were found to be infected with hydatid cysts. The most common locations of cysts were in the liver and lung. Liver cysts tended to be more fertile than lung cysts (81.53% v. 76.47%), though the difference was not significant. The mean number of viable protoscoleces in the liver and lung cysts were 12,400 and 5,800, respectively. In general, 1-10 cysts were found in liver (51.8%) and lung (64.7%). The findings of this study indicate that hydatid cysts are common in sheep and the fertility rate of cysts is quite high. Sheep play an important role in the life cycle of Echinococcus granulosus in this region.  相似文献   
3.
Increasing consumer demands for indigenous, non-sprayed with pesticides and less-known or “forgotten” fruits necessitate knowledge on their breeding, cultivation, biochemical content, harvesting and marketing. Anatolia is rich for wild edible fruit species and barberry is abundant throughout Anatolia. The aim of this study was to determine some important physicochemical characteristics, bioactive content and antioxidant capacity of fruits from nineteen promising barberry (Berberis vulgaris L.) genotypes grown in the Coruh valley, Northeastern Anatolia. The results indicated genotype-specific differences for most of the physicochemical characteristics, antioxidant capacity and the content of some bioactive compounds. Fruit mass ranged from 0.073 (‘Coruh-7’) to 0.267 g (‘Coruh-11’). Total phenolic content ranged from 2532 (‘Coruh-’) to 3719 mg GAE per liter fruit juice (‘Coruh-11’). The genotype ‘Coruh-12’ had the highest total monomeric anthocyanin content (1004 mg per liter fruit juice) as cyanidin-3-glucoside. The highest total antioxidant capacity was observed in fruits of ‘Coruh-8’ and ‘Coruh-9’ genotypes with all three antioxidant-determining methods. We conclude that the barberry fruits represent a good source of bioactive phytochemicals because of their high phenolic and anthocyanin contents.  相似文献   
4.
5.
Energy recovery from a crossflow ultrafiltration (UF) membraneunit employed in order to improve the performance of an anaerobic contact digester for the treatment of brewery wastewater was assessed. The performance of the pilot-scale anaerobic UF membrane system was studied for over 15 months. At steady-state conditions, an organic loading rate of 28.5 kg COD m-3 d-1, a hydraulic retention time of 4.2 days and overall COD and BOD removal efficiencies of 99% and almost 100% were achieved, respectively. Percent methane in biogas was found to be in a range of 67–79% with the corresponding methane yield of 0.28–0.35 m3 CH4 kg-1 CODremoved. The potential energy recovery from the system treating brewery wastewater at an OLR of 28.5 kg COD m-3 d-1 was 87 MJ d-1 which would enable to maintain all energy requirements of the feed pump, mixing and heating of the reactor contents. In addition to this, 71% of the energy requirement for recirculating the reactor content through the membranes would also be recovered.  相似文献   
6.
春尺蠖羽化发蛾特性研究表明,发蛾期与气温密切相关。邻近城区比郊外大田发蛾期早7~10d;发蛾前期雄蛾多于雌蛾,以后雌蛾增多;成虫为全日程羽化出土,雌雄性比为1:1.42;雌蛾交尾最多可达3次,雄蛾仅1次。应用佳多频振式杀虫灯诱捕春尺蠖雄蛾数量大。灯距120m范围内,树干表皮单位面积上的有效卵率较无灯对照区下降了24%~61.5%,控害效果显著。  相似文献   
7.
The aim of the current study was to evaluate the effects of high carbohydrate or fat diets, fed for 15 days at the end of breeding season, on leptin, GH and LH secretions in prepubertal fat‐tailed Tuj lambs. For that purpose, 9‐month‐old ram‐lambs were divided into three groups as control group (fed with basal ration, n = 4), high carbohydrate (HC) group, basal ration plus barley, n = 4), or high fat (HF) group (basal ration plus by‐pass fat, n = 4). For the measurement of leptin and GH, blood plasma samples were collected on days 1, 4, 9 and 14 of the experiment. For the measurement of LH pulse frequency, serial blood samples were collected every 15 min for 6 h on day 14. Lambs were weighed and body condition scored (BCS) on days 1 and 15. Body weight and BCS increased towards the end of the study (p < 0.05). The BCS was higher in high energy groups at the end of the experiment (p < 0.05). Diet affected plasma leptin concentrations (p = 0.002) but time did not. The GH concentrations were not affected by diet or time. The LH pulse frequency appeared to be higher in HC and HF groups but there were no statistical difference between the groups. There was a significant positive relationship between overall BCS and corresponding leptin concentrations (R2 = 0.263; p = 0.010) and between LH pulse frequency and leptin concentrations (R2 = 0.594; p = 0.003). In conclusion, the present study suggests that rather than type of energy, amount of energy intake and body energy reserves are much important regulators of plasma leptin concentrations and LH pulse frequency in fat‐tailed Tuj lambs.  相似文献   
8.
Bovine herpesvirus 1 (BHV-1) is the aetiological agent of many disease types and may predispose infected animals, possibly through immunosuppression, to secondary bacterial infections. Immunosuppression may directly be associated with the induction of programmed cell death (PCD) in some virus-infected cells. Nitric oxide (NO) has an important mediating role against fungal, bacterial, protozoal, viral pathogens and tumours. BHV-1 induced apoptosis between 0.5-3 h postinfection (PI) in MDBK cells; however, between 3 and 6 h PI the PCD response was found to be decreased. It was interesting to see that BHV-I inhibited staurosporin-induced PCD after 1 h. These results showed similarities with those obtained from herpes simplex type I infections in human epithelial cells. PCD response decreased 1 h following caspase-3 inhibitor applications, whereas NO response increased 3 h following infection in the presence of caspase-8 and -9 inhibitory peptides. In conclusion, BHV-1 inhibited the staurosporin-induced apoptotic response and also the NO response. We propose that this inhibition is caspase-3 dependent.  相似文献   
9.
Bovine tactile hairs in skin samples from the lateral side of the upper lip were examined using scanning electron and light microscopy. The root of these hairs has a variable length and is surrounded by a large sinus located between the internal and the external dermal sheath. With a prominent thickness, the external dermal sheath forms the external wall of the tactile hair and contains many nerves some of which extend into trabeculae. Trabeculae projecting from the internal dermal sheath and attaching to the external dermal sheath with two or more branches are present in the entire sinus. The trabeculae are interconnected by connective tissue sheets that support the integrity of the trabecular organization. The sinus surfaces as well as trabeculae are lined by endothelia. As a result, the bovine tactile hair is truly a cavernous type of tactile hair with a well organized microscopic anatomy. Thus, the bovine tactile hair most likely plays an important role in relatively immobile and insensitive bovine lips.  相似文献   
10.
The present study was conducted to investigate the effect of maternal dietary supplementation (n = 10 sows/treatment) with seaweed extract (SWE: 0 vs. 10.0 g/d) from d 107 of gestation until weaning (d 26) on neonatal piglet growth, humoral immunity, intestinal morphology, selected intestinal microflora, and VFA concentrations. Furthermore, this study examined the effect of dietary treatment on the immune response after an ex vivo Escherichia coli lipopolysaccharide (LPS) tissue challenge at weaning in a 2 × 2 factorial arrangement. The main factors consisted of sow dietary treatment (SWE or control) and immunological challenge (yes or no). The SWE supplement (10.0 g/d) contained laminarin (1.0 g), fucoidan (0.8 g), and ash (8.2 g) and was extracted from a Laminaria spp. The SWE-supplemented sows had greater colostrum IgA (P < 0.01) and had a trend for greater IgG (P = 0.062) concentrations compared with non-SWE-supplemented sows. Piglets suckling SWE-supplemented sows had greater serum IgG (P < 0.05) concentrations on d 14 of lactation compared with those suckling non-SWE-supplemented sows. Dietary SWE supplementation decreased fecal Enterobacteriaceae populations in sows at parturition (P < 0.05), and piglets suckling SWE-supplemented sows had a decreased colonic E. coli population at weaning (P < 0.01) compared with non-SWE-supplemented sows. Lipopolysaccharide challenge increased the mRNA abundances of the pro-inflammatory cytokines IL-1α and IL-6 (P < 0.01) in ileal tissue and tumor necrosis factor (TNF)-α in colonic (P < 0.01) tissue. There was a treatment × LPS challenge interaction for ileal TNF-α mRNA expression (P < 0.05). Piglets suckling SWE-supplemented sows had greater TNF-α mRNA expression after ex vivo LPS challenge compared with non-SWE-supplemented sows (P < 0.05). However, there was no effect of sow dietary treatment on TNF-α mRNA expression in the unchallenged ileal tissue. Piglet BW at birth and weaning, and small intestinal morphology were unaffected by sow dietary treatment under current experimental conditions. In summary, these results demonstrate an important immunomodulatory role of SWE supplementation characterized by enhanced colostral IgA and IgG concentrations, greater piglet circulatory IgG concentrations on d 14 of lactation, and enhanced TNF-α mRNA expression in the ileum after an ex vivo LPS challenge. These results indicate that SWE supplementation enhanced piglet immune function and colonic microflora at weaning.  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