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   97篇
  免费   22篇
  国内免费   4篇
林业   1篇
农学   1篇
  14篇
综合类   12篇
农作物   1篇
水产渔业   17篇
畜牧兽医   75篇
植物保护   2篇
  2023年   6篇
  2022年   5篇
  2021年   7篇
  2020年   14篇
  2019年   9篇
  2018年   9篇
  2017年   8篇
  2016年   7篇
  2015年   9篇
  2014年   6篇
  2013年   7篇
  2011年   5篇
  2010年   7篇
  2009年   7篇
  2008年   4篇
  2007年   3篇
  2006年   4篇
  2005年   2篇
  2004年   2篇
  2002年   2篇
排序方式: 共有123条查询结果,搜索用时 15 毫秒
71.
Background: Pulmonary hypertension (PH) is a disease condition leading to right-sided cardiac hypertrophy and, eventually, right-sided heart failure. Cardiac troponin I (cTnI) is a circulating biomarker of cardiac damage.
Hypothesis: Myocardial damage can occur in dogs with precapillary and postcapillary PH.
Animals: One hundred and thirty-three dogs were examined: 26 healthy controls, 42 dogs with mitral valve disease (MVD) without PH, 48 dogs with pulmonary hypertension associated with mitral valve disease (PH-MVD), and 17 dogs with precapillary PH.
Methods: Prospective, observational study. Serum cTnI concentration was measured with a commercially available immunoassay and results were compared between groups.
Results: Median cTnI was 0.10 ng/mL (range 0.10–0.17 ng/mL) in healthy dogs. Compared with the healthy population, median serum cTnI concentration was increased in dogs with precapillary PH (0.25 ng/mL; range 0.10–1.9 ng/mL; P < .001) and in dogs with PH-MVD (0.21 ng/mL; range 0.10–2.10 ng/mL; P < .001). Median serum cTnI concentration of dogs with MVD (0.12 ng/mL; range 0.10–1.00 ng/mL) was not significantly different compared with control group and dogs with PH-MVD. In dogs with MVD and PH-MVD, only the subgroup with decompensated PH-MVD had significantly higher cTnI concentration compared with dogs with compensated MVD and PH-MVD. Serum cTnI concentration showed significant modest positive correlations with the calculated pulmonary artery systolic pressure in dogs with PH and some echocardiographic indices in dogs with MVD and PH-MVD.
Conclusions and Clinical Importance: Serum cTnI is high in dogs with either precapillary and postcapillary PH. Myocardial damage in dogs with postcapillary PH is likely the consequence of increased severity of MVD.  相似文献   
72.
Diseases which cause skeletal muscle myopathy are some of the most economically damaging diseases in Atlantic salmon, Salmo salar L., aquaculture. Despite this, there are limited means of assessing fish health non‐destructively. Previous investigation of the serum proteome of Atlantic salmon, Salmo salar L., during pancreas disease (PD) has identified proteins in serum that have potential as biomarkers of the disease. Amongst these proteins, the enzyme enolase was selected as the most viable for use as a biomarker of muscle myopathy associated with PD. Western blot and immunoassay (ELISA) validated enolase as a biomarker for PD, whilst immunohistochemistry identified white muscle as the source of enolase. Enolase was shown to be a specific marker for white muscle myopathy in salmon, rising in serum concentration significantly correlating with pathological damage to the tissue.  相似文献   
73.
The present review presents data on fish requirement for B vitamins and describes their mechanism of action. Both general deficiency symptoms such as reduced growth and appetite, and more specific deficiency signs, for example abnormal swimming activity due to thiamine deficiency, are included. The rationale is to elucidate the need to establish B vitamin recommendations for fish fed practical diets where the major part consists of plant ingredients. Most requirement studies referred to were performed with semi‐purified diets with relatively low growth rate compared to the growth potential of the fish obtained with practical diets. Further, when giving salmon a plant‐based diet (70% plant ingredients), substantial lowered growth was obtained even when the diet was added vitamins according to the newest established requirements. New recommendations for B vitamin addition in plant‐based diets are therefore urgent. Few requirement studies exist and often with lack of dose–response data. For riboflavin and biotin, this review includes a meta‐analysis to support earlier requirement estimates. Too few data existed on the others to perform any meta‐analyses that made sense. Based on literature data, meta‐analyses, new experiments utilizing dose–response designs and identification of metabolic biomarkers, this review suggests new B vitamin recommendations for fish fed plant‐based diets.  相似文献   
74.
The present study describes signature lipid biomarkers in reclaimed mine soils (RMSs), an unreclaimed spoil and a natural soil (Vertisol) for a major coal mine basin in Eastern Europe. Alkanes, fatty acids and fatty alcohols, as well as coal biomarkers were abundant in the mine soils and the unreclaimed spoil. The alkanes distribution in the RMSs was bimodal with maxima at C18 and C29/C31 and points at two origins for the alkanes, terrigenous plants, including soil borne and from the coal source. Fatty acid carbon preference indices (CPIeven/odd = 10.4 and 8.1 for the mine soils under pine and grass vegetation) reflect the increasing role of terrestrial vegetation in the formation of organic matter. The higher concentrations of the long-chain alkanes, fatty acids and alcohols are speculated as the reason for the severe and extreme water repellency observed with the Vertisol and the unreclaimed spoil. The presence of terrigenous steroid and triterpenoid markers in the RMSs is an indication of the ongoing soil formation processes. The analysis of lipid extracts allowed for the assessment of sensitive molecular indicators of biogenic terrigenous and coal origin and the degree of soil recovery following >20 years of spoils reclamation.  相似文献   
75.
Presence of coastal aquaculture activities in marine landscapes is growing with impacts on the wild fish that share these habitats. However, it is difficult to disentangle subsequent ecological interactions between these activities and marine fish communities. We evaluated the impact of both salmon and halibut farms on mackerel (Scomber scombrus) and whiting (Merlangius merlangus) sampled near sea cages using condition indices and fatty acid (FA) biomarkers. Results of the stomach content analysis indicated that mackerel and whiting consumed waste feed which was also reflected in their modified FA profiles. Both mackerel and whiting had elevated levels of FAs that are of vegetable oils origin. The use of vegetable oils as replacement for marine oils is a lot more common in salmon farming than halibut farming. Additionally, the overall effects of the two fish farms were more pronounced in whiting than in mackerel sampled near the sea cages. By allowing discrimination between sources of trophic interactions, this method could lead to more informed decisions in managing different farming activities.  相似文献   
76.
ObjectiveAtrial natriuretic peptide (ANP) and cardiac troponin I (cTnI) serve as biomarkers for increased cardiac pressure/volume loading and for myocardial stress or damage. The objective was to describe the time course of plasma ANP concentrations (CpANP) and plasma cTnI concentrations (CpcTnI) in horses with mitral regurgitation (MR) compared to healthy horses at rest and after exercise, and to describe the relationship of CpANP with cardiac dimensions and intracardiac pressures.Animals15 healthy Warmblood horses and 7 Warmblood horses with MR.MethodsCardiac dimensions at rest were measured using echocardiography. All horses underwent standardized treadmill exercise. Biomarker concentrations and intracardiac pressures were measured at rest and after exercise. Hypotheses were tested using statistical methods. The level of significance was P < 0.05.ResultsHorses with MR showed increased left atrial (LA) and left ventricular (LV) dimensions but similar exercise capacity compared to healthy horses. Pulmonary capillary wedge pressures (PCWP) and CpANP increased with exercise. Horses with MR had higher PCWP and higher CpANP at rest and after exercise compared to healthy horses, with the maximum difference in CpANP reached 10 min after exercise. CpANP was significantly related to PCWP and – although inconsistently and only in healthy horses – to echocardiographic indices of LA and LV size and function. CpcTnI was low throughout the study in both groups.ConclusionsCpANP is increased in horses with MR and is related to LA pressures and to left heart dimensions. MR is not necessarily associated with exercise intolerance and exercise-induced myocardial stress or damage.  相似文献   
77.
Samples of invertebrates, primary producers, seawater and cores were taken surrounding several aquaculture sites in coastal British Columbia, Canada. Analysis of dissolved organic carbon (DOC) showed a significant decrease (P = 0.027) over 1 km and an overall average of 290 ± 40 μM at 1 m depth. At 10 m, the decrease was not significant and DOC averaged 81 ± 3 μM. The essential fatty acid 22:6ω3 (docosahexaenoic acid, DHA) was significantly lower nearer to the farm sites for all mollusc taxa as well as for mussels alone (P < 0.01). However, mussel wet weight as well as the zooplankton fatty acid marker (ZFA; Σ 20:1ω9, 22:1ω11, 22:1ω9) and 20:1ω9 individually, decreased significantly with distance from the farms (P < 0.03). Principal components analysis showed a similar trend with DHA being higher in molluscs further from the farm. Mussels had significantly higher amounts of DHA compared with other molluscs indicating their potential in multi‐trophic, co‐culturing systems. Bacterial fatty acid markers increased in molluscs with distance from the farms; however, 18:1ω7, which is representative of methane‐oxidizing bacteria, remained higher closer to the farm. In addition, DHA proportions in mussels showed a significant breakpoint at 339 m from the farm suggesting co‐cultured mussels would benefit from placement further than 339 m from farms where DHA would be optimized.  相似文献   
78.
Adults from spider crab, Maja brachydactyla, Balss, 1922 were kept in captivity for up to 2 years. Haemolymph of ten females was extracted monthly for monitoring several metabolites and the presence of Vibrionacea bacteria. A neurotoxic marker and hepatic metabolic and digestive enzyme capacities were contrasted between wild specimens and those reared in captivity. As a result, no differences were observed in hepatosomatic index (HSI) between males and females, but captive animals presented lower HSI than the wild ones. After 2 years of confinement, no changes in quantities of haemolymph microflora and metabolites were observed and this was considered indicative of adaptation of the broodstock to confinement. Spider crab also showed a large plasticity in their hepatopancreatic digestive capabilities suggested by the adaptation to the food supplied in captivity. Moreover, captivity conditions did not seem to negatively alter their antioxidant defences, xenobiotic capacity or neuromuscular activity, as no enhanced oxidative stress damage was shown in either males or females. These results indicate that although the confinement conditions used in this study do not mimic those from the wild, they could be considered as adequate for rearing M. brachydactyla in captivity, at least with regard to the set of parameters assessed.  相似文献   
79.
为了研究母猪妊娠早期外周血液中蛋白质的表达情况,寻找潜在的母猪妊娠早期生物标志物,本试验采集了 8头健康、生产表现正常且体况相近的配种后15 d妊娠与非妊娠的长大二元经产母猪外周血液,分离蛋白,利用iTRAQ技术及生物信息学方法筛选与胚胎附植相关的差异表达蛋白,用ELISA验证其表达情况,并进行ROC曲线分析.结果显示...  相似文献   
80.
Objective – To evaluate various surrogate markers associated with the inflammatory and counter‐inflammatory responses with respect to mortality in dogs with systemic inflammatory response syndrome (SIRS). Design – Prospective observational study. Setting – Veterinary Teaching Hospital. Animals – Twenty‐eight dogs with naturally occurring diseases and SIRS from January 2007 to May 2009. Interventions – Upon admission to the veterinary hospital, history and baseline data from the physical examination, including parameters previously defined for meeting SIRS criteria, were documented. Heparinized blood samples were collected and plasma cytokines interleukin‐6 (IL‐6), IL‐10, and high‐mobility group box 1 (HMGB1) were measured by sandwich ELISA. Measurements and Main Results – In nonsurvivors, median plasma HMGB1 concentrations (0.718 μg/L, interquartile range [IQR]; 0.300–1.626 μg/L) and the ratio of HMGB1 to IL‐10 (2.236, IQR; 0.972–5.367) were significantly increased as compared with those found in survivors (0.300 μg/L, IQR; 0.300–0.312 μg/L for HMGB1; 1.017, IQR; 0.862–1.126 for the ratio of HMGB1 to IL‐10, P=0.007 and 0.024, respectively). Plasma IL‐6, IL‐10, and the ratio of IL‐6 to IL‐10 were not significantly different between groups. Among the parameters studied, HMGB1 and the ratio of HMGB1 to IL‐10 performed the best in discriminating outcome in dogs with SIRS according to receiver operator characteristic curve analysis. Conclusions – Increases in plasma HMGB1 concentration and the ratio of HMGB1 to IL‐10 may predict poorer outcomes in dogs with SIRS. The approach described may lead to reliable prognostic biomarkers and new therapeutic concepts in the study of SIRS in dogs.  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