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   102篇
  免费   12篇
林业   3篇
农学   3篇
  13篇
综合类   6篇
农作物   2篇
水产渔业   44篇
畜牧兽医   37篇
园艺   3篇
植物保护   3篇
  2022年   1篇
  2020年   4篇
  2019年   4篇
  2018年   5篇
  2017年   9篇
  2016年   4篇
  2015年   3篇
  2014年   5篇
  2013年   18篇
  2012年   5篇
  2011年   11篇
  2009年   8篇
  2008年   7篇
  2007年   5篇
  2006年   6篇
  2005年   2篇
  2004年   3篇
  2003年   2篇
  2002年   6篇
  2001年   1篇
  2000年   2篇
  1998年   1篇
  1994年   1篇
  1993年   1篇
排序方式: 共有114条查询结果,搜索用时 15 毫秒
81.
The objective of this study was to assess the effects of a probiotic strain Clostridium butyricumMIYAIRI 588 (CBM588) on broiler and weaned piglet health and zootechnical performance. Five field studies were carried out in broilers and five in weaned piglets under European feed additive guidelines. Each study followed a randomized blocked design with two treatments: Control (basal diet) and CBM588 supplemented groups. The zootechnical performance parameters selected were body weight, daily gain, feed intake and feed efficiency (feed:gain). Broilers fed diets with CBM588 gained significantly more weight (+2%, p < .001) and exhibited significantly better feed efficiency (?1.6%, p < .001) in comparison with Controls. Similarly, analysis of pooled data of weaned piglet trials showed that CBM588‐fed piglets were significantly heavier than Controls (+2.6%, p = .014), exhibited significantly higher mean daily gain (+4.7%; p = .004), and significantly improved feed efficiency (?4.2%, p = .001). In addition to the zootechnical efficacy studies, the preventive effect of CBM588 on necrotic enteritis (NE) was assessed in a natural challenge model in broilers where CBM588 reduced the incidence and severity of NE lesions. These data indicate the potential of CBM588 to improve broiler and weaned piglet zootechnical performance, and to make a positive contribution to animal health.  相似文献   
82.
Immunosuppression in postweaning multisystemic wasting syndrome affected pigs   总被引:23,自引:0,他引:23  
The present review concentrates on the clinical, pathological and immunological aspects of pigs suffering from PMWS which strongly suggest that PCV2 may be, in particular conditions, a cause of secondary immunodeficiency in pigs. From a clinical point of view, the lack of antibiotic therapy response against the disease, the existence of a litter effect and the concurrence of other disease syndromes and well-known secondary pathogens, such as Pneumocystis carinii, Chlamydia spp. and Aspergillus spp., may account as features of immunosuppression in PMWS. Furthermore, pathologic, immunohistologic and flow cytometric studies also suggest that pigs with PMWS may be immunosuppressed. Lymphocyte depletion of follicular and interfollicular areas together with macrophage infiltration of lymphoid tissues is a unique lesion, which is the basic feature of PMWS affected pigs. These findings are highly correlated with the decrease of circulating B- and T-cells and the diminution of these cell types in lymphoid organs, and with the increase of macrophage/monocytes lineage cells both in peripheral blood and lymphoid tissues in both naturally and experimentally PMWS affected pigs. The altered populations of cells participating in the immune system response both in blood and tissues suggests, at least in those severely PMWS affected pigs, a transient inability of diseased pigs to mount an effective immune response. From these points of view, strong suspicions on the immunosuppressive status of PMWS affected pigs do exist; however, future studies are needed to characterise the exact role of PCV2 on the immune system of pigs affected with PMWS.  相似文献   
83.
Knitted wool and wool/nylon blend dyed fabrics were treated with low temperature plasma (LTP) to achieve optimum shrink-resistance without impairing surface topography, colour or fastness to washing of the fabrics. As LTP tends to impair handle of the fabrics, both wool and wool/nylon blend fabrics were submitted to industrial softening and/or biopolymer treatments after LTP treatment, leading to hydrophilic wool and wool/nylon blend fabrics with improved shrink-resistance without any colour changes and good fastness to washing. The results obtained were compared with those obtained by an industrial shrink-resist treatment.  相似文献   
84.
Several samples of P. splendida larvae were obtained from eggs until day 60 after hatching (dah) to determine acid and alkaline proteases, trypsin, chymotrypsin, leucine aminopeptidase, α-amylase, lipase, and acid and alkaline phosphatase activities using biochemical techniques. Additionally, SDS–PAGE alkaline protease zymogram and PAGE acid protease zymogram were carried out to identify active isoforms during larviculture. Alkaline protease and chymotrypsin were present at the moment of hatching, increased gradually reaching the maximum values at 35 dah. Trypsin and leucine aminopeptidase activities were low from hatching, increasing gradually as larvae grew. Alkaline protease zymogram showed four zymogens, which appears at different days, remaining present until the end of the larviculture (95.2 kDa at 11 dah, 26.4 kDa at 9 dah, 21.4 kDa at 3 dah, and 23.3 kDa at hatching). Pepsin activity was present at day 7 after hatching and increased progressively until the end of the larviculture. Acid protease zymogram only showed one zymogen (0.65 rf), which appear at 6 dah. Lipase was high at the time of hatching and increased until 15 dah, after which decreased gradually. Amylase was high from the beginning and until 15 dah and then decreased rapidly to almost nothing onward. Alkaline and acid phosphatases presented a high activity at the egg stage, fell slightly during the first feeding and increased again from 20 to 30 dah. Results obtained in this study show that larvae can be fed artificial diets starting on day 10 after hatching.  相似文献   
85.
The effect of spray‐dried porcine plasma (SDPP) on the intestinal histological organization and autochthonous microbiota composition was evaluated in Sparus aurata. Fish were fed a basal diet (51 g/kg protein, 17 g/kg fat, 20.6 MJ/kg gross energy) and a diet containing 3 g/kg SDPP for 95 days (initial body weight, BW = 9.5 ± 0.2g, mean ± SD). The inclusion of SDPP promoted growth (p < .05), being fish fed the SDPP diet 6.2% (BW = 88.2 ± 1.6 g) heavier than the control (BW = 82.7 ± 3.2 g). SDPP increased the density of intestinal goblet cells (p < .05), whereas no differences in villi height were found (p > .05) between both groups. Intestinal microbiota was dominated by Proteobacteria (>85%) and Firmicutes (5%–12%), whereas Bacteroidetes never represented more than 1.5%. γ‐Proteobacteria, and Bacilli and Clostridia were the predominant classes. The short administration of SDPP (20 days) resulted in changes in microbiota diversity and richness associated with an increase in the sequences of the genus Lactobacillus and to a decrease in the genus Vibrio, whereas these changes were reverted at 95 days. Intestinal goblet cell density was not correlated to microbiota diversity and richness changes rather than to the immunostimulatory effect of the SDPP.  相似文献   
86.
International trade in vulnerable marine species is regulated once they are listed in CITES Appendices (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Parties to the Convention submit proposal(s) 150 days prior to the CITES Conference for voting on the inclusion of new species in Appendices I and II, making a case for why CITES listing criteria are met in each case. Before the vote, Parties receive advice from (a) the Food and Agriculture Organization of the United Nations, (b) the International Union for Conservation of Nature—TRAFFIC and (c) the CITES Secretariat, among others. This paper offers an expert review of listing processes, which are the subject of much debate in fishery and environment‐protection communities, looking at two specific cases: silky shark (Carcharhinus falciformis, Carcharhinidae) and bigeye thresher shark (Alopias superciliosus, Alopiidae). The reviewers determine that the evidence made available to voting Parties is substantial, but suffers from non‐standard presentation across assessments. The best available data are not always presented or described transparently in relation to CITES criteria. An extension of the assessment period, as well as the opportunity to refute evidence, has been suggested as ways to support more informed and effective decision‐making by CITES Parties, whose composition of delegations varies greatly in their experience of marine species management and trade. Experts welcomed a greater coherence of advice between fishery and non‐fishery sources in the long term, and proposed a range of suggested improvements for the delivery of information and advice to CITES Parties.  相似文献   
87.
Different fasting and re‐feeding cycles were tested in a 60‐day trial in sobaity sea bream (Sparidentex hasta) juveniles to evaluate their effects on growth, physiological and biochemical parameters. Fish were exposed in triplicate to the following feeding regimes: control (fed everyday); F‐RF1+1 (1 day of starvation followed by 1 day of re‐feeding); F‐RF2+2 (2 days of starvation followed by 2 days of re‐feeding); F‐RF3+3 (3 days of starvation followed by 3 days of re‐feeding); F‐RF6+6 (6 days of starvation followed by 6 days of re‐feeding); and F‐RF1+2 (1 day of starvation followed by 2 days of re‐feeding). A reduction in body mass between 10.0% (F‐RF1+1) and 24.3% (F‐RF6+6) was found in comparison with the control group after 60 days. As the length of fasting increased, the compensation coefficients in feed intake and weight gain decreased. Body lipid content decreased as fasting cycles increased. Haemoglobin, plasma protein, lysozyme and alkaline phosphatase activities were the most reliable biomarkers for assessing the nutritional condition in sobaity sea bream. A feeding strategy based on 1 day of starvation followed by 2 days of re‐feeding (F‐RF1+2 group) may be advisable for on‐growing sobaity sea bream without reduction in growth and alteration of their haematological and physiological parameters.  相似文献   
88.
89.
Fish tissues, particularly rich in n‐3 PUFA, are prone to lipid peroxidation that can damage cellular membranes, cause severe lesions and subsequently incidences of disease and mortality. However, fish possess antioxidant defences, such as vitamin E (VE) and antioxidant enzymes, to protect them against oxidative damage. This study investigated the effects of an increasing gradient of oxidized dietary lipid on the survival, growth performance, skeletogenesis and antioxidant defensive processes occurring in Senegalese sole (Solea senegalensis) larvae. Four groups of fish were fed live prey enriched with experimental emulsions containing an increasing gradient of oxidized oil: non‐oxidized, NO+VE, 34.5 nmol MDA g?1 w.w.; mildly oxidized, MO+VE, 43.1 nmol MDA g?1 w.w.; highly oxidized, HO+VE, 63.3 nmol MDA g?1 w.w. and highly oxidized without VE, HO‐VE, 78.8 nmol MDA g?1 w.w. The oxidation levels increased in enriched rotifers following the oxidation gradient of the emulsions, but were not affected in enriched Artemia metanauplii. The oxidation status of Senegalese sole larvae increased during development, but this was not related to the dietary treatments. The increasing dietary oxidation levels did not affect the fatty acid profile, survival, growth performance and metamorphosis processes of sole larvae. Senegalese sole seem to activate antioxidant defence mechanisms in response to the increasing amounts of dietary peroxidized lipids, in a manner efficiently enough to prevent detection of any alterations of these physiological processes. Antioxidant systems and detoxification mechanisms appeared to occur through the consumption of dietary α‐tocopherol, the activation of the antioxidant enzymes (catalase, superoxide dismutase, glutathione S‐transferase, glutathione reductase) and the retention of oxidized fat in the intestinal enterocytes for detoxification prior to their utilization. However, fish fed the highest oxidized diet presented a reduction in bone mineralization, but lower incidence of deformities in the vertebral and caudal regions than fish fed the other diets. This study exemplifies the importance of rearing Senegalese sole larvae on non‐oxidized diets during the early larval development to avoid detrimental consequences in older fish, most notably in the process of skeletogenesis.  相似文献   
90.
Dicentrarchus labrax were fed from 10 to 40 days posthatching with six microdiets differing in the inclusion level (60 g kg‐1 and 120 g kg‐1) and type of protein hydrolysate (PH; yeast, YPH; pig blood, PBPH; pig red blood cells, PRBCPH). A microdiet containing 120 g kg‐1 fish PH (FPH) was used as a control. PH differed in their amino acid (AA) profile and molecular weight distribution and therefore the tested microdiets too. The estimated content in FAA and di‐ and tripeptides in the FPH microdiet was 2 g kg‐1 and 44 g kg‐1, respectively. FAA estimated levels in YPH and PBPH microdiets were 26 g kg‐1 and 53 g kg‐1, whereas levels of di‐ and tripeptides were 30 g kg‐1 and 60 g kg‐1, respectively. The estimated levels of FAA in PRBCPH microdiets were 8 g kg‐1 and 17 g kg‐1, whereas estimated levels of di‐ and tripeptides were 11 g kg‐1 and 22 g kg‐1, respectively. Results revealed that FPH may be replaced by alternative PH from yeast and pig blood products, as fish fed those diets performed, in terms of growth, survival, digestive function and incidence of skeletal deformities, as well as those fed the FPH microdiet. Using YPH, PBPH and PRBCPH, the inclusion level of PH in microdiets might be reduced to a half with respect to current practices using FPH.  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