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   21篇
  免费   2篇
  国内免费   1篇
农学   1篇
综合类   5篇
水产渔业   4篇
畜牧兽医   12篇
植物保护   2篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2017年   2篇
  2014年   2篇
  2013年   2篇
  2011年   3篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2001年   1篇
  1992年   1篇
排序方式: 共有24条查询结果,搜索用时 46 毫秒
1.
建立CSFV疫苗免疫状态下猪繁殖与呼吸综合征病毒(PRRSV)感染动物模型。测定CSFV抗体阻断率和PRRSV抗体S/P值,根据CSFV抗体阻断率和PRRSV感染情况分析猪外周血中T淋巴细胞亚群变化和对PRRS的保护促进作用。采用流式细胞术(FAC)检测猪外周血T淋巴细胞CD3、CD4、CD8亚群的变化。结果,CSFV...  相似文献   
2.
陕北红碱淖湿地遗鸥资源分布与保护管理对策   总被引:10,自引:0,他引:10  
鄂尔多斯繁殖群作为自然界中的全球遗鸥的最大种群,其对遗鸥有效种群(全部繁殖个体的总量)的保有量应占全球总量的60%以上。陕西省榆林市神木县红碱淖湿地的遗鸥数量从2000年调查报告初步估计的约200只发展到了2005年测定的11 000多只,形成了世界上最大的遗鸥繁殖种群。红碱淖湿地不仅挽救了鄂尔多斯种群,并为其发展成为全球最稳定、最庞大、最富生机的种群奠定了良好基础,因此,对其进行保护具有重大意义。在研究红碱淖湿地遗鸥种群的资源分布及保护意义的基础上,详细介绍了“保岛护岸”、建立保护观察站等保护红碱淖湿地及其遗鸥种群所采取的多样综合管理措施,为湿地保护及发展提供借鉴。  相似文献   
3.
4.
  1. Geospatial models are used to predict the distribution of terrestrial and marine species, according to their ecological and ethological habits. The bottlenose dolphin is a cosmopolitan marine top predator, inhabiting most of the ocean, with the exception of polar and subpolar waters. This wide distribution is associated with a remarkable plasticity in ecological and behavioural habits, which makes it difficult to model and predict its distribution.
  2. This study proposes a ‘multi‐type approach’ to predict the presence and distribution of the bottlenose dolphin in the Pelagos Sanctuary, a Specially Protected Area of Mediterranean Importance located in the north‐west Mediterranean Sea. A multi‐type model based on random forest regression was developed, analysing the distribution habits of two geographical units living in the Pelagos area.
  3. When compared with a classical single‐type model, the multi‐type model performed much better in a prediction test (true skill statistics, TSS = 85% vs. 52%), confirming the value of this experimental approach. This work suggests that wild species should not be considered as one single‐type entity, as local specialization may change and shape their distribution habits.
  相似文献   
5.
为研究灰树花发酵产物提取出的胞内多糖的免疫活性,采用50只雄性昆明小鼠,随机分为5组,每组10只,设100、200和400mg/(kg·d)3个水平处理组,并设阳性对照组(黄芪多糖400mg/(kg·d))和阴性对照组(生理盐水),饲养30d后观察多糖对细胞免疫功能的影响。通过流式细胞仪检测脾细胞表面分子的CD4和CD8及对T淋巴细胞增殖的影响;用实时荧光定量PCR(RT-PCR)检测其细胞因子IL-6、IL-8、CRP和TNF-α的表达。结果表明:灰树花胞内多糖使小鼠脏器显著增大(P≤0.05);并显著增加了脾淋巴细胞的增殖能力(P≤0.05);对于T淋巴细胞亚群中免疫细胞CD4/CD8的比值随着用药量的增加而提升(P≤0.05);同时小鼠肠道中的细胞因子IL-6、IL-8和TNF-α的分子表达量起到了上调作用(P≤0.05);并且下调了炎症因子CRP的分子表达量(P≤0.05)。灰树花菌丝体胞内多糖能使小鼠体内免疫器官增大,免疫细胞分泌增多,相关免疫因子表达量增加。  相似文献   
6.
For maintenance of immunity and tolerance, organs and tissues of the organism are connected by migrated and positioned lymphocytes. Lymphocytes extensively distribute in vivo, almost in all tissues, except which blood can’t reach, for example, central nervous system (CNS), cornea, anterior chamber of eye, and so on. Understanding lymphocyte distribution is essential for evaluating the immune state of organism, meanwhile has an important reference value for diseases diagnosis. This paper systematically discusses lymphocyte distribution in various of immune organs and tissues, and it will supply important foundations for preventing and controlling diseases.  相似文献   
7.
Day length-related alterations of several metabolic factors (glucose, leptin, insulin, and insulin-like growth factor-1 [IGF-1]), cytokines (interleukin-2 [IL-2], IL-4, IL-6, tumor necrosis factor-alpha [TNF-α], interferon-gamma [IFN-γ], and lymphocyte subpopulations [CD2, CD3, CD4, CD8, CD19, natural killer (NK) cells) were evaluated in Arabian and Thoroughbred horses. Plasma glucose, leptin, IGF-1, insulin, and cytokines levels were measured on the longest day of the breeding season and on the shortest day of the nonbreeding season. Determination of lymphocyte subpopulations was performed by flow cytometry. Glucose and IL-2 levels, CD4:CD8 ratio, and NK cells showed variations that depended on the day length. Mean concentrations of plasma leptin were higher in Arabian horses than in Thoroughbred horses, whereas mean concentrations of IGF-1 and IL-2 were lower in Arabian horses. Day length-by-breed-by-gender interaction was found for insulin, IFN-γ, and IL-4 levels. An interaction was also found between day length and gender for the expressions of CD2, CD3, CD8, and CD19. Correlations were detected between expression of CD8+ cells and levels of TNF-α and IFN-γ and between percentages of NK cells and levels of IGF-1, insulin, and glucose. Results suggested that day length and, therefore, season are important determinants or factors in modulating the immune system and could affect lymphocyte subpopulations depending on the sex of the horse. Additionally, it seems that a complex relationship in horses, as in humans and mice, exists between the immune and metabolic system, which changes according to day length, breed, and gender.  相似文献   
8.
给出了当亲本间的数量性状的差异仅为1对基因时,该数量性状位点(QTL)与DNA限制性片段长度多态性(RFLP)标记位点连锁值测定的2个无偏估计量及其抽样方差,以及当亲本间数量性状为多基因差异时,分别地数量性状的加性效应、显性效应及加性显性混合效应与标记基因的连锁关系进行检验的3个统计量。最后对上述2个估计量和3个统计量的意义、应用范围及有关问题进行了讨论。  相似文献   
9.
The aim of the study was to evaluate the selected lymphocyte subpopulations TCD4, TCD8, BCD21, BCD25, CD18, CD11b, and MHC II in blood and uterine flush of cows with endometritis, before and after intrauterine (i.u.) administration of cefapirin and methisoprinol. The research was carried out on 28 cows with clinical endometritis. Animals were divided into four groups, each composed of seven cows, depending on the i.u. preparation used: Group A, cefapirin; Group B, methisoprinol; Group C, cefapirin and methisoprinol simultaneously; and a control group—without medication. The study was performed using flow cytometry method. Summarizing the results of the research, i.u. infusion of cefapirin caused a weakening of the effector phase of the local uterine immune response; however, it enhanced leukocyte chemotaxis and antigen presentation. After i.u. administration of methisoprinol, the stimulation of specific uterine immunity mechanisms was mainly observed. The use of both mentioned preparations showed the strengthening of specific uterine immunological mechanisms presumably caused by methisoprinol, despite the inhibitory effect of the antibiotic. Intrauterine use of immunostimulatory substances can improve the effectiveness of the endometritis treatment in cows by improving specific local mechanisms of uterine immunity. As a consequence, it may enhance the effector function of immune competent cells and finally eliminate inflammation.  相似文献   
10.
Genomic prediction (GP), which could predict the breeding value of crop plants genotyped with molecular markers, has been carried out in multiple species. Prediction accuracy (PA) of GP depends on various factors, including genetic relatedness and genetic basis. In this study, we examined the rationale for the low PA of GP when the training and validation populations were distinct using 170 temperate inbred lines and 210 tropical and subtropical inbred lines, respectively. All inbred lines were evaluated for 17 traits and genotyped with 550K high‐density markers. The results show that: (a) the influences of heritability and marker number on PA reflected variations in phenotypic variance captured by the genetic information; (b) the low PA of GP when the training and validation populations represent structured subpopulation is related to the ratio of subpopulation‐common alleles (RSCA) and the genetic relatedness between the two subpopulations; (c) RSCA and PA increased with the increase of genetic relatedness, suggesting that these three factors were related. Our findings would provide references when performing GP, and guidance when designing breeding populations.  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