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   147篇
  免费   18篇
  国内免费   9篇
林业   6篇
农学   7篇
  2篇
综合类   33篇
农作物   4篇
水产渔业   4篇
畜牧兽医   109篇
园艺   1篇
植物保护   8篇
  2024年   1篇
  2023年   9篇
  2022年   7篇
  2021年   11篇
  2020年   5篇
  2019年   4篇
  2018年   7篇
  2017年   6篇
  2016年   6篇
  2015年   7篇
  2014年   5篇
  2013年   12篇
  2012年   6篇
  2011年   6篇
  2010年   6篇
  2009年   8篇
  2008年   6篇
  2007年   4篇
  2006年   3篇
  2005年   6篇
  2004年   7篇
  2003年   5篇
  2001年   5篇
  2000年   2篇
  1999年   3篇
  1998年   3篇
  1997年   4篇
  1995年   3篇
  1994年   3篇
  1993年   2篇
  1992年   2篇
  1991年   5篇
  1990年   1篇
  1989年   1篇
  1987年   2篇
  1975年   1篇
排序方式: 共有174条查询结果,搜索用时 0 毫秒
51.
Reason for performing the study: There are few published data regarding the success rates of cheek tooth (CT) removal by lateral buccotomy in the horse. Objectives: A retrospective study of 114 horses admitted to 2 private equine referral hospitals over a 10 year period (1999–2009), which underwent CT removal via a lateral buccotomy. Methods: Hospital records were analysed and details including case details, presenting complaint and results of all diagnostic tests and surgical reports were documented. Information obtained during post operative reassessment was also available for analysis. Long‐term follow‐up information (>2 months) was obtained for 112 horses. Results: Short‐term complications (<2 months) occurred in 24/77 horses (31%) undergoing exodontia of the maxillary CT and 10/37 horses (27%) involving mandibular CT, with the majority arising from partial wound dehiscence and infection following 16 extractions (47%). All healed well by second intention. Other complications included both temporary (n = 6) and permanent (n = 3) facial nerve paralysis, myositis (n = 4) and the inadvertent establishment of an oroantral fistula (n = 4). One myositis case was subjected to euthanasia 24 h post operatively. Five horses had persistent sinusitis following surgery due to dental remnants (n = 2) and excessive packing material (n = 1) found in the sinuses. No inciting cause could be found in the remaining 2 horses. One further horse suffered a fatal cardiac arrest at induction of anaesthesia. Of all horses, 92% operated on had returned to their previous level of work after >2 months with no complications. Conclusion: Horses with CT removal by a lateral buccotomy have a reasonable prognosis for long‐term outcome. Potential relevance: Performing a lateral buccotomy is a justified treatment alternative for the surgical removal of equine CT following unsuccessful attempts by standing oral extraction, offering advantages over alternatives such as retropulsion, endodontic therapy and periapical curettage.  相似文献   
52.
Groups of striped skunks (Mephitis mephitis) were inoculated intramuscularly with graded doses of street rabies virus. At various intervals after inoculation, saliva and sera were tested for rabies virus and neutralizing antibodies, respectively. Skunks that developed rabies were killed in terminal stages of the disease and the following examinations were made: titers of virus and antibody in submandibular salivary glands and brain, extent of immunofluorescence in submandibular salivary glands, and histologic examination of various tissues.

Skunks that received inocula containing 4 × 104 to 4 × 105 mouse intracerebral lethal dose50 (MICLD50) had detectable serum neutralizing antibodies by 7–12 days postinoculation; however, most of the skunks that received lower doses (40 to 4 × 103 MICLD50) did not have detectable serum neutralizing antibodies until clinical signs began. In the salivary glands, slight and extensive immunofluorescence corresponded to high and low titers of tissue neutralizing antibody. Also low viral titers were associated with high tissue neutralizing antibody titers. There was a close correlation between viral titers in right and left submandibular salivary glands.

The results suggest that the immune response can impede the process of infection of the salivary glands resulting in lack of antigen or low amounts of antigen in this tissue. This could occur through interference with centrifugal neural transport of virus and/or neutralization of virus during transfer from neural elements to epithelial cells. Lack of infectious virus or low viral titers in salivary glands containing antigen and high levels of tissue neutralizing antibodies can be caused partly by postmortem virus neutralization (during viral titration).  相似文献   

53.
对青海省海北州西海镇的30头黑白花奶牛和20头黄牛的唾液钠、钾含量进行了测定。结果表明:(1)黑白花奶牛唾钠为98.63mmol/L,唾液钾为16.87mmol/L, 钠/钾之比为6.68/1;(2)黄牛唾液钠为121.6mmol/L,唾液钾为16.41mmol/L,黄/钾之比为10.97/1;(3)黑白花奶牛和黄牛的唾液钠含量之间有显著性差异(P<0.05)。  相似文献   
54.
55.
为了探究夏季高温时皖东牛与荷斯坦牛皮肤组织形态和皮肤散热调节特征的差异,在30℃以上的夏日,选择皖东牛和荷斯坦牛母牛各4头,屠宰后采集颈部、肩部、背部、腹部、臀部和腿部6个部位的皮肤样本,通过HE染色切片分析皮肤的汗腺(SWG)与皮脂腺(SEG)的分布与形态,测定皮肤组织乙酰胆碱(ACh)浓度及乙酰胆碱转移酶(AChT)和酯酶(AChE)活力,采用RT-qPCR和Western blot检测皮肤组织乙酰胆碱M3受体(ACh M3R)、一氧化氮合酶(eNOs)及水通道蛋白5(AQP5)mRNA和蛋白的表达。结果:部位间比较,皖东牛与荷斯坦牛表皮厚度均为背部最厚,颈部最薄(P<0.05)。品种间比较,皖东牛平均皮肤厚度较高,平均表皮厚度较薄(P<0.05);汗腺密度与皮脂腺密度品种间无显著差异(P>0.05);皖东牛汗腺和皮脂腺的平均长度、直径、深度、体积均显著增加(P<0.05)。肩部、背部和臀部皮肤对比:夏季皖东牛和荷斯坦牛皮肤组织ACh浓度品种间无显著差异(P>0.05),部位间以臀部最高,肩部次之,背部最低(P<0.05)。ACh M3R和AQP...  相似文献   
56.
A 110-week-old male F344 rat from the high-dose group of a 104-week carcinogenicity study, exhibited a spontaneously occurring subcutaneous mass in the left axilla extending to the chest. Histologically, the mass was well-demarcated from the adjacent mammary tissue and slightly encapsulated without evidence of infiltration into the surrounding tissues. The mass contained both epithelial and adipose components. The epithelial component consisted of ductal structures of various sizes lined by a single layer of flattened to cuboidal epithelial cells with relatively clear or vacuolated cytoplasm. These ductal structures were well-intermingled with an adipose component that consisted of a uniform monomorphic cell population of mature adipocytes. Both cell types were well-differentiated and did not exhibit cellular atypia. Within the mass, fibrous connective tissue was found in the stroma with infiltration of numerous mast cells. Based on these findings, the mass was diagnosed as an adenolipoma of the mammary gland.  相似文献   
57.
本试验利用母猪行为以及唾液皮质醇和淀粉酶含量探索空间限制对母猪生理心理状态造成的影响。试验选择大白妊娠母猪64头,随机平均分成2组,分别采用限位栏(180 cm×60 cm×110 cm)和群养模式(568 cm×448 cm×50 cm)饲养,群养模式下每圈8头母猪,共4圈。于试验1、3、5、6、8、10、11、13、15周第1、2天分别采用10 min间隔扫描取样法记录母猪行为和采集试验母猪唾液样本,检测唾液皮质醇水平和唾液淀粉酶含量。结果表明:限位栏母猪表现无食咀嚼、啃栏、啃槽行为的次数显著高于群养母猪。限位栏母猪的唾液皮质醇和淀粉酶表现出相反的分泌趋势,无食咀嚼与唾液淀粉酶含量之间存在显著的正相关关系(r=0.336,P=0.048)。群养模式下试验母猪的唾液皮质醇水平、淀粉酶含量与无食咀嚼行为之间没有显著性相关的关系。  相似文献   
58.
刘宗才  白小玲  焦铸锦 《安徽农业科学》2013,(20):8817-8818,8823
通过半薄切片,研究了比克氏棉休眠种子内色素腺体的分布、发育状态。根据色素腺体的发育状态,分为不具分泌腔的色素腺体即"色素腺体原"以及具有分泌腔的色素腺体2种类型。不具分泌腔的色素腺体主要位于分化程度较低的胚轴、子叶顶端等组织部位。具有分泌腔的色素腺体主要分布在靠近子叶基部分化程度较高的组织部位。该研究验证了比克氏棉休眠种子内子叶和胚轴含有色素腺体,并首次发现子叶内部分色素腺体已发育出分泌腔。  相似文献   
59.
蜱的免疫预防是目前国内外研究的热点,以抗血清为探针筛选cDNA表达文库是获取功能抗原基因的有效的方法之一,为了获得抗长角血蜱免疫原基因,用兔抗长角血蜱血清和兔抗长角血蜱唾液腺蛋白血清对长角血蜱雌蜱唾液腺cDNA表达文库进行了免疫筛选,经过两轮筛选共获得34个阳性克隆,所得阳性噬菌体转染宿主菌BM25.8使之亚克隆为重组质粒,用此质粒转化宿主菌JM109并进行序列测定和生物信息学分析.结果表明:在长角血蜱雌蜱唾液腺cDNA表达文库中获得26个长角血蜱免疫相关cDNA序列,其编码蛋白与长角血蜱HL35、黏附素hlim3假定蛋白、热休克蛋白、NADH脱氢酶、钙网蛋白以及杂色花蜱和肩突硬蜱的二硫异构酶等具有同源性.所获阳性克隆为长角血蜱保护性抗原基因的筛选奠定了基础.  相似文献   
60.
为探讨摩杂一代水牛与广西沼泽型水牛生产性能的差异,对其肾上腺组织结构进行比较研究。结果表明:水牛两侧肾上腺的形状大小不同,不同个体同侧的形状也不同,其被膜可清晰地分为外环层和内纵层,且广西沼泽型水牛被膜比摩杂一代水牛厚。广西沼泽型水牛比摩杂一代水牛的肾上腺球状带细胞长轴长2.00~4.00μm,网状带细胞长轴长4.00~5.00μm、短轴长2.00~3.00μm。由于广西沼泽型水牛肾上腺的被膜、球状带和束状带均比摩杂一代水牛厚,且网状带细胞显著大于摩杂一代水牛。因此可以推断,广西沼泽型水牛在调节心脏的活动和血管压力、抵御冷应激、对抗药物毒副作用等方面均优于摩杂一代水牛。  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