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   432篇
  免费   75篇
  国内免费   24篇
林业   4篇
农学   2篇
基础科学   1篇
  1篇
综合类   39篇
农作物   61篇
水产渔业   35篇
畜牧兽医   372篇
园艺   16篇
  2024年   3篇
  2023年   15篇
  2022年   29篇
  2021年   59篇
  2020年   36篇
  2019年   45篇
  2018年   25篇
  2017年   37篇
  2016年   29篇
  2015年   26篇
  2014年   25篇
  2013年   34篇
  2012年   18篇
  2011年   23篇
  2010年   16篇
  2009年   16篇
  2008年   5篇
  2007年   11篇
  2006年   10篇
  2005年   7篇
  2004年   9篇
  2003年   8篇
  2002年   2篇
  2001年   4篇
  2000年   5篇
  1999年   1篇
  1998年   3篇
  1997年   5篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   4篇
  1956年   1篇
排序方式: 共有531条查询结果,搜索用时 375 毫秒
61.
本试验旨在研究表达Ⅰ型耐热肠毒素(STa)的重组大肠杆菌诱发7日龄仔猪小肠炎症反应。选取24头7日龄健康仔猪,随机分为4个处理组:对照组(人工乳)、STa组(人工乳+2×10~9 CFU重组菌LMG194-pBAD-STa)、LMG194组(人工乳+2×10~9 CFU大肠杆菌LMG194)和K88组(人工乳+2×10~9 CFU大肠杆菌K88),每组6头。试验第5天进行攻毒,第7天屠宰取样,观察空肠组织形态学变化,并检测血清中炎性细胞因子含量及空肠免疫相关基因的相对表达量。结果显示,与对照组相比,STa与K88组仔猪空肠绒毛明显萎缩变短,有明显损伤甚至脱落;STa、LMG194及K88组血清中IL-10、IL-8和IL-6浓度均显著升高(P<0.05),LMG194和K88组血液和肠道iFABP浓度均显著降低(P<0.05),STa和K88组血清中TNF-α浓度显著降低、NF-κB浓度显著升高,LMG194组NF-κB浓度显著降低、TNF-α浓度显著升高(P<0.05);STa和LMG194组CCL2和CXCL9基因表达水平显著上调(P<0.05),VNN1基因表达水平显著下调(P<0.05),STa和LMG194组IFN-γ组基因水平分别显著上升和下降(P<0.05);K88组CXCL9和IFN-γ基因表达水平显著下调(P<0.05),VNN1基因表达水平显著上调(P>0.05),CCL2基因表达水平无明显差异(P>0.05)。以上结果表明,表达Ⅰ型耐热肠毒素STa的重组大肠杆菌几乎具有与K88一样的毒性,可导致7日龄仔猪小肠黏膜受损,诱发严重的炎症反应,导致仔猪腹泻,可作为仔猪腹泻模型的候选菌株。  相似文献   
62.
Aim: To compare the concentration of faecal cytokines interleukin (IL)-6, -8, -10, and tumour necrosis factor (TNF)-α in dogs with acute diarrhoea with clinically normal (non-diarrhoeic) dogs.

Methods: A total of 14 dogs presenting with acute diarrhoea, and 25 dogs with no history of gastrointestinal signs in the 2 months prior to enrolment, were recruited from two veterinary hospitals in Melbourne, Australia. Concentrations of IL-6, -8, -10, and TNF-α were measured in faecal samples using canine-specific ELISA.

Results: The diarrhoeic dogs were diagnosed with or managed for acute gastroenteritis (n?=?6), extra-intestinal neoplasia (n?=?2), parvoviral enteritis (n?=?1), hepatopathy (n?=?1), acute pancreatitis (n?=?1), hypoadrenocorticism (n?=?1), gastric dilatation volvulus (n?=?1) and myelopathy (n?=?1). IL-6 was detectable in the faeces of 10/14 (71%) diarrhoeic and 7/25 (28%) non-diarrhoeic dogs, and median concentrations were 10.8 (min 0.0, max?54.0) and 2.0 (min 0.0, max15.0) pg/mL, respectively (p?=?0.01). IL-8 was detectable in the faeces of all diarrhoeic and 11 non-diarrhoeic dogs, and median concentrations were 149.7 (min 3.72, max?730.1) and 3.4 (min 0.0, max?22.5)?pg/mL, respectively (p?<?0.001). TNF-α was detected in the faeces of two of the diarrhoeic dogs (3.4 and 15.6?pg/mL) and none of the non-diarrhoeic dogs. IL-10 was not detected in the faeces of any dog.

Conclusions: Faecal concentrations of IL-6 and -8 were higher in diarrhoeic compared to non-diarrhoeic dogs, and are therefore potential candidates for non-invasive biomarkers to assess the severity and resolution of acute intestinal disease in dogs. However their correlation with disease progression and severity needs to be further investigated before their full clinical application can be determined.  相似文献   

63.
64.
Tissue factor (TF), a cell surface-associated cofactor and activator of coagulation factor VII, has been implicated in the local and systemic activation of coagulation associated with sepsis. This study describes the pattern of TF expression in experimental bovine pneumonic pasteurellosis and endotoxemia. Immunohistochemical techniques were used to localize TF antigen in tissue sections. Tissue factor expression was not observed in tissues from control animals. In response to Pasteurella haemolytica challenge, TF was expressed within alveolar walls, by mononuclear inflammatory cells within alveoli, and in walls of arteries, arterioles, bronchi, and bronchioles. Tissue factor was not detected in unaffected lung, liver, spleen, lymph node or kidney tissue. Administration of Escherichia coli endotoxin intravenously resulted in tissue factor expression in lung, spleen, and lymph node tissue. Results of this study indicate that TF is expressed locally at sites of inflammation and systemically in endotoxemia. Therefore, TF may be involved in coagulation events associated with pneumonic pasteurellosis.  相似文献   
65.
抗菌肽抑制脂多糖诱导的炎症反应   总被引:1,自引:0,他引:1  
抗菌肽是一种对多重耐药菌株表现出特异性抗菌机制的小分子多肽。同时,抗菌肽还具有抗炎活性,可以通过直接中和脂多糖(LPS)、抑制生物性炎症因子的产生来减轻炎症反应;亦可通过趋化白细胞、促进免疫细胞增殖等来影响获得性免疫,从而调节宿主免疫系统发挥保护作用。本文综述了近年来LPS诱导炎症产生的机制及抗菌肽抑制LPS诱导炎症反应的作用机理。  相似文献   
66.
BACKGROUND: Sepsis is still a major cause of death in both human and veterinary medicine. Early diagnosis is essential for appropriate treatment. Identification of patients at risk for developing sepsis is already possible in human medicine through the measurement of plasma interleukin-6 (IL-6) levels. In veterinary medicine, however, this has been investigated only in canine experimental models. OBJECTIVES: The purpose of this study was to measure IL-6 plasma levels in dogs with naturally occurring systemic inflammatory response syndrome (SIRS) and sepsis and to analyze the value of IL-6 as a predictive parameter for severity and mortality. METHODS: Included in the study were 79 dogs that had been admitted to the small animal clinics of Munich and Berlin from July 2004 to July 2005 and that satisfied the diagnostic criteria for SIRS and sepsis as defined using established parameters. Measurement of plasma IL-6 levels on days 0, 1, and 2 was performed by the use of a colorimetric bioassay based on IL-6-dependent cell growth. RESULTS: Septic foci were identified in 43 patients (septic group), and 36 patients were enrolled in the SIRS group. The frequency of positive blood cultures was 11%. The overall mortality rate was 48%. Higher plasma IL-6 levels on the day of admission were significantly correlated with a more severe degree of disease, increased mortality rate, and earlier fatality. CONCLUSIONS: Plasma IL-6 concentration is predictive of outcome in canine SIRS and sepsis and may be a valuable laboratory parameter for assessing critically ill dogs.  相似文献   
67.
Histopathological lesions due to third‐larval stage of nematode Brevimulticaecum sp. within the liver of a subpopulation of 31 Gymnotus inaequilabiatus from the Pantanal Region (Brazil) were studied with histochemical and immunohistochemical methods. In 93.5% of fish, livers harboured nematode larvae and the intensity of infection ranged from 8 to 293. In livers with highest number of larvae, the hepatic tissue was occupied primarily by the nematodes. Each larva was encircled by focal inflammatory granulomatous reaction. Within the thickness of the granuloma, three concentric layers were recognized: an inner layer of densely packed epithelioid cells, a middle layer of mast cells (MCs) entrapped in a thin fibroblast‐connective mesh and an outer layer of fibrous connective tissue with fibroblasts. Epithelioid cells and fibroblasts within the thickness of the granuloma wall were positive for proliferative cell nuclear antigen (PCNA). Moreover, several hepatocytes in infected liver were immunoreactive to PCNA. Occurrence of rodlet cells and MCs in parenchyma, in close proximity to the encysted nematode larvae and near the blood vessel of infected liver, was observed. Macrophage aggregates (MAs) were numerous within the granulomas and scattered in parenchyma of the infected liver. High quantity of haemosiderin was encountered in MAs and hepatocytes of infected liver.  相似文献   
68.
Mycobacteriosis in fish is a chronic progressive ubiquitous disease caused by Mycobacterium marinum, M. gordonae and M. fortuitum in most cases. The aim of this study was to describe the morphology and distribution of lesions in 322 freshwater ornamental fish across 36 species. Granulomatous inflammation was diagnosed by gross examination and histopathology testing in 188 fish (58.4%); acid‐fast rods (AFR) were determined in only 96 (51.1%) fish from 19 species after Ziehl–Neelsen staining. The most often affected organs with AFR were the kidney (81.2%), digestive tract (54.1%), liver (48.2%), spleen (45.9%) and skin (21.2%); sporadically, AFR were found in the branchiae (9.4%) and gonads (4.7%). In 14 randomly selected fish originating from four different fish tanks, the distribution of mycobacterial infection was studied by culture examination of the skin, gills, muscle tissue, digestive tract, liver, spleen and kidney. In 12 fish, the species M. marinum, M. gordonae, M. fortuitum, M. triviale, and M. avium subsp. hominissuis (serotypes 6 and 8 and genotype IS901? and IS1245+) were detected; mixed infection caused by different mycobacterial species was documented in five of them.  相似文献   
69.
Vegetable oils (Vo) are an alternative to fish oil (Fo) in aquaculture feeds. This study aimed to evaluate the effect of dietary soybean oil (Vo diet), rich in linoleic acid, and of dietary fish oil (Fo diet) on the development of spinal deformities under bacterial lipopolysaccharide (LPS)‐induced chronic inflammation conditions in Atlantic salmon, Salmo salar L. Fish [25 g body weight (BW)] were fed the experimental diets for 99 days. On day 47 of feeding (40 g BW), fish were subjected to four experimental regimes: (i) intramuscular injections with LPS, (ii) sham‐injected phosphate‐buffered saline (PBS), (iii) intraperitoneally injected commercial oil adjuvant vaccine, or (iv) no treatment. The fish continued under a common feeding regime in sea water for 165 more days. Body weight was temporarily higher in the Vo group than in the Fo group prior to immunization and was also affected by the type of immunization. At the end of the trial, no differences were seen between the dietary groups. The overall prevalence of spinal deformities was approximately 14% at the end of the experiment. The Vo diet affected vertebral shape but did not induce spinal deformities. In groups injected with LPS and PBS, spinal deformities ranged between 21% and 38%, diet independent. Deformed vertebrae were located at or in proximity to the injection point. Assessment of inflammatory markers revealed high levels of plasma prostaglandin E2 (PGE2) in the Vo‐fed and LPS‐injected groups, suggesting an inflammatory response to LPS. Cyclooxigenase 2 (COX‐2) mRNA expression in bone was higher in fish fed Fo compared to Vo‐fed fish. Gene expression of immunoglobulin M (IgM) was up‐regulated in bone of all LPS‐injected groups irrespective of dietary oil. In conclusion, the study suggests that Vo is not a risk factor for the development of inflammation‐related spinal deformities. At the same time, we found evidence that localized injection‐related processes could trigger the development of vertebral body malformations.  相似文献   
70.
During the last decade, Piscine orthoreovirus was identified as the main causative agent of heart and skeletal muscle inflammation (HSMI) in Atlantic Salmon, Norway. A recent study showed that PRV-1 sequences from salmonid collected in North Atlantic Pacific Coast (NAPC) grouped separately from the Norwegian sequences found in Atlantic Salmon diagnosed with HSMI. Currently, the routine assay used to screen for PRV-1 in NAPC water and worldwide cannot differentiate between the two groups of PRV-1. Therefore, this study aimed at developing a real-time polymerase chain reaction (RT-qPCR) assay to target the PRV-1 genome segments specific for variants associated with HSMI. The assay was optimized and tested against 71 tissue samples collected from different regions including Norway, Chile and both coast of Canada and different hosts farmed Atlantic Salmon, wild Coho Salmon and escaped Atlantic Salmon collected in British Columbia, West Coast of Canada. This assay has the potential to be used for screening salmonids and non-salmonids that may carry PRV-1 potentially causing HSMI.  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