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   271篇
  免费   6篇
  国内免费   3篇
林业   78篇
农学   7篇
基础科学   1篇
  56篇
综合类   23篇
农作物   6篇
水产渔业   6篇
畜牧兽医   66篇
园艺   7篇
植物保护   30篇
  2020年   2篇
  2019年   3篇
  2018年   3篇
  2016年   6篇
  2015年   4篇
  2014年   7篇
  2013年   16篇
  2012年   22篇
  2011年   10篇
  2010年   3篇
  2009年   4篇
  2008年   18篇
  2007年   8篇
  2006年   13篇
  2005年   14篇
  2004年   10篇
  2003年   6篇
  2002年   5篇
  2001年   6篇
  2000年   6篇
  1999年   5篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1987年   2篇
  1976年   2篇
  1973年   2篇
  1968年   2篇
  1950年   2篇
  1938年   5篇
  1936年   4篇
  1933年   3篇
  1932年   1篇
  1931年   2篇
  1930年   4篇
  1928年   4篇
  1926年   4篇
  1925年   8篇
  1924年   4篇
  1923年   2篇
  1922年   3篇
  1921年   9篇
  1920年   2篇
  1918年   8篇
  1909年   3篇
  1906年   1篇
  1857年   1篇
排序方式: 共有280条查询结果,搜索用时 15 毫秒
121.
122.
123.
Pruritic skin diseases are common in cats and demand rigorous diagnostic workup for finding an underlying etiology. Measurement of a serum allergen-specific IgE in a pruritic cat is often used to make or confirm the diagnosis of a skin hypersensitivity disease, although current evidence suggests that elevated allergen-specific IgE do not always correlate with a clinical disease and vice versa. The aim of the study was to to assess the possible influence of age, deworming status, lifestyle, flea treatment, and gender on allergen-specific IgE levels and to evaluate the reliability of IgE testing in predicting the final diagnosis of a pruritic cat. For this purpose sera of 179 cats with pruritus of different causes and 20 healthy cats were evaluated for allergen-specific IgE against environmental, food and flea allergens using the Fc-epsilon receptor based enzyme-linked immunosorbent assay (ELISA) test. The results of the study showed positive correlation between age, outdoor life style, absence of deworming, absence of flea control measures and levels of allergen-specific IgE. Gender and living area (urban versus rural) did not seem to affect the formation of allergen-specific IgE. According to these findings, evaluating allergen-specific IgE levels, is not a reliable test to diagnose hypersensitivity to food or environmental allergens in cats. On the contrary, this test can be successfully used for diagnosing feline flea bite hypersensitivity.  相似文献   
124.
125.
In vitro generated monocyte-derived dendritic cells (moDCs) have frequently been used to study the influence of porcine reproductive and respiratory syndrome virus (PRRSV) infection on antigen presenting cells. However, obtained results have often been conflicting in regard to expression of co-stimulatory molecules and interaction with T cells. In this study we performed a detailed phenotypic characterisation of PRRSV-infected moDCs and non-infected moDCs. For CD163 and CD169, which are involved in PRRSV-entry into host cells, our results show that prior to infection porcine moDCs express high levels of CD163 but only very low levels for CD169. Following infection with either PRRSV-1 or PRRSV-2 strains after 24 h, PRRSV-nucleoprotein (N-protein)+ and N-protein moDCs derived from the same microculture were analyzed for expression of swine leukocyte antigen-DR (SLA-DR) and CD80/86. N-protein+ moDCs consistently expressed higher levels of SLA-DR and CD80/86 compared to N-protein moDCs. We also investigated the influence of PRRSV-infected moDCs on proliferation and frequency of Foxp3+ regulatory T cells present within CD4+ T cells in in vitro co-cultures. Neither CD3-stimulated nor unstimulated CD4+ T cells showed differences in regard to proliferation and frequency of Foxp3+ T cells following co-cultivation with either PRRSV-1 or PRRSV-2 infected moDCs. Our results suggest that a more detailed characterisation of PRRSV-infected moDCs will lead to more consistent results across different laboratories and PRRSV strains as indicated by the major differences in SLA-DR and CD80/86 expression between PRRSV-infected and non-infected moDCs present in the same microculture.  相似文献   
126.
127.
A 4-year-old female guinea pig was presented with pruritic, erythematous, hypotrichotic and scaling skin lesions, mainly involving the abdomen and the hindlegs. Clinical abnormalities were limited to the skin, and the guinea pig was otherwise healthy. The dermatological diagnostic work-up excluded ectoparasites, dermatophytosis and an endocrinopathy as differential diagnoses for the pruritus and hair loss. An allergic dermatitis was under investigation when the general and skin condition deteriorated. A neoplastic skin disorder was suspected, and skin biopsies revealed changes consistent with a cutaneous epitheliotropic T-cell lymphoma. Pautrier's microabscesses and immunophenotyped CD3(+) CD79(-) lymphocytes were identified. Owing to the deteriorating condition of the animal and the unknown but most likely poor prognosis of this disease, the guinea pig was euthanized. To the authors' knowledge, this is the first case report of cutaneous epitheliotropic T-cell lymphoma in the guinea pig with characteristic histopathological and immunohistochemical features.  相似文献   
128.
The aim of this study was to investigate the tissue distribution of two different field isolates and two vaccine strains of porcine parvoviruses (PPV) in infected piglets after transplacental infection. The viral load in 10 different foetal organs was determined by real-time polymerase chain reaction assays with SYBR Green targeting the viral VP2 gene and the genomic c-myc gene in 12 foetuses. The viral load in foetal tissues differed greatly among the different parvoviruses. Between one virulent field isolate compared with the other field isolate and the vaccine strains, the detected viral copy number differed in an order of magnitude of 10(9). The virulent isolate contained PPV in all 10 organs with viral loads varying between 10(11) and 10(15) per 10(6) cells. Concerning the other field isolate and the two vaccine strains, if PPV was detected, in most of the cases the highest viral load was found in foetal kidneys with a maximum viral load of 10(3) per 10(6) cells. Additionally, PPV was found in the heart of one foetus, in the liver and duodenum of one foetus and in the thymus of one foetus with viral loads varying between 10(2.1) and 10(3.5) per 10(6) cells. In completely mummified foetuses with no discriminable organs of foetuses infected with the vaccine strains and the less virulent isolate, PPV was present in very low amounts or even below the detection limit.  相似文献   
129.
Journal of Plant Diseases and Protection - An isolate of plum pox virus (PPV) was detected in sour cherry (Prunus cerasus) in the Eastern region of Germany. Symptoms observed on infected sour...  相似文献   
130.
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