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   988篇
  免费   129篇
林业   27篇
农学   26篇
基础科学   3篇
  119篇
综合类   61篇
农作物   48篇
水产渔业   70篇
畜牧兽医   705篇
园艺   19篇
植物保护   39篇
  2021年   11篇
  2020年   15篇
  2019年   24篇
  2018年   21篇
  2017年   22篇
  2016年   33篇
  2015年   16篇
  2014年   34篇
  2013年   56篇
  2012年   48篇
  2011年   50篇
  2010年   25篇
  2009年   22篇
  2008年   44篇
  2007年   45篇
  2006年   32篇
  2005年   26篇
  2004年   47篇
  2003年   43篇
  2002年   39篇
  2001年   41篇
  2000年   33篇
  1999年   27篇
  1998年   15篇
  1995年   7篇
  1992年   10篇
  1991年   14篇
  1990年   16篇
  1989年   14篇
  1988年   13篇
  1987年   7篇
  1986年   14篇
  1985年   20篇
  1984年   10篇
  1983年   11篇
  1982年   7篇
  1981年   10篇
  1980年   7篇
  1979年   15篇
  1977年   7篇
  1976年   7篇
  1975年   11篇
  1974年   18篇
  1973年   13篇
  1972年   10篇
  1970年   7篇
  1969年   7篇
  1968年   8篇
  1967年   7篇
  1966年   10篇
排序方式: 共有1117条查询结果,搜索用时 15 毫秒
51.
Among the 57 monoclonal antibodies analyzed within the T-cell group of the Second International Swine CD Workshop, one mAb fell within cluster T14a that included the CD6 standard a38b2 (No. 175). The new mAb MIL8 (No. 082) and a38b2 both precipitated from activated T-cells a 150 kDa monomeric protein. Staining patterns on the various cell types were similar. There was no inhibition of binding of either mAb to peripheral blood T-cells with the opposite mAb. The new mAb, MIL8, reacts with a separate epitope on porcine wCD6.  相似文献   
52.
Based on an analysis of their reactivity with porcine peripheral blood lymphocytes (PBL), only three of the 57 mAbs assigned to the T cell/activation marker group were grouped into cluster T9 along with the two wCD8 workshop standard mAbs 76-2-11 (CD8a) and 11/295/33 (CD8b). Their placement was verified through the use of two-color cytofluorometry which established that all three mAbs (STH101, #090; UCP1H12-2, #139; and PG164A, #051) bind exclusively to CD8+ cells. Moreover, like the CD8 standard mAbs, these three mAbs reacted with two proteins with a MW of 33 and 35 kDa from lymphocyte lysates and were, thus, given the wCD8 designation. Because the mAb STH101 inhibited the binding of mAb 76-2-11 but not of 11/295/33, it was given the wCD8a designation. The reactivity of the other two new mAbs in the T9 cluster with the various subsets of CD8+ lymphocytes were distinct from that of the other members in this cluster including the standards. Although the characteristic porcine CD8 staining pattern consisting of CD8low and CD8high cells was obtained with the mAb UCP1H12-2, a wider gap between the fluorescence intensity of the CD8low and CD8high lymphocytes was observed. In contrast, the mAb PG164A, not only exclusively reacted with CD4/CD8high lymphocytes, but it also failed to recognize CD4/CD8 double positive lymphocytes. It was concluded that this mAb is specific for a previously unrecognized CD8 epitope, and was, thus, given the wCD8c designation. A very similar reactivity pattern to that of PG164A was observed for two other mAbs (STH106, #094; and SwNL554.1, #009). Although these two mAbs were not originally positioned in the T cell subgroup because of their reactivity and their ability to inhibit the binding of PG164A, they were given the wCD8c designation. Overall, five new wCD8 mAbs were identified. Although the molecular basis for the differences in PBL recognition by these mAbs is not yet understood, they will be important in defining the role of CD8+ lymphocyte subsets in health and disease.  相似文献   
53.
Among the 57 monoclonal antibodies (mAb) analyzed within the T-cell group from the Second Swine CD Workshop, six mAb fell within clusters T10 and T11 (No. 088, STH164; No. 148, FY1A3; No. 149, FY2C1; No. 150, FY1H2; No. 151, FY2A11; No. 169, BB23-8E6). The mAb within these two groups gave a similar appearance on flow cytometry and stained all peripheral blood T-cells as defined by CD4 and wCD8 staining. All six mAb precipitated a 24 kDa protein. On the basis of inhibition analyses performed as part of the workshop and from published data, the mAb define at least three epitopes. There is only minimal stimulation of resting peripheral lymphocytes, but four of the mAb produce strong stimulation in the presence of PMA. With the exception of STH164, all have been shown to react with CD3-transfected COS cells. The new mAb, therefore, react with three epitopes on porcine CD3 designated CD3a (BB23-8E6, FY2A11), CD3b (FY1A3, FY2C1), and CD3c (FY1H2). mAb STH164 appears to be reactive with another epitope, however, since its reactivity with CD3 has not been confirmed it is designated as wCD3.  相似文献   
54.
The severity of lymphoproliferative disease associated with malignant catarrhal fever was extremely variable among 25 animals at the San Diego Wild Animal Park. Severe lymphoproliferative disease was seen in 3 of 10 Formosan Sika deer (Cervus nippon taiouanus), 3 of 6 Indian Axis deer (Cervus a axis), 3 of 6 Barasingha deer (Cervus d duvauceli), and 1 of 3 Nilgai (Boselaphus tragocamelus). Two Sika deer and 2 Barasingha deer had lesions morphologically indistinguishable from lymphosarcoma. Our findings were consistent with the hypothesis that alcelaphine herpesvirus-1 has oncogenic potential.  相似文献   
55.
56.
57.
An enzyme immunoassay that utilizes antigen bound to a matrix which can be removed from the substrate to stop development is described. The assay which is performed in glass or plastic disposable tubes uses Gel-Bond film strips for attachment of antigen. The only equipment requirements are a rotary shaker and a spectrophotometer (optional). The antigen coated strips are passed through a series of tubes containing test serum, wash solution, antibody-enzyme conjugate, wash solution and substrate-chromogen taking about 45 minutes to perform. In testing sera with or without antibody to Brucella abortus a very high correlation existed between same day tests and tests performed over several days as well as with data on the same sera obtained by an enzyme immunoassay in a microtiter format.  相似文献   
58.
Immunity obtained by vaccination with Haemophilus pleuropneumoniae is type specific and protection will only be obtained against the serotype contained in the vaccine. Serotype 8 is closely related to serotypes 3 and 6 and the objective of the present study was therefore to examine if cross immunity between the three serotypes could be obtained at vaccination.  相似文献   
59.
60.
1. Observations of vigorous wing movements and measurements of bone strength were compared in two experiments with birds in three different housing systems: a semi-intensive alternative system under development, a battery cage system and a deep-litter system. 2. A significant effect of housing system on the frequency of vigorous wing movements was found. The highest frequency was seen in the deep-litter system, about half this number in the alternative system, while in the battery cages they were never observed. 3. Corresponding to this a reduction in humerus strength of 9% was found in hens from the alternative system and of 45% in hens from cages, compared with deep-litter. A reduction in tibial breaking strength was also found in caged hens, when compared to deep-litter hens. 4. Keeping hens in cages thus restricts their movements, especially wing movements, to the degree that bone strength is greatly reduced. 5. This has welfare implications, for hens with low bone breaking strength risk a possibility of breakage, especially when handled and transported. When alternative systems are designed opportunities for movement in the three dimensions should be considered.  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