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   366篇
  免费   20篇
林业   5篇
农学   9篇
基础科学   3篇
  18篇
综合类   59篇
农作物   10篇
水产渔业   5篇
畜牧兽医   263篇
园艺   4篇
植物保护   10篇
  2023年   3篇
  2021年   3篇
  2020年   4篇
  2019年   10篇
  2018年   5篇
  2017年   9篇
  2016年   3篇
  2015年   5篇
  2014年   6篇
  2013年   12篇
  2012年   14篇
  2011年   16篇
  2010年   7篇
  2009年   12篇
  2008年   12篇
  2007年   14篇
  2006年   26篇
  2005年   9篇
  2004年   19篇
  2003年   8篇
  2002年   17篇
  2001年   12篇
  2000年   18篇
  1999年   6篇
  1997年   4篇
  1992年   3篇
  1991年   4篇
  1990年   2篇
  1989年   6篇
  1988年   5篇
  1986年   10篇
  1985年   6篇
  1984年   4篇
  1982年   2篇
  1981年   4篇
  1980年   2篇
  1979年   3篇
  1978年   6篇
  1977年   6篇
  1976年   4篇
  1975年   4篇
  1974年   7篇
  1973年   2篇
  1972年   4篇
  1971年   3篇
  1970年   5篇
  1969年   5篇
  1968年   3篇
  1967年   5篇
  1966年   2篇
排序方式: 共有386条查询结果,搜索用时 15 毫秒
91.
A cross-sectional study evaluating potential risk factors for odontoclastic resorptive lesions (ORL) in feline teeth was conducted. Owners of 32 cats with ORL and 27 cats without ORL were interviewed regarding their respective cat's demographic characteristics, diet, and medical and dental histories. Four factors were identified as significantly associated with ORL using unconditional logistic regression. A history of dental disease (gingivitis, calculus, or periodontal disease; odds ratio [OR], 4.5); city residence (OR, 4.4); and being an exclusively indoor cat (OR, 4.5) were associated with an increased risk for ORL. Consumption of commercial treats (OR, 0.3) appeared protective for ORL.  相似文献   
92.
Infectious diarrhea in piglets can be caused by TGE, EVD and rota virus. The present report shows another viral agent (para-rota virus) to be present. In addition the report describes light and electronmicroscopic findings of the enteric mucosa caused by the agents mentioned. The degree and distribution of villous atrophy, one of the main histological findings, of infections with TGE, EVD, rota and para-rota virus is compared. A correlation of the results obtained with fluorescent antibody staining and ultrastructural diagnosis of agents was done. An application of the latter seems advisable in case of negative FA staining results.  相似文献   
93.
Objective: To determine endogenous serum insulin concentration in dogs with diabetic ketoacidosis (DKA), and to compare it to endogenous serum insulin concentration in diabetic dogs with ketonuria but no acidosis (KDM), diabetic dogs with uncomplicated diabetes mellitus (DM) that did not have ketonuria or acidosis, and dogs with non‐pancreatic disease (NP). Design: Prospective study. Setting: Veterinary Hospital of the University of Pennsylvania. Animals: Forty‐four client‐owned dogs; 20 dogs with newly diagnosed diabetes mellitus (7 dogs with DKA, 6 dogs with KDM, and 7 dogs with DM) and 24 dogs with non‐pancreatic disease. Interventions: Blood and urine samples were obtained at the time of admission to the hospital. Measurements and main results: Signalment, clinical signs, physical examination findings, and concurrent disease were recorded for all dogs. Blood glucose concentration, venous blood pH, venous blood HCO3? concentration, urinalysis, and endogenous serum insulin concentration were determined in all dogs. Dogs with DKA have significantly decreased endogenous serum insulin concentrations compared to dogs with DM (P = 0.03) and dogs with non‐pancreatic disease (P = 0.0002), but not compared to dogs with KDM (P = 0.2). Five of 7 dogs with DKA had detectable endogenous serum insulin concentrations, and 2 of these dogs had endogenous serum insulin concentration within the normal range. Conclusions: Diabetic dogs with ketoacidosis have significantly decreased endogenous serum insulin concentration compared to dogs with uncomplicated diabetes mellitus. However, most dogs with DKA have detectable endogenous serum insulin concentrations, and some dogs with DKA have endogenous serum insulin concentrations within the normal range.  相似文献   
94.
Thirty-three pigs in three groups of nineteen, ten, and four pigs were infected with three different African swine fever (ASF) virus isolates, respectively. All virus isolates were attenuated to varying degrees by passaging in cell cultures, and they retained sufficiently low virulence to produce subacute and chronic infections in pigs. Sera collected at various intervals were tested for antibody activity by the immunoelectroosmophoresis, agar gel diffusion precipitin, and complement-fixation tests using a modified Kolmer technique. Results clearly indicated that the immunoelectroosmophoresis test is a rapid (30 minute) and accurate method with extreme sensitivity and superior to the complement-fixation and agar gel diffusion precipitin tests in detecting antibody against ASF virus. Possible use of this method in detecting ASF virus infection is suggested.  相似文献   
95.
Rotavirus antibodies were demonstrated in lacteal secretions and sera of 20 parturient sows and in sera of their newborn by an enzyme-linked immunosorbent assay blocking technique, using bovine rotavirus cell culture antigen and monospecific antibody to bovine rotavirus. Antibodies to rotavirus occur in the 3 immunoglobulin (Ig) classes IgM, IgA, and IgG in lacteal secretions. High and long-persisting antibody activity was mainly associated with the IgA class. The IgM and IgG decreased to undetectable concentrations in most sows during the 14-day investigation period. Serum antibodies of newborn pigs nursing their dams also decreased rapidly during this time. The heterologous enzyme-linked immunosorbent assay blocking technique was a reliable and rapid procedure for the demonstration of rotavirus antibodies.  相似文献   
96.
Immunology of African swine fever   总被引:2,自引:0,他引:2  
  相似文献   
97.
98.
Wheat leaves (cv. Kormoran) floated on water and kept in darkness turned yellow. This induced senescence was accompanied by a loss of electrolytes and amino acids, and by disorganisation of all cellular organelles except cell walls. Treatment with a solution of carbendazim (20 μg ml?1) prevented the leakage of electrolytes and disorganisation of cell organelles. At 100 μg ml?1, the fungicide did not prevent the damage caused by senescence but stimulated the loss of electrolytes from the leaves. It is proposed that one of the major mechanisms of the antisenescent activity of carbendazim is its protective effect on membranes.  相似文献   
99.
Chronic pneumonia developed in 14 pigs inoculated with an attenuated strain of African swine fever (ASF) virus. The pathogenesis of the pneumonia was as follows: (1) Interalveolar septums became thickened by accumulation of lymphocytes and monocytes; (2) lung developed focal areas of lymphocytes and macrophages; (3) necrosis began abruptly in these foci, beginning with the cells in the alveolar lumens, developing in centrifugal direction, and eventually affecting all structures in its path; (4) necrotic tissue became calcified; and (5) a mantle of mononuclear cells (including plasma cells) and fibrous tissue formed around the necrotic area. Viremia occurred in the 14 pigs at postinoculation day (PID) 14, and precipitating antibody was increased significantly at PID 58.  相似文献   
100.
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