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   587篇
  免费   38篇
林业   18篇
农学   14篇
基础科学   1篇
  44篇
综合类   117篇
农作物   9篇
水产渔业   23篇
畜牧兽医   371篇
园艺   14篇
植物保护   14篇
  2022年   4篇
  2021年   6篇
  2019年   9篇
  2018年   5篇
  2017年   4篇
  2016年   13篇
  2014年   15篇
  2013年   25篇
  2012年   18篇
  2011年   16篇
  2010年   11篇
  2009年   11篇
  2008年   28篇
  2007年   29篇
  2006年   16篇
  2005年   17篇
  2004年   33篇
  2003年   12篇
  2002年   16篇
  2001年   20篇
  2000年   16篇
  1999年   10篇
  1998年   6篇
  1997年   7篇
  1995年   4篇
  1994年   5篇
  1992年   13篇
  1991年   19篇
  1990年   13篇
  1989年   11篇
  1988年   4篇
  1987年   10篇
  1986年   8篇
  1985年   17篇
  1984年   7篇
  1983年   8篇
  1980年   10篇
  1979年   8篇
  1978年   6篇
  1977年   7篇
  1975年   4篇
  1974年   12篇
  1973年   11篇
  1972年   5篇
  1971年   6篇
  1970年   6篇
  1969年   4篇
  1966年   4篇
  1942年   4篇
  1911年   4篇
排序方式: 共有625条查询结果,搜索用时 375 毫秒
71.
72.
73.
The prevalence of antibody titres to a range of 20 leptospira antigens in the serum of horses and ponies with no ophthalmic abnormalities and with ophthalmoscopic evidence of endogenous uveal inflammatory disease was determined using a microscopic agglutination technique. Titres against leptospira antigens were observed in 13 out of 138 (9.1 per cent) animals with no ophthalmic abnormalities, and in three out of 27 (11.1 per cent) animals with anterior uveitis. Serovar sejroe was common to all seropositive animals with anterior uveitis. The results show that leptospira infection is not a major factor in the aetiology of equine anterior uveitis in the UK, but suggests that the organism may be associated with some cases of recurrent anterior uveitis.  相似文献   
74.
A preliminary investigation of the blood levels of carbenicillin, after the administration of a single intramuscular injection, suggests that the tortoise's bladder may act as a reservoir of antibiotic that is available for resorption. This phenomenon could confound the establishment of a safe, effective dose regime for antibiotics, in tortoises, which are excreted in an unchanged active form in urine.  相似文献   
75.
Equine ehrlichial colitis (Potomac horse fever), a newly identified colitis of the horse, was first recognized in Maryland. In this report, we document occurrence of the disease in Pennsylvania, New Jersey, New York, Ohio, Idaho, and Connecticut. Enzootic areas were recognized by a characteristic pattern. Frequently there was a seasonal pattern and high prevalence of sporadic colitis in unstressed horses. The attack rate per farm generally was low. Horses on pasture, as well as those stabled, were affected. Clinical signs varied from fever and depression to severe diarrhea and laminitis. Occasionally horses developed profound ileus and severe colic. Diagnosis was based on detection of an increase or decrease in serum antibody titers to Ehrlichia risticii, using an indirect fluorescent antibody technique.  相似文献   
76.
77.
The concentrations of several post mortem aqueous humour chemical constituents were compared with ante mortem serum chemical values in the horse. Urea nitrogen and creatinine values in post mortem aqueous humour were good predictors of ante mortem serum values. Aqueous humour urea nitrogen increased only slightly and creatinine did not change significantly for up to 24 h after death. Formulae were derived for calculating estimated ante mortem serum urea nitrogen and creatinine from aqueous humour values obtained after death. These results from normal horses identify analytes that are accurate predictors of ante mortem serum values. Determination of post mortem aqueous humour urea nitrogen of creatinine may assist in interpretation of the functional significance of equivocal histological lesions in the kidney.  相似文献   
78.
The ceroid-lipofuscinoses are a group of inherited neurodegenerative diseases of humans and animals characterised by the accumulation of a fluorescent lipopigment in neurons and other cells within the body. Syndromes occurring in dogs are classified, on the basis of the age of onset and, to a lesser degree, the course of the disease, as prepubertal-protracted, early adult acute and adult onset. Clinical signs are generally those of progressive loss of vision, motor disturbances such as ataxia, tremors, seizures and proprioceptive deficits together with behavioural changes including loss of learned behaviour, fearfulness and aggression. The various syndromes can be expected to reflect different mutations, at least some of which affect the catabolism of subunit c of mitochondrial adenosine triphosphate (ATP) synthase. Confirmation of diagnosis depends on the demonstration of lipopigment in brain or skin biopsies by histochemistry, fluorescence or electron microscopy.  相似文献   
79.
The records of 3,952 equine patients presenting to the Veterinary Teaching Hospital at North Carolina State University College of Veterinary Medicine were evaluated to determine risk factors associated with thrombocytopenia. Of 2,346 horses from which a CBC was obtained, 35 (1.49%) were thrombocytopenic (platelet count < 75,000/μL). A reference population of 189 horses with normal platelet counts (75,000 to 300,000/μL) was also studied. Standardbred horses were at increased risk for thrombocytopenia. but age and gender were not identified as significant risk factors. Horses with infectious or inflammatory diseases were at increased risk for thrombocytopenia. The potential association of clinical and clinicopathologic factors with thrombocytopenia were assessed by reviewing a series of multiple logistic regression models. Clinical and clinicopathologic variables significantly associated with thrombocytopenia in the final model included increased PCV, increased band neutrophil count, increased total WBC, and decreased plasma protein concentration. Increased mature neutrophil count was associated with normal platelet counts. Thrombocytopenic horses were significantly more likely to die or be euthanized than were horses with normal platelet counts. J Vet Intern Med 1996;10:127–132. Copyright © 1996 by the American College of Veterinary Internal Medicine .  相似文献   
80.
This study was conducted to ascertain the effect of autoclaving, source of calcium and phosphate, vitamin D3 level and strain of turkey poults on the rachitogenic activity of isolated soybean protein (C‐1 protein‐Skidmore). One‐day‐old poults were fed purified diets of the glucose—C‐1 protein type. The diets contained calcium, phosphorus and vitamin D3 at levels equal to or greater than the National Research Council's (1960) recommendations. The findings demonstrate that USP hydrated dicalcium phosphate was more effective than food‐grade dicalcium phosphate in overcoming the rachitogenic activity of the C‐1 protein. Autoclaving the C‐1 protein for 80 min destroyed its rachitogenic activity: Vitamin D3 was also effective in reducing the rachitogenic effect of C‐1 protein. The Broad Breasted White strain proved to be more susceptible to the rachitogenic property of C‐1 protein than the Wrolstad Small White strain. Substituting USP hydrated dicalcium phosphate for food‐grade dicalcium phosphate, autoclaving the C‐1 protein or increasing the vitamin D3 level increased body weight gains and tibia ash values. The interactions which were shown to exist between source of calcium and phosphate × autoclaving, strain × autoclaving, and vitamin D3 level × strain demonstrate an interrelationship between these factors.  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