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   146957篇
  免费   8394篇
  国内免费   89篇
林业   5482篇
农学   4388篇
基础科学   1043篇
  17055篇
综合类   25695篇
农作物   5431篇
水产渔业   7502篇
畜牧兽医   76593篇
园艺   1815篇
植物保护   10436篇
  2018年   1838篇
  2017年   2044篇
  2016年   1903篇
  2015年   1669篇
  2014年   2032篇
  2013年   5481篇
  2012年   3901篇
  2011年   4896篇
  2010年   3043篇
  2009年   3036篇
  2008年   4796篇
  2007年   4598篇
  2006年   4443篇
  2005年   4143篇
  2004年   4038篇
  2003年   4025篇
  2002年   3937篇
  2001年   4716篇
  2000年   4555篇
  1999年   3700篇
  1998年   1470篇
  1997年   1491篇
  1996年   1403篇
  1995年   1761篇
  1994年   1589篇
  1993年   1506篇
  1992年   3161篇
  1991年   3289篇
  1990年   3331篇
  1989年   3331篇
  1988年   3058篇
  1987年   3136篇
  1986年   3229篇
  1985年   3095篇
  1984年   2611篇
  1983年   2312篇
  1982年   1576篇
  1981年   1474篇
  1980年   1427篇
  1979年   2317篇
  1978年   1912篇
  1977年   1627篇
  1976年   1444篇
  1975年   1541篇
  1974年   2074篇
  1973年   2086篇
  1972年   2053篇
  1971年   1818篇
  1970年   1712篇
  1969年   1572篇
排序方式: 共有10000条查询结果,搜索用时 775 毫秒
861.
A review of the literature on stringhalt in horses is presented, including the aetiology, clinical signs, pathology and treatment of this disease. Three New Zealand outbreaks of stringhalt are reported and discussed. The occurrence of these (and most previously reported outbreaks) in the late summer and autumn, and the association of the disease with various weeds, indicates a likely toxic aetiology.  相似文献   
862.
In response to farmer complaints about unfair penalties, for the presence of inhibitory substances in early lactation following the use of dry-cow antibiotic therapy, a two-part study was carried out to try and establish why these unexplained grades occur. A survey of instructions supplied with each of 13 registered dry-cow products suggested that the directions for drug use were in some cases inappropriate for long-acting antibiotics. A residue release study was conducted at the beginning of lactation following antibiotic therapy at various times during the dry period. The results showed, for the-three dry-cow preparations studied, that treatment during the dry period, especially within six weeks of calving, could lead to detectable residues in milk from treated quarters.  相似文献   
863.
864.
865.
866.
Pemphigus and pemphigoid are uncommon dermatological entities in domestic animals and of a presumed autoimmune nature. In one form or another, they have been reported in the dog, cat, horse and goat. Although these diseases are considered to be bullous dermatoses, the clinical presentation may vary from ulcerative to exfoliative to proliferative depending on the individual condition. Currently, four variants of pemphigus are recognized (vulgaris, vegetans, foliaceus, erythematosus) and two of pemphigoid (bullous, cicatricial) although cicatricial pemphigoid has not yet been conclusively demonstrated in animals. Diagnosis is based on history, clinical signs, histopathology and immunopathology. Therapy must be immunosuppressive to be effective and is palliative rather than curative.  相似文献   
867.
Reference ranges for five parameters of blood coagulation were established in clinically normal farmed fallow deer (Dama dama) and red deer (Cervus elaphus). Storage of plasma at -15 degrees C resulted in small increases in activated partial thromboplastin time (APTT) for both species, and in the one stage prothrombin time (OSPT) of fallow deer, between days 1 and 30. These times were then stable between days 30 and 60. The fibrinogen levels of fallow deer plasma showed a small apparent increase over 60 days. These storage artefacts were not of sufficient magnitude to preclude the use of such plasma for diagnostic purposes although they could limit its use in research. Levels of fibrin/fibrinogen degradation products (FDP) were not affected by storage at -15 degrees C. Rabbit brain thromboplastin appeared adequate for OSPT determination in both species. The activated clotting time (ACT) is recommended as a field test for screening the intrinsic and common pathways of blood coagulation in deer.  相似文献   
868.
869.
870.
An endoscopic survey was performed to assess arytenoid cartilage movement during quiet respiration in 48 Clydesdale horses. Physical characteristics which could influence the length of the recurrent laryngeal nerves were also recorded from these horses and the relationship of these characteristics to the presence of abnormal left arytenoid cartilage movements was assessed statistically. Some degree of abnormal arytenoid movement was observed in 50% of the animals over one year of age. No significant correlation between sex, age, estimated weight, height, or neck length could be found although affected animals were, on average, slightly taller, lighter and longer necked.  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