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   749篇
  免费   57篇
林业   16篇
农学   23篇
基础科学   3篇
  52篇
综合类   146篇
农作物   20篇
水产渔业   35篇
畜牧兽医   478篇
园艺   5篇
植物保护   28篇
  2023年   5篇
  2021年   5篇
  2020年   7篇
  2019年   12篇
  2018年   14篇
  2017年   6篇
  2016年   12篇
  2015年   9篇
  2014年   9篇
  2013年   40篇
  2012年   16篇
  2011年   21篇
  2010年   25篇
  2009年   19篇
  2008年   15篇
  2007年   32篇
  2006年   34篇
  2005年   34篇
  2004年   21篇
  2003年   23篇
  2002年   27篇
  2001年   24篇
  2000年   19篇
  1999年   21篇
  1998年   26篇
  1997年   10篇
  1996年   10篇
  1995年   10篇
  1994年   6篇
  1993年   9篇
  1992年   26篇
  1991年   19篇
  1990年   16篇
  1989年   17篇
  1988年   18篇
  1987年   14篇
  1986年   7篇
  1985年   14篇
  1984年   5篇
  1983年   5篇
  1980年   5篇
  1979年   9篇
  1977年   9篇
  1976年   6篇
  1973年   6篇
  1971年   10篇
  1970年   4篇
  1969年   5篇
  1914年   4篇
  1902年   4篇
排序方式: 共有806条查询结果,搜索用时 234 毫秒
1.
2.
3.
The behavioural and sedative effects of intravenous (iv) romifidine (40 and 80 μg/kg bodyweight [bwt]) alone or in combination with iv butorphanol (50 μg/kg bwt) were investigated in four ponies and one Thoroughbred horse. Apparent sedation, as judged by the lowering of the head, and by the response to imposed touch, visual and sound stimuli was assessed. The combination with butorphanol reduced the animals' response to imposed stimuli when compared with the effect of the same dose of romifidine alone. Following the administration of romifidine/butorphanol combinations muzzle tremor was noted and some animals attempted to walk forward. In a separate series, the cardiopulmonary effects of iv romifidine (80 μg/kg bwt) alone, or in combination with butorphanol (50 μg/kg bwt) were investigated. Romifidine and the romifidine/butorphanol combination caused similar cardiovascular changes, these being bradycardia with heart block, and hypertension followed by hypotension. Romifidine caused a transient decrease in arterial oxygen tensions and arterial carbon dioxide tensions had increased significantly by the end of the 90 min recording period. Romifidine/butorphanol combinations produced significantly higher arterial carbon dioxide tensions during the first 15 mins after drug administration than did romifidine alone. Butorphanol at 50 μg/kg bwt iv reduced the response to imposed stimuli in horses sedated with romifidine. The combination produced no cardiovascular changes beyond those induced by romifidine alone, but did increase the degree of respiratory depression.  相似文献   
4.
5.
6.
7.
8.
9.
Abstract Sir, - Andrews'((2)) checklist of helminth parasites of wild ruminants in New Zealand recorded the presence of 10 species of gastrointestinal nematodes in chamois (Rupicapra rupicapra rupicapra L.) from "Central South Island". In October 1978 we examined 28 freshly-shot chamois cadavers from the Harper-Avoca watershed in the headwaters of the Rakaia River. Six of the nematode species reported by Andrews were found again; viz. Ostertagia ostertagi, O. circumcincta, O. trifurcata, Nematodirus filicollis, Oesophagostomum venulosum and Trichuris ovis. The 4 species found by Andrews that were not recovered by us from the animals we examined were: Trichostrongylus axei, T. vitrinus, Spiculotragia spiculoptera and S. asymmetrica. On the other hand we found 4 helminths not encountered by Andrews: 3 nematodes: Nematodirus spathiger (Railliet, 1896), N. abnormalis (May, 1920), and Chabertia ovina (Fabricius, 1794), and 7 specimens of the cestode Moniezia expansa (Rud., 1805). Nematodirus spathiger was the most commonly encountered Nematodirus species, but generally the numbers of all 3 species encountered were low as might be expected in a sample of adult and almost year-old animals. It is probable that most of the adults had acquired some measure of immunity((3)), and the most susceptible group, the kids, would not be born until late November. Because peptic digestion was not used to recover juveniles from the intestinal submucosa, only small numbers of adults were obtained.  相似文献   
10.
Feline ureteral obstructions are an increasingly recognised and challenging diagnostic and management problem. Many cats with ureteral obstructions are critically ill at the time of diagnosis, especially if there is dysfunction of the contralateral kidney. They may present with varying severities of acute kidney injury, electrolyte disturbances, and may have comorbidities such as heart disease that complicate perioperative and long‐term management. Medical management, which may consist of rehydration and restoration of intravascular volume with intravenous fluid therapy, osmotic diuresis, ureteral muscle relaxation, and antimicrobials for infection, is important in feline ureteral obstruction patients. Despite medical management, many cats with ureteral obstructions will require decompression of the obstructed kidney to relieve pressure‐nephropathy and restore urine flow. However, some cats may be too unstable for traditional medical management and require more emergent intervention to relieve the obstruction and address the life‐threatening sequelae to acute kidney injury, such as hyperkalaemia and fluid overload. Both surgical and interventional methods to address ureteral obstructions have been described in veterinary medicine, though debate continues as to the ideal approach.  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