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   4641篇
  免费   326篇
  国内免费   4篇
林业   373篇
农学   165篇
基础科学   28篇
  1193篇
综合类   400篇
农作物   188篇
水产渔业   366篇
畜牧兽医   1811篇
园艺   97篇
植物保护   350篇
  2023年   66篇
  2022年   46篇
  2021年   117篇
  2020年   129篇
  2019年   62篇
  2018年   144篇
  2017年   154篇
  2016年   189篇
  2015年   153篇
  2014年   199篇
  2013年   324篇
  2012年   388篇
  2011年   330篇
  2010年   160篇
  2009年   105篇
  2008年   286篇
  2007年   275篇
  2006年   270篇
  2005年   240篇
  2004年   213篇
  2003年   199篇
  2002年   163篇
  2001年   110篇
  2000年   92篇
  1999年   60篇
  1998年   29篇
  1997年   27篇
  1996年   19篇
  1995年   18篇
  1994年   20篇
  1993年   19篇
  1992年   23篇
  1991年   25篇
  1990年   21篇
  1989年   17篇
  1988年   15篇
  1987年   9篇
  1986年   12篇
  1985年   16篇
  1984年   11篇
  1983年   10篇
  1982年   9篇
  1981年   11篇
  1979年   11篇
  1978年   10篇
  1977年   12篇
  1976年   16篇
  1974年   10篇
  1971年   12篇
  1969年   10篇
排序方式: 共有4971条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
In this study, we evaluated the efficacy of monensin as a preventive therapy for porcine neonatal coccidiosis. Fifteen three-day-old piglets were given 50,000 sporulated oocysts of Isospora suis and eight of them received 15 mg/kg of monensin orally every other day. Seven piglets served as normal controls. Fecal samples were collected and checked for oocyst shedding. At 18 days of age, piglets were euthanized and necropsied.

The onset of clinical signs was delayed in the treated group, but all inoculated piglets displayed anorexia, soft stool, or diarrheic feces. Treated piglets shed large numbers of oocysts in their feces (up to 201,200 oocysts per gram of feces). All infected piglets had lesions of villous atrophy in the jejunum and most of them were in the late atrophic or villous regrowth stages.

The results of this study suggest that monensin does not prevent clinical signs, oocyst shedding, and intestinal lesions caused by I. suis in neonatal piglets.

  相似文献   
996.
997.
998.
Thirty resident horses at a boarding stable in Alberta were used to evaluate the relative efficacies of ivermectin, oxibendazole, and pyrantel pamoate in reducing fecal egg output in adult horses under routine management conditions during spring and early summer, and to more clearly define the duration of suppression of fecal egg production following anthelmintic treatment. Horses were blocked according to pretreatment egg counts and randomly assigned to one of three treatments: pyrantel pamoate at 6.6 mg/kg body weight; oxibendazole at 10 mg/kg body weight; or ivermectin at 200 μg/kg body weight. All treatments were administered orally as a paste on day 0.Fecal samples were collected for examination by the modified Wisconsin procedure before treatment, and then at 4-11 day intervals up to day 72.

Very few if any strongyle eggs were found in the feces of any horses up to day 35. On days 42, 50 and 57, the geometric mean egg count for the ivermectin group was significantly (p<0.05) lower than that for the oxibendazole or pyrantel pamoate groups. Based on a survival curve analysis of the data, the mean number of days for recurrence of eggs in the feces was significantly longer for the ivermectin group than for the oxibendazole and pyrantel pamoate groups.

Under conditions encountered in this study, the posttreatment interval to resumption of fecal egg out-put in horses treated with ivermectin was eight to nine weeks, compared with five to six weeks for horses treated with oxibendazole or pyrantel pamoate.

  相似文献   
999.
1000.
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