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   152264篇
  免费   7823篇
  国内免费   75篇
林业   8666篇
农学   5506篇
基础科学   933篇
  19243篇
综合类   25709篇
农作物   7342篇
水产渔业   8377篇
畜牧兽医   71313篇
园艺   2608篇
植物保护   10465篇
  2019年   1180篇
  2018年   4636篇
  2017年   4866篇
  2016年   3071篇
  2015年   1783篇
  2014年   2001篇
  2013年   5342篇
  2012年   4597篇
  2011年   6833篇
  2010年   5299篇
  2009年   4495篇
  2008年   5921篇
  2007年   6195篇
  2006年   4068篇
  2005年   3840篇
  2004年   3654篇
  2003年   3779篇
  2002年   3501篇
  2001年   4195篇
  2000年   4112篇
  1999年   3336篇
  1998年   1454篇
  1997年   1385篇
  1996年   1227篇
  1995年   1464篇
  1994年   1331篇
  1993年   1337篇
  1992年   2773篇
  1991年   2867篇
  1990年   2748篇
  1989年   2807篇
  1988年   2507篇
  1987年   2564篇
  1986年   2646篇
  1985年   2604篇
  1984年   2094篇
  1983年   1899篇
  1982年   1325篇
  1979年   1841篇
  1978年   1499篇
  1977年   1361篇
  1976年   1318篇
  1975年   1391篇
  1974年   1684篇
  1973年   1700篇
  1972年   1638篇
  1971年   1531篇
  1970年   1512篇
  1969年   1398篇
  1967年   1201篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
861.
862.
Treatment of sarcoptic mange in canadian cattle with ivermectin   总被引:1,自引:1,他引:0       下载免费PDF全文
In 1982, approximately 13,000 Canadian cattle were treated once for sarcoptic mange with ivermectin at a dose of 10 mg per 45.4 kg of body weight. The results showed 100% efficacy against Sarcoptes scabiei and other ectoparasites present. All cattle showed marked improvement in general condition with new hair growth and apparent weight gains by 31 days posttreatment. Surveillance of treated herds for a year following treatment showed that one parenteral treatment with ivermectin eradicated the disease from closed herds.  相似文献   
863.
A condition resembling chronic malignant catarrhal fever was seen in a 9-month-old pet sika hind (Cervus nippon). From an initial acute depression, pyrexia, and anorexia, the condition progressed to include hypopyon, keratitis, lethargy, loss of condition, sloughing of one hoof and eventually death after seven weeks. There were multiple, 5 to 8mm diameter dark-red nodules throughout the mesenteries and mediastinum, along abdominal organ ligaments, and about the uterus and kidneys. Histopathology showed the nodules to be organising vascular thrombi. Concurrent perivascular mononuclear infiltrations and intravascular thrombi in many tissues confirmed that the condition was malignant catarrhal fever.  相似文献   
864.
865.
866.
Lymphosarcoma in a six year old male Doberman pinscher was accompanied by hypercalcemia, generalized osteolysis and renal calcification. Tumor involvement of bone marrow was extensive. The possible pathogenesis of hypercalcemia was thought to be the result of a locally active bone-resorbing factor secreted by the tumor cells.  相似文献   
867.
Data obtained from faecal samples from 508 domestic cats and 481 dogs, previously found to have a high frequency of Sarcocystis spp. infections, were further examined to provide information on levels of sporocyst shedding and to ascertain the influence of host, environmental and seasonal factors on the prevalence of naturally acquired infections. Statistical analysis of prevalence data revealed that, of the factors examined, only host age in cats exerted any apparent influence. Infections were significantly more common in cats up to, rather than over, 6 months of age. Although they tended to be greater in dogs than cats, faecal sporocyst counts in both hosts were generally low, with the majority of infected samples containing 200 sporocysts per gram or less. In infected dogs the highest count recorded was 144,600/g with a mean of 2270/g, and in infected cats it was 11,100/g with a mean of 597/g.  相似文献   
868.
The occurrence of anthelmintic resistance in a field strain of Nematodirus spathiger is reported for the first time. In a controlled anthelmintic trial with naturally-acquired infections, oxfendazole at 5 mg/ kg and levamisole at 8 mg/kg were 0 and 86% effective respectively, against this strain.  相似文献   
869.
A cyst involving the gland of the 3rd eyelid was removed from an 8-year-old dog. Clinically the circumscribed mass resembled a pigmented neoplasm. Histologically the cyst was multiloculated, with homogeneous eosinophilic periodic acid-Schiff-positive content. Melanin pigment was present in epithelial cells and cystic lumens. Protective functions of the 3rd eyelid were retained following excisional biopsy.  相似文献   
870.
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