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   323758篇
  免费   17875篇
  国内免费   690篇
林业   24829篇
农学   14329篇
基础科学   3020篇
  47646篇
综合类   42943篇
农作物   17694篇
水产渔业   18522篇
畜牧兽医   140598篇
园艺   6552篇
植物保护   26190篇
  2019年   3775篇
  2018年   4516篇
  2017年   4954篇
  2016年   5197篇
  2015年   4593篇
  2014年   5956篇
  2013年   16654篇
  2012年   8313篇
  2011年   10779篇
  2010年   8240篇
  2009年   8595篇
  2008年   10061篇
  2007年   9174篇
  2006年   9573篇
  2005年   8663篇
  2004年   8489篇
  2003年   8279篇
  2002年   7667篇
  2001年   8942篇
  2000年   8561篇
  1999年   7443篇
  1998年   4447篇
  1997年   4495篇
  1996年   4210篇
  1995年   4845篇
  1994年   4306篇
  1993年   3974篇
  1992年   6062篇
  1991年   6272篇
  1990年   6115篇
  1989年   6051篇
  1988年   5433篇
  1987年   5513篇
  1986年   5509篇
  1985年   5634篇
  1984年   4977篇
  1983年   4536篇
  1982年   3544篇
  1981年   3349篇
  1980年   3282篇
  1979年   4443篇
  1978年   3857篇
  1977年   3426篇
  1976年   3157篇
  1975年   3195篇
  1974年   3776篇
  1973年   3766篇
  1972年   3493篇
  1971年   3330篇
  1970年   3196篇
排序方式: 共有10000条查询结果,搜索用时 22 毫秒
991.
992.
Bacterial isolations were reviewed from equine trachea, guttural pouch, uterus, wounds, abscesses, blood, synovial fluid, and abdominal fluid submitted to the Clinical Bacteriology Laboratory of the School of Veterinary Medicine at the University of Montreal for aerobic bacterial culture from 1986 to 1988. Of the 733 samples submitted, 324 (44%) were positive for bacterial growth, and 233 antimicrobial sensitivity tests were performed. Seventy-six percent of all positive samples yielded one bacterial species and two were isolated from 22% of positive samples. Streptococcus zooepidemicus, Escherichia coli, and Actinobacillus spp. were isolated from 39%, 18%, and 15% of the samples, respectively.

Bacterial growth was most common from guttural pouches, wounds and abscesses, and transtracheal washes (TTW), but was less common from uterus, blood, abdominal fluid, and synovial fluids. Streptococcus zooepidemicus was the most common bacterium recovered from guttural pouches, TTW, uterus, and wounds and abscesses. Escherichia coli predominated in abdominal fluids, blood, and synovia. Bacterial sensitivities to common antimicrobials are presented.

  相似文献   
993.
A complicated, segmented fracture of the femoral diaphysis in a dog is presented. Complications arose from multiple surgeries and subsequent osteomyelitis. Repair was staged by firstly removing all implants, secondly treating the osteomyelitis with appropriate antibiotics while spanning the cortical-deficient fracture site with a Kirschner external fixator, and finally rigid fixation of the fracture with incorporation of an ethylene oxide-sterilised intercalary cortical allo-implant. Principles of bone grafting are reviewed.  相似文献   
994.
995.
A 90-day finishing trial involving 144 feedlot heifers was conducted to compare the performance parameters and carcass characteristics of open heifers, therapeutically aborted heifers, and pregnant heifers. In the first 28 days of the trial, the aborted heifers had reduced (p < 0.05) feed intake (FI), average daily gain (ADG), and feed efficiency (FE) compared to pregnant and open heifers. Over the entire trial, on a live weight basis, the aborted group had reduced (p < 0.05) final weight, ADG, and FE compared to pregnant and open heifers. However, when the data were adjusted for total uterine weight, the aborted and open heifers had improved (p < 0.05) final weight, ADG, and FE compared to pregnant heifers. The aborted and open group had a higher (p < 0.05) carcass weight, rib eye area, dressing percentage, and cutability estimate compared to the pregnant heifers. The aborted group had lower (p < 0.05) carcass weight than the open heifers. Over the entire 90-day feeding period, there were no statistically significant differences among the groups with respect to feed intake (FI), average fat, grade fat, and carcass grades. Also, there were no significant health problems or mortality in any of the groups.

In the economic analysis, aborted heifers returned $26.41 per head more than pregnant heifers. Open heifers returned $39.94 per head more than aborted heifers, and $66.35 more than pregnant heifers. Thus, aborting feedlot heifers during the second trimester was determined to be a safe and cost effective management decision.

  相似文献   
996.
997.
Regulatory authorities are facing increasing challenges with respect to the newly-recognised public health risks associated with meat products. Meat inspection resources should be allocated according to their maximum ability to reduce food-borne hazards, rather than according to the classical rules of meat inspection. Scientific evaluation of routine post-mortem inspection procedures for each class of livestock, introduction of the Hazard Analysis Critical Control Point approach to process control, on-line testing for microbiological hazards and residues, and effective management of production, processing and inspection data are central to this process. The meat inspection system that has evolved in New Zealand reflects a response to non-scientific forces such as market requirements and industrial practices rather than scientific discipline. In the future, the daily routine of meat inspectors will be extended well beyond their current slaughterfloor responsibilities, and veterinarians will require specialist skills. Science should be the basis for international food regulation and policy concepts such as equivalence or mutual acceptance are achievable on this basis.  相似文献   
998.
An adrenal tumour was diagnosed in a 12-year-old female cross-bred terrier. The dog was presented to the veterinary clinic because she had been gaining weight and had started urinating in the owners' house. Clinical findings included obesity, abdominal enlargement, thinning of the hair coat, seborrhoea sicca, and polydipsia and polyuria. The diagnosis was made by clinical pathology, endocrine function tests and abdominal radiography. Surgical removal of the neoplastic right adrenal gland resulted in resolution of the clinical signs, including regrowth of the hair coat.  相似文献   
999.
1000.
Guidelines for euthanasia of domestic animals by firearms   总被引:2,自引:2,他引:0       下载免费PDF全文
All animals that are to be killed, whether for food, for humane reasons, or because they are homeless, must receive a quick and painless death. In some smaller communities, veterinary or humane society expertise may not be readily available to humanely kill stray and unwanted animals. An alternative that provides for a humane death for the animal is by shooting. The following guidelines are intended to assist persons who must perform this usually distasteful task; they contain recommended techniques that will help to ensure that any animals killed by shooting will die in a humane way.  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