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   23篇
  免费   2篇
林业   1篇
基础科学   2篇
  1篇
综合类   4篇
农作物   1篇
畜牧兽医   14篇
园艺   1篇
植物保护   1篇
  2016年   2篇
  2014年   1篇
  2013年   3篇
  2011年   1篇
  2010年   1篇
  1999年   1篇
  1998年   3篇
  1997年   1篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1990年   1篇
  1989年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
排序方式: 共有25条查询结果,搜索用时 31 毫秒
1.
2.
Livestock is one of the growth sectors in the rural economy. In the third world the provision of livestock services for smallholders has generally been in the hands of the governments, leading to erratic, insufficient, and unreliable delivery systems. Especially in cases where the benefits of services accrue to the owners of the animals, privatization of some of the animal services may improve the delivery system. In order to explore the impact of such a private system, a group of sheep farmers in North Sumatra, Indonesia, were organized in an Animal Health Delivery Network (AHDN). The experience with AHDN indicates that the scope of private sector involvement is promising. Farmers were able to recognize the benefits and willing to pay for the drugs. However, they seem to be reluctant to apply the drugs themselves, thereby relying on the help of extension agents and traders. Selling drugs via poultry shops to farmers was not successful because drug wholesaler firms do not make their products available in small quantities. The study confirmed that the role of Government and private sector in the delivery of livestock services needs to be redefined.The authors are all members of the Small Ruminant Collaboration Research Support Program's (SR-CRSP) Economics Project being implemented by Winrock International Institute for Agricultural Development (WI) in the United States and the Center of Research Institutes for Animal Sciences (CRIAS) in Indonesia. Kartamulia was resident scientist at the Animal Research Station in Sei Putih, North Sumatra for the duration of this study under a collaboration agreement with INI ANSREDEF, an Indonesian NGO supporting livestock research and development. Misniwaty is a member of the socioeconomic group at the same station and staff of the Agency of Agricultural Research and Development (AARD). Knipscheer is Winrock's Regional Director for Asia and based in Morrilton, Arkansas.  相似文献   
3.
Disease of geese caused by a new herpesvirus   总被引:3,自引:0,他引:3  
A goose flock farmed outdoors in south-eastern Queensland suffered an outbreak of peracute disease with high death rate (97%). Small button ulcers and large plaques overlying lymphocyte aggregates were present on the mucosa of the small intestine of affected birds. Small white foci of necrosis and focal haemorrhages were seen in the livers. Numerous intranuclear inclusion bodies were observed microscopically in hepatocytes and a herpesvirus which grew rapidly in chicken kidney cells was isolated from tissues. Duck virus enteritis (DVE) was suspected but DVE antiserums failed to neutralise the virus. Further serological studies with a limited range of known avian herpesviruses have failed to identify the virus. Experimental transmission resulted in high mortality in geese (100%), lower mortality in ducklings and nil mortality in chickens. Surveillance studies showed no evidence of infection in domestic and wild birds beyond the original farm and the infection appears not to have been established in the area. Wild ducks, which were frequent visitors to the farm dam, were considered the most likely source of the infection.  相似文献   
4.
5.
本项研究旨在探明甘蓝型油菜突变体Ap-Tengbe无花瓣性状的遗传规律,‘Ap-Tengbe’和德国栽培品种‘Falcon’之间通过正反交产生两个方向的F1,BC1-1(F1和‘Ap-Tengebe’之间),BC1-2(F1和‘Falcon’之间)以及F2各遗传群体,根据田间各遗传群体PDgr(花瓣度)的观察和统计,作者提出‘Ap-Tenge’突变体无花瓣性状的遗传由细胞质和两对核隐性基因共同控制  相似文献   
6.
7.
The appropriate form of evaluation of new farming systems depends on the stage of development of the technology. At each state of technology development new systems are screened and the most promising ones selected for further research. Linear programming is a cost-effective tool for the evaluation of preliminary technologies as it allows interaction between the production parameters, quantifies the impact of limiting factors by shadow prices and can also be used for simulation. The screening of potential zero-tillage systems for West Africa is a concrete example.  相似文献   
8.
The aim of this study was to investigate the course of expression of platelet‐activating factor (PAF), PAF‐receptor (PAF‐R), epidermal growth factor (EGF), EGF‐R, vascular endothelial growth factor (VEGF), VEGF‐R1 and VEGF‐R2 in uterine tissue during canine pregnancy. For this purpose, 20 bitches were ovariohysterectomized at days 10–12 (n = 10), 18–25 (n = 5) and 28–45 (n = 5) days after mating, respectively. The pre‐implantation group was proven pregnant by embryo flushing of the uterus after the operation, the others by sonography. Five embryo negative, that is, non‐pregnant, bitches in diestrus (day 10–12) served as controls. Tissue samples from the uterus (placentation sites and horn width, respectively) were excised and snap‐frozen in liquid nitrogen after embedding in Tissue Tec®. Extraction of mRNA for RT‐PCR was performed with Tri‐Reagent. In the embryos, mRNA from all factors except VEGF was detected. In the course of pregnancy, significantly higher expression of PAF and PAFR as well as VEGF and VEGFR2 during the pre‐implantation stage than in all other stages and a strong upregulation of EGF during implantation were characteristic. The course of EGF was in diametrical opposition to the course of the receptor. These results point towards an increased demand for VEGF, EGF and PAF during the earliest stages of canine pregnancy.  相似文献   
9.
Organic farming (OF) has significantly increased in importance in recent decades. Disease management in OF is largely based on the maintenance of biological diversity and soil health by balanced crop rotations, including nitrogen‐fixing and cover crops, intercrops, additions of manure and compost and reductions in soil tillage. Most soil‐borne diseases are naturally suppressed, while foliar diseases can sometimes be problematic. Only when a severe disease outbreak is expected are pesticides used that are approved for OF. A detailed overview is given of cultural and biological control measures. Attention is also given to regulated pesticides. We conclude that a systems approach to disease management is required, and that interdisciplinary research is needed to solve lingering disease problems, especially for OF in the tropics. Some of the organic regulations are in need of revision in close collaboration with various stakeholders. © 2015 Society of Chemical Industry  相似文献   
10.
Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.  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