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   202篇
  免费   16篇
  国内免费   6篇
林业   2篇
农学   2篇
  4篇
综合类   31篇
农作物   2篇
水产渔业   31篇
畜牧兽医   143篇
植物保护   9篇
  2023年   8篇
  2022年   4篇
  2021年   7篇
  2020年   8篇
  2019年   13篇
  2018年   6篇
  2017年   3篇
  2016年   2篇
  2015年   4篇
  2014年   8篇
  2013年   29篇
  2012年   12篇
  2011年   16篇
  2010年   12篇
  2009年   6篇
  2008年   4篇
  2007年   13篇
  2006年   14篇
  2005年   5篇
  2004年   6篇
  2003年   2篇
  2002年   5篇
  2001年   4篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1996年   3篇
  1995年   4篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1984年   2篇
  1983年   1篇
  1979年   3篇
排序方式: 共有224条查询结果,搜索用时 13 毫秒
91.
中国兽药知识产权保护问题分析与对策建议   总被引:1,自引:1,他引:0  
为更好地保护和利用兽药知识产权,从现代知识产权保护规则和基本概念着手,分析了兽药知识产权保护现状和存在问题,就如何借鉴我国药品专利、行政保护、植物资源保护经验进行了探讨,提出了兽药知识产权保护、兽医微生物菌(毒、虫)种资源保护对策建议和思路,希望能为我国兽药知识产权保护工作提供参考。  相似文献   
92.
Previously, proliferating microflora transferred with abomasal nematodes, were suspected to be the source of the gastrin inhibitor in some parasite excretory/secretory products. Aerobic cultures in HBSS of abomasal fluid from uninfected sheep became inhibitory during the static growth phase, unless antibiotics were present. Basal gastrin secretion was reduced by up to 90%. Rumen fluid and incubates and medium in which Streptococcus bovis and ovine rumen Actinomycete spp. had been grown also contained the inhibitor. Unlike abomasal cultures, rumen fluid and incubates also reduced the measurement of gastrin standards. Rumen incubates were less potent after exposure to pH 2-3, suggesting that inactivation normally occurs in the unparasitised abomasum. Contaminating bacteria which generate the gastrin inhibitor in parasite ES products are probably rumen organisms which survive in the abomasum and proliferate during subsequent incubation. Significantly, rumen bacteria have been shown to be capable of affecting the secretory activity of the gastric mucosa.  相似文献   
93.
Seriously escalating global anthelmintic resistance in gastrointestinal nematodes of small ruminants has spawned a variety of alternatives to anthelmintics for worm management, based on the need for sustainable Integrated Parasite Management (sIPM). Pivotal to the sIPM approach is the concept of refugia, the proportion of a given parasite population that escapes exposure to control measures. By balancing drug applications with the maintenance of refugia, the accumulation of anthelmintic resistance alleles in worm populations can be considerably delayed, while still providing good levels of control. The over-dispersed nature of parasitic infections provides an opportunity to achieve this balance, by targeting treatments to the members of a flock or herd that are least tolerant to nematode infection. However, implementation of this strategy has only recently become feasible, with the development of the FAMACHA((c)) system for clinical evaluation of anaemia due to haemonchosis. Subsequently, the use of milk yields has proven an effective indicator in dairy goats infected predominantly with nematodes other than Haemonchus contortus. In addition, short-term weight changes and perhaps also body condition scoring may provide indices of parasitism, permitting the rapid identification of animals likely to benefit from treatment. However, sIPM and refugia-based approaches are more complex than whole-flock treatments in conventional programs, and adoption by farmers is most likely where the theoretical basis is understood. As close communication with informed advisors is generally limited, there is a danger that sIPM will remain a theoretical concept without alternative modes of communication. The development of computer-based decision support programs, which use epidemiological, seasonal and clinical information to provide recommendations for specific situations, should be accorded high priority in the future development of worm management systems.  相似文献   
94.
Objective   To compare the effectiveness of a single long-acting injection of moxidectin, given in either summer or winter, with a two-summer ('standard') treatment strategy for controlling gastrointestinal nematodes in spring-lambing Merino ewes.
Design   A replicated study over 2 years in the high winter rainfall environment of western Victoria.
Methods   Measures of worm infection were worm egg counts of ewes and total worm counts of tracer lambs. Measures of production were body weight, proportion of pregnant ewes and number of weaned lambs.
Results   The egg counts of ewes given the standard strategy followed a characteristic pattern, rising to 300 to 600 eggs per gram before the second summer treatment in February. During this time, ewes given long-acting moxidectin in December had zero or negligible counts. There were no consistent differences between tracer worm counts or production measures for the two groups treated in summer, but when data from both years were pooled, the total egg output from December to May was significantly lower for ewes treated with long-acting moxidectin in December. Ewes not treated during summer had lower body weights, and higher worm egg counts and tracer worm counts, showing that this was not a suitable strategy at that time of the year. However, following treatment with long-acting moxidectin in winter, ewes had rapid compensatory weight gain and lower egg output than ewes treated in summer.
Conclusion   A single injection of long-acting moxidectin in December is an effective treatment strategy for Merino ewes lambing in spring.  相似文献   
95.
目的 研究分析新疆昭苏地区不同性别、不同年龄段纯血马在不同月份的寄生虫感染情况,为纯血马的健康养殖以及科学驱虫提供参考。方法 随机选取不同年龄段纯血马122匹,分为5组,哺乳马驹30匹,青年母马25匹,青年公马20匹,繁殖母马35匹,种公马12匹。采用马场分栏群体舍饲和单厩饲养模式,保证不同年龄段纯血马饲料和饮水充足,分别在5月和10月采集粪便样品。使用虫卵计数法检测马匹粪便中的寄生虫,计算不同年龄纯血马在不同时间段的寄生虫感染率和感染强度。结果 5月纯血马马蛲虫以及马球虫感染率较高,除种公马外,感染率均在94.00%以上,其中,哺乳马驹马蛲虫的感染率高达98.89%,哺乳马驹马球虫的感染率高达98.33%。10月纯血马马副蛔虫以及马球虫的感染率均在93.00%以上,其中,繁殖母马马副蛔虫感染率高达99.52%,哺乳马驹马球虫感染率高达98.33%。5月哺乳马驹的马副蛔虫、毛圆线虫、盅口线虫与细颈三齿线虫感染强度均显著(P<0.05)高于其他年龄段的纯血马;马蛲虫、马球虫和埃氏腹盘吸虫的感染强度显著(P<0.05)高于种公马,与其他阶段纯血马相比差异不显著(P>0.05)。10月哺乳马驹马副蛔虫、毛圆线虫、裸头绦虫感染强度显著(P<0.05)高于除繁殖母马以外的其他年龄段纯血马,细颈三齿线虫感染强度显著(P<0.05)高于其他年龄段纯血马,马球虫和埃氏腹盘吸虫的感染强度显著(P<0.05)高于种公马。种公马马副蛔虫与细颈三齿线虫感染强度显著(P<0.05)低于其他阶段的纯血马。不同年龄段纯血马马蛲虫感染强度差异不显著(P>0.05)。结论 纯血马感染的肠道寄生虫主要有马蛲虫、马球虫、毛圆线虫、细颈三齿线虫、盅口线虫、马副蛔虫、裸头绦虫以及埃氏腹盘吸虫,不同年龄段、不同月份均有感染,且混合感染较为严重。哺乳马驹感染强度及感染率普遍高于其他年龄段纯血马。  相似文献   
96.
Abstract – Stable δ13C and δ15N isotopes, diet and parasites demonstrated that the prey consumed by ninespine stickleback Pungitius pungitius in a small lake on Baffin Island changed during the summer and also revealed intraspecific variation in their ecological niche. In July, there were differences in the diets of male and female ninespine stickleback as indicated by the stable isotopes, differences corroborated by the data on diet composition and the parasite fauna. Differences suggested that the sexes occupied different habitats during spawning. During July, females utilise the shallower littoral areas consuming zooplankton and benthic organisms, while males occupy deeper areas of the littoral zone feeding mainly on pelagic zooplankton. Parasite data support these observations as males had higher infections of copepod‐transmitted parasites than females. There appeared to be no segregation of resources between males and females in late August, although the diet of both male and female ninespine stickleback shifted towards more benthic organisms, compared with July. Differences in δ13C isotope, diet composition and infections of co‐occurring parasites demonstrated that sympatric ninespine stickleback and Arctic char Salvelinus alpinus captured in the littoral zone occupied separate niches. Ninespine stickleback preyed mainly on zooplankton and chironomids, while Arctic char consumed a greater variety of prey items, including zooplankton and larger‐sized prey such as insects and ninespine stickleback. The multifaceted approach improved our understanding of the trophic ecology of ninespine stickleback in southern Baffin Island and quantified resource use and dietary overlap with Arctic char.  相似文献   
97.
对广东省南海市的69只沙皮犬进行了肠道寄生虫调查。采用粪便检查法,检出虫卵9种,其中绦虫2种(细粒棘球绦虫和复孔绦虫);线虫6种(犬弓首蛔虫、犬钩虫、狮蛔虫、巴西钩口线虫、犬鞭虫和犬胃线虫);吸虫1种(抱茎隙吸虫)。检出优势种为犬复孔绦虫,犬钩虫,犬弓首蛔虫,是驱虫的主要对象。  相似文献   
98.
Anthelmintic resistance was first confirmed in New Zealand in 1979 and since then has become common-place; more than 50 % of sheep farms now have detectable levels of resistance to one or more chemical classes of anthelmintic. Farmer drenching practices have changed little over the last 15–20 years and are clearly exerting a significant level of selection for resistance. In the absence of new chemical classes of anthelmintics, current parasite control practices will be unsustainable in the long-term. Once substantial resistance has developed, significant reversion to susceptibility is unlikely and re-introduction of failed drugs is likely to result in the rapid re-emergence of control problems. The number of anthelmintic treatments applied is not necessarily a reliable indicator of selection pressure and should not be the only factor considered in strategies for minimising the development of resistance. The relative potential of the different anthelmintics now available, particularly the long- acting products, to select for resistance varies with the way they are used and with other epidemiological and management factors; generalisations about their respective roles in the development of resistance are often unreliable. In many cases, literal extrapolation of recommendations for the management of resistance from Australia to New Zealand is unsupportable, given the differences in climate, parasite ecology and farming practices between the 2 countries. In the absence of a refuge for susceptible genotypes, as occurs when anthelmintic treatments are used as a means of generating low-contamination ‘safe’ pasture for young stock, the rapid development of resistance is likely. Anthelmintic treatments applied to animals with a high level of immunity, or which become immune while the anthelmintic is active, are likely to select for resistance faster than treatments applied to non-immune stock.  相似文献   
99.
100.
美洲斑潜蝇寄生蜂种类及描述   总被引:5,自引:0,他引:5  
本文报道和描述斑港蝇的7种寄生峰。  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