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   209篇
  免费   19篇
林业   12篇
农学   1篇
  41篇
综合类   12篇
农作物   4篇
水产渔业   22篇
畜牧兽医   112篇
园艺   1篇
植物保护   23篇
  2023年   1篇
  2022年   1篇
  2021年   6篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   4篇
  2016年   3篇
  2015年   3篇
  2014年   7篇
  2013年   14篇
  2012年   13篇
  2011年   13篇
  2010年   4篇
  2009年   10篇
  2008年   14篇
  2007年   9篇
  2006年   11篇
  2005年   13篇
  2004年   18篇
  2003年   10篇
  2002年   15篇
  2001年   3篇
  2000年   2篇
  1999年   2篇
  1998年   3篇
  1997年   2篇
  1996年   2篇
  1993年   1篇
  1992年   1篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   5篇
  1981年   1篇
  1980年   4篇
  1979年   4篇
  1978年   4篇
  1977年   1篇
  1973年   3篇
排序方式: 共有228条查询结果,搜索用时 156 毫秒
51.
An 8-year-old, castrated male, miniature wire-haired dachshund was presented with a 4-month history of intermittent facial twitching (myoclonus). The myoclonic episodes progressed over a 16-month period. Generalized seizure activity was infrequent. Clinical examination revealed visually stimulated myoclonus. Response to therapy with antiepileptic drugs was equivocal. Genetic testing identified the dog as being affected by Lafora disease.  相似文献   
52.
Cynomolgus macaques (also known as longtail or crab-eating macaques) Macaca fascicularis, are an important non-human primate model for biomedical research. Using a case study involving a suspected occurrence of twin birth, we demonstrate that the highly polymorphic human variable-number tandem repeat (VNTR) mini-satellite probes D1S7, D2S44, D3S42 and D4S184 can be successfully employed as a rapid screening strategy to complement husbandry records in order to establish genetic relatedness in a captive colony.  相似文献   
53.
Objective-To identify gait characteristics during trotting on a treadmill in nonlame Labrador Retrievers presumed predisposed or not predisposed to cranial cruciate ligament disease (CCLD). Animals-Clinically normal Labrador Retrievers presumed predisposed (n = 10) or not predisposed (7) to CCLD. Procedures-The right hind limb of each dog was classified by use of a predictive score equation that combined tibial plateau angle and femoral anteversion angle as presumed predisposed (high score [> -1.5]) or not predisposed (low score [≤ -1.5]) to CCLD. Tarsal joint, stifle joint, and hip joint kinematics, net moments, and powers were computed. Results-The stifle joint was held at a greater degree of flexion in limbs presumed predisposed to CCLD (130.9° vs 139.3°). More power was generated by muscles acting on the stifle joint in the early stance phase of limbs presumed to be predisposed to CCLD (2.93 vs 1.64 W/kg). The tarsal joint did not reach the same degree of extension in limbs presumed predisposed to CCLD, compared with that in limbs presumed not predisposed to CCLD (179.0° vs 161.0°). Velocity, stance time, vertical and craniocaudal forces, angular velocities, and net joint muscle moments did not differ between groups. Conclusions and Clinical Relevance-Gait mechanics of dogs with high (> -1.5) and low (≤ -1.5) tibial plateau angle and femoral anteversion angle scores were characterized on a treadmill, which may help in the identification of dogs predisposed to CCLD.  相似文献   
54.
55.
Possums are a wildlife vector of bovine tuberculosis in New Zealand. Vaccination of possums with BCG is being considered as a measure to control the spread of bovine tuberculosis to cattle and deer. Delivery via oral bait is feasible but BCG is degraded in the stomach. The aim was to determine whether ranitidine (Zantac) would reduce gastric acidity and enhance the efficacy of intragastrically administered BCG. A dose of 75 mg reduced gastric acidity for at least 4 h. Thus, possums were vaccinated intragastrically with BCG after receiving 75 mg ranitidine or ranitidine or BCG alone, as controls, before challenge with virulent Mycobacterium bovis. Proliferative responses of blood lymphocytes to M. bovis antigens after vaccination were significantly higher in possums given ranitidine/BCG compared to controls and seven weeks after challenge they had significantly lower lung weights and spleen bacterial counts than ranitidine alone controls. Vaccination with BCG alone only gave a reduction in loss in body weight. Agents that reduce gastric acidity may be useful in formulating BCG for oral bait delivery to wildlife for vaccination against bovine tuberculosis.  相似文献   
56.
57.
ABSTRACT The species X. index, X. diversicaudatum, X. vuittenezi, and X. italiae are established (E) or putative (P) vectors of Grapevine fanleaf virus (GFLV) (E), Arabis mosaic virus (E), Grapevine chrome mosaic virus (P), and GFLV (P) nepoviruses of grapevine, respectively. All four species are very closely related taxonomically and their low field densities make them difficult to identify from morphological and morphometrical diagnostic characters when only single or few individuals are detected. To improve diagnostic accuracy, a simple method was developed. The internal transcribed spacer 1 (ITS1) region spanning the 18S and 5.8S ribosomal genes was sequenced in one population of each species using two conserved primers from these genes. The ITS1 fragments were 1,132 bp (X. vuittenezi), 1,153 bp (X. index), 1,175 bp (X. diversicaudatum), and 1,190 bp (X. italiae), i.e., a difference of over 5% between the extremes. The sequence variability made it possible to design species-specific internal sense primers that amplified, in combination with the same antisense ITS1 primer, a single signature fragment (340 bp for X. index, 414 bp for X. italiae, 591 bp for X. vuittenezi, and 813 bp for X. diversicaudatum). Tests with DNA from a single adult or juvenile nematode confirmed the specificity of the primers from diverse isolates or populations. The primers were successfully used in a multiplex test for the reliable detection of two to four mixed species, each represented by a single individual. This multiplex-based diagnostic tool will be particularly useful for successful nematode management practices in vineyards.  相似文献   
58.
A sexagenarian couple operating a dairy farm, where there were also many horses, suffered a severe respiratory infection associated with the bacterium Streptococcus equi ssp. zooepidemicus. The investigation revealed that the source of infection was due to contacts with a horse having an infected wound from which we isolated this zoonotic agent.  相似文献   
59.
60.
Barley was sown and grown normally in an experimental field. At the growth stage J,
  • 1 Growth stage J: during the stem extension stage; second node of stem formed and next-to-last leaf just visible.
  • the aerial part of the plants was sprayed with an aqueous emulsion of a mixture of triforine and [3H]triforine (uniformly labelled in the piperazine ring) using the recommended dose rate of about 240g triforine ha?1. The barley was harvested when ripe and the straw and grain were analysed separately. The total radioactivity concentration was 20 times higher in straw than in grain. In straw and grain, 12 and 25% respectively of the total incorporated radioactivity in each of these tissues was methanol soluble. The composition of the methanol-soluble radioactive residue was investigated and was shown to contain triforine and its metabolites which were free and unbound in barley straw and grain. No radioactive piperazine was observed, in spite of the high detection sensitivity for radioactivity. The concentrations of triforine and its identified metabolites in straw and grain respectively (mg kg?1, relative to the fresh weight of tissue) were: triforine, 0.034 and 0.0018; N-[(2,2,2-trichloro-1-(piperazin-1-yl)ethyl]formamide), 0.009 and 0.0006; iminodiacetic acid, 0.021 and 0.001; glycine, 0.043 and 0.0033. Other radioactive water-soluble and very polar, unidentified compounds were observed, corresponding to advanced metabolic products of triforine.  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