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   632篇
  免费   47篇
  国内免费   1篇
林业   14篇
农学   10篇
基础科学   4篇
  37篇
综合类   160篇
农作物   28篇
水产渔业   35篇
畜牧兽医   333篇
园艺   6篇
植物保护   53篇
  2023年   6篇
  2021年   11篇
  2020年   12篇
  2019年   10篇
  2018年   17篇
  2017年   14篇
  2016年   17篇
  2015年   11篇
  2014年   8篇
  2013年   53篇
  2012年   13篇
  2011年   23篇
  2010年   16篇
  2009年   11篇
  2008年   18篇
  2007年   23篇
  2006年   15篇
  2005年   16篇
  2004年   22篇
  2003年   12篇
  2002年   7篇
  2001年   7篇
  2000年   14篇
  1999年   7篇
  1998年   11篇
  1997年   9篇
  1996年   5篇
  1995年   7篇
  1994年   6篇
  1993年   5篇
  1992年   11篇
  1991年   15篇
  1990年   11篇
  1989年   15篇
  1988年   28篇
  1987年   27篇
  1986年   24篇
  1983年   8篇
  1982年   7篇
  1976年   6篇
  1973年   4篇
  1972年   6篇
  1971年   5篇
  1970年   4篇
  1968年   4篇
  1967年   5篇
  1959年   5篇
  1949年   5篇
  1948年   6篇
  1946年   5篇
排序方式: 共有680条查询结果,搜索用时 15 毫秒
101.
102.
Genetically engineered (GE) animals are likely to have an important role in the future in meeting the food demand of a burgeoning global population. There have already been many notable achievements using this technology in livestock, poultry and aquatic species. In particular, the use of RNA interference (RNAi) to produce virus‐resistant animals is a rapidly‐developing area of research. However, despite the promise of this technology, very few GE animals have been commercialised. This review aims to provide information so that veterinarians and animal health scientists are better able to participate in the debate on GE animals.  相似文献   
103.
A three‐year‐old male greyhound was presented with acute onset right forelimb lameness because of medial displacement of the biceps tendon of origin. Ultrasonographic examination confirmed the diagnosis, and a concomitant partial tear of the medial glenohumeral ligament was detected during arthroscopy. To stabilise the biceps tendon, polypropylene mesh was fixed across the intertubercular groove to replace the torn transverse humeral retinaculum. Recovery was uneventful and lameness resolved. Fifteen months later, the dog was presented with medial displacement of the biceps tendon of origin of the left shoulder, and was treated successfully using the same technique.  相似文献   
104.
105.
Abstract

Extract

The paper by Goodwin et al (2004 Goodwin, KA, Jackson, R, Brown, C, Davies, PR, Morris, RS and Perkins, NR. 2004. Pneumonic lesions in lambs in New Zealand: patterns of prevalence and effects on production. New Zealand Veterinary Journal, 52: 1759. [Taylor &; Francis Online], [Web of Science ®] [Google Scholar]) which appeared in the August 2004 issue of the New Zealand Veterinary Journal highlighted the prevalence and costs to the sheep industry of pneumonia in lambs. The costs are considerable, and the article begs the question, “what can sheep farmers do to reduce the effects of pneumonia in lambs?”  相似文献   
106.
Carrots ( Daucus carota L.) contain phytochemicals including carotenoids, phenolics, polyacetylenes, isocoumarins, and sesquiterpenes. Purple carrots also contain anthocyanins. The anti-inflammatory activity of extracts and phytochemicals from purple carrots was investigated by determining attenuation of the response to lipopolysaccharide (LPS). A bioactive chromatographic fraction (Sephadex LH-20) reduced LPS inflammatory response. There was a dose-dependent reduction in nitric oxide production and mRNA of pro-inflammatory cytokines (IL-6, IL-1beta, TNF-alpha) and iNOS in macrophage cells. Protein secretions of IL-6 and TNF-alpha were reduced 77 and 66% in porcine aortic endothelial cells treated with 6.6 and 13.3 microg/mL of the LH-20 fraction, respectively. Preparative liquid chromatography resulted in a bioactive subfraction enriched in the polyacetylene compounds falcarindiol, falcarindiol 3-acetate, and falcarinol. The polyacetylenes were isolated and reduced nitric oxide production in macrophage cells by as much as 65% without cytotoxicity. These results suggest that polyacetylenes, not anthocyanins, in purple carrots are responsible for anti-inflammatory bioactivity.  相似文献   
107.
108.
Thirty pheasants which had been reared in captivity for 19 weeks were killed by dislocating the neck and hung for up to 15 d at 10 °C. Microbiological, sensory and chemical assessments were made at 0, 3, 6, 8, 10, 13 and 13 d and this paper reports the microbiological results.

Examination of the duodenum, small intestine and caecum showed very little multiplication of coli‐aerogenes bacteria during hanging, although there was some increase in the numbers of faecal streptococci. Psychrophilic clostridia, mainly Clostridium putrefaciens, were found in the small intestine after 8 d and these organisms increased in number up to the 15th d.

The muscle remained relatively free from bacteria for most of the hanging period, but at 15 d Cl. putrefaciens was found in two out of three muscle samples at io3 and io4 per g.

No signs of spoilage due to greening were observed.

Twelve 16½>‐week‐old chickens were also killed by dislocating the neck and hung without plucking for 12 d at 10 °C with the pheasants. Although initially there were no major differences between the intestinal flora of the chickens and pheasants, faecal streptococci and coli‐aerogenes bacteria multiplied rapidly in the small intestine of the chickens during the first week. Greening occurred around the vent within 5 d.

Reasons for the differences between the two types of bird are discussed, particularly in relation to the diet.  相似文献   

109.
110.
Although 36 DLA-DRB1 and 10 DLA-DQA1 allele sequences have been published to date, no data on individual allele frequencies exists, either for specific breeds or cross breeds, and the full extent of the polymorphism at each of these loci is still not known. We have used sequence-specific oligonucleotide probing (SSOP) to characterise a series of 367 dogs for their DRB1 and DQA1 alleles. These included individual animals from over 60 different breeds, with numbers per breed ranging from 1 to 39. DLA types were generated from 218 dogs for DRB1 and from 330 dogs for DQA1, while 181 dogs were characterised for both these loci. The frequency of individual DRB1 and DQA1 alleles showed considerable interbreed variation, e.g. 83% of West Highland White Terriers were DRB1*01 as opposed to 9% of Collies. No breed had >9 of the 22 DRB1 types defined in this study; several breeds had only two DRB1 types. DLA-DQA1 showed less variation in allele numbers per breed, but also showed considerable interbreed frequency variation. Haplotype analysis revealed over 44 different DRB1/DQA1 combinations. Of these, 25 were in a number of animals, and also in an animal that was homozygous for one or both of these loci. Some DRB1 alleles could be found in combination with several different DQA1 alleles, while others were only present in one haplotypic combination. DLA allele frequency data in normal dogs will be critical for disease association studies. It may also be possible to use haplotype data to establish the genetic relationships between different dog breeds.  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