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   224篇
  免费   12篇
  国内免费   7篇
林业   33篇
农学   18篇
  47篇
综合类   11篇
农作物   14篇
水产渔业   28篇
畜牧兽医   84篇
园艺   1篇
植物保护   7篇
  2023年   1篇
  2022年   6篇
  2021年   6篇
  2020年   1篇
  2019年   2篇
  2018年   6篇
  2017年   3篇
  2016年   7篇
  2015年   6篇
  2014年   8篇
  2013年   29篇
  2012年   13篇
  2011年   26篇
  2010年   9篇
  2009年   12篇
  2008年   13篇
  2007年   11篇
  2006年   14篇
  2005年   16篇
  2004年   8篇
  2003年   10篇
  2002年   10篇
  2001年   7篇
  2000年   3篇
  1999年   1篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1991年   1篇
  1978年   1篇
排序方式: 共有243条查询结果,搜索用时 0 毫秒
101.
102.
In Japan, few grape cultivars related to Vitis vinifera existed 200 years ago, on account of Japan’s high rainfall. Many V. labruscana and vinifera cultivars were introduced to Japan in the 19th century. Labruscana was grown instead of vinifera, mainly because of severe disease problems and a high incidence of berry cracking. Grape breeding for table use started in the 20th century, with the goal of combining the berry quality of vinifera with the ease of cultivation of labruscana. By 1945, three strategies were used: 1) crossing among introduced diploid vinifera and vinifera-related cultivars of Japanese origin, 2) interspecific crossing in tetraploid cultivars, and 3) interspecific crossing in diploid cultivars, resulting in ‘Neo Muscat’, ‘Kyoho’, and ‘Muscat Bailey A’. Later, tetraploid interspecific crossing over generations developed many ‘Kyoho’-related cultivars, including ‘Pione’, many of which have large berries, intermediate flesh texture between the two species, a labruscan or neutral flavor, and moderate disease resistance. Interspecific diploid crossing over generations developed ‘Shine Muscat’ in 2006, with large berries, crispy flesh, a muscat flavor, no cracking, seedless fruit by gibberellin application, and moderate resistance to downy mildew and ripe rot.  相似文献   
103.
Unique secondary metabolites, glucosinolates (S-glucopyranosyl thiohydroximates), are naturally occurring S-linked glucosides found mainly in Brassicaceae plants. They are enzymatically hydrolyzed to produce sulfate ions, D-glucose, and characteristic degradation products such as isothiocyanates. The functions of glucosinolates in the plants remain unclear, but isothiocyanates possessing a pungent or irritating taste and odor might be associated with plant defense from microbes. Isothiocyanates have been studied extensively in experimental in vitro and in vivo carcinogenesis models for their cancer chemopreventive properties. The beneficial isothiocyanates, glucosinolates that are functional for supporting human health, have received attention from many scientists studying plant breeding, plant physiology, plant genetics, and food functionality. This review presents a summary of recent topics related with glucosinolates in the Brassica family, along with a summary of the chemicals, metabolism, and genes of glucosinolates in Brassicaceae. The bioavailabilities of isothiocyanates from certain functional glucosinolates and the importance of breeding will be described with emphasis on glucosinolates.  相似文献   
104.
105.
A 10-year-old castrated male Shih Tzu presented with severe generalized pruritus. Skin scrapings revealed the presence of Sarcoptes scabiei var. canis. A Yorkshire terrier in the same household simultaneously developed pruritus due to scabies. Both dogs were treated with 300 μg/kg ivermectin, at first orally and then subcutaneously at 14 day intervals. However, live mites were still found on day 35, and the skin condition deteriorated in both dogs. These findings suggested that the S. scabiei in these dogs was clinically refractory to ivermectin. The pruritus in both dogs rapidly and completely disappeared following topical fipronil administration. This appears to be the first report of canine scabies refractory to ivermectin treatment.  相似文献   
106.
The aims of this study were to investigate the diversity of lactic acid bacteria (LAB) isolated from traditional Mongolian dairy products, and to estimate the probiotic potential of the isolated strains. We collected 66 samples of the traditional Mongolian dairy products tarag (n = 45), airag (n = 7), aaruul (n = 8), byasulag (n = 1) and eezgii (n = 5), from which 543 LAB strains were isolated and identified based on 16S ribosomal DNA sequence. The predominant species of those products were Lactobacillus (L.) delbrueckii ssp. bulgaricus, L. helveticus, L. fermentum, L. delbrueckii ssp. lactis and Lactococcus lactis ssp. lactis. However, we could not detect any LAB strains from eezgii. All LAB isolates were screened for tolerance to low pH and to bile acid, gas production from glucose, and adherence to Caco‐2 cells. In vitro, we found 10 strains possess probiotic properties, and almost identified them as L. plantarum or L. paracasei subspecies, based on 16S ribosomal DNA and carbohydrate fermentation pattern. These strains were differentiated from each other individually by randomly amplified polymorphic DNA analysis. Additionally, it was notable that 6/10 strains were isolated from camel milk tarag from the Dornogovi province.  相似文献   
107.
Mutants edficient in nitrate reductase(NR)were clasfied into two groups,nia types are deficient in apoprotein and cnx types are lack of Mo-Co.This paper reports the characteristics of low NR mutants,which are not edficient in NRactivity but 40%-60%of the NRactivity of the wild type,Nipponbare.Mu-tants NR676and NR827 were selected as seedings showing poor growth with nitrate as sole mitrogen-source from M2 population.They exhibited chlorate reistance.Genetic analysis in the F1and F2indicated that chlo-rate resistance in the mutants was transmitted by a single recessive nuclear gene and that NR676 and NR827 were induced by a mutation at a single locus.In the F2population,all of the seedings showing yellow green leaves were resistant to chlorate and low in NRactivity,Photosynthetic rate and mRNA expression of NR676and NR827 were lower than wild type.These results suggested that low NR activity and chlorate resistance of NR676and NR827 were Caused by a defect in photosynthetic process.  相似文献   
108.
109.
To examine the possibility that the Al13 polymer ([A104Al12(OH)24(H20)12]7+) could be formed in soils after gypsum application, an analytical method using a cation exchange resin and 27Al nuclear magnetic resonance (NMR) spectroscopy was applied to gypsum-treated Kitakami Andosol (fine, mixed, mesic, Andic Dystrochrept). The NMR spectra of the cation exchange resins which retained artificially synthesized hydroxy-AI, showed two broad peaks at 0 and 63 ppm. These results indicated that monomer and/or dimer Al and Al13 polymers adsorbed on the cation exchange resin could be detected with 27Al NMR. The amount of polymer Al increased by gypsum application in the Kitakami soil. The NMR spectrum of this resin showed only one peak at 0 ppm indicating that the polymer Al formed in the gypsum treated Kitakami soil was not the Al13 polymer.  相似文献   
110.
The efficiency of planting a hybrid larch F1 at two planting densities and of using seedlings of hybrid larch F1 or rooted cuttings of Gream, the registered variety, was investigated. Significantly more time was required to move from one planting spot to the next in plots with 625 seedlings/ha than in plots with 1,333 seedlings/ha, but there was no significant difference between seedlings and rooted cuttings. Approximately 18% more time was needed to plant a single planting stock at the low planting density than at the high density. The need to prune roots or enlarge a planting hole occurred more often for rooted cuttings than for seedlings, and 17% more time was needed to plant rooted cuttings of Gream than seedlings.  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