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   221篇
  免费   26篇
林业   20篇
农学   20篇
基础科学   8篇
  20篇
综合类   13篇
农作物   28篇
水产渔业   2篇
畜牧兽医   120篇
园艺   4篇
植物保护   12篇
  2023年   1篇
  2022年   4篇
  2021年   2篇
  2020年   10篇
  2019年   8篇
  2018年   7篇
  2017年   10篇
  2016年   12篇
  2015年   10篇
  2014年   10篇
  2013年   22篇
  2012年   10篇
  2011年   12篇
  2010年   13篇
  2009年   6篇
  2008年   7篇
  2007年   8篇
  2006年   3篇
  2005年   2篇
  2004年   1篇
  2003年   5篇
  2002年   3篇
  2001年   2篇
  2000年   2篇
  1999年   4篇
  1998年   3篇
  1997年   7篇
  1996年   5篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1992年   7篇
  1991年   6篇
  1990年   6篇
  1989年   8篇
  1988年   5篇
  1987年   4篇
  1979年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1969年   2篇
  1968年   1篇
  1967年   1篇
  1958年   1篇
排序方式: 共有247条查询结果,搜索用时 15 毫秒
241.
The leaf rust resistance gene Lr19, transferred from Agropyron elongatum into wheat (Triticum aestivum L.) imparts resistance to all pathotypes of leaf rust (Puccinia recondita f.sp. tritici) in South‐east Asia. A segregating F2 population from a cross between the leaf rust resistant parent ‘HW 2046’ carrying Lr19 and a susceptible parent ‘Agra Local’ was screened in the phytotron against a virulent pathotype 77‐5 of leaf rust with the objective of identifying the molecular markers linked to Lr19. The gene was first tagged with a randomly amplified polymorphic DNA (RAPD) marker S73728. The RAPD marker linked to the gene Lr19 which mapped at 6.4 ± 0.035 cM distance, was converted to a sequence characterized amplified region (SCAR) marker. The SCAR marker (SCS73719) was specific to Lr19 and was not amplified in the near‐isogenic lines (NILs) carrying other equally effective alien genes Lr9, Lr28 and Lr32 enabling breeders to pyramid Lr19 with these genes.  相似文献   
242.
FtsZ is an essential bacterial guanosine triphosphatase and homolog of mammalian beta-tubulin that polymerizes and assembles into a ring to initiate cell division. We have created a class of small synthetic antibacterials, exemplified by PC190723, which inhibits FtsZ and prevents cell division. PC190723 has potent and selective in vitro bactericidal activity against staphylococci, including methicillin- and multi-drug-resistant Staphylococcus aureus. The putative inhibitor-binding site of PC190723 was mapped to a region of FtsZ that is analogous to the Taxol-binding site of tubulin. PC190723 was efficacious in an in vivo model of infection, curing mice infected with a lethal dose of S. aureus. The data validate FtsZ as a target for antibacterial intervention and identify PC190723 as suitable for optimization into a new anti-staphylococcal therapy.  相似文献   
243.
Two switchable, mesoscopically periodic materials were created by combining crystalline colloidal array (CCA) self-assembly with the temperature-induced volume phase transition of poly(N-isopropylacrylamide) (PNIPAM). Body-centered-cubic CCAs of hydrated, swollen PNIPAM particles Bragg-diffract infrared, visible, and ultraviolet light weakly, whereas arrays of compact shrunken particles diffract efficiently. A tunable diffracting array was also created by embedding a CCA of polystyrene spheres within a PNIPAM hydrogel that swells and contracts with temperature; thus the array lattice constant varies with temperature, and the diffracted wavelength was thermally tunable across the entire visible spectrum. These materials may find applications in many areas of optics and materials science.  相似文献   
244.
The effects of different domestic processing and cooking methods on starch digestibility (in vitro) and protein digestibility (in vitro) of four strains of amphidiploids (black gram×mung bean) were investigated. An increase of 35 to 48% and 22 to 25% was observed in starch digestibility and protein digestibility, respectively, when the seed of amphidiploids were soaked for 18 h. Cooking (both of unsoaked and soaked seeds) and germination improved significantly the starch digestibility and protein digestibility of all the varieties.  相似文献   
245.
Protein digestibility (in vitro) of grains of chickpea (Cicer arietinum) and blackgram (Vigna mungo) cultivars varied from 48 to 53% and 52 to 58%, respectively. Soaking, cooking (both of unsoaked and soaked seeds), autoclaving and sprouting improved significantly the protein digestibility of all the cultivars of chickpea and blackgram. Autoclaving was found to be most effective followed by cooking and sprouting; cooking of sprouts had only marginal effect. Protein digestibility was higher when soaked instead of unsoaked grains were cooked.  相似文献   
246.
The aim of this study was to assess, by a clinical trial, the efficacy of an ivermectin‐based pour‐on treatment against gastrointestinal parasitic nematodes in naturally infected horses using 2 groups of mature indigenous Pura Raza Galega grazing mares. Faecal and blood samples were collected individually over a 21 week period. Faeces were analysed by the coprological flotation, sedimentation and migration techniques. Changes in circulating blood cells were monitored over the study period. The administration of the ivermectin suppressed the eggelimination of ascarids and pinworms throughout the study and no strongyle‐eggs were observed in the treatment group between the 3rd and 10th weeks. The numbers of red cells increased significantly after the anthelmintic therapy, and a statistical reduction in circulating leucocytes was recorded. No side effects were observed. The pour‐on ivermectin formulation was highly successful against gastrointestinal nematodes and appears to be a useful therapeutic routine for large groups of horses.  相似文献   
247.
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