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   180篇
  免费   4篇
  国内免费   1篇
林业   23篇
农学   20篇
基础科学   8篇
  47篇
综合类   9篇
农作物   23篇
水产渔业   14篇
畜牧兽医   22篇
园艺   6篇
植物保护   13篇
  2023年   3篇
  2022年   7篇
  2021年   3篇
  2020年   4篇
  2019年   9篇
  2018年   10篇
  2017年   9篇
  2016年   6篇
  2015年   4篇
  2014年   5篇
  2013年   18篇
  2012年   11篇
  2011年   11篇
  2010年   16篇
  2009年   8篇
  2008年   12篇
  2007年   6篇
  2006年   7篇
  2005年   5篇
  2004年   1篇
  2003年   3篇
  2002年   1篇
  2001年   3篇
  1999年   1篇
  1998年   1篇
  1996年   4篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1973年   1篇
  1965年   1篇
排序方式: 共有185条查询结果,搜索用时 156 毫秒
181.
Salinity is one of the major environmental stressors which has deleterious effects on the growth, development, and yield of crops. Because of the gradual increase in soil and water salinity in the East Azarbaijan, Iran, Tanacetum balsamita L. cultivation in this region has always been associated with many problems. To study the effect of foliar spray of iron sulfate (FeSO4) (0, 750, and 1500 mg L?1) under sodium chloride (NaCl) salinity (0, 50, and 100 mM) on some physiological characteristics of Tanacetum balsamita L. plants, an experiment was conducted as a factorial based on complete randomized block design with three replications. Total soluble solids (TSS) and essential oil contents were significantly affected by the interaction effects of FeSO4 foliar application and salinity levels. The highest TSS and essential oil content were found in the plants under NaCl0 × FeSO4 1500 mg L?1 treatment combination. Leaf length, leaf fresh and dry weights were influenced by both Fe foliar application and salinity levels. Foliar application of iron (Fe) positively affected leaf length, leaves fresh and dry weights, root fresh and dry weights and peroxidase (POD) content, especially at 1500 mg L?1. Other traits such as leaf length, leaf fresh and dry weights, malondialdehyde (MDA), POD and catalase (CAT) contents were influenced by salinity levels. For POD, MDA, and CAT contents, the highest values were recorded with NaCl 50 and 100. The highest values of leaf length, leaf fresh and dry weights were found in the control plants.  相似文献   
182.
183.
Manipulation of flowering time to develop cultivars with desired maturity dates is fundamental in plant breeding.It is desirable to generate polyploid rapeseed(Brassica napus L.)germplasm with varying flowering time controlled by a few genes.In the present study,Bna SVP,a rapeseed homolog of the Arabidopsis SVP(Short Vegetative Phase)gene,was characterized and a set of mutants was developed using a CRISPR/Cas9-based gene-editing tool.A single construct targeting multiple sites was successfully applied to precisely mutate four copies of Bna SVP.The induced mutations in these copies were stably transmitted to subsequent generations.Homozygous mutants with loss-of-function alleles and free transgenic elements were generated across the four Bna SVP homologs.All mutant T1lines tested in two environments(summer and winter growing seasons)showed early-flowering phenotypes.The decrease in flowering time was correlated with the number of mutated Bna SVP alleles.The quadruple mutants showed the shortest flowering time,with a mean decrease of 40.6%–50.7%in length relative to the wild type under the two growth conditions.Our study demonstrates the quantitative involvement of Bna SVP copies in the regulation of flowering time and provides valuable resources for rapeseed breeding.  相似文献   
184.
Fucoidans constitute a large family of sulfated polysaccharides with several biochemical properties. A commercial fucoidan from brown algae, containing low molecular weight polysaccharidic species constituted of l-fucose, uronic acids and sulfate groups, was simply treated here with calcium acetate solution. This treatment led to a purified fraction with a yield of 45%. The physicochemical characterizations of the purified fucoidan using colorimetric assay, MALLS, dRI, FT-IR, NMR, exhibited molecular weight distributions and chemical profiles similar for both fucoidans whereas the sulfate and l-fucose contents increased by 16% and 71%, respectively. The biodistribution study in rat of both compounds labeled with 99mTc evidenced a predominant renal elimination of the purified fucoidan, but the crude fucoidan was mainly retained in liver and spleen. In rat myocardial ischemia-reperfusion, we then demonstrated the better efficiency of the purified fucoidan. This purified sulfated polysaccharide appears promising for the development of molecular imaging in acute coronary syndrome.  相似文献   
185.
Chemosensory proteins(CSPs) are important molecular components of the insect olfactory system, which are involved in capturing, binding, and transporting hydrophobic odour molecules across the sensillum in sensillar lymph in regulating insect behavior. This protein family(CSPs) is also involved in many other systems that are not linked to olfactory receptors in olfactory sensilla. The brown planthopper(BPH) is a monophagous pest of rice that causes damage by sucking phloem sap and transmitting a...  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