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   105篇
  免费   10篇
林业   37篇
农学   11篇
  13篇
综合类   5篇
农作物   3篇
水产渔业   22篇
畜牧兽医   19篇
植物保护   5篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   3篇
  2018年   6篇
  2017年   5篇
  2016年   18篇
  2015年   7篇
  2014年   6篇
  2013年   3篇
  2012年   6篇
  2011年   7篇
  2010年   6篇
  2009年   5篇
  2008年   7篇
  2007年   4篇
  2006年   3篇
  2005年   5篇
  2004年   3篇
  2003年   3篇
  2001年   7篇
  2000年   1篇
  1997年   1篇
  1995年   1篇
  1968年   1篇
  1963年   1篇
  1948年   1篇
排序方式: 共有115条查询结果,搜索用时 15 毫秒
111.
A bovine myeloid antimicrobial peptide antimicrobial peptide (BMAP‐28) is a member of the cathelicidin family and acts as a component of innate immunity. There are few reports of susceptibility difference of methicillin‐resistant Staphylococcus aureus (MRSA) and susceptible strains (MSSA) against BMAP‐28. This study aims to clarify how a few amino acid substitutions of BMAP‐28 are related to its antimicrobial activity using four analog peptides of BMAP‐28. We also compared cellular fatty acid components of MSSA and MRSA using gas chromatography. We found that a few amino acid substitutions of BMAP‐28 do not change antimicrobial activity. It was also revealed that the percentage of cis‐11‐eicosenoic acid in total detected fatty acids of MRSA was significantly higher than that of MSSA. In addition, the percentage of palmitic acid in total detected fatty acids of MRSA tended to be lower than that of MSSA. Our results will provide new information to deal with the question of differences in bacterial susceptibility against BMAP‐28.  相似文献   
112.
Decadal change in abundance of surface migratory myctophid fishes was examined in the Kuroshio region of the western North Pacific for the 35 yr from 1957 to 1994 in relation to the Kuroshio regime shift, indicated by changes in its transport volume and sea surface temperature in the early 1970s. Each year, samples were collected from the 0‐ to 1‐m depth layer at night, from January to March, at 83 stations on average. Ten species belonging to five genera occurred. Juveniles [standard length (SL) ≤ 40 mm] and adults (SL > 40 mm) of each species were analysed. In juveniles, Myctophum asperum, M. nitidulum, Symbolophorus evermanni and Centrobranchus brevirostris accounted for 91.1% of the total catch (7419 individuals), while M. nitidulum contributed 82.4% of the total adult catch (494 individuals). The abundance of juvenile S. evermanni, C. brevirostris and M. nitidulum showed prominent peaks in 1971, together with adult M. nitidulum. These peaks corresponded to extraordinarily high zooplankton abundance in the Kuroshio region in 1971, suggesting high recruitment success and low adult mortality in surface migratory myctophids. Smaller changes in abundance in other years were species‐specific, and the fluctuation patterns were mainly explained by year‐to‐year fluctuations in the strength of the Kuroshio and the geographical distribution of each species, i.e. an increased Kuroshio flow volume resulted in an increase in tropical species and a decrease in temperate species, but no change in the pan‐Kuroshio species.  相似文献   
113.
To gain better understanding of rates of decay of wooden check dams with different structures under different climate conditions, several dams of this type were examined under different environmental conditions over a 3 to 5-year period post-construction. Because a linear relationship was found between the mean (μ) and standard deviation (σ) of pilodyn penetration depth, mean penetration depth was taken as the indicator of deterioration, and relationships with check dam structural features and climate data recorded by AMEDAS were investigated. Multiple linear regression analysis revealed that temperature, climate index (CI) computed from rain days, warmth index computed from daily and annual mean air temperature, and altitude were the climate variables with the most effect on the rate of decay. With regard to dam structural features, factors such as specific discharge rate, water through width, dam length, and dam height had the most effect. Accordingly, in an effort to summarize the effects of climatic conditions and structural features, CI, altitude, and dam height were extracted as the most significant explanatory variables, and a formula for prediction of μ was obtained for each factor for up to 5 years post construction. The results showed that by taking into consideration regional conditions and calculating CI values from AMEDAS data, it is possible to predict the extent of decay of wooden check dams.  相似文献   
114.
115.
To investigate the presence of non-native anguillid eels in Japanese waters, 141 eels were collected from seven sampling sites throughout the Tone River system. Genetic species identification showed an extraordinary dominance of the non-native European eel Anguilla anguilla in the uppermost site of the study area. Estimation of age from otoliths suggested that the European eels were introduced into the river in the 1990s, corresponding to previous reports from other Japanese water systems. Comparison of the von Bertalanffy growth curve parameters indicated that the European eels caught in the Tone River system appeared to have a similar or even higher growth rate than the same species in the original habitats in Europe. The long-term inhabitation and the normal development of European eels in Japanese waters suggest that regulations prohibiting the release of non-native eels and safeguards against accidental escape from culture ponds must be strictly maintained in order to ensure the conservation of the native Japanese eel.  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