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   27篇
  免费   1篇
林业   3篇
  8篇
综合类   1篇
农作物   1篇
水产渔业   1篇
畜牧兽医   10篇
植物保护   4篇
  2023年   3篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   4篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2013年   1篇
  2012年   1篇
  2010年   1篇
  2009年   2篇
  2007年   3篇
  2006年   2篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
排序方式: 共有28条查询结果,搜索用时 843 毫秒
1.
2.
To determine the diverse motivations of eastern wild turkey (Meleagris gallopavo) hunters, a self-administered questionnaire was developed and mailed to a sample of 5,000 licensed turkey hunters in Tennessee (response rate = 36%). A cluster analysis yielded three types of respondents in terms of their hunting motivations: social harvesters (44%), experiential harvesters (22%), and social outdoor enthusiasts (34%). Hunters in these segments were then analyzed to compare their support for various hunting regulations. While 61% of Tennessee eastern wild turkey hunters reported to be satisfied with current regulations, harvest-motivated hunters were less receptive to regulations that would limit season lengths or bag limits while socially motivated hunters were more accepting. The hunter groups did not differ in their preference for decentralizing regulations by management zones. Findings from this article may guide wildlife managers in designing socially acceptable regulations.  相似文献   
3.
The present study analyzes the structure and dynamics of the forest landscape in a peri-urban area(Rome, Italy) during the city's expansion from 1949 to2008 using landscape metrics and change detection analysis of digital maps of the area(1500 km2). While urban settlements increased continuously from 6.5 to 27.5 % of the study area, woodlands changed less clearly, with a moderate increase(from 11.2 to 11.9 % of the total area)and a higher fragmentation as a consequence of Rome's expansion. The structure of forest landscape changed along the urban-to-rural gradient with patch size increasing with the distance to the inner city in 1949 and substantial landscape homogeneity in 2008. The indicators proposed in this study inform dedicated measures for conserving forest and maintaining landscape diversity. Measures adopted in Rome's forestation plan to counteract woodlandffragmentation were analyzed and discussed. Based on the complex landscape dynamics found for Rome, an integrated multiscale planning approach targeting forest conservation is considered a key contribution to urban sustainability.  相似文献   
4.
Wild pigs are a free-ranging invasive species capable of inflicting significant damage on rural property. Wildlife management personnel may benefit from understanding the negative societal impact of wild pigs. A statewide mail survey of randomly selected landowners was conducted in rural Tennessee counties known to have wild pigs. The economic value of damage caused by wild pigs in 2015 in these counties was estimated at $26.22 million, whereas the cost incurred in control and eradication was $2.09 million. Input-output modeling of damage in these counties on the state’s economy showed $32.8 million in lost industrial output, $4.6 million in lost labor income, and 332 jobs or job equivalents affected. Findings are useful in understanding the types of damage, and the extent of these impacts on the rural economy. They could also facilitate comparing the expected benefit with the cost of control programs in Tennessee and comparable areas facing similar invasions from wild pigs.  相似文献   
5.
6.
7.
8.
9.
10.
Roots, cotyledons, leaves, stems, pods, and seeds of three soy cultivars were analyzed for their content of isoflavones, flavonols, coumarins, and phenolic acid derivatives with three samplings during a three-month period. The extracts were analyzed by HPLC/DAD and HPLC/MS, allowing us to confirm the presence of daidzein and genistein derivatives as the major isoflavones and to characterize coumarins, most flavonols and phenolic acid derivatives. Seeds exhibited the highest content of isoflavones: 12.61 g/kg of dry weight (DW) in cv. Emiliana; 8.97 g/kg of DW in cv. Elvir; 4.49 g/kg of DW in cv. Kure, and roots are the only part with coumarins, ranging from 4.08 g/kg of DW (cv. Emiliana) to 1.29 g/kg of DW (cv. Elvir) for the longest sampling period. Leaves, pods, and stems have flavonols, and in particular leaves showed: 7.28 g/kg of DW in cv. Emiliana; 6.57 g/kg of DW in cv. Elvir; 7.08 g/kg of DW in cv. Kure. The high content of isoflavones found in the seeds could be ascribed to the natural conditions under which the soy plants were grown.  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