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   34篇
  免费   0篇
林业   2篇
农学   2篇
  9篇
综合类   3篇
农作物   4篇
水产渔业   2篇
畜牧兽医   10篇
园艺   1篇
植物保护   1篇
  2023年   1篇
  2020年   2篇
  2019年   1篇
  2017年   1篇
  2014年   2篇
  2013年   3篇
  2012年   1篇
  2011年   5篇
  2010年   1篇
  2009年   2篇
  2008年   3篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2003年   2篇
  2002年   2篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
排序方式: 共有34条查询结果,搜索用时 375 毫秒
31.
Temperatures in tropical regions are estimated to have increased by 3° to 5°C, compared with Late Paleocene values, during the Paleocene-Eocene Thermal Maximum (PETM, 56.3 million years ago) event. We investigated the tropical forest response to this rapid warming by evaluating the palynological record of three stratigraphic sections in eastern Colombia and western Venezuela. We observed a rapid and distinct increase in plant diversity and origination rates, with a set of new taxa, mostly angiosperms, added to the existing stock of low-diversity Paleocene flora. There is no evidence for enhanced aridity in the northern Neotropics. The tropical rainforest was able to persist under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculations that tropical ecosystems were severely compromised by heat stress.  相似文献   
32.
Pedicinus spp. parasitize several species of nonhuman primates. This is the first published report confirming the presence of Pedicinus albidus (Rudow) infestation in the free-ranging macaques (Macaca sylvanus) of Gibraltar. The diagnosis of pediculosis was based upon finding adult lice on host animals.  相似文献   
33.
The developmental pattern of jicama (Pachyrhizus erosus (L.) Urban) was studied by sampling plants aged 20 to 36 weeks at weekly intervals. There was an increase in all characteristics of foliage: fresh and dry weight, number of leaves per plant, main stem length, number of leaves, nodes and internodes of the main stem; and in all root characteristics: fresh and dry weight, diameter and length. The chemical analysis was determined for roots at different plant ages. The range values for dry matter were 16.19–22.28%, protein 1.11–1.62%, fat 0.553–0.867%, crude fiber 0.3048–0.3943%, and ash 0.669–1.089%. The chemical constituents fluctuated with age but without specific trends. These values are considered the first record of roots produced by plants grown in Mexico.  相似文献   
34.
Several new bermudagrass cultivars are available and commonly used on golf course fairways. However, little is known about their cultural requirements or how these cultivars perform under lower inputs regimes. A 2-year study was conducted at University of Florida, Fort Lauderdale Research and Education Center, to assess performance of four hybrid bermudagrass [Cynodon dactylon L. Pers. X Cynodon transvaalensis (Burtt-Davy)] cultivars (‘Latitude 36’, ‘Tifway 419’, ‘TifGrand’ and ‘TifTuf’), and 2 common bermudagrass (Cynodon dactylon L. Pers.) cultivars (‘Bimini’ and ‘Celebration’) irrigated at either 50% or 80% reference evapotranspiration (ETo) and fertilised at either 0, 146, 244, or 342 kg N ha−1 year−1. Plots were evaluated monthly for turfgrass quality, dark green colour index (DGCI), normalised difference vegetation index (NDVI), and Chlorophyll Index, and seasonally for N tissue content. Plots watered at 80% ETo enhanced bermudagrass quality compared to 50% ETo, DGCI and NDVI only in two months out of 24. Latitude 36 and Celebration were the top-rated cultivars, and their quality was not affected by no N fertilisation. Conversely, TifGrand, TifTuf and Tifway that received no N fertilisation resulted in insufficient quality during the second year of the study. Insufficient quality may be linked to reduced N metabolization compared to the highest rated cultivars. Results show that new cultivars such as Latitude 36 and Bimini could be maintained at sufficient quality levels with reduced water and N inputs in South Florida.  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