全文获取类型
收费全文 | 184篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 1篇 |
环保管理 | 7篇 |
综合类 | 119篇 |
基础理论 | 31篇 |
污染及防治 | 18篇 |
评价与监测 | 3篇 |
社会与环境 | 5篇 |
出版年
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 4篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 6篇 |
2008年 | 2篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1974年 | 2篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 4篇 |
1966年 | 5篇 |
1965年 | 3篇 |
1964年 | 8篇 |
1963年 | 2篇 |
1962年 | 5篇 |
1961年 | 4篇 |
1960年 | 3篇 |
1959年 | 4篇 |
1958年 | 2篇 |
1957年 | 4篇 |
1956年 | 5篇 |
1955年 | 5篇 |
1954年 | 5篇 |
1953年 | 2篇 |
1952年 | 4篇 |
1948年 | 1篇 |
1943年 | 2篇 |
1941年 | 2篇 |
1939年 | 1篇 |
1936年 | 3篇 |
1933年 | 1篇 |
1930年 | 2篇 |
1929年 | 1篇 |
1928年 | 3篇 |
1920年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 15 毫秒
31.
32.
Palaeobiological evidence indicates that gymnosperms were wind-pollinated and that insect pollination began in angiosperms in the Lower Cretaceous (ca. 135 mya) leading to close associations between higher plants and their pollinators. Cycads, which were widespread and pervasive throughout the Mesozoic (250-65 mya) are among the most primitive living seed-plants found today. Because pollination by beetles and by thrips has now been detected in several modern cycads, it is attractive to speculate that some insects and cycads had already developed similar mutualistic interactions in the Triassic (250-205 mya), long before the advent of angiosperms. We also draw attention to another key factor in this insect-plant relationship, namely secondary, defensive plant substances which must always have controlled interspecific interactions. Cycads mainly produce toxic azoglucosides and neurotoxic non-protein amino acids (e.g. BMAA), which apparently are crucial elements in the development and maintenance of mutualism (pollination) and parasitism (herbivory) by cycad-linked herbivores. We now add new results on the uptake and storage of the main toxin, cycasin, of the Mexican cycad Zamia furfuracea by its pollinator, the weevil Rhopalotria mollis, and by a specialist herbivore of Zamia integrifolia, the aposematic Atala butterfly Eumaeus atala. 相似文献
33.
Elisabeth Görge Sebastian Brandt Dietrich Werner 《Environmental science and pollution research international》1994,1(4):229-233
The fate of the explosive 2,4,6-TNT in plants is of major interest. Therefore, a method was developed to analyse TNT and derivatives in plant tissue. The method was utilized to investigate the uptake and metabolism of TNT inMedicago sativa andAllium schoenoprasum grown in hydroponic cultures containing TNT levels of 0.1 to 10 mg/1. Detectable concentrations of nitrotoluenes were significantly higher inAllium schoenoprasum than inMedicago sativa. The uptake of TNT in plants was directly related to the initial TNT level. The principal nitroaromatic components in roots and shoots of both plant species were identified as 4-ADNT and 2-ADNT in equal amounts, with substantially less TNT. 相似文献
34.
The Science of Nature - 相似文献
35.
36.
37.
38.
39.
40.