全文获取类型
收费全文 | 1009篇 |
免费 | 14篇 |
国内免费 | 10篇 |
专业分类
安全科学 | 40篇 |
废物处理 | 29篇 |
环保管理 | 212篇 |
综合类 | 118篇 |
基础理论 | 232篇 |
环境理论 | 2篇 |
污染及防治 | 229篇 |
评价与监测 | 78篇 |
社会与环境 | 73篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 19篇 |
2016年 | 29篇 |
2015年 | 12篇 |
2014年 | 39篇 |
2013年 | 100篇 |
2012年 | 34篇 |
2011年 | 53篇 |
2010年 | 46篇 |
2009年 | 46篇 |
2008年 | 64篇 |
2007年 | 57篇 |
2006年 | 48篇 |
2005年 | 45篇 |
2004年 | 28篇 |
2003年 | 37篇 |
2002年 | 33篇 |
2001年 | 16篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 24篇 |
1995年 | 16篇 |
1994年 | 21篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 17篇 |
1982年 | 13篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1958年 | 1篇 |
排序方式: 共有1033条查询结果,搜索用时 15 毫秒
671.
672.
Howard Passell 《Conservation biology》2000,14(4):924-925
673.
674.
675.
676.
677.
678.
Ian D. Thompson Michael D. Flannigan B. Michael Wotton Roger Suffling 《Environmental monitoring and assessment》1998,49(2-3):213-233
The predicted increase in climate warming will have profound impacts on forest ecosystems and landscapes in Canada because of increased temperature, and altered disturbance regimes. Climate change is predicted to be variable within Canada, and to cause considerable weather variability among years. Under a 2 × CO2 scenario, fire weather index (FWI) is predicted to rise over much of Ontario by 1.5 to 2 times. FWI may actually fall slightly, compared to current values, in central eastern Ontario (Abitibi), but for central-south Ontario it is expected to rise sharply by as much as 5 times current values. We predict that the combination of temperature rise and greater than average fire occurrence will result in a shrinkage of area covered by boreal forest towards the north and east; that some form of Great Lakes forest type will occupy most of central Ontario following the 5 C isotherm north; that pyrophilic species will become most common, especially jack pine and aspen; that patch sizes will initially decrease then expand resulting in considerable homogenization of forest landscapes; that there will be little 'old-growth' forest; and that landscape disequilibrium will be enhanced. If climate change occurs as rapidly as is predicted, then some species particularly those with heavy seeds may not be able to respond to the rapid changes and local extinctions are expected. Anthropogenically-altered species compositions in current forests, coupled with fire suppression over the past 50 years, may lead to forest landscapes that are different then were seen in the Holocene period, as described by paleoecological reconstructions. In particular, forests dominated by white pine in the south and black spruce in the middle north may not be common. Wildlife species that respond at the landscape level, i.e., those with body sizes >1 kg, will be most affected by changes in landscape structure. In particular we expect moose and caribou populations to decline significantly, while white-tailed deer will likely become abundant across Ontario and Quebec. 相似文献
679.
680.