全文获取类型
收费全文 | 262篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 6篇 |
环保管理 | 16篇 |
综合类 | 118篇 |
基础理论 | 65篇 |
污染及防治 | 34篇 |
评价与监测 | 10篇 |
社会与环境 | 13篇 |
灾害及防治 | 1篇 |
出版年
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 13篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1967年 | 5篇 |
1966年 | 4篇 |
1965年 | 10篇 |
1964年 | 8篇 |
1963年 | 9篇 |
1962年 | 6篇 |
1961年 | 5篇 |
1960年 | 4篇 |
1959年 | 2篇 |
1957年 | 2篇 |
1956年 | 2篇 |
1954年 | 5篇 |
1951年 | 2篇 |
1942年 | 2篇 |
1940年 | 2篇 |
1939年 | 2篇 |
1932年 | 1篇 |
1925年 | 2篇 |
排序方式: 共有267条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
96.
Bark samples of spruce, pine and oak trees were collected at two sites in southern Bavaria which are characterized by high agricultural ammonia emissions. The samples were taken using a recently developed bark sampling device which removes a defined layer of the bark. The bark was then analysed for ammonium concentration in order to reflect the environmental ammonia immission. The measured bark concentrations decreased with rising distance between the sample trees and the ammonia source. This applied (i) to measurements inside a closed forest stand ranging from forest edge with high immission to forest interior with much lower immission, and (ii) to the open field where single-standing trees were sampled. Comparing the ammonium concentrations among the three different tree species revealed significant correlations. Thus, it could be shown that old spruce trees are as usable for bark bio-monitoring as the traditionally used pine and oak trees. The ammonium concentrations of the bark were significantly correlated to measurements taken by ammonia passive samplers at the same locations. These results indicate that bark samples may be used for a standardised monitoring of airborne ammonia load. A major advantage of the technique is the determination of the long-term accumulative ammonia load using a single measurement. 相似文献
97.
Ohne Zusammenfassung 相似文献
98.
Haas K Köhler U Diehl S Köhler P Dietrich S Holler S Jaensch A Niedermaier M Vilsmeier J 《Ecology》2007,88(11):2915-2925
It is notoriously difficult to study population interactions among highly mobile animals that cannot be meaningfully confined to experimental plots of limited size. For example, migratory water birds are believed to suffer from competition with resident fish populations for shared food resources. While observational evidence in support of this hypothesis is accumulating, replicated experiments addressing this issue at the proper spatial scale are lacking. Here, we report from a replicated whole-system experiment in which we stocked large (0.07 km2), shallow (< or =2.5 m deep), highly eutrophic ponds in the bird protection area "Ismaninger Speichersee mit Fischteichen" with different densities of carp and assessed the responses of water birds and their food resources during summer over several years. In all years, the biomasses of benthic macroinvertebrates, macroalgae, and macrophytes as well as the densities of herbivorous, carnivorous, and omnivorous water birds were reduced in carp ponds compared to fishless ponds. The negative effects of carp on food resources and on the numbers of water birds feeding in carp ponds increased over the season (May-September) and were stronger at high than at low stocking densities of carp. Consequently, differences in resource densities between ponds with and without carp increased, and the ranking of ponds with respect to resource densities became more predictable over the season. These factors may have contributed to a seasonal improvement of the birds' abilities to track resource densities across ponds, as suggested by tight correlations of bird numbers on ponds with resource densities late, but not early, in the season. 相似文献
99.
Impacts of business-as-usual management on ecosystem services in European mountain ranges under climate change 总被引:1,自引:0,他引:1
Harald Bugmann Thomas Cordonnier Heimo Truhetz Manfred J. Lexer 《Regional Environmental Change》2017,17(1):3-16
Mountain forests provide a multitude of services beyond timber production. In a large European project (ARANGE—Advanced multifunctional forest management in European mountain RANGEs), the impacts of climate change and forest management on ecosystem services (ES) were assessed. Here, we provide background information about the concept that was underlying the ARANGE project, and its main objectives, research questions, and methodological approaches are presented. The project focused on synergies and trade-offs among four key ES that are relevant in European mountain ranges: timber production, carbon storage, biodiversity conservation, and protection from gravitational natural hazards. We introduce the concept and selection of case study areas (CSAs) that were used in the project; we describe the concept of representative stand types that were developed to provide a harmonized representation of forest stands and forest management in the CSAs; we explain and discuss the climate data and climate change scenarios that were applied across the seven CSAs; and we introduce the linker functions that were developed to relate stand- and landscape-scale forest features from model simulations to ES provisioning in mountain forests. Finally, we provide a brief overview of the Special Feature, with an attempt to synthesize emerging response patterns across the CSAs. 相似文献
100.
Laura Bouriaud Mariella Marzano Manfred Lexer Liviu Nichiforel Christopher Reyer Christian Temperli Heli Peltola Ché Elkin Gabriel Duduman Philip Taylor Stephen Bathgate Jose G. Borges Sandra Clerkx Jordi Garcia-Gonzalo Carlos Gracia Geerten Hengeveld Seppo Kellomäki Georgi Kostov Michael Maroschek Bart Muys Gert-Jan Nabuurs Bruce Nicoll Marc Palahí Werner Rammer Duncan Ray Mart-Jan Schelhaas Louise Sing Margarida Tomé Juergen Zell Marc Hanewinkel 《Regional Environmental Change》2015,15(8):1595-1609