全文获取类型
收费全文 | 789篇 |
免费 | 24篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 27篇 |
废物处理 | 34篇 |
环保管理 | 161篇 |
综合类 | 81篇 |
基础理论 | 221篇 |
环境理论 | 2篇 |
污染及防治 | 174篇 |
评价与监测 | 56篇 |
社会与环境 | 52篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 34篇 |
2017年 | 23篇 |
2016年 | 30篇 |
2015年 | 25篇 |
2014年 | 25篇 |
2013年 | 69篇 |
2012年 | 38篇 |
2011年 | 61篇 |
2010年 | 32篇 |
2009年 | 33篇 |
2008年 | 40篇 |
2007年 | 51篇 |
2006年 | 31篇 |
2005年 | 40篇 |
2004年 | 26篇 |
2003年 | 35篇 |
2002年 | 23篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有818条查询结果,搜索用时 453 毫秒
811.
Relationships between functional leaf traits across large sets of plant species emphasized the existence of a major axis describing a trade-off between rapid acquisition and conservation of resources forming the so-called “leaf economics spectrum”. It is uncertain which environmental factors determine the economics spectrum and whether traits associated with reproduction co-vary with the economics spectrum. To determine these trait-environment relationships for agricultural ecosystems, this study was conducted at field, pasture, and heathland sites forming a strong land use gradient in Northwest Germany. The abundance of 49 species was recorded in 85 plots together with their traits (canopy height, specific leaf area, leaf N, leaf N:P, leaf and stem dry matter content, life cycle, reproductive investment (RI) in seed mass and seed number), as well as parameters describing soil resources and land use disturbances. RLQ multivariate analysis of the data set related an environmental table to a species trait table using a species abundance table to extract the joint structure between them. Thereafter, we clustered the species on the RLQ axis to extract functional groups. Traits associated with the leaf economics spectrum were strongly related to soil resources that co-varied with disturbance intensity. A division of the whole land use gradient into agricultural and heathland sites showed that RI was not decoupled from trait-environment relationships although the direction of the RI-environment relationship was opposite in the two subsets. Species were clumped rather than linearly arranged in the trait-environment space and the functional groups broadly corresponded to weed communities, pastures with differing intensities, and heathlands. The trade-off in plant economics responding to soil resources supports predictions of previous theoretical and empirical work. Different RI-environment relationships in agricultural sites and heathlands emphasize the relevance of local scales in trait-environment studies. In general, the results point to some of the biological mechanisms controlling functions and services of agricultural ecosystems. 相似文献
812.
813.
814.
815.
Höhener Patrick Guers Delphine Malleret Laure Boukaroum Ouassim Martin-Laurent Fabrice Masbou Jérémy Payraudeau Sylvain Imfeld Gwenaël 《Environmental Chemistry Letters》2022,20(6):3927-3942
Environmental Chemistry Letters - The transfer of pesticides from agricultural soils to food and drinking water is a major health issue. There are actually few robust methods to identify,... 相似文献
816.
Wesley M. Knapp Anne Frances Reed Noss Robert F. C. Naczi Alan Weakley George D. Gann Bruce G. Baldwin James Miller Patrick McIntyre Brent D. Mishler Gerry Moore Richard G. Olmstead Anna Strong Kathryn Kennedy Bonnie Heidel Daniel Gluesenkamp 《Conservation biology》2021,35(1):360-368
Extinction rates are expected to increase during the Anthropocene. Current extinction rates of plants and many animals remain unknown. We quantified extinctions among the vascular flora of the continental United States and Canada since European settlement. We compiled data on apparently extinct species by querying plant conservation databases, searching the literature, and vetting the resulting list with botanical experts. Because taxonomic opinion varies widely, we developed an index of taxonomic uncertainty (ITU). The ITU ranges from A to F, with A indicating unanimous taxonomic recognition and F indicating taxonomic recognition by only a single author. The ITU allowed us to rigorously evaluate extinction rates. Our data suggest that 51 species and 14 infraspecific taxa, representing 33 families and 49 genera of vascular plants, have become extinct in our study area since European settlement. Seven of these taxa exist in cultivation but are extinct in the wild. Most extinctions occurred in the west, but this outcome may reflect the timing of botanical exploration relative to settlement. Sixty-four percent of extinct plants were single-site endemics, and many occurred outside recognized biodiversity hotspots. Given the paucity of plant surveys in many areas, particularly prior to European settlement, the actual extinction rate of vascular plants is undoubtedly much higher than indicated here. 相似文献
817.
Cuprys Agnieszka Thomson Paisley Suresh Gayatri Roussi Tarek Brar Satinder Kaur Drogui Patrick 《Environmental science and pollution research international》2022,29(7):10112-10121
Environmental Science and Pollution Research - Ciprofloxacin (CIP), a widely used antibiotic, is frequently detected in the environment due to insufficient wastewater and water treatment. Hence,... 相似文献
818.
Lichtfouse Eric Morin-Crini Nadia Bradu Corina Boussouga Youssef-Amine Aliaskari Mehran Schfer Andrea Iris Das Soumya Wilson Lee D. Ike Michihiko Inoue Daisuke Kuroda Masashi Don Sbastien Fievet Patrick Crini Grgorio 《Environmental Chemistry Letters》2022,20(3):2019-2041
Environmental Chemistry Letters - Worldwide contamination of waters by metals, metalloids, and organometallic pollutants is a major health issue. In particular, the occurrence of the selenium... 相似文献