全文获取类型
收费全文 | 415篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 6篇 |
环保管理 | 30篇 |
综合类 | 214篇 |
基础理论 | 78篇 |
污染及防治 | 56篇 |
评价与监测 | 17篇 |
社会与环境 | 9篇 |
灾害及防治 | 4篇 |
出版年
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 15篇 |
2012年 | 6篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 15篇 |
2008年 | 7篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1981年 | 7篇 |
1967年 | 5篇 |
1961年 | 5篇 |
1959年 | 6篇 |
1958年 | 4篇 |
1957年 | 4篇 |
1955年 | 10篇 |
1954年 | 5篇 |
1940年 | 3篇 |
1939年 | 4篇 |
1935年 | 3篇 |
1934年 | 8篇 |
1932年 | 5篇 |
1931年 | 3篇 |
1929年 | 6篇 |
1928年 | 5篇 |
1926年 | 3篇 |
1921年 | 4篇 |
1918年 | 4篇 |
1915年 | 3篇 |
1913年 | 8篇 |
排序方式: 共有421条查询结果,搜索用时 0 毫秒
51.
Urban ecologists have demonstrated that cities are functioning ecosystems. It follows then that species living in these contexts should participate in and experience the same suite of biological processes, including evolution, that have occupied scientists for centuries in more “natural” contexts. In fact, urban ecosystems with myriad novel contexts, pressures, and species rosters provide unprecedentedly potent evolutionary stimuli. Here, we present the case for studying adaptive evolution in urban settings. We then review and synthesize techniques into a coherent approach for studying adaptive evolution in urban settings that combines observations of phenotypic divergence, measurements of fitness benefits of novel genetically based phenotypes, and experimental manipulations of potential drivers of adaptation. We believe that studying evolution in urban contexts can provide insights into fundamental evolutionary biology questions on rate, direction, and repeatability of evolution, and may inform species and ecosystem service conservation efforts. 相似文献
52.
53.
Mitchell J. Small Bernard J. Cosby Ronald J. Marnicio Max Henrion 《Environmental monitoring and assessment》1995,35(2):113-136
The empirical direct distribution model for lake acidification is calibrated for use in an integrated assessment model which predicts the regional impact of an acid deposition control strategy. The calibration is based on the mechanistic Model of Acidification of Groundwater in Catchments (MAGIC). The models are applied jointly to a set of 33 statistically-selected lakes in the Adirondack region of New York. Calibration of the direct distribution model is based on a step-function application of acid deposition to MAGIC. Comparative evaluations of the resulting model predictions are made using historic deposition estimates and two alternative future deposition scenarios. The predictions of the direct distribution model match well the shapes and patterns of change of the regional distributions of ANC and pH predicted by MAGIC, the short- and medium-term dynamics of these changes, and the effect of including organic acids. However, small, long-term decreases in the fraction of incoming acid deposition neutralized by lakes and their watersheds predicted by MAGIC are not reproduced. 相似文献
54.
The Midlands Region of the Environment Agency has developed a management system, in the form of an Environmental Action Plan (EAP) to ensure that the constraints and mitigation measures identified in the Environmental Statement document are delivered on the ground. The reasons are considered for developing such procedures and examples are provided of the environmentalobjectives and targets which lie at the heart of the new procedures. The EAP is designed to provide a summary of the environmental constraints, adverse effects and their associated mitigation measures, and monitoring requirements, in an easily accessible document for both technical and non-technical readers. 相似文献
55.
56.
Sam H. Johnson Alan C. Early Max K. Lowdermilk 《Journal of the American Water Resources Association》1977,13(6):1253-1268
ABSTRACT: Examples are drawn from the Indus Basin to explain why on-farm water management problems restrict the output of agricultural products in many LDC's. Data is presented to illustrate the low level of water management knowledge of both the farmers and the current extension agents. Examples of the level of corruption and its effect on the operating system are illustrated. Several requirements that must be met before a large-scale irrigation scheme will actually increase the welfare of LDC's farmers are presented. 相似文献
57.
58.
59.
60.