全文获取类型
收费全文 | 185篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 56篇 |
废物处理 | 8篇 |
环保管理 | 33篇 |
综合类 | 15篇 |
基础理论 | 46篇 |
污染及防治 | 22篇 |
评价与监测 | 13篇 |
社会与环境 | 4篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 3篇 |
2013年 | 23篇 |
2012年 | 15篇 |
2011年 | 16篇 |
2010年 | 19篇 |
2009年 | 9篇 |
2008年 | 6篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有197条查询结果,搜索用时 15 毫秒
1.
A water quality assessment was conducted on three Appalachian streams polluted by coal mining at the Big South Fork National River and Recreation Area, Tennessee and Kentucky. Results showed that sulfate was an excellent parameter for detecting the effects of coal mining and that sulfate analyses used in conjunction with conductivity readings provided the best detection index. Acidity and pH readings were relatively insensitive indicators, reflecting the mining pollution only after sulfate concentrations already indicated severe pollution levels.Hydrologist, Big South Fork NRRA, during the study; presently at Cape Lookout National SeashoreHydrologist, NPS, during the study; presently with USDA-Forest Service, Washington, DC. 相似文献
2.
Grant R. Sutherland Elizabeth Baker Stuart Purvis-Smith Athel Hockey Ed Krumins Sam Z. Eichenbaum 《黑龙江环境通报》1987,7(3):197-202
Eleven pregnancies in ten patients at risk for the fragile X were monitored by amniocentesis or chorion villus biopsy and induction of the fragile site using thymidine, methotrexate and FUdR. Three female fetuses and one male fetus were found to have the fragile X. The results obtained using thymidine induction were superior to those using methotrexate induction and probably better than those obtained using FUdR induction. 相似文献
3.
4.
5.
6.
Sam S. Cruickshank Arpat Ozgul Silvia Zumbach Benedikt R. Schmidt 《Conservation biology》2016,30(5):1112-1121
Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy‐modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red‐list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence‐only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation. 相似文献
7.
8.
Spatio‐Temporal Patterns of Open Surface Water in the Central Valley of California 2000‐2011: Drought,Land Cover,and Waterbirds 下载免费PDF全文
9.
This paper examines the relationship between North American beef consumption and deforestation in South and Central America.
Some writers have argued that consumption of hamburgers in North America, particularly hamburgers consumed in fast food restaurants,
contributes to the depletion of the rainforest in South and Central America. We survey the published policy literature on
the causes of rainforest depletion in the region. We also review the published estimates of the rate and extent of clearing
of rainforest that has occurred in South and Central America since 1970. Finally, we review the data on beef imports and consumption
in Canada and the United States in a effort to assess the importance of South and Central America as suppliers of beef to
the North American market. We conclude that the relationship between beef consumption in North America should not be considered
an important cause of forest depletion in South and Central America. Domestic policies and market forces in the countries
where rainforests are located are the leading causes of rainforest depletion in this region. This lesson seems to have been
lost on some popular and even some textbook writers on this subject.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
Fish and Invertebrate Flow‐Biology Relationships to Support the Determination of Ecological Flows for North Carolina 下载免费PDF全文