全文获取类型
收费全文 | 386篇 |
免费 | 22篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 37篇 |
废物处理 | 10篇 |
环保管理 | 97篇 |
综合类 | 44篇 |
基础理论 | 124篇 |
环境理论 | 2篇 |
污染及防治 | 52篇 |
评价与监测 | 26篇 |
社会与环境 | 16篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 9篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 14篇 |
2019年 | 11篇 |
2018年 | 21篇 |
2017年 | 15篇 |
2016年 | 26篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 35篇 |
2011年 | 26篇 |
2010年 | 14篇 |
2009年 | 27篇 |
2008年 | 22篇 |
2007年 | 20篇 |
2006年 | 21篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有413条查询结果,搜索用时 31 毫秒
221.
222.
Rebecca S. Roberts David R. Lighthall 《Journal of the American Water Resources Association》1991,27(3):437-446
ABSTRACT: The growing problem of nonpoint source ground water contamination from agricultural chemicals is conceptualized as an historical outcome of the production environment of capitalist agriculture in the Corn Belt. Chronic overproduction and ground water contamination reveal different aspects of the same technological treadmill. The debate over Iowa's 1987 Ground Water Protection Act symbolizes the contradiction between popular demand for clean water and structural limits on policymaking. Although the Act does provide for expanded research, education, and monitoring, a coalition of commercial farmers, local chemical dealers, and the national chemical industry defeated a tax on pesticide use. Analysis of alternate policy responses - Best Management Practices (BMPs), cross compliance, site-specific regulation of chemical use, and taxation of synthetic chemicals - reveals that all tend to founder on the same structural constraints. Without practical, profitable, low-input technologies that farmers, over time, would choose to adopt, both voluntary and regulatory approaches encounter major political or implementation difficulties. The public agricultural research agenda, therefore, emerges as a central control variable for ground water quality management and a central focus for political struggle. 相似文献
223.
Carolyn E. Gombert Stephen T. Lancaster Gordon E. Grant Rebecca L. Flitcroft 《Journal of the American Water Resources Association》2023,59(4):615-634
In the Willamette River, OR, main channel temperatures can be too warm for cold water fishes, causing fish to concentrate in secondary channel features that provide thermal refugia. However, temperature regimes vary among and within features. Improved understanding of physical processes controlling thermal regimes is needed. This study developed a dimensionless index for assessment of thermal refugia on the upper Willamette River. The novel hyporheic insolation (HIN) index uses minimal field measurements to predict thermal refugia resulting from buffering. Continuous water temperature measurements at one side channel, eight alcoves, and six beaver ponds provided data to ground truth calculated predictions. Water temperature records were first used to characterize stratification at sites. Calculation of the Richardson number, an index of stability, showed two well-mixed sites and 13 stratified sites. At stratified sites, calculated values characterized the ratio of cooling flux from hyporheic discharge to heat flux from incoming solar radiation. As increased, measured temperatures at sites decreased. Despite overall scatter, a logarithmic fit to bin-averaged values showed R2 = 0.91. Calculations suggest that secondary channel features characterized by stratification and cool hyporheic discharge can provide thermal refugia. Accordingly, the HIN index may serve as a practical tool grounded in physical processes governing temperature across a floodplain. 相似文献
224.
Rebecca S. Wargo Richard N. Weisman 《Journal of the American Water Resources Association》2006,42(4):989-995
ABSTRACT: Single‐barrel culverts are a common means of roadway crossings for smaller streams. While this culvert design provides an economical solution for a crossing, the adverse effects of conveying the stream through a single opening can be far reaching. The single‐barrel culvert is typically sized for a design storm much greater than the channel forming discharge. This oversizing causes an interruption of the normal flow patterns and sediment transport for the system. Shallow depths at low flow in the pipe and perching at the outlet can impede fish passage. Multicell culverts (where the main culvert at the channel invert is sized for bankfull discharge, and additional pipes are placed at the floodplain elevation to convey overbank flow up to the design discharge) have been recommended as a best management practice to minimize erosion and improve fish passage. This flume study scaled a prototype single‐barrel culvert to both a single‐cell model, and a multicell design to compare outlet scour and flow depths within the culvert. The results provide designers and planners with evidence of the benefits of multicell culverts to justify the higher cost of installation compared to single‐barrel culverts. 相似文献
225.
226.
Agricultural BMP Effectiveness and Dominant Hydrological Flow Paths: Concepts and a Review
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rebecca A. Rittenburg Audrey L. Squires Jan Boll Erin S. Brooks Zachary M. Easton Tammo S. Steenhuis 《Journal of the American Water Resources Association》2015,51(2):305-329
We present a conceptual framework that relates agricultural best management practice (BMP) effectiveness with dominant hydrological flow paths to improve nonpoint source (NPS) pollution management. We use the framework to analyze plot, field and watershed scale published studies on BMP effectiveness to develop transferable recommendations for BMP selection and placement at the watershed scale. The framework is based on the location of the restrictive layer in the soil profile and distinguishes three hydrologic land types. Hydrologic land type A has the restrictive layer at the surface and BMPs that increase infiltration are effective. In land type B1, the surface soil has an infiltration rate greater than the prevailing precipitation intensity, but there is a shallow restrictive layer causing lateral flow and saturation excess overland flow. Few structural practices are effective for these land types, but pollutant source management plans can significantly reduce pollutant loading. Hydrologic land type B2 has deep, well‐draining soils without restrictive layers that transport pollutants to groundwater via percolation. Practices that increased pollutant residence time in the mixing layer or increased plant water uptake were found as the most effective BMPs in B2 land types. Matching BMPs to the appropriate land type allows for better targeting of hydrologically sensitive areas within a watershed, and potentially more significant reductions of NPS pollutant loading. 相似文献
227.
Featured Collection Introduction: Synthesis and Analysis of Conservation Effects Assessment Projects for Improved Water Quality
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
228.
A recent turn towards a more contextually sensitive apprehension of the challenge of making everyday life less resource hungry has been partly underwritten by widespread evidence that the environmental values people commonly profess to hold do not often translate into correspondingly low impact actions. Yet sometimes the contexts of everyday life can also conspire to make people limit their consumption without ever explicitly connecting this to the environmental agenda. This paper considers this phenomenon with reference to UK studies from both ends of the generational spectrum. The first questioned how older people keep warm at home during winter and the second examined how young people get rid of no longer wanted possessions. Both found that, though the respondents involved were acting in certain ways that may be deemed comparatively low impact, they were hitherto relatively indifferent to the idea of characterising these actions as such. We outline three ways in which sustainability advocates might respond to the existence of such “inadvertent environmentalists” and consider how they might inspire studies that generate fresh intervention ideas instead of lingering on the dispiriting recognition that people do not often feel able to act for the environment. 相似文献
229.
In recent decades, there has been an increasing emphasis on proactive efforts to conserve species being considered for listing under the U.S. Endangered Species Act (ESA) before they are listed (i.e., preemptive conservation). These efforts, which depend on voluntary actions by public and private land managers across the species’ range, aim to conserve species while avoiding regulatory costs associated with ESA listing. We collected data for a set of social, economic, environmental, and institutional factors that we hypothesized would influence voluntary decisions to promote or inhibit preemptive conservation of species under consideration for ESA listing. We used logistic regression to estimate the association of these factors with preemptive conservation outcomes based on data for a set of species that entered the ESA listing process and were either officially listed (n = 314) or preemptively conserved (n = 73) from 1996 to 2018. Factors significantly associated with precluded listing due to preemptive conservation included high baseline conservation status, low proportion of private land across the species’ range, small total range size, exposure to specific types of threats, and species’ range extending over several states. These results highlight strategies that can help improve conservation outcomes, such as allocating resources for imperiled species earlier in the listing process, addressing specific threats, and expanding incentives and coordination mechanisms for conservation on private lands. 相似文献
230.
Research shows that relationship conflict has a negative impact on job performance. There is scant theoretical work, however, explaining the interpersonal dynamics that lead to this outcome. A conceptual model is developed that explores how relationship conflict impacts performance through its effects on trust and exchange. We argue that relationship conflict has a detrimental effect on trust motivating coworkers to rely more on calculus‐based trust than on relationship‐based trust. This, in turn, affects the form of exchange coworkers use with one another, leading them to rely on negotiated exchange to the exclusion of reciprocal exchange. This kind of exchange relationship, finally, affects in‐role, extra‐role, and attitudinal outcomes. The literature shows that superordinate goals can mitigate relationship conflict and we use social and self‐categorization theories to explain and explore this effect on both relationship conflict and trust. How trust and exchange might change over time is also explored. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献