全文获取类型
收费全文 | 504篇 |
免费 | 18篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 19篇 |
环保管理 | 135篇 |
综合类 | 66篇 |
基础理论 | 124篇 |
污染及防治 | 119篇 |
评价与监测 | 26篇 |
社会与环境 | 16篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 3篇 |
2020年 | 1篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 14篇 |
2016年 | 11篇 |
2015年 | 13篇 |
2014年 | 10篇 |
2013年 | 60篇 |
2012年 | 19篇 |
2011年 | 22篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 18篇 |
2007年 | 45篇 |
2006年 | 17篇 |
2005年 | 24篇 |
2004年 | 11篇 |
2003年 | 22篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1968年 | 3篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有525条查询结果,搜索用时 15 毫秒
141.
Moberly RL White PC Webbon CC Baker PJ Harris S 《Journal of environmental management》2004,70(2):129-143
Economic analysis is a useful tool to aid decisions on what to do about wildlife impacts, such as those of vertebrate predators on livestock farmers. The case-study of lamb predation by foxes in Britain is used to develop a theoretical economic model, with the aim of determining a financially optimal solution to minimise the total costs of livestock predation at the farm-level. Total costs include output losses and expenditure on preventive and control measures, in this case indoor housing and lethal fox control. The model is tested empirically with data from a questionnaire survey of sheep farmers and field data on fox population densities in Britain. Regression analyses are used to determine the relationships between lamb losses and expenditure on indoor housing, fox population density and other non-management characteristics. The effect of fox abundance on the cost of fox control is also assessed. Marginal analysis is used to determine the total cost-minimising solution from the farmer's point-of-view, in terms of how many ewes should be housed indoors and for how long, as well as how many foxes should be killed in addition to any lethal control already carried out. Optimal solutions vary according to farm characteristics, including flock size and the regional location of farms. In all cases, to minimise the costs of predation, as many ewes as possible should be housed. However, it is not worthwhile housing them for more than a day after lambing. Efficient fox predation management does not necessarily mean that lamb losses should be reduced to zero, and additional fox control is not worthwhile on the majority of farms. The analysis provides a framework for future evaluations of wildlife impacts and cost-effective management of these problems. 相似文献
142.
143.
依靠大自然:尼日利亚北部的野生食品 总被引:2,自引:0,他引:2
Frances M.A.Harris Salisu Mohammed 《Ambio-人类环境杂志》2003,32(1):24-29
引言 在西非半干旱地区,当地农村社区都使用许多野生植物来补充其日常食品的不足,他(她)们的日常食品主要来自靠雨水浇灌种植出来的主食,比如小米、高粱、花生和豇豆等. 相似文献
144.
In a 1989 article, Ben Twight and Fremont Lyden compared the attitudes of national forest managers in the United States in 1981 with those of its major constituents to assess the extent to which the U.S. Forest Service was biased: were the beliefs and values of agency employees concerning resource management more representative of one of two major constituent groups, environmentalists and forest utilizers? The research tested Culhane's (Public Lands Politics: Interest Group Influence on the Forest Service and the Bureau of Land Management. Baltimore, Maryland: John Hopkins University Press. 1981) theory that the Forest Service occupies a middle ground in its attitudes relative to those of its environmental and utilization constituencies. They concluded that the agency did not; ideologically, district rangers were quite close to the Forest Service's utilizer constituency and relatively far from its environmentalist constituency. Given recent changes in the attitudes of Forest Services managers, the present study sought to answer the question: what do these changes reveal about the ideological position of the agency in 1981 vis a vis its position in 1990, and what are their implications for continuing concerns over the agency's representation of all interest groups? The response to survey questions of four groups—1990 district rangers and district rangers, environmentalists and forest utilizers in 1981—were combined for statistical comparison. Discriminant analyses were conducted to clarify the differences in the groups. Although the hypothesized bias of the Forest Service toward the traditional utilizer position was confirmed, the results also suggested that managers' values and attitudes had changed over the decade. The major issue underlying this bias—preservation versus utilization of resources—no longer adequately represented the agency's position, which has been fragmented into concerns with multiple issues. 相似文献
145.
Richard R. Harris 《Environmental management》1988,12(2):219-228
Ten streams in the eastern Sierra Nevada, California, were classified into six geomorphic valley types and sampled to determine environmental and riparian vegetation conditions. The geomorphic valley types were relatively uniform geologically and hydrologically, collectively representing the range of stream environments in the region. There were significant associations between the geomorphic valley types and riparian community composition. These geomorphic-vegetation units are landscape elements which comprise the riparian ecosystems in the region. They differ in their ecological charactersitics and sensitivity to management. The system of landscape elements can be used to classify streams for the purposes of resource inventory, detailed ecological studies, and impact prediction. 相似文献
146.
Patricia Bobrow Barbara Gaige Glenn Harris Joyce Kennedy Leslie King William Raymond Darrin Werbitsky 《Environmental management》1984,8(1):45-53
This study compares the effectiveness of two regional planning agencies in terms of public support for various planning activities. The Adirondack Park Agency and the Temporary State Commission on Tug Hill have fundamentally different approaches to planning. The Adirondack Park Agency has implemented a restrictive regulatory program with little citizen participation by Adirondack residents. The Tug Hill Commission has implemented an advisory and coordinating program with an emphasis on public input. Residents of two towns in each region were surveyed to determine environmental concern and support for regional planning activities. Respondents from both regions favored a planning agency that incorporates citizen input; controls air, water, and toxic waste pollution; and develops recreation areas. They strongly opposed an agency that regulates private land-use. Basic demographic characteristics and levels of environmental concern were similar in all four towns, but receptivity to various planning activities was consistently greater among residents of the Tug Hill Region. Paired comparisons of the four towns demonstrated no differences between towns of the same region and significant differences between towns of different regions. Public support for regional planning is greater in the Tug Hill Region than in the Adirondack Park. 相似文献
147.
Many small communities are concerned about health effects from environmental pollutants. One such community, Orwell, in Oswego County, New York, was investigated to determine if the level of cancer was significantly high in comparison to the county and the state. A pilot health study was administered among residents living in a defined area. Results of the survey demonstrated that cancer incidence was higher than both Oswego County and New York State, while cancer mortality was higher for men and lower for woman. A closer examination of the data showed that the way in which health surveys are usually analyzed may not be appropriate for small communities. In particular, some parametric statistics, such as chi-square analysis, might show significant differences between populations when standardized incidence and mortality rates are derived from small samples, yet standard deviations calculated from these data are so large as to cast doubt on the analysis. Researchers have discussed this problem theoretically, but empirical studies illustrating the difficulties have not heretofore appeared in the published literature. For health studies in small communities, greater consideration should be given to risk ratios and the implications of standard deviations. 相似文献
148.
Biological monitoring of a pulp and paper mill wastewater 总被引:1,自引:0,他引:1
The physico-chemical testing required under the E.P.A. licence enables one to gauge the chemical effects of the APM wastewater on the Latrobe River, but it tells us nothing about likely effects on the aquatic biota. The APM bio-monitoring programme was instigated to provide evidence of any effects of wastewater discharges on the rivers biota. To date the programme has shown no adverse impact downstream. The laboratory bioassays on fish and algae have recently given way to the river fauna surveys as the regular monitor of wastewater quality. It is intended to continue with regular river surveys using the river's residents as indicators of water quality and future surveys will investigate reasons for the presently obscure variation in macro-invertebrate populations. 相似文献
149.
Summary The distributions of mountain hare (Lepus timidus) and European hare (L. europaeus) overlap in central Sweden, but they occupy separate food niches in winter. In Scandinavia, the European hare is mainly a grazer while mountain hare is a predominant browser. Browse contain high amounts of secondary metabolites, such as phenols, compared to grass. This raises the question if the two hare species differ in their metabolic tolerance of plant phenols and that these differences influence their food choice.Phenolic excretion in urine increased significantly with phenolic intake in both species. Excretion of glucuronic acid conjugates, one of the major pathways of elimination of phenols in both hare species, is positively correlated to phenolic intake and excretion. However, the extent of excretion of phenolics by this route was different in the two species of hare. European hares excreted substantially more glucuronic acid per amount of phenolics than mountain hare. The phenols were metabolized to a larger extent in the mountain hare, indicating a higher detoxification capacity. From these results it is likely that European hare have a higher cost for the detoxification of plant phenols compared to mountain hare. This cost and negative effect on sodium balance when feeding on browse may prevent exploitation of forest habitats by European hares, whereas mountain hare are better able to do so. 相似文献
150.
Cameron R Dale Bass Cameron Dale Bass Martin Davis Karin Rafaels Mark Steve Rountree Robert M Harris Ellory Sanderson Walter Andrefsky Gina DiMarco Michael Zielinski 《International journal of occupational safety and ergonomics》2005,11(4):347-361
To reduce human casualties associated with explosive ordnance disposal, a wide range of protective wear has been designed to shield against the blast effects of improvised explosive devices and munitions. In this study, 4 commercially available bomb suits, representing a range of materials and armor masses, were evaluated against 0.227 and 0.567 kg of spherical C-4 explosives to determine the level of protection offered to the head, neck, and thorax. A Hybrid III dummy, an instrumented human surrogate [1], was tested with and without protection from the 4 commercially available bomb suits. 20 tests with the dummy torso mounted to simulate a kneeling position were performed to confirm repeatability and robustness of the dummies, as well as to evaluate the 4 suits. Correlations between injury risk assessments based on past human or animal injury model data and various parameters such as bomb suit mass, projected area, and dummy coverage area were drawn. 相似文献