全文获取类型
收费全文 | 654篇 |
免费 | 16篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 16篇 |
环保管理 | 152篇 |
综合类 | 103篇 |
基础理论 | 192篇 |
环境理论 | 1篇 |
污染及防治 | 110篇 |
评价与监测 | 30篇 |
社会与环境 | 27篇 |
灾害及防治 | 16篇 |
出版年
2023年 | 10篇 |
2022年 | 9篇 |
2021年 | 25篇 |
2020年 | 13篇 |
2019年 | 28篇 |
2018年 | 20篇 |
2017年 | 30篇 |
2016年 | 31篇 |
2015年 | 20篇 |
2014年 | 19篇 |
2013年 | 50篇 |
2012年 | 36篇 |
2011年 | 35篇 |
2010年 | 31篇 |
2009年 | 28篇 |
2008年 | 38篇 |
2007年 | 27篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 24篇 |
2003年 | 18篇 |
2002年 | 26篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有681条查询结果,搜索用时 15 毫秒
621.
The present study aimed to determine the extent to which variation in the uptake of serum screening for Down syndrome reflects variation in the way the test is offered. A higher uptake of serum screening was seen at hospitals that offered the blood test as part of a routine visit than at those where screening required a separate visit. The type of screening test offered and whether a reminder was sent were not associated with uptake. Given the consensus that undergoing screening should be the result of an informed choice, further research is needed to determine which methods of offering serum screening facilitate and which impede informed choice. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
622.
623.
Andrew C. Harper John L. Cordery Nick H. de Klerk Peter Sevastos Elizabeth Geelhoed Christine Gunson Lesley Robinson Michael Sutherland Derek Osborn John Colquhoun 《Safety Science》1996,24(3):173-179
Behavior-based safety has been found universally efficacious when evaluated under controlled conditions. The Curtin Trial aimed to test the general acceptability of behavior-based safety in Australian industry. A 50% failure rate was observed. This paper presents the results of a qualitative analysis of observed managerial behavior in relation to program effectiveness. Field notes taken in the course of 325 hours of participant observation during implementation of behavior-based safety in 9 work areas were analyzed qualitatively and categorized. These data were compared with statistical results of the safety program's effectiveness on improving safe practices and good housekeeping. Nine dimensions to managerial behavior were identified which were associated with program effectiveness. A relatively small number of studies investigating organizational characteristics and safety have found generally similar social environmental features to those observed in this study. Behavior-based safety appears to be effective only in organizations with recognizable managerial styles. 相似文献
624.
Martin H. David Elizabeth L. David 《Journal of the American Water Resources Association》1983,19(3):421-428
With the pressure from industries and municipalities to reduce the waste water treatment costs associated with the permit limits needed to attain the goals of the Clean Water Act, attention has turned ways of introducing flexibility into the regulations without sacrificing the water quality goals. Wisconsin is the first state to have adopted a variety of options from which dischargers may choose when meeting their water quality requirements. These options were developed for the express purpose of minimizing the costs and maximizing the flexibility of the point source water quality regulations while ensuring that permitted discharge would not violate the water quality standards. This paper presents five options that the state has made available to dischargers, as well as one the state did not adopt. The conclusion is that a mix of options can substantially increase the flexibility and reduce the costs of meeting water quality standards on effluent limited streams. 相似文献
625.
Deserai A. Crow Elizabeth A. Albright 《Journal of Environmental Policy & Planning》2019,21(3):257-274
ABSTRACTWhen communities experience disaster, emergency response and recovery are led internally, based on local-level policy decisions and priorities. Decisions about how or whether to rebuild are made by local governments. Higher governmental authorities such as states and provinces may institute their own disaster recovery processes and policies in addition to or in competition with local governments. Greater intergovernmental engagement could increase resources and knowledge, which would yield higher levels of learning and result in superior disaster recovery policy outcomes. The role of higher authorities, then, can have important implications for policy processes and outcomes. The learning literature includes a dearth of studies that analyze the relationships between state and local governments during disaster recovery. We move the learning literature forward by analyzing intergovernmental relationships during disaster recovery. We find that learning within local governments is associated with higher levels of resource flows from state agencies as well as more collaborative intergovernmental relationships. We also find that state governments can improve processes for disaster recovery assistance and bring together disaster-affected local governments to promote learning during the recovery process. While this study focused on relationships constrained by U.S. federal dynamics, the lessons are useful to other multilevel governance systems. 相似文献
626.
We examined regional conditions and trends related to quality of life and potential vulnerabilities of these factors to changes in the condition of natural resources in the Mid-Atlantic Region, USA. We selected a variety of variables on economic and socio-demographic conditions that demonstrate links between the condition of natural areas and human concerns and that quantify dependencies on resources. We extracted data from economic and population census databases for counties within the study area and present a subset of results of the cluster analyses used to describe condition and potential risks due to distinct combinations of variables. We found that the same variables used to judge quality of life were often correlated with increasing population and thus were likely to be related to land pressures and risks to natural resources. Within the region, economic dependence on resource-harvesting industries such as forestry and fisheries was low (less than 4% of total earnings at most), however, the potential for natural amenities to attract residents appeared to be growing as the self-employed and otherwise mobile people settled in areas with affordable housing and natural amenities. Suburban residential spread had been occurring in both the close-in and distant suburbs of the region's urban areas and some rural, growth appeared to be driven, in part, by businesses migrating to suburbs. Further work is needed to tease apart causal factors for the trends we observed, but correlations clearly existed in some areas between increasing populations and quality of natural surroundings. 相似文献
627.
Mathematical Methods for Spatially Cohesive Reserve Design 总被引:1,自引:0,他引:1
Mark D. McDonnell Hugh P. Possingham Ian R. Ball Elizabeth A. Cousins 《Environmental Modeling and Assessment》2002,7(2):107-114
The problem of designing spatially cohesive nature reserve systems that meet biodiversity objectives is formulated as a nonlinear integer programming problem. The multiobjective function minimises a combination of boundary length, area and failed representation of the biological attributes we are trying to conserve. The task is to reserve a subset of sites that best meet this objective. We use data on the distribution of habitats in the Northern Territory, Australia, to show how simulated annealing and a greedy heuristic algorithm can be used to generate good solutions to such large reserve design problems, and to compare the effectiveness of these methods. 相似文献
628.
G. S. Balamurali Elizabeth Nicholls Hema Somanathan Natalie Hempel de Ibarra 《Die Naturwissenschaften》2018,105(1-2):8
The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees’ responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees’ preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects. 相似文献
629.
Elizabeth A Wilman 《Journal of Environmental Economics and Management》1980,7(3):272-286
This paper examines the role of time costs—both on-site and travel—in models describing recreation behavior, and draws implications for the travel-cost approach to recreation site benefit estimation. The analysis shows that both recreation and travel time are costly. The latter can be valued in terms of its scarcity value, but the former may be most appropriately valued in terms of the “alue of travel time saved.” Although there are cases in which on-site time costs need not be explicitly considered in recreation benefit models, it is not clear such cases are the rule rather than the exception. Suggestions are made for measuring on-site and travel time costs. 相似文献
630.
Virginia McConnell Elizabeth Kopits Margaret Walls 《Journal of Environmental Planning and Management》2006,49(5):631-651
This paper reviews different approaches to using transferable development rights (TDRs) as a way to preserve rural lands in the face of development pressure. One TDR program is examined in detail, that of Calvert County, Maryland, which has had an active TDR market since the mid-1980s. This program uses TDRs as a key policy tool for achieving a total amount of preserved acreage in the county, and for providing incentives for preservation in some areas and development in others. The paper examines both the early difficulties in developing participation in the program, and the events that lead eventually to an active TDR market. It assesses the workings of the market including factors that influence the demand and supply of TDRs, the movement of prices over time, and the location of preserved areas and of additional developed areas. The study found that the program is achieving many of the county's land preservation goals because of the high level of activity in the TDR market. However, most of the additional density is being channeled into rural areas with underlying low-density zoning. 相似文献