全文获取类型
收费全文 | 1761篇 |
免费 | 226篇 |
国内免费 | 177篇 |
专业分类
安全科学 | 579篇 |
废物处理 | 20篇 |
环保管理 | 367篇 |
综合类 | 471篇 |
基础理论 | 361篇 |
环境理论 | 6篇 |
污染及防治 | 45篇 |
评价与监测 | 21篇 |
社会与环境 | 169篇 |
灾害及防治 | 125篇 |
出版年
2024年 | 4篇 |
2023年 | 45篇 |
2022年 | 66篇 |
2021年 | 91篇 |
2020年 | 98篇 |
2019年 | 105篇 |
2018年 | 77篇 |
2017年 | 108篇 |
2016年 | 134篇 |
2015年 | 84篇 |
2014年 | 69篇 |
2013年 | 166篇 |
2012年 | 128篇 |
2011年 | 101篇 |
2010年 | 85篇 |
2009年 | 95篇 |
2008年 | 80篇 |
2007年 | 97篇 |
2006年 | 82篇 |
2005年 | 62篇 |
2004年 | 59篇 |
2003年 | 56篇 |
2002年 | 36篇 |
2001年 | 29篇 |
2000年 | 35篇 |
1999年 | 31篇 |
1998年 | 22篇 |
1997年 | 19篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有2164条查询结果,搜索用时 67 毫秒
101.
危险品运输实时监控及应急救援服务平台构建 总被引:5,自引:2,他引:3
针对我国危险品运输监管及应急救援现状,提出构建"危险品运输实时监控及应急救援服务平台"的技术方案。设计了平台系统的技术框架,介绍装载于危险品运输车辆之上的"监控终端"以及应急救援车辆之上的"智能终端"的基本功能,并以环保部门为例阐述了服务平台与危险废物监管政务平台之间的数据交换及功能耦合,以及利用服务平台开展危险品运输事故应急救援联动流程。该平台可望解决"危险品运输多部门监管数据不一致以及多部门联动应急救援调度困难"这一实际问题。 相似文献
102.
Abstract: We examined how differences in local forest‐management institutions relate to disparate anthropogenic forest disturbance and forest conditions among three neighboring montane forests in Tanzania under centralized, comanaged, or communal management. Institutional differences have been shaped by decentralization reforms. We conducted semistructured interviews with members of forest management committees, local government, and village households and measured anthropogenic disturbance, tree structure, and species composition in forest plots. We assessed differences in governance system components of local institutions, including land tenure, decision‐making autonomy by forest users, and official and de facto processes of rule formation, monitoring, and enforcement among the three management strategies. We also assessed differences in frequencies of prohibited logging and subsistence pole cutting, and measures of forest condition. An adjacent research forest served as an ecological reference for comparison of forest conditions. Governance was similar for comanaged and centralized management, whereas communal managers had greater tenure security and decision‐making autonomy over the use and management of their forest. There was significantly less illegal logging in the communal forest, but subsistence pole cutting was common across all management strategies. The comanaged forest was most disturbed by recent logging and pole cutting, as were peripheral areas of the larger centralized forest. This manifested in more degraded indicators of forest conditions (lower mean tree size, basal area, density of trees ≥ 90 cm dbh, and aboveground biomass and higher overall stem density). Greater tenure security and institutional autonomy of the communal strategy contributed to more effective management, less illegal logging, and maintenance of good forest conditions, but generating livelihood benefits was a challenge for both decentralized strategies. Our results underscore the importance of well‐designed institutional arrangements in forest management and illustrate mechanisms for improved forest governance and conservation in the context of Tanzanian decentralization reforms. 相似文献
103.
H. Ken Cordell John C. Bergstrom Gregory A. Ashley John Karish 《Journal of the American Water Resources Association》1990,26(1):53-60
ABSTRACT: Outdoor recreation is a major, growing use of water resources in the United States. The economic effects of expenditures by visitors to three recreational river sites on local economies surrounding the sites were estimated using an input-output model (IMPL.AN). Expenditure data were from the Public Area Recreation Visitors Study (PARVS). Results indicate that visitor spending stimulates a considerable amount of economic activity and growth in local economies. Economic effects include increases in total gross output ranging from $2.6 million to $13.4 million, increases in total income ranging from $1.2 million to $5.6 million, and increases in employment ranging from 60 to 292 jobs. 相似文献
104.
ABSTRACT: Local governments often face environmental problems that cross political boundaries. The onus for solution usually falls on the moat severely affected jurisdiction, others do nothing until impacted. Resolution of these problems requires cooperation across political boundaries which means that local governments must be persuaded first that there is a problem, and second that action is required to solve it. This paper presents a method to supply low cost, credible information that can be used to achieve consensus on problem solution. A case study of a lake water quality management problem is described. Formative evaluation techniques was adapted to provide a minimum of evidence which was then used to persuade less impacted local jurisdictions to cooperate in the problem solution. 相似文献
105.
ABSTRACT: Drought has been a prevalent feature of the American landscape during the latter part of the 1980s, producing serious socioeconomic and environmental consequences. These recent experiences with drought have renewed concern about the inadequacy of federal and state contingency planning efforts and the lack of coordination for assessment and response efforts between these levels of government. This paper presents the results of research aimed at facilitating the preparation of drought contingency plans by state government in conjunction with a state's overall water management planning activity. The ten-step drought plan development process reported is intended to improve mitigation efforts through more timely, effective, and efficient assessment and response activities. Officials in appropriate state agencies should examine the proposed framework and alter it to best address drought-related concerns, adding or deleting elements as necessary. 相似文献
106.
Paul Lawless 《Journal of Environmental Planning and Management》1988,31(1):13-18
There has been a marked proliferation of local economic development initiatives in recent years. Enterprise Boards have proved one of the most successful of these innovations. In the early 1980s five were established. Two, the Greater London and the West Midlands Enterprise Boards, were initially designed to intervene radically within their local economies, although subsequent events moderated their activities. The remaining three in Lancashire, West Yorkshire and Merseyside, have successfully widened their operations to embrace collaborate projects with the private sector, training, boosting co‐operatives, and research. By many economic evaluations, for example, jobs supported, leverage ratios and investment per job, Enterprise Boards have performed better than other instruments of urban and regional development. Wider socio‐political objectives have proved more difficult to achieve. 相似文献
107.
Kwawe DB 《Journal of environmental management》2002,66(4):345-359
Records in public archives were evaluated for the period 1981-1991. Simple surveys of peoples and of technology and physical premises provided insight to gauge the attitudes of a local community in the Melbourne municipality and the Melbourne City Council towards composting of organic waste materials. There is a lag in perception and attitudes between the local community and the local government towards composting of organic refuse as a solid waste treatment option. The simple methodology of the study still made it possible to verify past and present perceptions and attitudes. 相似文献
108.
N. K. Woodfield J. W. S. Longhurst C. I. Beattie D. P. H. Laxen 《Water, Air, & Soil Pollution: Focus》2002,2(5-6):677-688
Across the United Kingdom, the majority of local authoritieshave now completed their first phase of local air qualityreview and assessment work, as required under the AirQuality Strategy for England, Scotland, Wales and NorthernIreland (DETR, 2000a). Emerging from this first phasework is an anticipated suite of over 110 Air QualityManagement Areas (AQMAs). These areas are identifiedlocations where one or more of the national air qualityobjectives are predicted to exceed by specific target dates,and their spatial extent and shape is emerging as highlyvariable. Local authorities are guided to use a variety ofscientific tools to underpin the scientific assessments, anda consideration of uncertainty in both the tools used andsubsequent delineation of AQMAs is likely to affect theemerging management areas significantly. With subsidiarity underpinning the process of local air qualitymanagement (LAQM), local decision-making is anticipated toinfluence the outcome of the LAQM process in its entirety,with the declaration of AQMAs necessitating the preparationand implementation of air quality action plans. UKexperience of the effective management of local air quality,through the designation of AQMAs, demonstrates a valuableframework for other European countries developing mechanismsto manage air quality locally. 相似文献
109.
110.
随着计算机的普及 ,局域网络越来越广为利用 ,但也出现了相应的失密问题。本文从信息及实体两个方面 ,论述了局域网络的保密措施。 相似文献