首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2307篇
  免费   176篇
  国内免费   67篇
安全科学   129篇
废物处理   18篇
环保管理   1059篇
综合类   627篇
基础理论   368篇
环境理论   2篇
污染及防治   52篇
评价与监测   62篇
社会与环境   138篇
灾害及防治   95篇
  2023年   26篇
  2022年   51篇
  2021年   51篇
  2020年   52篇
  2019年   52篇
  2018年   60篇
  2017年   85篇
  2016年   95篇
  2015年   93篇
  2014年   80篇
  2013年   124篇
  2012年   85篇
  2011年   134篇
  2010年   92篇
  2009年   114篇
  2008年   102篇
  2007年   119篇
  2006年   110篇
  2005年   88篇
  2004年   71篇
  2003年   79篇
  2002年   53篇
  2001年   58篇
  2000年   55篇
  1999年   69篇
  1998年   42篇
  1997年   39篇
  1996年   42篇
  1995年   41篇
  1994年   28篇
  1993年   18篇
  1992年   22篇
  1991年   18篇
  1990年   12篇
  1989年   13篇
  1988年   13篇
  1987年   21篇
  1986年   22篇
  1985年   25篇
  1984年   22篇
  1983年   13篇
  1982年   12篇
  1980年   15篇
  1979年   17篇
  1978年   20篇
  1977年   14篇
  1975年   10篇
  1973年   16篇
  1972年   14篇
  1971年   16篇
排序方式: 共有2550条查询结果,搜索用时 13 毫秒
951.
A zero waste program was established at a university campus in response to grassroots student concern over environmental management issues. The implementation procedure consisted of initial discussions with academic and local authority staff at a university environmental forum, the formation of a working group, the preparation of a funding proposal and the establishment of an externally funded research, educational and promotional program led by an academic staff member. Support from senior management existed in the form of a written environmental policy and a signed commitment to environmental responsibility in tertiary education and university funding support followed the success of the initial funding application. Projects were typically conducted by paid research associates, assisted by student volunteers and supervised by a program leader from the academic staff. Co-operation and support from facilities management staff was obtained on an informal basis. A campus environmental committee was established in order to facilitate communication on environmental matters between the School for the Environment, senior university management, facilities management staff, academic staff and students. In order to enable full program development however, a need for linkages between all sectors involved in the program and the introduction of a formal environmental management system was identified.  相似文献   
952.
城镇建设用地需求预测与配置研究   总被引:11,自引:0,他引:11  
针对我国现行城镇建设用地预测方法存在的问题,对城镇建设用地预测方法进行了探索性研究;通过构建科学的建设用地需求预测方法,为土地利用规划提供科学依据。在C—D生产函数的基础上,提出了土地、资本与产出GDP的要素关系模型、恩格尔系数与人均建设用地面积关系模型和时间序列的ARIMA建设用地模型。对成都市城镇建设用地总量进行了实证分析,对4种预测方法的结果进行了定量评价,并据此提出成都市建设用地的配置方案。  相似文献   
953.
黄龙溪古镇旅游开发与再造   总被引:1,自引:0,他引:1  
黄龙溪古镇具有川西民居的典型风格,开发已初具规模,但是在开发过程中未体现出古镇应有的古朴典雅的氛围和气息。通过提出一些实质性的对策建议——硬软件并重、挖掘“古”与“水”,以期解决当地居民的实际困难和问题,把黄龙溪打造成为四川名副其实的著名旅游古镇。  相似文献   
954.
Forest management planners require analytical tools to assess the effects of alternative strategies on the sometimes disparate benefits from forests such as timber production and wildlife habitat. We assessed the spatial patterns of alternative management strategies by linking two models that were developed for different purposes. We used a linear programming model (Spectrum) to optimize timber harvest schedules, then a simulation model (HARVEST) to project those schedules in a spatially explicit way and produce maps from which the spatial pattern of habitat could be calculated. We demonstrated the power of this approach by evaluating alternative plans developed for a national forest plan revision in Wisconsin, USA. The amount of forest interior habitat was inversely related to the amount of timber cut, and increased under the alternatives compared to the current plan. The amount of edge habitat was positively related to the amount of timber cut, and increased under all alternatives. The amount of mature northern hardwood interior and edge habitat increased for all alternatives, but mature pine habitat area varied. Mature age classes of all forest types increased, and young classes decreased under all alternatives. The average size of patches (defined by age class) generally decreased. These results are consistent with the design goals of each of the alternatives, but reveal that the spatial differences among the alternatives are modest. These complementary models are valuable for quantifying and comparing the spatial effects of alternative management strategies.  相似文献   
955.
ABSTRACT: Since 1989, the government of Pierce County, Washington, has prepared four watershed action plans. The watersheds cover almost 800,000 acres and include about 600,000 residents and diverse land uses, from the city of Tacoma to Mount Rainier National Park. The primary purpose of these plans was to address water quality impacts from nonpoint sources of pollution and to protect beneficial uses of water. Pierce County has experienced problems such as shellfish bed closures and the Federal Clean Water Act Section 303(d) listing of local water bodies as a result of declining water quality. Pierce County achieved improvements by engaging diverse groups of stakeholders in generating solutions to nonpoint sources of water pollution through our watershed planning process. Using participatory methods borrowed from private industry, Pierce County was able to reach consensus, build trust, maximize participation, facilitate learning, encourage creativity, develop partnerships, shorten time frames for the planning processes, and increase the level of commitment participants had to implementing the plans. As a result, the earliest plans have a high rate of voluntary implementation. This indicates that the process and methodology used to develop watershed plans has a significant, if not critical, impact on their success.  相似文献   
956.
ABSTRACT: Many studies can be found in the literature pertaining to the effects of urbanization on surface runoff in small watersheds and the hydrologic response of undeveloped watersheds. However, an extensive literature review yielded few published studies that illustrate differing hydrologic responses from multiple source areas within a watershed. The concepts discussed here are not new, but the methods used provide a unique, basic procedure for investigating stormwater hydrology in topographically diverse basins. Six storm hydrographs from three small central Pennsylvania watersheds were analyzed for this paper; five are presented. Two important conclusions are deduced from this investigation. First, in all cases we found two distinct peaks in stream discharge, each representing different contributing areas to direct discharge with greatly differing curve numbers and lags representative of urban and rural source regions. Second, the direct discharge represents only a small fraction of the total drainage area with the urban peak becoming increasingly important with respect to the rural peak with the amount of urbanization and as the magnitude of the rain event decreases.  相似文献   
957.
徐州市建设生态园林城市的概况及几点建议   总被引:1,自引:0,他引:1  
创建生态园林城市越来越成为一个很响亮的提法,成为一种趋势。然而,在这个过程中势必要出现各种问题。如何处理这些问题呢?对于徐州市来讲,创建生态园林城市有其自身的优势,当然也会遇到不少问题,本文在简单介绍了徐州建设生态园林城市的概况之后,对创建过程中出现的某些问题提出了几点建议,重点就环境治理方面的问题阐述自己的看法。  相似文献   
958.
ABSTRACT: Appearances matter for managing riparian landscapes because the appearance of landscapes affects public willingness to accept plans and designs that improve ecological quality. Riparian landscape design and planning should respect and strategically incorporate characteristics that the public values and expects to see. Such design can be quite novel in its ecological effects, but it also should be sufficiently familiar in appearance to correspond with cultural values. This paper describes some influential cultural values for riparian landscapes and demonstrates how attention to such values supports public acceptance of ecologically innovative design in rural and urban watersheds.  相似文献   
959.
Land-use planning using geographic information systems (GIS) commonly emphasizes biophysical spatial data; however planning can be improved by integrating spatial sets of socioeconomic data into the GIS. As an example, we compared a traditional GIS-aided forestry planning protocol that considered only biophysical suitability, with an integrated GIS-aided approach that incorporated both biophysical and socioeconomic suitability. The analyses were conducted for the planning of plantation investments in the Kyaukpadaung Township in the dry zone of central Myanmar. The traditional approach used three biophysical layers for suitability: land use, slope, and accessibility. In contrast, the integrated GIS approach included biophysical suitability data, perceptions and preferences of local villagers towards forestry (social suitability), and quantitative socioeconomic data. The results indicated that the integrated approach provided two principal benefits over the traditional method. First, the integrated method resulted in a more precise idea of suitable sites for plantation investment that could benefit more rural people and also lead to greater investment efficiency. Second, incorporating social preference into the GIS takes into account the crucial element of social capital (viz., social preference), which should lead to higher levels of community acceptance of plantation projects because those plantations would be established on socially suitable land. A second GIS exercise showed how conservation investment decisions could be informed using the integrated method. The results of this study support the idea that GIS-aided planning activities can be enhanced through the incorporation of social data into the analysis. When applicable, spatial data collection efforts for GIS-based planning exercises should incorporate spatial socioeconomic data.  相似文献   
960.
The restoration of degraded systems is essential for maintaining the provision of valuable ecosystem services, including the maintenance of aesthetic values. However, restoration projects often fail to reach desired goals for a variety of ecologic, financial, and social reasons. Feasibility studies that evaluate whether a restoration effort should even be attempted can enhance restoration success by highlighting potential pitfalls and gaps in knowledge before the design phase of a restoration. Feasibility studies also can bring stakeholders together before a restoration project is designed to discuss potential disagreements. For these reasons, a feasibility study was conducted to evaluate the efficacy of restoring a tidal freshwater marsh in the Potomac River near Alexandria, Virginia. The study focused on science rather than engineering questions, and thus differed in approach from other feasibility studies that are mostly engineering driven. The authors report the framework they used to conduct a feasibility study to inform other potential restoration projects with similar goals. The seven steps of the framework encompass (1) initiation of a feasibility study, (2) compilation of existing data, (3) collection of current site information, (4) examination of case studies, (5) synthesis of information in a handbook, (6) meeting with selected stakeholders, and (7) evaluation of meeting outcomes. By conducting a feasibility study using the seven-step framework, the authors set the stage for conducting future compliance studies and enhancing the chance of a successful restoration.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号