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   399篇
  免费   29篇
  国内免费   38篇
安全科学   33篇
废物处理   15篇
环保管理   119篇
综合类   170篇
基础理论   22篇
环境理论   2篇
污染及防治   15篇
评价与监测   8篇
社会与环境   75篇
灾害及防治   7篇
  2023年   6篇
  2022年   7篇
  2021年   7篇
  2020年   10篇
  2019年   16篇
  2018年   12篇
  2017年   25篇
  2016年   20篇
  2015年   15篇
  2014年   12篇
  2013年   27篇
  2012年   31篇
  2011年   27篇
  2010年   17篇
  2009年   21篇
  2008年   16篇
  2007年   32篇
  2006年   31篇
  2005年   13篇
  2004年   14篇
  2003年   13篇
  2002年   20篇
  2001年   6篇
  2000年   9篇
  1999年   11篇
  1998年   6篇
  1997年   5篇
  1996年   4篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1988年   2篇
  1986年   1篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有466条查询结果,搜索用时 125 毫秒
441.
以模仿为主要手段的旅游地开发   总被引:2,自引:0,他引:2  
引入博弈论中的豪泰林(Hottelling)价格竞争模型与“偏离-份额分析法”,讨论了无直接竞争状态、价格竞争状态、产品组合竞争状态下的旅游产品模仿问题。通过分析,试图为旅游产品开发提供一种新视角,为旅游产品生产者服务。  相似文献   
442.
国有自然资产流失探析   总被引:3,自引:0,他引:3  
本文探讨了国有自然流失的主要途径;即国有自然资产被无价或低价使用;生产的外部不经济性使自然资产在数量或质量上下降;自然资产未得到有效配置,造成自然资源的痫置与浪费。本文同时提出了解决国有自然流失的对策。  相似文献   
443.
水资源价值量核算的初步构想   总被引:3,自引:0,他引:3  
本文根据水资源的特点,阐述了水资源价值量核算的目的意义,分析了水资源价值量核算的基本原则,提出了进行水资源价值量核算的理论和方法的初步构想。  相似文献   
444.
不同尺度的区域城镇土地基准地价平衡研究   总被引:2,自引:0,他引:2  
区域基准地价平衡是区域城镇基准地价评估的重要内容,对地价管理具有重要的现实意义。分析了不同尺度基准地价平衡的内涵、实质及不同尺度平衡的机理,运用多种方法从宏观尺度的城镇间基准地价平衡、中观尺度的土地级别之间基准地价平衡、微观尺度地块间的区片价平衡进行了研究。以广西县级市——桂平市为例,对桂平市所辖的28个城镇基准地价平衡进行了实例研究,为区域城镇基准地价平衡提供了实用的模式与方法,为培育、发展城镇土地市场奠定了基础。  相似文献   
445.
如何科学评估国有土地使用权挂牌底价,是国有土地使用权以挂牌方式出让工作中极为重要的环节。通过分析挂牌出让底价评估特点、地价内涵,探讨挂牌出让底价的评估方法,指出挂牌出让底价评估宜重点选用市场比较法和假设开发法两种评估方法,明确了市场比较法和假设开发法评估国有土地使用权挂牌出让底价的实施步骤和参数选取标准。  相似文献   
446.
ABSTRACT: In addition to offsetting water supply shortages, water conservation is recognized as serving many purposes, ranging from reduced energy consumption to lower capital costs. Since the discussion of these benefits has been a recent development and has generally excluded local water supply managers, a question arises as to whether supply managers are implementing conservation programs to exploit these benefits. A survey of the managers at 35 Maryland water utilities provides insight into the prevailing attitude toward conservation in a water rich eastern state. The results indicate that most managers continue to view conservation only as a short term response to temporary supply shortages. Only 12 Maryland utilities have undertaken any form of water conservation activity and just two systems have ongoing, comprehensive conservation programs. Institutional, perceptual, economic, political, and time constraints all contribute to the managers’attitudes and general inaction. If water conservation is to be widely practiced, these issues must be addressed and the benefits attributed to conservation must be better documented and articulated to supply managers.  相似文献   
447.
ABSTRACT: Economics is concerned with the allocation of resources between alternative uses. Traditionally, in the western United States, water resources have been committed to agriculture and irrigation. Other competitive uses such as power, industry, and recreation are challenging this allocation. What are the impacts of shifting water out of agriculture into other uses, is a question that needs to be given consideration. Ilia paper attempts to evaluate the tradeoff between using farm land for either irrigated or dryland production and the resulting impacts on gross farm income and the average price of land. Baaed on historical data, reducing irrigated acreage and increasing dryland acreage could greatly reduce both farm income and the equity in farming. The model presented in this paper should be useful for evaluating the tradeoffs between dryland and irrigated land use, especially when there are gat differences in productivity such as those that exist in the inter-mountain region of the Western United States.  相似文献   
448.
Overuse of recreation sites seems to justify regulation, and the principal tools for this are fee charging or physical exclusion. Both seem equally costly to administer. Both involve equal costs to consumers if recreationists visit from one origin, but if they come from different origins, costs may be greater and consumers' surplus less under either tool, depending on the shape of the demand curve. Which is the more equitable tool depends on the relative representation of rich and poor participants from near and distant origins. Potentially beneficial use of site revenues is an advantage of charging. Neither availability of substitutes nor variation in daily demand seems likely to change these results substantially, but a system of booking admissions before the trip outset might neutralize the advantages of charging. The optimal level of use varies with the regulatory tool chosen. The optimal admissions under exclusion could be fewer than or more than under charging, or may even be equal to unregulated use.  相似文献   
449.
A multivariate time series model is formulated to study monthly variations in municipal water demand. The left hand side variable in the multivariate regression model is municipal water demand (gallons per connection per day) and the right hand side contains (explanatory) variables which include price (constant dollars), average temperature, total precipitation, and percentage of daylight hours. The application of the regression model to Salt Lake City Water Department data produced a high multiple correlation coefficient and F-statistic. The regression coefficients for the right hand side variables all have the appropriate sign. In an ex post forecast, the model accurately predicts monthly variations in municipal water demand. The proposed monthly multivariate model is not only found useful for forecasting water demand, but also useful for predicting and studying the impact of nonstructural management decisions such as the effect of price changes, peak load pricing methods, and other water conservation programs.  相似文献   
450.
佛山市顺德区工业VOCs污染问题突出,以中小企业为主的家具行业排放是第二大来源(17%),因此,顺德区率先在广东省开展了家具行业VOCs排污权交易试点工作.本文以区内木质家具行业为例,研究了排污权交易定价方法,得到VOCs平均污染治理成本(5363.26元·t~(-1)·a~(-1))并将其作为排污权交易的初始价格,之后运用多级模糊综合评价法计算的地区调整系数(γ=1.47)进行修正,得到最终参考交易价格(7883.99元·t~(-1)·a~(-1)).该价格与2016年交易底价(8000元·t~(-1)·a~(-1))偏差较小(1.45%).本文还开发了内置核心算法的挥发性有机物排污权交易辅助定价工具,综合利用数据库中企业基本信息、挥发性有机物排放数据等,为排污权交易定价提供辅助决策服务.  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