全文获取类型
收费全文 | 305篇 |
免费 | 31篇 |
国内免费 | 59篇 |
专业分类
安全科学 | 81篇 |
废物处理 | 9篇 |
环保管理 | 34篇 |
综合类 | 152篇 |
基础理论 | 50篇 |
污染及防治 | 21篇 |
评价与监测 | 11篇 |
社会与环境 | 18篇 |
灾害及防治 | 19篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 11篇 |
2021年 | 11篇 |
2020年 | 21篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 24篇 |
2012年 | 25篇 |
2011年 | 34篇 |
2010年 | 18篇 |
2009年 | 23篇 |
2008年 | 11篇 |
2007年 | 29篇 |
2006年 | 7篇 |
2005年 | 16篇 |
2004年 | 9篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 8篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有395条查询结果,搜索用时 93 毫秒
251.
张世秋 《中国人口.资源与环境》2007,17(6):7-12
根据技术效率、经济效率、自然效率、社会效率之间的关系,探讨了四个效率背离所导致的资源配置效率丧失以及由此引发的社会福利损失问题。在分析价格信号在资源配置过程中的作用的基础上,探讨了市场失效和价格背离现象。进一步指出了中国经济转型时期存在着自然资本富聚现象,并进一步分析其根源。包括:政府有效干预不足、现行经济增长方式和经济效率实现以对自然资本的低成本占用、机会导向型的资源配置方式、资本的价值取向、对经济财富以及单一行为人的效率追逐、产权缺位等。强调需要强化环境管理的公共管理属性,并对环境资源的权益主体的权利、责任和利益进行有效的界定和实施,通过制度和政策变革,干预和规范市场运作,促进资源的高效和公平配置。 相似文献
252.
253.
AbstractThis paper addresses the relevance of the demand side for the achievement of sustainable transport in urban areas. The underlying thesis is that a better understanding of user habits, perceptions and attitudes with its specific dynamics is essential for a successful design of targeted transport policies. In line with this, the paper at hand is based on research that aims at improving the knowledge of urban-transport-related habits and attitudes of young adults. The results of three interview meetings that were held in Karlsruhe, Budapest, and Copenhagen with participants aged between 20 and 30 are presented. Background of the interviews is a range of studies that indicate that young people in urban areas seem to be less interested in cars than the generation before. And indeed, the interview meetings reveal that participants had a rather pragmatic attitude towards transport modes. They wished a transport system that is flexible, convenient and cheap. Despite many differences, most participants showed rather positive attitudes towards policies supporting alternatives to car-based transport. However, it will be crucial for policy shaping to what extent the observed behaviour patterns and attitudes will persist over time. 相似文献
254.
《International Journal of Sustainable Engineering》2013,6(1):16-23
Traditional supply chain design is merely based on the open loop or forward flow of materials, neglecting reverse flow for recovery of materials despite the recent concerns of customers and governments about environmental and production cost reductions. New supply chain design should be closed loop which implements traditional supply chain concepts with reverse flow or a material recovery system to reduce production cost and enhance customer satisfaction about environmental consciousness and to meet legal requirements. In our research, we designed a closed-loop supply chain which consists of recovery options such as collection centres and remanufacturing plants (reverse flow) in addition to traditional supply chain tiers (forward flow), and tried to find the best location for these facilities in a discrete space based on decision makers' opinions. Since there are uncertainties about decision parameters in an uncapacitated facility location problem, we implemented the fuzzy TOPSIS method to solve the location decision problem and find the best place to locate a remanufacturing facility. 相似文献
255.
256.
Linking Riparian Dynamics and Groundwater: An Ecohydrologic Approach to Modeling Groundwater and Riparian Vegetation 总被引:3,自引:0,他引:3
The growing use of global freshwater supplies is increasing the need for improved modeling of the linkage between groundwater
and riparian vegetation. Traditional groundwater models such as MODFLOW have been used to predict changes in regional groundwater
levels, and thus riparian vegetation potential attributable to anthropogenic water use. This article describes an approach
that improves on these modeling techniques through several innovations. First, evapotranspiration from riparian/wetland systems
is modeled in a manner that more realistically reflects plant ecophysiology and vegetation complexity. In the authors’ model
programs (RIP-ET and PRE-RIP-ET), the single, monotonically increasing evapotranspiration flux curve in traditional groundwater
models is replaced with a set of ecophysiologically based curves, one for each plant functional group present. For each group,
the curve simulates transpiration declines that occur both as water levels decline below rooting depths and as waters rise
to levels that produce anoxic soil conditions. Accuracy is further improved by more effective spatial handling of vegetation
distribution, which allows modeling of surface elevation and depth to water for multiple vegetation types within each large
model cell. The use of RIP-ET in groundwater models can improve the accuracy of basin scale estimates of riparian evapotranspiration
rates, riparian vegetation water requirements, and water budgets. Two case studies are used to demonstrate that RIP-ET produces
significantly different evapotranspiration estimates than the traditional method. When combined with vegetation mapping and
a supporting program (RIP-GIS), RIP-ET also enables predictions of riparian vegetation response to water use and development
scenarios. The RIP-GIS program links the head distribution from MODFLOW with surface digital elevation models, producing moderate-
to high-resolution depth-to-groundwater maps. Together with information on plant rooting depths, these can be used to predict
vegetation response to water allocation decisions. The different evapotranspiration outcomes produced by traditional and RIP-ET
approaches affect resulting interpretations of hydro-vegetation dynamics, including the effects of groundwater pumping stress
on existing habitats, and thus affect subsequent policy decisions. 相似文献
257.
含膦磺酸基共聚物PAMPS的合成及阻垢性能研究 总被引:10,自引:1,他引:10
利用实验方法合成了含膦磺酸基共聚物PAMPS,通过正交试验评价优选出最佳合成条件,对其阻垢性能进行了评价。将含膦磺酸基共聚物PAMPS与HEDP和含膦基共聚物PCA进行了比较,结果表明,当PAMPS用量为10mg/L时,阻止碳酸钙结垢率达到83.73%,优于同等条件下HEDP与PCA阻止碳酸钙结垢率;当PAMPS用量达到3mg/L时,阻垢率达到98.32%,对硫酸钙的阻垢性能优于HEDP和PCA。同时还可看出,含膦磺酸基共聚物PAMPS对阻止碳酸钙结垢具有低剂量效应,对阻止硫酸钙结垢具有低剂量效应和溶限效应。这说明PAMPS是一种优良的阻垢分散剂。 相似文献
258.
为了研究有感领导对建筑施工不同经验工人群体不安全行为的影响,采用问卷调查方法,以群体安全氛围为中介变量,建立了多群组结构方程模型(SEM),并运用AMOS软件分析了有感领导核心四要素(能见度、关系、对工作团体的投入、主动管理)对群体不安全行为的影响及路径系数。结果表明:有感领导对经验缺乏的新工人群体的影响均大于老工人群体;对新工人群体,能见度和主动管理对其不安全行为影响较大,路径系数分别为0.654和0.639;而对老工人群体,关系和对工作团体的投入对其影响较大,路径系数分别为0.577和0.561。因此,在实施有感领导管理时,面对不同经验工人群体,应该因人而宜,以实现更加有效的管理。 相似文献
259.
层次分析模糊群体决策法评价大气环境质量 总被引:2,自引:0,他引:2
提出了层次分析模糊群体决策评价方法以层次分析法作定权方法,采用模糊群体决策法中的Borda法为评价方法,对大气环境质量进行评价,并将评价结果与灰色聚类法,模糊综合评判法所得评价结果进行对比,结果令人满意。 相似文献
260.