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   983篇
  免费   23篇
  国内免费   50篇
安全科学   90篇
废物处理   13篇
环保管理   237篇
综合类   322篇
基础理论   78篇
污染及防治   144篇
评价与监测   87篇
社会与环境   42篇
灾害及防治   43篇
  2024年   3篇
  2023年   10篇
  2022年   18篇
  2021年   28篇
  2020年   32篇
  2019年   16篇
  2018年   16篇
  2017年   29篇
  2016年   38篇
  2015年   21篇
  2014年   38篇
  2013年   37篇
  2012年   43篇
  2011年   90篇
  2010年   33篇
  2009年   72篇
  2008年   80篇
  2007年   63篇
  2006年   54篇
  2005年   31篇
  2004年   38篇
  2003年   31篇
  2002年   26篇
  2001年   26篇
  2000年   27篇
  1999年   23篇
  1998年   13篇
  1997年   21篇
  1996年   12篇
  1995年   12篇
  1994年   16篇
  1993年   3篇
  1992年   8篇
  1991年   4篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   5篇
  1986年   8篇
  1985年   6篇
  1984年   6篇
  1983年   4篇
  1982年   3篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1973年   2篇
排序方式: 共有1056条查询结果,搜索用时 31 毫秒
991.
Most accounts of urban green space governance originate in cities where such initiatives have been successful. Meanwhile, there is too little information on cities where such initiatives develop with more difficulty. In order to overcome the problems that such cities face, their situations need to be studied more carefully to facilitate peer comparisons. This article provides an account of urban green space governance in three cities in Poland (Krakow, Lodz, Poznan), where environmental protection is still quite far down on the list of political priorities. With the use of a social network analysis we looked at the extent of relationships between different stakeholders and the roles of different actors within the network. The results indicate that the network's collaboration potential is barely used and that cross-sectoral collaboration is especially deficient. In particular, public institutions hold a relatively strong position and downplay the role of other actors. More collaboration is necessary and the potential bridging role of NGOs should be used to a larger extent. However, this requires more openness and trust within the network.  相似文献   
992.
Recent extreme weather events worldwide have highlighted the vulnerability of many urban settlements to future climatic change. These events are expected to increase in frequency and intensity under climate change scenarios. Although the climatic change may be unavoidable, effective planning and response can reduce its impacts. Drawing on empirical data from a 3-year multi-sectoral study of climate change adaptation for human settlements in the South East Queensland region, Australia, this paper draws on multi-sectoral perspectives to propose enablers for maximising synergies between disaster risk reduction and climate change adaptation to achieve improved planning outcomes. Multi-sectoral perspectives are discussed under four groups of identified enablers: spatial planning; cross-sectoral planning; social/community planning; and strategic/long term planning. Based on the findings, a framework is proposed to guide planning systems to maximise synergies between the fields of disaster risk reduction and climate change adaptation to minimise the vulnerability of communities to extreme weather events in highly urbanised areas.  相似文献   
993.
To improve quality of life as well as the adaptive capacity in the city of Rotterdam over the past 15 years there has been a lot of focus on improving green infrastructure and finding new ways for integrated planning. As many cities face similar challenges they are looking for novel approaches in urban ecosystem governance. The Rotterdam case can be an interesting example but can also reveal new questions to be researched.Before local policies and projects where developed a regional and urban green blue vision of how to improve overall quality of life using green infrastructure were developed. This provided policy frameworks for politicians, policymakers and other actors. Later on the same was done with Urban Waterplan 2, using the Rotterdam Watercity 2030 vision document as a basis. This vision was the result of a stakeholder based planning process which was made for the International Architecture Biennale 2005. Within these frameworks many interesting projects have been built and tested in the city and city region; ranging from a) a roof park over a railway yard to connect neighbourhoods to the waterfront, to b) water squares and c) digging new waterways with connected walking and biking routes. To go from projects to an overall implementation at city level required tools and approaches for better decision making. For the ‘Dakpark’ project as well as for the Zomerhofkwartier, the first climate proof neighbourhood in the city, stakeholder sessions were held and plans were drawn together with urban planners and landscape architects. To feed these processes even better and to know what would be an optimal solution for certain challenges, city data were studied and linked to scalable GIS mapping in the ‘smart city planner’. This tool gives the decision maker the possibility to quickly have an overview of an area and can be used in a stakeholder process to provide relevant additional information and to define joint projects. The tool makes it possible to do this for all 90 neighbourhoods in the city.Overall the urban ecosystem governance in the city of Rotterdam has – with trial and error- lead to a series of innovative projects. The next steps are acceleration and scaling up to city and regional level. Valuing the crucial role of green blue infrastructure for several aspects of the quality of life in cities are paramount.  相似文献   
994.
Studies relating urban design to health have been impeded by the unfeasibility of conducting field observations across large areas and the lack of validated objective measures of urban design. This study describes measures for five dimensions of urban design - imageability, enclosure, human scale, transparency, and complexity - created using public geographic information systems (GIS) data from the US Census and city and state government. GIS measures were validated for a sample of 588 New York City block faces using a well-documented field observation protocol. Correlations between GIS and observed measures ranged from 0.28 to 0.89. Results show valid urban design measures can be constructed from digital sources.  相似文献   
995.
We investigated relationships between adolescents’ perceptions of their neighbourhood, their mental health and independently assessed indicators of conditions in their residential neighbourhood. The Research with East London Adolescents Community Health Survey (RELACHS) provided information for 2370 adolescents on area perceptions (specifically alienation from/attachment to the area and satisfaction/dissatisfaction with local amenities and services), and on individual and family attributes including mental distress (measured by the Strengths and Difficulties Questionnaire). These were combined for this study with independently assessed small area geographical indicators proposed by government to measure local deprivation in England. A Bayesian regression analysis using Gibbs sampling investigated associations between the predictor variables and neighbourhood perception. Alienation from neighbourhood and dissatisfaction with local amenities was greater for girls than for boys and for the older adolescents sampled. Those of ‘Asian’ or ‘Black’ ethnicity, from relatively harmonious families, or with higher levels of social support were less likely to express negative area perceptions. While previously published research found no significant direct association between mental health and small area indicators, this analysis suggests that those with relatively high levels of distress did have worse area perceptions. Also, certain independently assessed area indicators were associated with adolescents’ views of their neighbourhood.  相似文献   
996.
Policymakers today are faced with a difficult task of planning for large scale infrastructure that can cater to the climatic and socio-economic changes that the future will bring. To address the deeply uncertain nature resulting from long-term changes, it is becoming necessary to develop strategies that support flexibility and react more strategically than traditional planning approaches. This paper applies the concept of adaptation tipping points and adaptation pathways to a case study in Singapore for the planning of long-term urban drainage infrastructure. Using conventional grey and sustainable green solutions in isolation and in combination, adaptation pathway maps are developed and compared across outlined climatic and landuse scenarios. To understand and justify if the imparted flexibility is worth its cost, economic assessments are performed. This is a valuable extension of the existing framework, helps to identify the preferred configuration of land use and sub-select adaptation actions that should be implemented at the current time frame. The main finding of this study is that the adaptation pathways map for the sustainable grey landuse scenario economically outperforms those of the other outlined land uses. This provides a valuable insight for policy makers, as it implies that if carefully planned development is undertaken, the requirements of storm water management can be met in a sustainable manner, while simultaneously freeing up land for other purposes. This is especially important in the context of highly dense urban areas such as Singapore, where land is a scare resource.  相似文献   
997.
The use of the oxygenate methyl tert-butyl ether (MTBE) in gasoline has led to detectable concentrations in urban and rural air up to 160 ppbV. Results from MTBE measurement in precipitation have not been reported so far. In the present study, 120 samples of precipitation collected at 17 sampling locations all over Germany have been analyzed for their MTBE content. Analysis is performed by a combination of headspace-solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC-MS). A 75 μm poly(dimethylsiloxane)/Carboxene fiber and a cryostat is used for SPME. The detection limit is 10 ng/l. In precipitation samples, MTBE was detected in wintertimes only with a maximum concentration of 85 ng/l. Measurement at Frankfurt/M City from 6 September 2000 to 12 March 2001 provided for 49% of the data concentrations in the range of 30–85 ng/l (n=17). Sampling in winter 2000/2001 at several German cities and rural locations showed that MTBE is more often detectable in urban (86%, n=78) than in rural (18%, n=42) precipitation. By comparing the results with corresponding temperatures and amounts of precipitation it can be concluded that the detection of MTBE in urban precipitation is observed at ambient temperatures lower than about 10–15°C. Moreover, the first precipitation after a dry period accumulates more MTBE than precipitation during or at the end of a wet period (wash-out effect). Highest concentrations occurred in snow samples. Corresponding mean air equilibrium concentrations of 0.04 ppbV (urban samples) and 0.01 ppbV (rural samples) are calculated. This is about one magnitude lower than year round and summertime measurements in the US and in Switzerland. Urban runoff (n=12) and corresponding precipitation sampling indicate that urban runoff might be composed of about 20% MTBE that is already transported by air and precipitation, whereas about 80% may be attributed to direct uptake of vehicle emissions and leakage near the road during precipitation.  相似文献   
998.
Reviewed the change of ARGs and ARB in full-scale urban drinking water systems. Conventional processes are more promising than BAC process in ARGs removal. Mechanisms of ARGs enrichment and spread in BAC filter and DWDSs are discussed. Raise the need of future research on ARGs and ARB change in building plumbing systems. Antibiotic resistance in aquatic environment has become an important pollution problem worldwide. In recent years, much attention was paid to antibiotic resistance in urban drinking water systems due to its close relationship with the biosafety of drinking water. This review was focused on the mechanisms of antibiotic resistance, as well as the presence, dissemination and removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the urban drinking water system. First, the presence of ARB and ARGs in the drinking water source was discussed. The variation of concentration of ARGs and ARB during coagulation, sedimentation and filtration process were provided subsequently, in which filtration was proved to be a promising technology to remove ARGs. However, biological activated carbon (BAC) process and drinking water distribution systems (DWDSs) could be incubators which promote the antibiotic resistance, due to the enrichment of ARGs and ARB in the biofilms attached to the active carbon and pipe wall. Besides, as for disinfection process, mechanisms of the inactivation of ARB and the promotion of conjugative transfer of ARGs under chlorine, ozone and UV disinfection were described in detail. Here we provide some theoretical support for future researches which aim at antibiotic resistance controlling in drinking water.  相似文献   
999.
The concentrations and characteristics of volatile organic hazardous air pollutants (HAPs) in the urban city of Kaohsiung from motor vehicles and dense pollutant sources has become a national concern. To continuously monitor volatile organic HAPs, sampling sites were selected near the four air-quality monitoring stations established by Ethe nvironmental Protection Administration of Taiwan ROC, namely Nan-tz, Tso-ying, San-min and Hsiao-kang, from north to south. An on-site automated online monitor of volatile organic compounds (VOCs) was used for continuous monitoring. This study performed two consecutive days of 24-h monitoring of five volatile organic HAPs form August to October 2005 at the four monitoring sites, which cover the northern, central, and southern areas of Kaohsiung city. The average monitored concentration was 2.78–4.84 ppb for benzene, 5.90–9.66 ppb for toluene, 3.62–5.90 ppb for ethylbenzene, 3.73–5.34 ppb for m,p-xylene, 3.38–4.22 ppb for o-xylene, and 4.48–7.00 ppb for styrene. The average monitored concentrations of the major volatile organic HAPs tended to follow the pattern San-min > Nan-tz > Hsiao-kang > Tso-ying. Among all the species monitored in this study, toluene had the highest ambient concentration, followed by styrene, m,p-xylene, ethylbenzene, o-xylene, and benzene. The results showed that the concentration at night was higher than that in the day for toluene at Nan-tz, San-min, Hsiao-kang, and for benzene at Nan-tz and Hsiao-kang.  相似文献   
1000.
Regarding various energy and materials flowing in the urban ecosystem and the merit of emergy as an embodied energetic equivalent for integrated ecological economic evaluation, an evaluation framework of emergy-based urban ecosystem health indicators (UEHIem) was established in view of five aspects including vigor, structure, resilience, ecosystem service function maintenance and environmental impact to depict the urban ecosystem health states. Further, set pair analysis (SPA) was employed to assess the urban ecosystem health level based on the UEHIem, by which the approximate degree of real index set to the optimal one was defined and evaluated to describe the relative health state of the concerned urban ecosystems. Choosing twenty typical Chinese cities in 2005 as cases, we evaluated and compared their urban ecosystem health levels based on UEHIem and SPA. The results showed that health levels of Xiamen, Qingdao, Shenzhen and Shanghai are pretty well, while those of Wuhan, Harbin, Yinchuan, Beijing and Urumchi are relatively weak. Moreover, the relative health levels were analyzed by SPA to discern the influences of the mentioned five aspects on the UEHIem. It is concluded that emergy synthesis combined with SPA can serve as an effective relative-measure to compare different ecosystem health levels of urban ecosystems.  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