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   754篇
  免费   37篇
  国内免费   4篇
安全科学   42篇
废物处理   123篇
环保管理   123篇
综合类   110篇
基础理论   176篇
环境理论   4篇
污染及防治   124篇
评价与监测   36篇
社会与环境   44篇
灾害及防治   13篇
  2023年   6篇
  2022年   10篇
  2021年   16篇
  2020年   14篇
  2019年   18篇
  2018年   30篇
  2017年   28篇
  2016年   40篇
  2015年   33篇
  2014年   20篇
  2013年   61篇
  2012年   30篇
  2011年   46篇
  2010年   40篇
  2009年   45篇
  2008年   38篇
  2007年   45篇
  2006年   40篇
  2005年   27篇
  2004年   21篇
  2003年   15篇
  2002年   20篇
  2001年   10篇
  2000年   9篇
  1999年   11篇
  1998年   9篇
  1997年   8篇
  1996年   8篇
  1995年   7篇
  1994年   4篇
  1993年   6篇
  1992年   6篇
  1991年   10篇
  1990年   5篇
  1989年   4篇
  1986年   6篇
  1984年   2篇
  1981年   2篇
  1972年   2篇
  1971年   2篇
  1961年   3篇
  1959年   2篇
  1958年   2篇
  1957年   5篇
  1955年   5篇
  1954年   2篇
  1940年   2篇
  1937年   1篇
  1934年   1篇
  1926年   1篇
排序方式: 共有795条查询结果,搜索用时 46 毫秒
651.
A comprehensive assessment of indoor carbonyl compounds for the academic staff, workers, and students was conducted on a university campus in Xiamen, China. A total of 15 representative environment categories, including 12 indoor workplaces and three residential units, were selected. The potential indoor pollution sources were identified based on the variability in the molar compositions and correlation analyses for the target carbonyls. Furnishing materials, cooking emissions, and electronic equipment, such as photocopiers, can generate various carbonyls in the workplace. Comparison studies were conducted in the clerical offices, demonstrating that off-gases from wooden furniture and lacquer coatings, environmental tobacco smoke (ETS), and the use of cleaning reagents elevated the indoor carbonyl levels. The measured concentrations of formaldehyde and acetaldehyde in most locations surpassed the exposure limit levels. The lifetime cancer hazard risk (R) associated with formaldehyde was above the concern risk level (1 × 10?6) in all of the workplaces. The results indicate that formaldehyde exposure is a valid occupational health and safety concern. Wooden furniture and refurbishing materials can pose serious health threats to occupants. The information in this study could act as a basis for future indoor air quality monitoring in Mainland China.
Implications:A university campus represents a microscale city environment consisting of all the working, living, and commercial needs of staff and students. The scope of this investigation covers 21 hazardous carbonyl species based on samples collected from 15 categories of workplaces and residential building in a university campus in southern China. Findings of the study provide a comprehensive assessment of indoor air quality with regards to workers’ health and safety. No similar study has been carried out in China.  相似文献   
652.
Buffer strips alongside watercourses are a widely accepted method of reducing nutrient and sediment run-off from agricultural land thereby improving water quality. Little attention, however, has been paid to the ecological status of these areas despite the fact that riparian habitats in good condition can provide multiple benefits. We investigated vegetation patterns and plant-environment relationships within three categories of riparian margins in northeast Scotland. The margins were categorized as unbuffered, buffered, or reference (target), the latter representing the best sites available within the catchments. Vascular plant and soil data were collected from 41 sites along the tributaries of two rivers during 2008 and 2009. Ellenberg indicator values revealed trends of decreasing light availability ( < 0.05) and decreasing pH ( < 0.01) from unbuffered sites to buffered sites to reference sites. Multivariate analysis showed that soil parameters and channel morphology, together with canopy cover and bryophyte abundance, were discriminatory in separating species assemblages. The presence of a tree canopy layer appears to be the key instigator of change in soil conditions and corresponding plant species assemblages. An understanding of the underlying processes is important if vegetation characteristics are to be used effectively as indicators of riparian and water quality and to aid the restoration of riparian habitats.  相似文献   
653.
Under the Canadian Species at Risk Act (SARA), Garry oak (Quercus garryana) ecosystems are listed as “at-risk” and act as an umbrella for over one hundred species that are endangered to some degree. Understanding Garry oak responses to future climate scenarios at scales relevant to protected area managers is essential to effectively manage existing protected area networks and to guide the selection of temporally connected migration corridors, additional protected areas, and to maintain Garry oak populations over the next century. We present Garry oak distribution scenarios using two random forest models calibrated with down-scaled bioclimatic data for British Columbia, Washington, and Oregon based on 1961–1990 climate normals. The suitability models are calibrated using either both precipitation and temperature variables or using only temperature variables. We compare suitability predictions from four General Circulation Models (GCMs) and present CGCM2 model results under two emissions scenarios. For each GCM and emissions scenario we apply the two Garry oak suitability models and use the suitability models to determine the extent and temporal connectivity of climatically suitable Garry oak habitat within protected areas from 2010 to 2099. The suitability models indicate that while 164 km2 of the total protected area network in the region (47,990 km2) contains recorded Garry oak presence, 1635 and 1680 km2 of climatically suitable Garry oak habitat is currently under some form of protection. Of this suitable protected area, only between 6.6 and 7.3% will be “temporally connected” between 2010 and 2099 based on the CGCM2 model. These results highlight the need for public and private protected area organizations to work cooperatively in the development of corridors to maintain temporal connectivity in climatically suitable areas for the future of Garry oak ecosystems.  相似文献   
654.
Various types of advanced oxidation processes (AOPs), such as UV photolysis, ozonation, heterogeneous photocatalysis and their combinations were comparatively examined at the same energy input in a home-made reactor. The oxidative transformations of the phenylurea herbicides fenuron, monuron and diuron were investigated. The initial rates of transformation demonstrated that UV photolysis was highly efficient in the cases of diuron and monuron. Ozonation proved to be much more effective in the transformation of fenuron than in those of the chlorine containing monuron and diuron. In heterogeneous photocatalysis, the rate of decomposition decreased with increase of the number of chlorine atoms in the target molecule. Addition of ozone to UV-irradiated solutions and/or TiO2-containing suspensions markedly increased the initial rates of degradation. Dehalogenation of monuron and diuron showed that each of these procedures is suitable for the simultaneous removal of chlorinated pesticides and their chlorinated intermediates. Heterogeneous photocatalysis was found to be effective in the mineralization.  相似文献   
655.
Global degradation of coastal ecosystems is influencing the provision of ecosystem services, including fisheries maintenance services. Degradation of the Australian coastal zone and its resources following European occupation has been recognised for some time. This includes the loss of ecologically important coastal wetlands, which have strong trophic and habitat links to fisheries. In NSW, structural flood mitigation works are a principle driver of the decline of coastal wetlands; however, little action has been taken to quantify the extent of decline due to limited information of the pre-European settlement extent of coastal wetlands. We use spatial data sets in GIS to quantify prime fish habitat and calculate the loss of fish habitat for the large coastal floodplains of northern NSW, which are significant contributors to the commercial and recreational fisheries of NSW. The technique is validated by comparison with early maps of wetland distribution. We identified pre-European distribution of available fish habitat of approximately 477,000 ha, of which 87,000 ha was identified as prime fish habitat. Approximately 62,000 ha of prime fish habitat was impacted by drainage of the coastal floodplains in association with flood mitigation works which intensified in the mid-1950s and were largely completed by 1971, equating to a loss of approximately 72 % of prime fish habitat. The declining value of the ecosystem services provided by prime fish habitat following drainage is likely to be substantial. Some actions have taken place to restore the functions of this habitat although significant opportunities remain to reverse this decline through management actions that restore natural drainage and reinstate tidal exchange. These actions become even more important as pressures on coastal wetlands increase with climate change and associated sea-level rise.  相似文献   
656.
657.
Resilience has emerged as a prominent paradigm for interpreting and shaping human–environment connections in the context of global environmental change. Resilience emphasizes dynamic spatial and temporal change in social–ecological systems where humans are inextricably interwoven with the environment. While influential, resilience thinking has been critiqued for an under-theorized framing of socio-cultural dynamics. In this paper, we examine how the resilience concepts of planetary boundaries and reconnecting to the biosphere frame human–environment connection in terms of mental representations and biophysical realities. We argue that focusing solely on mental reconnection limits further integration between the social and the ecological, thus countering a foundational commitment in resilience thinking to social–ecological interconnectedness. To address this susceptibility we use Tim Ingold’s ‘dwelling perspective’ to outline an embodied form of human–environment (re)connection. Through dwelling, connections are not solely produced in the mind, but through the ongoing interactivity of mind, body and environment through time. Using this perspective, we position the biosphere as an assemblage that is constantly in the making through the active cohabitation of humans and nonhumans. To illustrate insights that may emerge from this perspective we bring an embodied connection to earth stewardship, given its growing popularity for forging local to global sustainability transformations.  相似文献   
658.
Winfried Schröder  Stefan Nickel  Simon Schönrock  Michaela Meyer  Werner Wosniok  Harry Harmens  Marina V. Frontasyeva  Renate Alber  Julia Aleksiayenak  Lambe Barandovski  Alejo Carballeira  Helena Danielsson  Ludwig de Temmermann  Barbara Godzik  Zvonka Jeran  Gunilla Pihl Karlsson  Pranvera Lazo  Sebastien Leblond  Antti-Jussi Lindroos  Siiri Liiv  Sigurður H. Magnússon  Blanka Mankovska  Javier Martínez-Abaigar  Juha Piispanen  Jarmo Poikolainen  Ion V. Popescu  Flora Qarri  Jesus Miguel Santamaria  Mitja Skudnik  Zdravko Špirić  Trajce Stafilov  Eiliv Steinnes  Claudia Stihi  Lotti Thöni  Hilde Thelle Uggerud  Harald G. Zechmeister 《Environmental science and pollution research international》2016,23(11):10457-10476
For analysing element input into ecosystems and associated risks due to atmospheric deposition, element concentrations in moss provide complementary and time-integrated data at high spatial resolution every 5 years since 1990. The paper reviews (1) minimum sample sizes needed for reliable, statistical estimation of mean values at four different spatial scales (European and national level as well as landscape-specific level covering Europe and single countries); (2) trends of heavy metal (HM) and nitrogen (N) concentrations in moss in Europe (1990–2010); (3) correlations between concentrations of HM in moss and soil specimens collected across Norway (1990–2010); and (4) canopy drip-induced site-specific variation of N concentration in moss sampled in seven European countries (1990–2013). While the minimum sample sizes on the European and national level were achieved without exception, for some ecological land classes and elements, the coverage with sampling sites should be improved. The decline in emission and subsequent atmospheric deposition of HM across Europe has resulted in decreasing HM concentrations in moss between 1990 and 2010. In contrast, hardly any changes were observed for N in moss between 2005, when N was included into the survey for the first time, and 2010. In Norway, both, the moss and the soil survey data sets, were correlated, indicating a decrease of HM concentrations in moss and soil. At the site level, the average N deposition inside of forests was almost three times higher than the average N deposition outside of forests.  相似文献   
659.
We report on our recent efforts towards identifying bacteria in environmental samples by means of Raman spectroscopy. We established a database of Raman spectra from bacteria submitted to various environmental conditions. This dataset was used to verify that Raman typing is possible from measurements performed in non-ideal conditions. Starting from the same dataset, we then varied the phenotype and matrix diversity content included in the reference library used to train the statistical model. The results show that it is possible to obtain models with an extended coverage of spectral variabilities, compared to environment-specific models trained on spectra from a restricted set of conditions. Broad coverage models are desirable for environmental samples since the exact conditions of the bacteria cannot be controlled.  相似文献   
660.
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