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   948篇
  免费   39篇
  国内免费   6篇
安全科学   45篇
废物处理   132篇
环保管理   147篇
综合类   132篇
基础理论   240篇
环境理论   4篇
污染及防治   179篇
评价与监测   46篇
社会与环境   53篇
灾害及防治   15篇
  2023年   7篇
  2022年   15篇
  2021年   17篇
  2020年   19篇
  2019年   18篇
  2018年   32篇
  2017年   33篇
  2016年   44篇
  2015年   38篇
  2014年   24篇
  2013年   70篇
  2012年   45篇
  2011年   62篇
  2010年   47篇
  2009年   54篇
  2008年   54篇
  2007年   51篇
  2006年   56篇
  2005年   42篇
  2004年   26篇
  2003年   23篇
  2002年   21篇
  2001年   13篇
  2000年   13篇
  1999年   14篇
  1998年   10篇
  1997年   11篇
  1996年   10篇
  1995年   8篇
  1994年   6篇
  1993年   8篇
  1992年   8篇
  1991年   11篇
  1990年   6篇
  1989年   4篇
  1986年   6篇
  1985年   3篇
  1983年   4篇
  1981年   3篇
  1976年   3篇
  1974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
排序方式: 共有993条查询结果,搜索用时 703 毫秒
31.
It has been suggested that obese individuals, because of an increased dilution space (body fat) for lipophilic organochlorines compounds, may have greater levels of toxic pollutants than lean sedentary individuals. It is important to further examine this possibility because of the potential contribution of organochlorine pesticides in the development of Parkinson's disease and other neurological diseases. The aim of this study was to further investigate the relationship between the magnitude of obesity and the plasma concentration of organochlorines for a wide range of BMI (with participants at steady state body weight). Fifty-three individuals were selected on the basis of their body mass index (BMI): lean controls (n=16; mean BMI 22.8+/-2.2 kg/m(2); mean age 38.8+/-9.4 years), obese individuals (n=19; mean BMI 33.4+/-3.0 kg/m(2); mean age 38.6+/-7.6 years) and morbidly obese individuals (n=18; mean BMI 49.3+/-6.5 kg/m(2); mean age 44.3+/-9.2 years). Blood samples were analyzed for organochlorine compounds. The relationship between the total plasma organochlorine concentration and BMI was tested using a multiple regression analysis. Age was included in the model. There was no relationship between the total plasma organochlorine concentration and BMI. Organochlorine concentrations, however, were correlated with age (BMI-adjusted R(2)=0.46; p<0.001). At steady state body weight, toxic pollutant concentrations are not associated to obesity but strongly correlate with age.  相似文献   
32.
Vetter W  Gaul S  Olbrich D  Gaus C 《Chemosphere》2007,66(10):2011-2018
The marine halogenated natural product 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1) is widely distributed in the environment. In this study, we screened samples which have previously been found to contain remarkably high residues of Q1 (blubber of marine mammals from Australia, samples from Antarctica, human milk from the Faroe Island) for the additional presence of mixed chlorinated and brominated congeners. Using GC/ECNI-MS, all samples tested were positive and many contained four out of five possible bromohexachloro congeners (BrCl6-MBPs), five out of 14 possible dibromopentachloro congeners (Br2Cl5-MBPs), five of 21 possible tribromotetrachloro-congeners (Br3Cl4-MBPs), as well as several higher brominated congeners. About 20 heptahalo congeners of Q1 are described for the first time in the scientific literature. Isomers eluted within about one minute, respectively. Hence it is possible, that the peak clusters identified may be composed of more, co-eluting congeners. Similarities in the GC/ECNI-MS mass spectra with polychlorinated biphenyls (PCBs) were addressed. We also suggest an acronym system similar to that in use for polychlorinated biphenyls that may simplify the use of this substance class in scientific papers. In the samples from Australia, BrCl6-MBPs and Br2Cl5-MBPs amounted for 7-27.5% and 0.4-4.2% of Q1, respectively whereas Br3Cl4-MBPs and higher brominated MBPs were found in the range of <1% of Q1 or less.  相似文献   
33.
Environmental degradation by mud in tropical estuaries   总被引:3,自引:0,他引:3  
In wet tropical countries, the intense rainfall and the lack of effective restrictions on human activities in the river catchment leads to increased rates of soil erosion. This has increased the sediment loads many times over from the natural level. As a result, estuarine and coastal waters are becoming increasingly muddy with associated losses for society in terms of increased flooding and a degradation of the environment, the fisheries and the economic use of these waters. It is suggested that science-based models be used to predict the fate of mud in estuaries and coastal waters when planning development in river catchments, particularly in wet tropical countries. This would help integrate land and water management. Modelling technology is demonstrated by a combination of field and model studies in four turbid tropical estuaries, namely the Fly River in Papua New Guinea, the Mekong River in Vietnam, the Cimanuk River in Indonesia, and Hinchinbrook Channel in Australia. The final model is adapted to local conditions and extensively uses data assimilation especially for open boundary conditions. There can be a feedback between the hydrodynamics and the mud dynamics when the system silts; in wet tropical countries this can occur rapidly, sometimes in only 30 years. Electronic Publication  相似文献   
34.
Corals and coral-associated species are highly vulnerable to the emerging effects of global climate change. The widespread degradation of coral reefs, which will be accelerated by climate change, jeopardizes the goods and services that tropical nations derive from reef ecosystems. However, climate change impacts to reef social–ecological systems can also be bi-directional. For example, some climate impacts, such as storms and sea level rise, can directly impact societies, with repercussions for how they interact with the environment. This study identifies the multiple impact pathways within coral reef social–ecological systems arising from four key climatic drivers: increased sea surface temperature, severe tropical storms, sea level rise and ocean acidification. We develop a novel framework for investigating climate change impacts in social–ecological systems, which helps to highlight the diverse impacts that must be considered in order to develop a more complete understanding of the impacts of climate change, as well as developing appropriate management actions to mitigate climate change impacts on coral reef and people.  相似文献   
35.
Longer-term environmental studies are increasingly used to better understand contemporary ecosystems conditions and for forecasting their future trajectories. Here, we use radiometric measurements and the characterisation of sediment properties from six mountain and a lowland lake in Central Eastern Europe with the aim to assess temporal and spatial variability in sediment accumulation rates (SARs) in relation to three socio-economic regimes: traditional (1840–1948), socialist (1948–1989) and post-socialist (post-1990). We also set out to determine reference conditions for these lakes i.e. conditions before significant human impact. Our results show a trend of increasing SARs from basal sediments (pre 1840) towards the present at only two sites. This contrasts with findings from Western and Central European lakes where SARs have predominantly increased from 1850 towards the top of cores. We highlight the differential impacts of the traditional, socialist and post-socialist periods on the SARs at these lakes. Lowland and mid-elevations lakes (n = 2) were most markedly impacted by the socialist period of land use regime; lakes from the southern Carpathians (n = 2) were more impacted in the traditional period (transhumance pastoral activities), whereas those from the north (n = 3) in the socialist and post-socialist periods (summer pastoralism). Results from our study show a continuous anthropogenic impact during the entire period considered, even in remote mountain areas. This suggests that a temporal frame of 100–150 years is too short to meaningfully register the reference conditions of these lakes. Furthermore, a predominantly natural state may not have existed for centuries in this region.  相似文献   
36.
In recent years, climate impact assessments of relevance to the agricultural and forestry sectors have received considerable attention. Current ecosystem models commonly capture the effect of a warmer climate on biomass production, but they rarely sufficiently capture potential losses caused by pests, pathogens and extreme weather events. In addition, alternative management regimes may not be integrated in the models. A way to improve the quality of climate impact assessments is to increase the science–stakeholder collaboration, and in a two-way dialog link empirical experience and impact modelling with policy and strategies for sustainable management. In this paper we give a brief overview of different ecosystem modelling methods, discuss how to include ecological and management aspects, and highlight the importance of science–stakeholder communication. By this, we hope to stimulate a discussion among the science–stakeholder communities on how to quantify the potential for climate change adaptation by improving the realism in the models.  相似文献   
37.
38.
This scoping review provides a summary of research findings on social support dynamics in the wake of disasters that occurred on the continent of Australia and Oceania between 1983 and 2013. Forty-one studies, quantitative and qualitative, were summarised, investigating different facets of post-disaster supportive interactions. All inquiries assessed disasters resulting from natural hazards, with the majority of them conducted following events in Australia and New Zealand. The review revealed similar patterns of post-disaster social support dynamics that routinely unfold after disastrous incidents all over the world. Consistent with the disaster mental health literature, the documentation of social support mobilisation and social support deterioration processes was common. Salutary direct effects of supportive behaviours on post-disaster psychological distress were also highly evident. Most studies, however, posed research questions or hypotheses that lacked empirical or theoretical grounding. In conclusion, the review offers several recommendations on how to advance research on post-disaster social support.  相似文献   
39.
Pastoralists face increasing competition for land with crop farmers and nature in and around the W Biosphere Reserve (WBR) in Benin. Our aim was to describe and analyse land use changes in order to understand their drivers, and to describe and analyse the viewpoints of relevant stakeholders in order to understand the competition for land. To this end, remote sensing data, regional statistics, and survey data were collected. We found that crop land expansion around the WBR was the direct driver of decrease of the grazing land area. Population growth and rising demand for food crops, and government support to the cotton sector were indirect drivers of grazing land reduction. Furthermore, competing claims on land among users arose from the complex interaction of crop expansion, presence of WBR and the way it is governed, the lack of support to pastoralists, and the increasing shift of pastoralists’ lifestyle into one of settled crop farmers. Pastoralism is under threat and its survival depends on the successful implementation of policies to support pastoralists and protect grazing lands.  相似文献   
40.
Cambodian subsistence communities within the Tonle Sap Great Lake area rely on resource extraction from the lake to meet livelihood needs. These fishing communities—many of which consist of dwellings floating on the lake—face potentially profound livelihood challenges because of climate change and changing hydrology due to dam construction for hydroelectricity within the Mekong Basin. We conducted interviews across five village communities, with local subsistence fisher people in the Tonle Sap in 2015, and used thematic analysis methods to reveal a fishery system that is undergoing rapid ecological decline, with local fishing communities increasingly experiencing reductions in available fish stocks. As a result, over 100 000 people living in these communities are experiencing a direct loss of well-being and livelihood. We discuss these losses and consider their implications for the future viability of Cambodian floating village communities.  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