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   442篇
  免费   11篇
  国内免费   5篇
安全科学   12篇
废物处理   30篇
环保管理   49篇
综合类   65篇
基础理论   95篇
环境理论   1篇
污染及防治   146篇
评价与监测   36篇
社会与环境   20篇
灾害及防治   4篇
  2023年   7篇
  2022年   21篇
  2021年   20篇
  2020年   10篇
  2019年   16篇
  2018年   21篇
  2017年   14篇
  2016年   13篇
  2015年   16篇
  2014年   34篇
  2013年   40篇
  2012年   28篇
  2011年   42篇
  2010年   20篇
  2009年   19篇
  2008年   25篇
  2007年   22篇
  2006年   20篇
  2005年   20篇
  2004年   8篇
  2003年   8篇
  2002年   9篇
  2001年   3篇
  2000年   5篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1994年   1篇
  1991年   2篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1979年   1篇
排序方式: 共有458条查询结果,搜索用时 218 毫秒
381.
382.
The microalgae genus Scenedesmus is commonly found in freshwater bodies, wastewater facilities and water polluted with heavy metals. Phenotypic plasticity in Scenedesmus has been documented in response to a wide variety of conditions; however, heavy metals have not been comprehensively documented as phenotypic plasticity inducers. In this study, we report the phenotypic plasticity of Scenedesmus incrassatulus (a non-spiny, four-cell coenobium forming species) in response to EC50 value of copper, cadmium and hexavalent chromium. S. incrassatulus was grown in batch cultures in the presence of each metal. Chlorophyll-a content, cell size, parameters derived from the schematic energy-flux model for photosystem II, and morphotype expressions were recorded. Divalent cation metals induced unicellular forms, and hexavalent chromium produced out-of-shape coenobia corresponding to various stages of autospore formation. The changes induced by divalent metals were interpreted as phenotypic plasticity, because they were always associated to population doublings and were reversible when toxicant pressure was removed (only for Cu). Copper was the best inductor of unicellular forms and also affected significantly all the photosynthetic parameters measured. The developed morphotypes could confer ecological advantages to S. incrassatulus in metal stressed environments.  相似文献   
383.
Objective: A zero tolerance alcohol restriction law was adopted in Brazil in 2008. In order to assess the effectiveness of this intervention, the present study compares specific mortality in 2 time series: 1980–2007 and 2008–2013.

Methods: Data on mortality and population were gathered from official Brazilian Ministry of Health information systems. Segmented regression analyses were carried out separately for 3 major Brazilian capitals: Belo Horizonte, Rio de Janeiro, and São Paulo.

Results: In 2 cities (Belo Horizonte and Rio de Janeiro) there were no significant changes in mortality rate trends in 2 periods, 1980 to 2007 and 2008 to 2013, where the observed rates did not differ significantly from predicted rates. In São Paulo, a decreasing trend until 2007 unexpectedly assumed higher levels after implementation of the law.

Conclusion: There is no evidence of reduced traffic-related mortality in the 3 major Brazilian capitals 5.5 years after the zero tolerance drinking and driving law was adopted.  相似文献   

384.
This paper describes an integrated approach to transform an industrial park into an eco-industrial park by combining three interconnected goals, namely, the consolidation of industrial symbiosis, the promotion of sustainable accessibility and the development of multi-functionalities. The result is an interdependent approach where industrial and territorial ecosystems are jointly planned, seeking a more sustainable level of development that considers industrial activity, the transportation of people and goods and the spatial articulation with the neighbouring environment and urban areas. The critical points and challenges for improving the territorial integration of the French industrial park of Salaise-Sablons are discussed, providing lessons for the future. Regardless of the specificities of the case study, this approach has the potential to be adopted in similar industrial parks.  相似文献   
385.
386.
Current studies indicate a need to integrate environmental management with manufacturing strategy, including topics like cross-functional integration, environmental impact, and waste reduction. Nevertheless, such studies are relatively rare, existing still a need for research in specific regional contexts. At the same time, the results found are not unanimous. Due to these gaps, the objective of this article is to analyze if environmental management can be considered a new competitive priority for manufacturing enterprises located in Brazil. A cross-sectional survey was conducted with Brazilian companies certified by ISO 14001. Sixty-five valid questionnaires were analyzed through Structural Equation Modelling (SEM). The first conclusion is that environmental management presents a preventive approach in the sample analyzed, focused on eco-efficiency, what potentially do not to create a competitive advantage. This preventive approach inhibits environmental management from being regarded as a new competitive manufacturing priority, in the full sense as defined by the literature. Another important result is that environmental management, although following a preventive focus, may influence positively the four manufacturing priorities: cost, quality, flexibility and delivery.  相似文献   
387.
Socio-economic, environmental, and governance impacts of illegal logging   总被引:2,自引:1,他引:1  
This article examines the main impacts of the illegal logging activities with emphasis on the most important timber production regions. Although the discussion is focused on the environmental, socio-economic and governance impacts, it must be stressed that the term forest governance is the umbrella where the economy, the environmental values, and welfare of forest-dependent communities are sheltered. Considering the effects/impacts of the illegal logging as a whole, we can summarize the following negative key points: (1) Degradation of the most valuable forest stands threatening biodiversity, including rare and endangered species. (2) Increase in soil erosion and landslides. Increase in CO2 release and climatic changes. (3) Human rights abuses and disrespect of the basic needs of local communities and their culture. (4) Corruption, crime, coercion, and money laundering. (5) Reduction of royalties, taxes, and other charges paid by logging companies to the producer States. (6) Depreciation of legal activities due to the unfair concurrence. Despite multiple efforts, the results in the combat of illegal logging are far from satisfactory. Increase the certification area in parallel with an accurate control, devolve the state land to the ancient local owners, increase the cooperation between civil society and forest authorities, and finally strongly improve forest governance, particularly anti-money laundering laws, are crucial aspects in the combat of illegal logging. Furthermore, governments and businesses must implement the triple bottom line concept in order to reach sustainability.  相似文献   
388.
The determination of 210Po and 210Pb was performed in marine organisms from the seashore to abyssal depths, encompassing a plethora of species from the microscopic plankton to the sperm whale. Concentrations of those radionuclides ranged from low values of about 5 × 10−1 Bq kg−1 (wet wt.) in jellyfish, to very high values of about of 3 × 104 Bq kg−1 (wet wt.) in the gut walls of sardines, with a common pattern of 210Po > 210Pb.These radionuclides are primarily absorbed from water and concentrated by phyto- and microzooplankton, and then are transferred to the next trophic level along marine food chains. Investigation in epipelagic, mesopelagic, bathypelagic and abyssobenthic organisms revealed that 210Po is transferred in the marine food webs with transfer factors ranging from 0.1 to 0.7, and numerically similar to those of the energy transfer in the marine food chains. As 210Po preferentially binds to amino acids and proteins, its transfer in food chains likely traces protein transfer and, thus, 210Po transfer factors are similar to ecotrophic coefficients. 210Pb is transferred less efficiently in marine food chains and this contributes to increased 210Po:210Pb activity ratios in some trophic levels.  相似文献   
389.
The concentrations of 17 polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in sediment and key species as an initial investigation on PCDD/Fs and dl-PCBs contamination in the Mondego estuary (Portugal). The results demonstrated that the values of the total PCDD/Fs (∑PCDD/Fs) concentrations were considerably lower than those of the sum of dl-PCBs (∑dl-PCBs) in all the studied samples. Regarding the contribution of individual congeners, OCDD was the predominant PCDD/F and the mono-ortho PCB 118 and PCB 105 were the dominant PCBs in the majority of the samples. Our results suggest that PCDD/Fs and PCBs behave quite differently along the aquatic food web: ∑PCDD/Fs concentrations were lower in higher trophic-level organisms with fish presenting a distinct PCDD/Fs congeners profile; on the contrary, the higher ∑dl-PCBs values were found in upper-level biota, although not exclusively, and quite similar dl-PCBs congener profiles were observed in nearly all the studied species.  相似文献   
390.
The objective of this study is to investigate the potential process for the removal of carbon dioxide (CO2) from flue gas using fundamental membrane contactor, which is a membrane gas absorption (MGA) system. The experiments consisted of microporous polyvinylidenefluoride (PVDF) flat sheet membrane with 0.1 μm (as module I) and 0.45 μm (as module II) pore size. 2-Amino-2-methyl-1-propanol (AMP) solution was employed as the liquid absorbent. The effect of AMP concentration was studied with variation in the range 1–5 M. In addition, the experiments were carried out with 10%, 20%, 30% and 40% gas ratio of CO2 to N2 and pure CO2 as well. Through contact angle measurement, membranes for module I and module II were obtained with CA values of around 130.25° and 127.77°, respectively. The mass transfer coefficients for module II are lower than those of module I for 1–5 M of AMP. Furthermore, the increase in CO2 concentration in the feed gas stream enhanced the CO2 flux as the driving force of the system was increased in sequence from 1 M to 5 M of AMP. However, after the particular percentage (40%) of CO2 inlet concentration, the CO2 fluxes seem saturated. The combination of AMP as liquid absorbent and PVDF microporous membrane in MGA system has shown the potential to remove the CO2 from flue gas. In addition, the higher AMP concentration gave higher mass transfer coefficient at low liquid flow rates.  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