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   106篇
  免费   1篇
  国内免费   125篇
安全科学   1篇
废物处理   3篇
综合类   131篇
基础理论   54篇
污染及防治   28篇
评价与监测   7篇
社会与环境   6篇
灾害及防治   2篇
  2024年   7篇
  2023年   17篇
  2022年   24篇
  2021年   7篇
  2020年   11篇
  2019年   3篇
  2018年   10篇
  2017年   2篇
  2016年   3篇
  2015年   9篇
  2014年   17篇
  2013年   6篇
  2012年   15篇
  2011年   8篇
  2010年   4篇
  2009年   6篇
  2008年   10篇
  2007年   9篇
  2006年   6篇
  2005年   8篇
  2004年   10篇
  2003年   9篇
  2002年   2篇
  2001年   4篇
  2000年   6篇
  1999年   3篇
  1998年   7篇
  1997年   3篇
  1996年   2篇
  1994年   2篇
  1991年   2篇
排序方式: 共有232条查询结果,搜索用时 0 毫秒
211.
On the basis of field investigation and exploration survey,oceanic environment influence of all kinds of sewage sea draining schemes in Beidaihe Area was forecasted and evaluated.Construction scheme of deepsea draining with firstorder disposal was selected through comprehensive analysis comparison of oceanic environment benefit and engineering economic results This scheme has been adopted by construction units.  相似文献   
212.
Certainties and uncertainties of land cover statistics in China   总被引:2,自引:0,他引:2  
Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties d land cover statistics were analyzed by comparing three data sources: China‘ s Vegetation Map, IGPB DISCover, and University of Maryland Product. Great similarities in the statistics of 7 aggregated land cover types were found among the three data sources, particularly between the two global land cover maps. The per-pixel agreement between any 2 of 3 maps was between 38.0%--51.4% ; the per-pixel agreement among all three maps was only 27.1%. Certainties were found in regions where vegetation types are typical and human land use practice is relatively homogenous; the uncertainties occurred to either vegetation transition zones or regions where land cover types and land use practice are relatively diversified. Systematic and multidisciplinacy efforts are necessary to promote accurate mapping of nationwide land cover types in China. Intensive efforts should be made in regions where uncertainties of land cover information are found.  相似文献   
213.
The trans-regional characteristics of watershed governance produce more problems beyond the capacity of each individual water-related department, leading to the fragmentation of watershed management. The River Chief System (RCS) has experienced swift developments over the past decade in China by appointing the local government heads as river chiefs. RCS works efficiently in the short-term due to its superiority in the inclusion of clear responsibility, authority, and multi-sectoral collaboration. However, the characteristics of the authority-based vertical coordination of the hierarchical system remain unchanged, and therefore the problems of organizational logic and the responsibility dilemma still exist. Tasks including perfecting of laws, integrated watershed management, and public participation still need to be completed. RCS reflects the routine and characteristics of the migration of national governance, and as such provides new insights for other developing countries in the design of river management systems.  相似文献   
214.
The continuously increasing production of municipal solid waste incineration bottom ash (MSWIBA) has promoted its utilization as construction material and raised environmental concern. The physico-chemical properties and leaching behavior of MSWIBA were studied, and ecotoxicological testing using a luminescent bacterium bioassay was performed to assess the ecological pollution risks associated with its leached constituents. The MSWIBA was leached by two types of leachants, H2SO4/HNO3 and HAc solution, at different liquid to solid ratios and contact times. The concentrations of heavy metals and anions in the leachates were analyzed. Multivariate statistical analyses, including principle component analysis, Pearson's correlation analysis and hierarchical cluster analysis, were used to evaluate the contributions of the constituents to the toxicity (EC50) of the MSWIBA leachate. The statistical analyses of the ecotoxicological results showed that the Ba, Cr, Cu, Pb, F and total organic carbon (TOC) concentrations were closely correlated with the EC50 value, and these substances were the main contributors to the ecotoxicity of the MSWIBA leachate. In addition, the cluster of these variables indicated similar leaching behaviors. Overall, the research demonstrated that the ecotoxicological risks resulting from MSWIBA leaching could be assessed before its utilization, which provides crucial information for the adaptation of MSWIBA as alternative materials.  相似文献   
215.
In this study, an interval fuzzy mixed-integer energy planning model (IFMI-EPM) is developed under considering the carbon tax policy. The developed IFMIEPM incorporates techniques of interval-parameter programming, fuzzy planning and mixed-integer programming within a general energy planning model. The IFMIEPM can not only be used for quantitatively analyzing a variety of policy scenarios that are associated with different levels of carbon tax policy, but also tackle uncertainties expressed as discrete intervals and fuzzy sets in energy and environment systems. Considering low, medium and high carbon tax rates, the model is applied to an ideal energy and environment system. The results indicate that reasonable solutions have been generated. They can be used for generating decision alternatives and thus help decision makers identify desired carbon tax policy.  相似文献   
216.
新疆石河子城市道路尘土中重金属污染及潜在生态风险   总被引:1,自引:0,他引:1  
城市道路尘土中积累了大量的有毒有害物质,这些污染物可以通过地表径流、风力等因素的影响而迁移到大气、水体和土壤等各种环境介质中,直接或间接地对环境和人体造成危害.因此,城市道路尘土中重金属的污染研究及其风险评价具有重要意义.  相似文献   
217.
Yi L  Tahn TT  Zhong C  Songsheng Q  Ping S 《Chemosphere》2000,40(8):845-849
The heat output of the non-growth metabolism of Chlorella vulgaris has been determined using an LKB-2277 BioActivity Monitor. The experimental results indicate that there is a turn-point on the metabolic thermogenic curves, which can be divided into two parts, an early phase and a later phase. For the early phase, there is a linear relationship between the metabolic power (P) and the cell concentration (C), and that the heat output produced by a single cell's metabolism (P0) depends on the cell concentration (C) and is inhibited by the cell density, the thermokinetic equation of their metabolism is dP/dt = k0, k0 = 0.  相似文献   
218.
Atmospheric nitrogen (hi) deposition is currently high and meanwhile diffuse N pollution is also serious in China. The correlation between N deposition and riverine N export and the contribution of N deposition to riverine N export were investigated in a typical hilly red soil catchment in southern China over a two-year period. N deposition was as high as 26.1 to 55.8 kg N/(ha-yr) across different land uses in the studied catchment, while the riverine N exports ranged from 7.2 to 9.6 kg N/(ha-yr) in the forest sub-catchment and 27.4 to 30.3 kg N/(ha.yr) in the agricultural sub-catchment. The correlations between both wet N deposition and riverine N export and precipitation were highly positive, and so were the correlations between NH-N or NO2-N wet deposition and riverine NH4-N or NO3-N exports except for NH-N in the agricultural sub-catchment, indicating that N deposition contributed to riverine N export. The monthly export coefficients of atmospheric deposited N from land to river in the forest sub-catchment (with a mean of 14%) presented a significant positive correlation With precipitation, while the monthly contributions of atmospheric deposition to riverine N export (with a mean of 18.7% in the agricultural sub-catchment and a mean of 21.0% in the whole catchment) were significantly and negatively correlated with precipitation. The relatively high contribution of N deposition to diffuse N pollution in the catchment suggests that efforts should be done to control anthropogenic reactive N emissions to the atmosphere in hilly red soil regions in southern China.  相似文献   
219.
The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, together with two kinds of medium with different C/N ratios. Little lignin peroxidase (LIP) (〈 2 U/L) was detected in free culture with nitrogen-limited medium (C/N ratio: 56/2.2, in mmol/L), while manganese peroxidase (MnP) maximum activity was 231 and 240 U/L in 50 and 100 ml medium culture, respectively. Immobilized culture with 50 ml nitrogen-limited medium gave the highest MnP and LiP production with the maximum values of 410 and 721 U/L separately on the day 5; however, flasks containing 100 ml nitrogen-limited medium only produced less MnP with a peak value of 290 U/L. Comparatively, carbon-limited medium (C/N ratio: 28/44, in mmol/L) was adopted in culture but produced little MnP and LiE Medium type had the greatest impact on protease production. Large amount of protease was produced due to glucose limitation. Culture type and medium volume influence protease activity corporately by affecting oxygen supply. The results implied shallow immobilized culture was a possible way to gain high production of ligninolytic enzymes.  相似文献   
220.
Volumetric solar evaporations by using light-absorbing nanoparticles suspended in liquids (nanofluids) as solar absorbers have been widely regarded as one of the promising solutions for clean water production because of its high efficiency and low capital cost compared to traditional solar distillation systems. Nevertheless, previous solar evaporation systems usually required highly concentrated solar irradiation and high capital cost, limiting the practical application on a large scale. Herein, for the first time in this work, polydopamine (PDA)-capped nano Fe3O4 (Fe3O4@PDA) nanofluids were used as solar absorbers in a volumetric system for solar evaporation. The introduction of organic PDA to nano Fe3O4 highly contributed to the high light-absorbing capacity of over 85%in wide ranges of 200–2400 nm because of the existence of numerous carbon bonds and pi (π) bonds in PDA. As a result, high evaporation efficiency of 69.93%under low irradiation of 1.0 kW m-2 was achieved. Compared to other nanofluids, Fe3O4@PDA nanofluids also provided an advantage in high unit evaporation rates. Moreover, Fe3O4@PDA nanofluids showed excellent reusability and recyclability owing to the preassembled nano Fe3O4, which significantly reduced the material consumptions. These results demonstrated that the Fe3O4@PDA nanofluids held great promising application in highly efficient solar evapo-ration.  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