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   596篇
  免费   53篇
  国内免费   235篇
安全科学   82篇
废物处理   40篇
环保管理   99篇
综合类   420篇
基础理论   66篇
环境理论   1篇
污染及防治   101篇
评价与监测   43篇
社会与环境   29篇
灾害及防治   3篇
  2024年   5篇
  2023年   8篇
  2022年   15篇
  2021年   26篇
  2020年   24篇
  2019年   32篇
  2018年   46篇
  2017年   39篇
  2016年   56篇
  2015年   42篇
  2014年   66篇
  2013年   74篇
  2012年   57篇
  2011年   54篇
  2010年   45篇
  2009年   50篇
  2008年   33篇
  2007年   24篇
  2006年   28篇
  2005年   21篇
  2004年   13篇
  2003年   27篇
  2002年   15篇
  2001年   14篇
  2000年   12篇
  1999年   13篇
  1998年   11篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1994年   5篇
  1993年   4篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1985年   1篇
  1984年   1篇
  1979年   1篇
排序方式: 共有884条查询结果,搜索用时 421 毫秒
501.
The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant source of pharmaceutical loading to the receiving waters. Effluents from WWTPs with trickling filters or trickling filters in parallel with activated sludge resulted in the highest observed in-stream pharmaceutical concentrations. Azithromycin, caffeine, 1,7-dimethylzanthine, carbamazepine, cotinine, DEET, diphenhydramine, and sulfamethazine were detected at all locations. Methamphetamine, an illicit pharmaceutical, was detected at all but one of the sampling locations, representing only the second report of methamphetamine detected in WWTP effluent and in streams impacted by WWTP effluent.  相似文献   
502.
Andreeva Bay is one of the largest and most hazardous nuclear legacy sites in northwest Russia. The site is the location of large amounts of Spent Nuclear Fuel (SNF) and radioactive wastes and the risks associated with the site have precipitated an extensive international collaborative effort towards securing and rehabilitating the site. Given the location and proximity of the site, Norway has and continues to contribute in a number of ways towards this effort. Norway's activities in relation to rehabilitative efforts at Andreeva Bay are focused on both infrastructural and remediative initiatives as well as regulatory collaboration with Russia towards ensuring effective and safe operations during handling and removal of SNF and radioactive materials. This article describes Norway's role within international efforts in the context of the rehabilitation of Andreeva Bay and outlines previous activities and Norway's future direction with respect to the site.  相似文献   
503.
This article presents results pertaining to a risk assessment of the potential consequences of a hypothetical accident occurring during the transportation by ship of spent nuclear fuel (SNF) along an Arctic coastline. The findings are based on modelling of potential releases of radionuclides, radionuclide transport and uptake in the marine environment. Modelling work has been done using a revised box model developed at the Norwegian Radiation Protection Authority. Evaluation of the radioecological consequences of a potential accident in the southern part of the Norwegian Current has been made on the basis of calculated collective dose to man, individual doses for the critical group, concentrations of radionuclides in seafood and doses to marine organisms. The results of the calculations indicate a large variability in the investigated parameters above mentioned. On the basis of the calculated parameters the maximum total activity (“accepted accident activity”) in the ship, when the parameters that describe the consequences after the examined potential accident are still in agreement with the recommendations and criterions for protection of the human population and the environment, has been evaluated.  相似文献   
504.
Waste management activities contribute to global greenhouse gas emissions approximately by 4%. In particular the disposal of waste in landfills generates methane that has high global warming potential. Effective mitigation of greenhouse gas emissions is important and could provide environmental benefits and sustainable development, as well as reduce adverse impacts on public health. The European and UK waste policy force sustainable waste management and especially diversion from landfill, through reduction, reuse, recycling and composting, and recovery of value from waste. Energy from waste is a waste management option that could provide diversion from landfill and at the same time save a significant amount of greenhouse gas emissions, since it recovers energy from waste which usually replaces an equivalent amount of energy generated from fossil fuels. Energy from waste is a wide definition and includes technologies such as incineration of waste with energy recovery, or combustion of waste-derived fuels for energy production or advanced thermal treatment of waste with technologies such as gasification and pyrolysis, with energy recovery. The present study assessed the greenhouse gas emission impacts of three technologies that could be used for the treatment of Municipal Solid Waste in order to recover energy from it. These technologies are Mass Burn Incineration with energy recovery, Mechanical Biological Treatment via bio-drying and Mechanical Heat Treatment, which is a relatively new and uninvestigated method, compared to the other two. Mechanical Biological Treatment and Mechanical Heat Treatment can turn Municipal Solid Waste into Solid Recovered Fuel that could be combusted for energy production or replace other fuels in various industrial processes. The analysis showed that performance of these two technologies depends strongly on the final use of the produced fuel and they could produce GHG emissions savings only when there is end market for the fuel. On the other hand Mass Burn Incineration generates greenhouse gas emission savings when it recovers electricity and heat. Moreover the study found that the expected increase on the amount of Municipal Solid Waste treated for energy recovery in England by 2020 could save greenhouse gas emission, if certain Energy from Waste technologies would be applied, under certain conditions.  相似文献   
505.
Concentrated animal feeding operations around the globe generate large amounts of nitrous oxide (N2O) in the surrounding atmosphere. Liquid animal waste systems have received little attention with respect to N2O emissions. We hypothesized that the solution chemistry of animal waste aqueous suspensions would promote conditions that lead to N2O supersaturation at the liquid/air interface. The concentration of dissolved N2O in poultry litter (PL) aqueous suspensions at 25 °C was 0.36 μg N2O mL−1, at least an order of magnitude greater than that measured in water in equilibrium with ambient air, suggesting N2O supersaturation. There was a nonlinear increase in the N2O Henry constants of PL from 2810 atm/mole fraction at 35 °C to 17 300 atm/mole fraction at 41 °C. The extremely high N2O Henry constants were partially ascribed to N2O complexation with aromatic moieties. Complexed N2O structures were unstable at temperatures > 35 °C, supplying the headspace with additional free N2O concentrations.  相似文献   
506.
In the present work, the crude biodiesel produced from spent fish frying oil through alkaline catalyzed transesterification was purified using a low-cost adsorbent viz. sulfonated tea waste. After separating the glycerol, the crude biodiesel was purified using the suggested adsorbent. Various methods of purification using the said adsorbent were applied such as purification using adsorption column chromatography and shaking methods. The results showed that purification using adsorption column chromatography exhibited the bst result. Properties of the purified fuels were determined and found conformed to those specified by the ASTM standards. For the sake of comparison, purification using zeolite and water washing method was also investigated. The result indicated that the suggested adsorbent was more successful on purification of the crude biodiesel compared to other methods.  相似文献   
507.
A new variable-speed ground-coupled liquid desiccant air-conditioner was proposed and applied to a multi-storey office building in a temperate city of Kunming in China. Dynamic system simulations were performed to compare its performance with a constant-speed ground-source heat pump system. It was found that the use of the new system for a single-floor office reduced the annual unbalanced load to the ground heat exchanger borefield by nearly 70% together with a borehole depth reduction of up to 30%. For the case of a multi-storey office building, the number of floors served could be increased by 144% together with a reduction of CO2 emission by 43%. The results highlighted the merit of the new hybrid system with enhanced applicability when it was applied to a multi-storey office building in a temperate city.  相似文献   
508.
Nowadays microbial fuel cells (MFCs) are a rapidly evolving field and studied extensively because of their simultaneous dual functions of decomposing organic waste matter and eco-power generation. Now, facing their low power density, multiple effects including various gravity conditions ranging from 0 G to 2 G and three kinds of geometric flow channel (serpentine channel, serpentine tapered channel and bio-mixer channel) in MFCs were studied because of their ability to significantly impact the performance of MFCs.Numerical simulation technology, with its significant lessening of time needed and saving experimental costs required was used in this study. Results show that a better power performance was found at a condition of 0.125 G and Reynolds number Re = 41.3 regardless of flow channel in MFCs. In addition, the bio-mixer channel of the flow channels in MFCs will have a better performance than the other two channels because of its lower pressure drop and higher power generation. These findings will provide useful information on enhancing the performance of MFCs, especially with the application of low gravity conditions in the future.  相似文献   
509.
Microbial fuel cells (MFCs) are one of the bioreactors that produce electrons by metabolizing substrate from microorganisms, and have the ability to both degrade waste solution and produce electrons. Recently, the activity of microorganisms has limited the power performance of MFCs. Chaos has been used to stimulate activity of microorganisms, but it has not been used previously in MFCs. In this study, three types of acclimations – native acclimation (NA), MFC acclimation (MFCA), and MFC embedded with chaotic electric field acclimation (CMFCA) – are applied to realize their performance and chemical oxygen demand (COD) removal in MFCs, respectively. Results show that the current density and the power density of CMFCA were improved by 1.33 and 1.25 times than MFCA, and the COD removal of CMFCA reached 85% after five days. In addition, the acclimation stage at the condition of CMFCA appeared after 10 days, but was not found for the MFCA system. These observations would provide positive information for improving the performance of MCFs in the future.  相似文献   
510.
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