全文获取类型
收费全文 | 1919篇 |
免费 | 236篇 |
国内免费 | 600篇 |
专业分类
安全科学 | 186篇 |
废物处理 | 111篇 |
环保管理 | 267篇 |
综合类 | 1269篇 |
基础理论 | 237篇 |
污染及防治 | 222篇 |
评价与监测 | 52篇 |
社会与环境 | 96篇 |
灾害及防治 | 315篇 |
出版年
2024年 | 12篇 |
2023年 | 62篇 |
2022年 | 86篇 |
2021年 | 92篇 |
2020年 | 86篇 |
2019年 | 89篇 |
2018年 | 63篇 |
2017年 | 88篇 |
2016年 | 107篇 |
2015年 | 121篇 |
2014年 | 129篇 |
2013年 | 175篇 |
2012年 | 220篇 |
2011年 | 251篇 |
2010年 | 134篇 |
2009年 | 125篇 |
2008年 | 89篇 |
2007年 | 134篇 |
2006年 | 111篇 |
2005年 | 83篇 |
2004年 | 58篇 |
2003年 | 41篇 |
2002年 | 47篇 |
2001年 | 64篇 |
2000年 | 47篇 |
1999年 | 30篇 |
1998年 | 32篇 |
1997年 | 32篇 |
1996年 | 10篇 |
1995年 | 36篇 |
1994年 | 21篇 |
1993年 | 30篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2755条查询结果,搜索用时 218 毫秒
721.
722.
章桂琴 《中国环境管理干部学院学报》2010,20(1):45-47,55
秦皇岛经济技术开发区经济迅猛发展,为避免走发达国家"先污染,后治理"的老路,必须以科学发展观为导向,优化产业结构,提高资源利用效率,节能减排,加强工业污染源的治理,完善基础设施建设,实现企业清洁生产,建立生态工业园区,以生态文明建设为引领,不断提升循环经济水平和持续发展能力,从而达到提高人民生活水平和改善人民生活环境的目的。 相似文献
723.
Heavy metal removal and cyanide destruction in the metal plating industry: an integrated approach from egypt 总被引:1,自引:0,他引:1
Wastewater produced from a metal plating is a major environmental problem. Industrial auditing revealed that the main source
of pollution mainly originated from rinsing water. The characterization of final effluent showed that it is highly contaminated
with hazardous heavy metals and cyanide. The concentration of copper, hexavalent chromium, nickel, and cyanide in the rinsing
water of metal plating department was 14.8, 40.9, 13.3, and 19 mg/l, respectively. The concentration of cyanide and zinc from
the galvanizing department reached 60 and 80 mg/l. The remediation scheme included the application of in-plant control measures
via changing the rinsing process followed by the destruction of cyanide and reduction of hexavalent chromium bearing wastes.
The pretreated wastes were then mixed with other industrial wastes prior to a combined chemical coagulation-sedimentation
using lime and/or lime in combination with ferric chloride. The results indicated that, after applying the waste minimization
measures alone at the source, prior to final treatment of industrial waste, removal rates of cyanide, copper, nickel, and
chromium concentrations were 23.2%, 14.9%, 32.3%, and 55.3%, respectively in the rinse water from metal plating department.
Furthermore, the removal rates of cyanide and zinc in the galvanizing department reached 59.7% and 24.3. The integrated control
measures and treatment scheme led to more than 99% removal of copper, nickel, chromium, and zinc, while the complete removal
of cyanide was achieved in the final effluent. 相似文献
724.
Abstract: The Elman Discrete Recurrent Neural Networks Model (EDRNNM), which is one of the special types of neural networks model, is developed and applied for the flood stage forecasting at the Musung station (No. 1) of the Wi‐stream catchment, which is one of the International Hydrological Program representative basins, Korea. A total of 135 different training patterns, which involve hidden nodes, standardization process, data length, and lead‐time, are selected for the minimization of the architectural uncertainty. The model parameters, such as optimal connection weights and biases, are estimated during the training performance of the EDRNNM, and we apply them to evaluate the validation performance of the EDRNNM. Sensitivity analysis is used to reduce the uncertainty of input data information of the EDRNNM. As the results of sensitivity analysis, the Improved EDRNNM consists of four input nodes resulting from the exclusion of Dongkok station (No.5) in initial five input nodes group of the EDRNNM. The accuracy of flood stage forecasting during the training and validation performances of the Improved EDRNNM remains the same as that of the EDRNNM. The Improved EDRNNM, therefore, gives highly reliable flood stage forecasting. The best optimal EDRNNM, so called the Improved EDRNNM, is determined by elimination of the uncertainties of architectural and input data information in this study. Consequently, we can avoid unnecessary data collection and operate the flood stage forecasting system economically. 相似文献
725.
This paper uses the findings from a column study to develop a reactive model for exploring the interactions occurring in leachate-contaminated soils. The changes occurring in the concentrations of acetic acid, sulphate, suspended and attached biomass, Fe(II), Mn(II), calcium, carbonate ions, and pH in the column are assessed. The mathematical model considers geochemical equilibrium, kinetic biodegradation, precipitation-dissolution reactions, bacterial and substrate transport, and permeability reduction arising from bacterial growth and gas production. A two-step sequential operator splitting method is used to solve the coupled transport and biogeochemical reaction equations. The model gives satisfactory fits to experimental data and the simulations show that the transport of metals in soil is controlled by multiple competing biotic and abiotic reactions. These findings suggest that bioaccumulation and gas formation, compared to chemical precipitation, have a larger influence on hydraulic conductivity reduction. 相似文献
726.
This work addresses the effect that plants (Typha latifolia and Carex lurida) have on the reduction of Cr(VI) in wetland sediments. Experiments were carried out using tubular microcosms, where chemical species were monitored along the longitudinal flow axis. Cr(VI) removal was enhanced by the presence of plants. This is explained by a decrease in the redox potential promoted by organic root exudates released by plants. Under these conditions sulfate reduction is enhanced, increasing the concentration of sulfide species in the sediment pore water, which reduce Cr(VI). Evapotranspiration induced by plants also contributed to enhance the reduction of Cr(VI) by concentrating all chemical species in the sediment pore water. Both exudates release and evapotranspiration have a diurnal component that affects Cr(VI) reduction. Concentration profiles were fitted to a kinetic model linking sulfide and Cr(VI) concentrations corrected for evapotranspiration. This expression captures both the longitudinal as well as the diurnal Cr(VI) concentration profiles. 相似文献
727.
Moreels D Crosson G Garafola C Monteleone D Taghavi S Fitts JP van der Lelie D 《Environmental science and pollution research international》2008,15(6):481-491
BACKGROUND, AIM, AND SCOPE: The subsurface at the Oak Ridge Field Research Center represents an extreme and diverse geochemical environment that places different stresses on the endogenous microbial communities, including low pH, elevated nitrate concentrations, and the occurrence of heavy metals and radionuclides, including hexavalent uranium [U(VI)]. The in situ immobilization of U(VI) in the aquifer can be achieved through microbial reduction to relatively insoluble U(IV). However, a high redox potential due to the presence of nitrate and the toxicity of heavy metals will impede this process. Our aim is to test biostimulation of the endogenous microbial communities to improve nitrate reduction and subsequent U(VI) reduction under conditions of elevated heavy metals. MATERIALS AND METHODS: Column experiments were used to test the possibility of using biostimulation via the addition of ethanol as a carbon source to improve nitrate reduction in the presence of elevated aqueous nickel. We subsequently analyzed the composition of the microbial communities that became established and their potential for U(VI) reduction and its in situ immobilization. RESULTS: Phylogenetic analysis revealed that the microbial population changed from heavy metal sensitive members of the actinobacteria, alpha- and gamma-proteobacteria to a community dominated by heavy metal resistant (nickel, cadmium, zinc, and cobalt resistant), nitrate reducing beta- and gamma-proteobacteria, and sulfate reducing Clostridiaceae. Coincidentally, synchrotron X-ray absorption spectroscopy analyses indicated that the resulting redox conditions favored U(VI) reduction transformation to insoluble U(IV) species associated with soil minerals and biomass. DISCUSSION: This study shows that the necessary genetic information to adapt to the implemented nickel stress resides in the endogenous microbial population present at the Oak Ridge FRC site, which changed from a community generally found under oligotrophic conditions to a community able to withstand the stress imposed by heavy metals, while efficiently reducing nitrate as electron donor. Once nitrate was reduced efficient reduction and in situ immobilization of uranium was observed. CONCLUSIONS: This study provides evidence that stimulating the metabolism of the endogenous bacterial population at the Oak Ridge FRC site by adding ethanol, a suitable carbon source, results in efficient nitrate reduction under conditions of elevated nickel, and a decrease of the redox potential such that sulfate and iron reducing bacteria are able to thrive and create conditions favorable for the reduction and in situ immobilization of uranium. Since we have found that the remediation potential resides within the endogenous microbial community, we believe it will be feasible to conduct field tests. RECOMMENDATIONS AND PERSPECTIVES: Biostimulation of endogenous bacteria provides an efficient tool for the successful in situ remediation of mixed-waste sites, particularly those co-contaminated with heavy metals, nitrate and radionuclides, as found in the United States and other countries as environmental legacies of the nuclear age. 相似文献
728.
城市社区防灾减灾工作机制研究 总被引:1,自引:0,他引:1
在组织论指导下,提出在区民防办下设街道防减灾办公室,负责社区防减灾的领导工作。根据灾害管理过程,设置下属机构包括:社区灾害预防组、应急救援组和灾后恢复组。明确各相关方在具体工作中的角色和责任,完善社区防减灾机制。按自愿原则组建志愿者队伍,建立良好的培养和激励机制,确保服务人员的长期化。扩大基层防减灾宣传教育的广度,特别是基层领导干部和青少年的宣教。将宣教和防灾演练结合,使得防灾演练制度化。同时,需要重视在现有"120"急救网络上,建立院前急救体系,配备相应的物资和人员。 相似文献
729.
730.
The main object of the study was the development of a long-term efficient and inexpensive in-situ immobilization technology for uranium (U) and arsenic (As) in smaller and decentralized groundwater discharges from abandoned mining processing sites. Therefore, corrosion of grey cast iron (gcFe) and nano-scale iron particles (naFe) as well as hydrogen stimulated autotrophic sulphate reduction (aSR) were investigated. Two column experiments with sulphate reducing bacterias (SRB) (biotic gcFe , biotic naFe) and one abiotic gcFe-column experiment were performed. In the biotic naFe column, no particle translocation was observed and a temporary but intensive naFe corrosion indicated by a decrease in E(h), a pH increase and H(2) evolution. Decreasing sulphate concentrations and (34)S enrichment in the column effluent indicated aSR. Fe(II) retention could be explained by siderite and consequently FeS precipitation by geochemical modeling (PhreeqC). U and As were completely immobilised within the biotic naFe column. In the biotic gcFe column, particle entrapment in open pore spaces resulted in a heterogeneous distribution of Fe-enriched zones and an increase in permeability due to preferential flow. However, Fe(II) concentrations in the effluent indicated a constant and lasting gcFe corrosion. An efficient immobilization was found for As, but not for U. 相似文献