全文获取类型
收费全文 | 1206篇 |
免费 | 90篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 135篇 |
废物处理 | 18篇 |
环保管理 | 312篇 |
综合类 | 376篇 |
基础理论 | 163篇 |
污染及防治 | 48篇 |
评价与监测 | 21篇 |
社会与环境 | 151篇 |
灾害及防治 | 85篇 |
出版年
2025年 | 1篇 |
2024年 | 25篇 |
2023年 | 28篇 |
2022年 | 37篇 |
2021年 | 30篇 |
2020年 | 53篇 |
2019年 | 42篇 |
2018年 | 20篇 |
2017年 | 45篇 |
2016年 | 37篇 |
2015年 | 36篇 |
2014年 | 39篇 |
2013年 | 61篇 |
2012年 | 62篇 |
2011年 | 72篇 |
2010年 | 40篇 |
2009年 | 48篇 |
2008年 | 36篇 |
2007年 | 76篇 |
2006年 | 60篇 |
2005年 | 50篇 |
2004年 | 53篇 |
2003年 | 51篇 |
2002年 | 44篇 |
2001年 | 48篇 |
2000年 | 39篇 |
1999年 | 25篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 27篇 |
1995年 | 16篇 |
1994年 | 18篇 |
1993年 | 19篇 |
1992年 | 14篇 |
1991年 | 2篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1309条查询结果,搜索用时 0 毫秒
581.
对环保服务业和科技创新进行了科学的界定,论述了科技创新是全面提升环保服务业发展水平和建设资源节约型、环境友好型社会的重要保障。结合我国环保服务业发展存在的问题进行分析,探讨了提升我国环保服务业科技创新能力的策略和建议。 相似文献
582.
Mitigation of diffuse water pollution from agriculture is a key national environmental policy objective in England. With the recent introduction of the new agri-environment scheme, Countryside Stewardship, there is an increased emphasis on the macro-spatial targeting of on-farm mitigation measures to reduce pollutant pressures, and a concomitant need to forecast the technically feasible impacts of on-farm measures detailed in current policy and their associated costs and benefits. This paper reports the results of a modelling application to test these limits in the context of the associated costs and benefits for the reduction of diffuse water pollution from agriculture for each Water Framework Directive (WFD) water management catchment (WMC) and nationally. Four mitigation scenarios were modelled, including pollutant source control measures only (SC), mobilisation control measures only (MC), delivery control measures only (DC) and measures for source, mobilisation and delivery control (SMDC) combined. Projected impacts on nitrate, phosphorus and sediment export to water, ammonia, methane and nitrous oxide emissions to the atmosphere, together with the associated costs to the agricultural sector were estimated for each WFD WMC and nationally. Median WMC-scale reductions (with uncertainty ranges represented by 5th–95th percentiles) in current agricultural emissions, were predicted to be highest for the SMDC scenario; nitrate (18%, 11–23%), phosphorus (28%, 22–37%), sediment (25%, 18–43%), ammonia (26%, 17–32%), methane (13%, 7–18%) and nitrous oxide (18%, 16–20%). The median benefit-to-cost ratios (with uncertainty ranges represented by 5th–95th percentiles) were predicted to be in the following order; DC (0.15, 0.09–0.65), MC (0.19, 0.09–0.95), SMDC (0.31, 0.20–1.39) and SC (0.44, 0.19–2.48). Of the four scenarios simulated, the SC and SMDC suites of measures have the greatest potential to deliver reductions in BAU emissions from agriculture, and the best benefit:cost ratio. 相似文献
583.
为明确重大疫情中人群引流控制策略对室内呼吸暴露风险的影响,基于改进的行人动力学模型和呼吸传染概率模型,构建一般室内情况下人群运动多种场景,借助多智能体仿真技术,模拟防护优化策略、流量优化策略和路线优化策略对呼吸暴露风险影响。研究结果表明:室内呼吸暴露风险主要取决于行人总流量、个体停留时间、运动路径规划和污染区域持续时间;在行人社交距离遵循行为方面,个体因必须保持设定的物理距离而形成延滞效应,这会进一步增加暴露于污染区域时间;口罩病原体渗透率越低、空间通风量越大,群体呼吸传染概率越小。 相似文献
584.
Domagoj Vulin Maja Arnaut Daria Karasalihovi Sedlar 《Greenhouse Gases: Science and Technology》2020,10(1):230-248
CO2 storage projects are financially intensive and, without the European Union emission trading scheme that encourages CO2 emission reduction projects, they will not be cost effective, that is, feasible. Similar to the huge uncertainties involved in long‐term energy price prediction, CO2 market price is volatile. In this paper, indicators for key CO2 price changes are detected by moving average analysis. To prove the validity of the methods, geometric Brownian motion (GBM) simulations were performed for different drift and volatility values. Drift, the standard deviation of CO2 price changes and CO2 volatility were used on a daily, weekly and monthly basis for short term simulations and on a weekly basis for long term simulations. GBM simulation can help determine the probability of a European emission allowances (EUA) price, which is featured by great variations, depending on the period. Signals for periods were determined by momentum strategy, with 60 days for short and 365 days for the long moving average. They show correlation with natural gas prices, that is, EUA signals appear 13–17 months after the signal in natural gas price. Among the vast number of proposed hybrid prediction models, this correlation allows the prediction of a long‐term price trend. It seems that back‐loading measures obstructed risk estimates because they resulted in extreme price drift in some periods, as the consequence of rebalancing in supply and demand. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. 相似文献
585.
586.
黄玉源 《环境与可持续发展》2015,(4)
本文基于第一线调研和多年参政议政工作基础上,对珠三角区域的城市工业生态经济战略实施的过程、途径,可行性、原理及获得的重大效益进行了介绍与总结分析。研究指出,在实践过程中为更快更大规模地把生态经济战略与各地实际发展进程相结合加以推广和实施,则必须具备高度的社会责任感,勇于运用各种机会把生态经济的战略思路和实施策略很好地向社会各层面以及政府部门反映和建言,才能取得最好及更大的成效。 相似文献
587.
合理开发矿产资源,优化资源配置和产品结构,是贫困山区脱贫致富的实现选择,本文以北川县为例,立足市场需求和该县矿产资源,地理,经济等情况,综合分析了有利条件和制约因素,提出了开发北川矿产资源的战略指导思想,目标,重点和主要对策。 相似文献
588.
从长江流域水污染规律看四川省水环境保护战略 总被引:1,自引:0,他引:1
用流域系统联系的观点,从长江流域水污染特点规律及其发展趋势出发,分析了四川省水环境保护在长江流域的地位作用,及其面临的挑战,最后简要讨论四川水环境保护应采取的宏观战略。 相似文献
589.
Yajun Wang Xiaoming Zhang Qi Feng Jiexin Zou Chang Zhou Lin Zeng 《International Journal of Green Energy》2020,17(2):157-170
ABSTRACTCarbon corrosion caused by H2/O2 interface during the shut-down process is one of the factors that exacerbate the overall degradation of proton exchange membrane fuel cells (PEMFC) in automotive applications. Numerous studies have shown that system strategies are beneficial for reducing the duration of H2/O2 interface and alleviating performance degradation. In this paper, three different shut-down strategies are investigated and compared based on the internal behaviors acquired by in-situ measurements. For the three shut-down strategies, reverse current and high potential are mainly observed in a lower constant current and constant power strategy. Comparatively speaking, the internal uniformity of the cell under constant current and power load is better than that with constant voltage strategy when the shut-down time is about the same. The results suggest that adopting a higher constant power load followed by a larger voltage load during the shut-down process can effectively shorten the shut-down time and relieve carbon corrosion. These results add significant new insights into the shut-down process and will be of practical importance in directing design of combined shut-down strategy that can withstand carbon corrosion. 相似文献
590.
Due to increasing pressure from the European Union to meet recycling and recovery targets, (e.g. the packaging waste, waste electronic equipment and landfill directives), both the Irish and England's governments’ policy on waste management is changing to meet these pressures, with major emphasis upon the management of biodegradable municipal waste (BMW). In particular, the EU landfill directive requires reductions in the rate of biodegradable waste going to landfill to 35% by 2016. The objective of this paper is to examine how Ireland plans to meet this challenge and to compare the Irish strategy to that being adopted in England. The approach in England is driven by a clear understanding that the practice in the late 1990s was unlikely to ensure compliance with EU targets by the set dates. England has therefore developed a discrete, programme (Waste Implementation Programme) to drive a new approach, based on rigorous science and international best practice, which includes a Demonstrator Programme for new technologies. The dynamic, high cost, large scale programme in England stands in sharp contrast to that for Ireland and only future, detailed analysis of outcomes will be able to evaluate the cost effectiveness of each. 相似文献