全文获取类型
收费全文 | 687篇 |
免费 | 86篇 |
国内免费 | 71篇 |
专业分类
安全科学 | 201篇 |
废物处理 | 11篇 |
环保管理 | 126篇 |
综合类 | 246篇 |
基础理论 | 86篇 |
环境理论 | 2篇 |
污染及防治 | 37篇 |
评价与监测 | 31篇 |
社会与环境 | 56篇 |
灾害及防治 | 48篇 |
出版年
2023年 | 13篇 |
2022年 | 24篇 |
2021年 | 32篇 |
2020年 | 34篇 |
2019年 | 24篇 |
2018年 | 22篇 |
2017年 | 38篇 |
2016年 | 46篇 |
2015年 | 43篇 |
2014年 | 32篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 63篇 |
2010年 | 40篇 |
2009年 | 39篇 |
2008年 | 34篇 |
2007年 | 37篇 |
2006年 | 37篇 |
2005年 | 23篇 |
2004年 | 27篇 |
2003年 | 27篇 |
2002年 | 13篇 |
2001年 | 25篇 |
2000年 | 18篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有844条查询结果,搜索用时 437 毫秒
641.
There is an urgent need globally to trigger fundamental societal changes in water management away from existing unsustainable paradigms. This paper attempts to understand the evolution of newspaper coverage of water issues in China by analyzing water-related articles in a major national newspaper, the People’s Daily, over the period 1946–2012 using a content analysis approach. The major findings include the following: (1) water issues were in relatively prominent positions in the newspaper; (2) the reporting of water issues in China experienced three stages: 1946 to the middle of 1980s—flood and drought control and water for food production, the middle of 1980s to 1997—water for economic development, and 1998 to the present—water for the environmental sustainability and economic development; (3) the reporting of water issues in the People’s Daily clearly reflected China’s top-down water resources management system, and no “real” public opinions on water were reported during the study period; and (4) the People’s Daily is just a wind vane of Chinese mainstream values and policies on water. The findings supported the realist assumption that the societal value changes on water issues in China were triggered by a range of factors including biophysical pressure (floods and droughts), political campaign (the Cultural Revolution), macro-economic reform (Reform and Opening-up), water institutional arrangement (the Water Law), and water management reform (the No. 1 Central Document on water reform). While there are similarities and differences between this study and other studies, important implications for more sustainable water management are a need to strengthen academic specialists’ and NGO’s voices in the newspaper to create a better informed public, and to stimulate practices toward sustainable water use. 相似文献
642.
643.
The prospects of rapid climate change and the potential existence of tipping points in marine ecosystems where nonlinear change
may result from them being overstepped, raises the question of strategies for coping with ecosystem change. There is broad
agreement that the combined forces of climate change, pollution and increasing economic activities necessitates more comprehensive
approaches to oceans management, centering on the concept of ecosystem-based oceans management. This article addresses the
Norwegian experience in introducing integrated, ecosystem-based oceans management, emphasizing how climate change, seen as
a major long-term driver of change in ecosystems, is addressed in management plans. Understanding the direct effects of climate
variability and change on ecosystems and indirect effects on human activities is essential for adaptive planning to be useful
in the long-term management of the marine environment. 相似文献
644.
In this paper, a simple model for analysing variability in radon concentrations in homes is tested. The approach used here involves two error components, representing additive and multiplicative errors, together with variation between-houses. We use a Bayesian approach for our analysis and apply this model to two datasets of repeat radon measurements in homes; one based on 3-month long measurements for which the original measurements were close to the current UK Radon Action Level (200 Bq m−3), and the other based on 6-month measurement data (from regional and national surveys), for which the original measurements cover a wide range of radon concentrations, down to very low levels. The model with two error components provides a better fit to these datasets than does a model based on solely multiplicative errors. 相似文献
645.
为更好地解决海上船舶溢油应急管理能力评估过程中的不确定性问题,提出1种基于区间二型模糊层次分析法的云模型综合评估方法。针对评估体系的局部性,借鉴PPRR应急管理过程理论,对影响船舶溢油应急管理能力的因素进行分级和分类,构建全局评估指标体系;分别运用区间二型模糊层次分析法和逆向云发生器确定各指标权重和云模型参数;通过浮动云和综合云算法获得最终评估结果。结果表明:将5个评估等级和评估结果进行仿真得出评估云的“云滴”图可显示出评估结果的能力等级以及评估结果的可信度和稳定性。计算某海区船舶溢油应急管理能力的评估等级为“较好”,即管辖该海区的海事管理部门能较好地解决海上船舶溢油突发事故,验证了所提方法的可行性和有效性。 相似文献
646.
647.
区域农地市场发育对农户水土保持行为的影响及其空间差异--基于生态脆弱区江西省兴国县、上饶县、余江县村域农户调查的分析 总被引:7,自引:0,他引:7
分析农户水土保持决策过程、建立农户水土保持决策的两阶段概念模型,从理论上分析了土地市场对农户水土保持的影响.运用在江西省兴国县、上饶县和余江县的样本村农户调查资料,通过建立土地流转与农户水土保持相互关系模型,运用Heckman的两阶段法对模型参数进行了估计.运用模型估计结果,分析土地流转对农户水土保持决策的影响并且对其区域差异进行了探讨.结果表明:从全部样本来看,农户是否意识到水土流失问题的存在以及家庭土地税费负担量对农户是否采取水土保持决策有显著影响;在兴国县,土地流入面积和费用2个因素对水土保持决策有显著影响;在余江县土地流入面积和费用也有影响显著,并且土地流入面积对农户水土保持投入的影响更强,而且土地流出面积在余江也有显著影响;上饶县,土地流出面积有显著影响.在全部样本、兴国县以及余江县,土地流出收益对农户水土保持决策的影响都不显著.最后,就进一步推进区域水土流失治理促进土地持续利用提出了相关建议. 相似文献
648.
碳达峰与碳中和愿景的提出为我国低碳/脱碳发展明确了新方向,也对科技创新和技术发展提出了新要求。世界各国均将科技创新作为碳中和目标实现的重要保障。我国实现碳中和目标,归根结底也需要依靠科技进步。我国碳排放总量大、强度高,实现碳中和目标的时间周期短,现有技术尚存在不足,科技发展需要付出更多努力并提前部署。我国碳中和技术发展需要为保障我国碳排放高质量达峰和实现碳中和目标提供技术可行、经济可承受的科技支撑。各部门需要结合自身特点制定技术发展路径。"十四五"是碳达峰与碳中和目标实现的关键时期,应全面加强相关脱碳、零碳、负排放技术发展的全局性部署,加快开展研发示范。为了更好地推动面向碳中和愿景的科技发展,需要强化顶层设计、完善保障机制与加强国际合作。 相似文献
649.
An improved method,suitable for collecting nitrate from surface waters in the watershed for 15 N isotope tracing analysis,was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments.The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method.Being simple and practical in operation principle and procedures,cost-economic,and highly efficient in nitrate separation/enrichment,the method met the requirements of δ 15 N mass spectrum analysis and would lay a foundation for the application of 15 N isotope tracing approach to the research on non-point source pollution in watershed. 相似文献
650.
为解决管道状态的远程实时监测问题,基于现场地质灾害调查结果,根据某受到不稳定边坡影响的管道所处滑坡区域的特点,设计1种基于云服务平台的管道状态远程实时监测系统。系统由前端数据测量模块、中端数据采集和传输模块以及终端监测平台模块组成。采用振弦式应变计进行管道应变测量;应用数据采集仪、移动数据发射器及电源进行数据采集及传输;利用自主开发的基于云服务平台专用软件进行管道状态的数据分析及远程实时监测。结果表明:系统具有稳定地实时数据获取、高效地数据远程传输和操作便捷、功能丰富的终端监测能力,可较好地评估管道的运行状况,提高滑坡灾害预警能力,保证管道的安全运行。 相似文献