全文获取类型
收费全文 | 566篇 |
免费 | 39篇 |
国内免费 | 141篇 |
专业分类
安全科学 | 43篇 |
废物处理 | 9篇 |
环保管理 | 154篇 |
综合类 | 277篇 |
基础理论 | 111篇 |
污染及防治 | 28篇 |
评价与监测 | 61篇 |
社会与环境 | 50篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 17篇 |
2020年 | 27篇 |
2019年 | 17篇 |
2018年 | 16篇 |
2017年 | 19篇 |
2016年 | 31篇 |
2015年 | 19篇 |
2014年 | 24篇 |
2013年 | 65篇 |
2012年 | 33篇 |
2011年 | 41篇 |
2010年 | 27篇 |
2009年 | 45篇 |
2008年 | 33篇 |
2007年 | 60篇 |
2006年 | 29篇 |
2005年 | 27篇 |
2004年 | 22篇 |
2003年 | 23篇 |
2002年 | 27篇 |
2001年 | 22篇 |
2000年 | 28篇 |
1999年 | 16篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有746条查询结果,搜索用时 328 毫秒
481.
This paper describes a comparative analysis of alternative methods of constructing composite indicators to measure the sustainability of the agricultural sector. The three methods employed were Principal Component Analysis, the Analytic Hierarchy Process and a Multi-Criteria technique. The comparison focused on the irrigated agriculture of the Duero basin in Spain as a case study, using a dataset of indicators previously calculated for various farm types and policy scenarios. The results enabled us to establish a hierarchy of preferred policy scenarios on the basis of the level of sustainability achieved, and show that the most recent CAP reform is the most sustainable agricultural policy scenario. By analyzing the heterogeneity of different farms types in each scenario, we can also determine the main features of the most sustainable farms in each case. The analysis demonstrates that full-time farmers with small to medium-sized farms and sowing profitable crops are the most sustainable farm types in all the policy scenarios. All of this information is useful for the support of agricultural policy design and its implementation, as we attempt to improve the sustainability of this sector. 相似文献
482.
人类健康风险的定量评估与分析 总被引:1,自引:0,他引:1
通过深入研究.将人类健康风险解析环境污染、食物安全、疾病流行和医疗保障四个方面。在建立一套评价人类健康风险指标体系的基础上。对40个样本国家进行评估。用聚类分析的方法.将40个国家分为四类,在对每一类国家的人类健康风险特点进行对比发现,在同等经济发展水平下,中国的人类健康风险相对较高。通过分析人类健康风险与经济发展水平的关系得出,人均GNI 1000,3000美元是国家经济发展的关键时期。同样也是改善人类健康状况的关键时期,这一时期国家要高度重视改善人类健康状况。 相似文献
483.
何婧婷 《安全.健康和环境》2020,(4):27-31
针对中国石化销售企业所属油库特点,以专业性、先进性、定性与定量相结合、可操作性为原则,对照国家、中国石化相关标准规范,兼顾基层特色,深入调查研究,经现场测试、多次专家研讨,构建了以落实绿色行动要求、完善污染治理设施管理、节约资源能源等13项要求为重点考核内容,由55项具体指标组成的绿色油库评价指标体系,现已正式在中国石化销售板块发布实施,为纵深推进企业绿色发展提供了科学合理的标准支撑。 相似文献
484.
本研究运用电子顺磁共振波谱方法(EPR)发现道路沥青中含有大量的环境持久性自由基(EPFRs),说明道路沥青可能是道路源大气颗粒物中EPFRs的重要来源途径.因此,进一步通过溶剂萃取从沥青中分离出不同极性组分,研究不同沥青组分中EPFRs的含量和种类分布特征,并且在这基础上探究道路沥青在光化学作用下二次生成EPFRs的潜能和特征.结果表明:沥青中含有的EPFRs类型是以碳原子为中心的自由基和以氧原子为中心的自由基混合存在(g=2.0032~2.0038),主要可能是芳烃类自由基和半醌自由基.沥青中EPFRs主要存在于不可萃取组分和二氯甲烷可萃取组分中,推测沥青大多数的EPFRs可能源于沥青中的大分子芳香化合物和酚类组分.沥青在模拟太阳光照射后,可生成10%~20%的二次EPFRs,并且发现新生成的主要是以g因子较大的氧原子为中心的EPFRs. 相似文献
485.
耕地质量指标体系的构建 总被引:8,自引:0,他引:8
根据土地质量的概念及其影响因素,构建了耕地质量指标体系。认为耕地质量的影响因素包括自然、社会和经济因素,而PSR(压力——状态——响应)框架则是构建耕地质量指标体系的最佳思路。在此基础上提出具体评价指标,其中生态功能指标体系包括土壤质量、气候质量、生物多样性质量和景观生态质量,生产功能指标体系(即耕地生产力)则通过耕地生产潜力、耕地基础地力和耕地现实生产力进行评价。 相似文献
486.
Generally speaking, there is a greater amount of quantitative data available to measure and model the cumulative environmental or economic impacts of mining than the social impacts. In part, this is because social impacts are often inherently more difficult to quantify, but historically there have also been fewer regulatory drivers for companies or state agencies to invest in collecting such data. Regulators in some jurisdictions are now starting to require resource companies to report on aspects of their social performance, but companies and regulators are still struggling to identify appropriate metrics, particularly in regards to cumulative impacts. This paper describes an innovative quantitative approach to tracking how communities experience and respond to increased mining activity, using data from the complaints registers maintained by mines located in the Upper Hunter Valley in New South Wales, Australia. In this study, complaints lodged with five separate mines adjacent to the township of Muswellbrook over several years were aggregated and trends analysed. The aggregated set showed that complaint frequency increased with the increase in mining activity but then decreased as individual complaints were addressed. However, when complaints from near-neighbours were removed, it emerged that the proportion of complaints that came from the town itself steadily increased over time. Further analysis indicated that this increase was closely associated with the amount of mine-disturbed land that could be seen from the town over time, as measured using a combination of remotely sensed data and a digital elevation model. This is persuasive evidence of a cumulative social impact that is more than just the sum of the local impacts of individual mines. 相似文献
487.
Michael R. Meador 《Journal of the American Water Resources Association》2013,49(2):253-263
Abstract: Relationships between nutrient concentrations and fish nutrient tolerance were assessed relative to established nutrient criteria. Fish community, nitrate plus nitrite (nitrate), and total phosphorus (TP) data were collected during summer low‐flow periods in 2003 and 2004 at stream sites along a nutrient‐enrichment gradient in an agricultural basin in Indiana and Ohio and an urban basin in the Atlanta, Georgia, area. Tolerance indicator values for nitrate and TP were assigned for each species and averaged separately for fish communities at each site (TIVo). Models were used to predict fish species expected to occur at a site under minimally disturbed conditions and average tolerance indicator values were determined for nitrate and TP separately for expected communities (TIVe). In both areas, tolerance scores (TIVo/TIVe) for nitrate increased significantly with increased nitrate concentrations whereas no significant relationships were detected between TP tolerance scores and TP concentrations. A 0% increase in the tolerance score (TIVo/TIVe = 1) for nitrate corresponded to a nitrate concentration of 0.19 mg/l (compared with a USEPA summer nitrate criterion of 0.17 mg/l) in the urban area and 0.31 mg/l (compared with a USEPA summer nitrate criterion of 0.86 mg/l) in the agricultural area. Fish nutrient tolerance values offer the ability to evaluate nutrient enrichment based on a quantitative approach that can provide insights into biologically relevant nutrient criteria. 相似文献
488.
Zofia Pawłowska 《International journal of occupational safety and ergonomics》2013,19(3):284-290
Improvement of occupational safety and health (OSH) management is closely related to the development of OSH performance measurement, which should include OSH outcomes (e.g., occupational accidents), OSH inputs (including working conditions) and OSH-related activities. The indicators used to measure the OSH outcomes are often called lagging indicators, and the indicators of inputs and OSH activities are leading indicators. A study was conducted in 60 companies in order to determine what kinds of indicators were used for OSH performance measurement by companies with different levels of OSH performance. The results reveal that the indicators most commonly used in all of the companies are those related to ensuring compliance with the statutory requirements. At the same time, the leading indicators are much more often adopted in companies with a higher performance level. These companies also much more often monitor on a regular basis the indicators adopted for the evaluation of their OSH performance. 相似文献
489.
Framework for Measuring Sustainable Development in Catchment Systems 总被引:15,自引:0,他引:15
Walmsley JJ 《Environmental management》2002,29(2):195-206
Integrated catchment management represents an approach to managing the resources of a catchment by integrating environmental,
economic, and social issues. It is aimed at deriving sustainable benefits for future generations, while protecting natural
resources, particularly water, and minimizing possible adverse social, economic, and environmental consequences. Indicators
of sustainable development, which summarize information for use in decision-making, are invaluable when trying to assess the
diverse, interacting components of catchment processes and resource management actions. The Driving-Forces–Pressure–State–Impact–Response
(DPSIR) indicator framework is useful for identifying and developing indicators of sustainable development for catchment management.
Driving forces have been identified as the natural conditions occurring in a catchment and the level of development and economic
activity. Pressures include the natural and anthropogenic supply of water, water demand, and water pollution. State indicators
can be split into those of quantity and those of quality. Impacts include those that affect the ecosystems directly and those
that impact the use value of the resource. It core indicators are identified within each of the categories given in the framework,
most major catchment-based management issues can be evaluated. This framework is applied to identify key issues in catchment
management in South Africa, and develop a set of indicators for evaluating catchments throughout the country. 相似文献
490.
A strategy for management of giant sequoia groves is formulated using a conceptual framework for ecosystem management recently
developed by Region Five of the USDA Forest Service. The framework includes physical, biological, and social dimensions. Environmental
indicators and reference variability for key ecosystem elements are discussed in this paper. The selected ecosystem elements
include: 1) attitudes, beliefs, and values; 2) economics and subsistence; 3) stream channel morphology; 4) sediment; 5) water;
6) fire; 7) organic debris; and 8) vegetation mosaic. Recommendations are made for the attributes of environmental indicators
that characterize these elements. These elements and associated indicators will define and control management activities for
the protection, preservation, and restoration of national forest giant sequoia ecosystems. 相似文献