全文获取类型
收费全文 | 541篇 |
免费 | 31篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 32篇 |
废物处理 | 2篇 |
环保管理 | 249篇 |
综合类 | 129篇 |
基础理论 | 82篇 |
污染及防治 | 26篇 |
评价与监测 | 39篇 |
社会与环境 | 32篇 |
灾害及防治 | 10篇 |
出版年
2024年 | 3篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 14篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 30篇 |
2012年 | 22篇 |
2011年 | 39篇 |
2010年 | 25篇 |
2009年 | 39篇 |
2008年 | 39篇 |
2007年 | 41篇 |
2006年 | 25篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有601条查询结果,搜索用时 578 毫秒
11.
《循环经济发展战略及近期行动计划》指出了要推动各类产业园区实施循环化改造,促进园区绿色低碳循环发展的新要求。兰州新区是国务院批复的全国第五个、西北第一个国家级新区,对兰州新区循环化建设提出相应对策。 相似文献
12.
项目档案管理对于电子政务工程项目的成功实施具有十分重要的意义。通过对电子政务工程项目档案特性的分析,探讨了当前项目档案管理中存在的问题,提出了加强档案管理的措施和建议。并以国家环境信息与统计能力建设项目为例,对项目档案管理流程、手段和要求做了详细论述,为电子政务工程项目档案管理提供了有益的经验借鉴。 相似文献
13.
基于第二次全国土地调查的云南省坝区县、半山半坝县和山区县的划分 总被引:3,自引:0,他引:3
云南是我国西部的典型山区省份,地形坡度<8°的坝区面积仅占土地总面积的6%左右。应用云南省第二次全国土地调查中对各县(市、区)≥1 km2坝子的调查和核定成果,选取坝区耕地面积比例、坝区土地面积比例、≥100 km2坝子数等3 个单项指标,并构建了综合指标--坝区土地综合指数,采用主导指标与综合分析相结合的方法,对全省129 个县(市、区) 进行坝区县、半山半坝县和山区县的划分。结果表明,全省有21 个县属于坝区县,37 个县属于半山半坝县,71 个县属于山区县。这一研究修订了以往云南省仅以坝区耕地面积比例为指标而划分出的坝区县、半山半坝县和山区县方案,为云南省及各地合理地进行产业布局(尤其是农业生产布局)、保护坝区优质耕地资源提供科学依据和基础支撑。 相似文献
14.
Romero-Ruiz A Alhama J Blasco J Gómez-Ariza JL López-Barea J 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):1340-1347
Metallothionein (MT) and other biomarker levels were measured in Scrobicularia plana clams to assess pollution of the Guadalquivir Estuary possibly affected by metals released from Aznalcóllar pyrite mine in 1998. After optimizing reagent concentrations for monobromobimane derivatization, MT levels were quantified by reversed-phase high-performance liquid chromatography coupled to fluorescence detection (RP-HPLC-FD) in heated or unheated digestive gland extracts and compared to those obtained by differential pulse polarography (DPP). MT content assayed by RP-HPLC-FD in unheated samples was higher than that obtained by DPP and correlated better with metals and anti-oxidant activities. MT assay by RP-HPLC-FD in unheated extracts would be preferable for assessing metal pollution, due to its greater sensitivity and specificity. In addition to MT induction, glyoxalase II inhibition was well correlated with metal contents. Our results suggest that metals at the estuary do not originate from Aznalcóllar spill, but from those carried along by the river and deposited at its concave bank. 相似文献
15.
Lemly AD 《Environmental monitoring and assessment》2007,125(1-3):361-375
This paper gives step-by-step instructions for assessing aquatic selenium hazards associated with mining. The procedure was
developed to provide the U.S. Forest Service with a proactive capability for determining the risk of selenium pollution when
it reviews mine permit applications in accordance with the National Environmental Policy Act (NEPA). The procedural framework
is constructed in a decision-tree format in order to guide users through the various steps, provide a logical sequence for
completing individual tasks, and identify key decision points. There are five major components designed to gather information
on operational parameters of the proposed mine as well as key aspects of the physical, chemical, and biological environment
surrounding it — geological assessment, mine operation assessment, hydrological assessment, biological assessment, and hazard
assessment. Validation tests conducted at three mines where selenium pollution has occurred confirmed that the procedure will
accurately predict ecological risks. In each case, it correctly identified and quantified selenium hazard, and indicated the
steps needed to reduce this hazard to an acceptable level. By utilizing the procedure, NEPA workers can be confident in their
ability to understand the risk of aquatic selenium pollution and take appropriate action. Although the procedure was developed
for the Forest Service it should also be useful to other federal land management agencies that conduct NEPA assessments, as
well as regulatory agencies responsible for issuing coal mining permits under the authority of the Surface Mining Control
and Reclamation Act (SMCRA) and associated Section 401 water quality certification under the Clean Water Act. Mining companies
will also benefit from the application of this procedure because priority selenium sources can be identified in relation to
specific mine operating parameters. The procedure will reveal the point(s) at which there is a need to modify operating conditions
to meet environmental quality goals. By recognizing concerns early in the NEPA process, it may be possible for a mining company
to match operational parameters with environmental requirements, thereby increasing the likelihood that the permit application
will be approved. 相似文献
16.
Temporal Trends in the Spatial Distribution of Impervious Cover Relative to Stream Location
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J. Wickham A. Neale M. Mehaffey T. Jarnagin D. Norton 《Journal of the American Water Resources Association》2016,52(2):409-419
Use of impervious cover is transitioning from an indicator of surface water condition to one that also guides and informs watershed planning and management, including Clean Water Act (33 U.S.C. §1251 et seq.) reporting. Whether it is for understanding surface water condition or planning and management, impervious cover is most commonly expressed as summary measurement (e.g., percentage watershed in impervious cover). We use the National Land Cover Database to estimate impervious cover in the vicinity of surface waters for three time periods (2001, 2006, 2011). We also compare impervious cover in the vicinity of surface waters to watershed summary estimates of impervious cover for classifying the spatial pattern of impervious cover. Between 2001 and 2011, surface water shorelines (streams and water bodies) in the vicinity of impervious cover increased nearly 10,000 km. Across all time periods, approximately 27% of the watersheds in the continental United States had proximally distributed impervious cover, i.e., the percentage of impervious cover in the vicinity of surface waters was higher than its watershed summary expression. We discuss how impervious cover spatial pattern can be used to inform watershed planning and management, including reporting under the Clean Water Act. 相似文献
17.
Elena N. Bukvareva Karsten Grunewald Sergey N. Bobylev Dimitry G. Zamolodchikov Alexey V. Zimenko Olaf Bastian 《Ambio》2015,44(6):491-507
This paper focusses on a conceptual overview of ways to address a comprehensive analysis of ecosystem services (ES) in a country as large and heterogeneous as Russia. As a first step, a methodology for assessing the services for the federal subjects of Russia was chosen, i.e., its constituent provinces and similar entities, in physical terms. Russia harbors a great diversity of natural conditions and ecosystems which are suppliers of ES, and likewise a variety of the socio-economic conditions that shape the demand for these services and their consumption. The methodological approach described permits several important tasks to be addressed: the evaluation of the degree of satisfaction of people’s needs for ES, the identification of ecological donor and acceptor regions, and zoning of the country’s territory for ES assessment. The next step is to prepare a prototype of a National Report on ES in Russia, for which we are presenting the planned structure. 相似文献
18.
Svetlana V. Degteva Vasily I. Ponomarev Sasha W. Eisenman Vyacheslav Dushenkov 《Ambio》2015,44(6):473-490
Increasing anthropogenic pressure on the largest remaining tracts of old-growth boreal forest in Europe necessitates additional conservation of ecosystems and biodiversity in northeastern European Russia. In a regional network comprising 8 % of the Nenets Autonomous District and 13.5 % of the Komi Republic, 248 areas have varying protected statuses as state nature reserves (zapovedniks), national parks, reserves/sanctuaries (zakazniks), or natural monuments. Due to increased natural resource extraction in this relatively pristine area, designation of additional protected areas is critical for the protection of key ecological sites. The history of ecological preservation in these regions is herein described, and recent recommendations for incorporating additional ecologically representative areas into the regional network are presented. If the protected area network can be expanded, the overall environmental stability in these globally significant ecosystems may remain intact, and can help Russia meet the 2020 Aichi conservation targets, as set forth by the Convention of Biological Diversity. 相似文献
19.
Balancing recreation and conservation is an important issue in Canada's parks and protected areas. Increased levels of visitation to parks, especially to backcountry areas, create undue pressure on natural resources, resulting in a variety of ecological impacts. This paper illustrates the issue of visitor-induced changes on the chemical composition of soils in Mt Robson Provincial Park, British Columbia. Soil samples were collected from dish wash stations and fire pits (disturbed sites) at seven campgrounds located along two popular backcountry trails, and were compared to samples obtained from adjacent undisturbed control sites. Analysis of soil samples suggest that the lower amounts of aluminum, potassium, magnesium and sodium in many of the 'disturbed' samples can be related to intense leaching in dish wash stations, and can be attributed to frequent disposal of waste water from washing and cooking activities. Soils in wash stations generally had higher phosphorus, copper and zinc contents as compared to controls. Soils in fire pits were elevated in copper, relative to controls. Results of this study support park regulations that waste water disposal and camp fires be restricted to designated areas. Informing the public of scientific studies helps them understand the consequences of their activities; this may help persuade them to observe park rules and regulations. 相似文献
20.
Implications of changing national policies on land use in the Chittagong Hill Tracts of Bangladesh 总被引:2,自引:0,他引:2
Land use in the Chittagong Hill Tracts (CHT) of Bangladesh had undergone changes over the past several centuries. The landscape, which was mostly covered with forest with interspersed shifting cultivation plots until the beginning of the colonial period, has gradually changed into a landscape with a blend of land uses. Overall, the forest area has gradually declined, while the area under shifting cultivation and sedentary agriculture has expanded. The process of the change was multi-directional. National forestry, land use, land taxation, population migration policies, and development activities, such as construction of a hydroelectric dam and roads, played an important role in this process. Shifting cultivation had inflicted little damage on the forest until the beginning of the colonial period. The pace of deforestation accelerated with the nationalization of forests which abolished tribal people's customary use and management rights to the forest, and allowed large-scale commercial logging both legally and illegally. The pace was further intensified by the policy encouraging population migration to CHT and construction of a reservoir on the Karnafuli River. Efforts were made to replace shifting cultivation with more productive types of sedentary agriculture. However, much change could not take place in the absence of secure land rights, supportive trade policies, and the required support services and facilities, including infrastructure. Locationally suitable land use evolved in areas where transportation facilities were available and farmers were granted land title with the necessary extension services and credit facilities. These findings have important policy implications for the promotion of environmentally and economically sound land use in CHT. 相似文献