全文获取类型
收费全文 | 1025篇 |
免费 | 37篇 |
国内免费 | 80篇 |
专业分类
安全科学 | 70篇 |
废物处理 | 13篇 |
环保管理 | 312篇 |
综合类 | 416篇 |
基础理论 | 99篇 |
环境理论 | 1篇 |
污染及防治 | 139篇 |
评价与监测 | 50篇 |
社会与环境 | 34篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 17篇 |
2021年 | 22篇 |
2020年 | 28篇 |
2019年 | 14篇 |
2018年 | 17篇 |
2017年 | 23篇 |
2016年 | 28篇 |
2015年 | 30篇 |
2014年 | 36篇 |
2013年 | 41篇 |
2012年 | 55篇 |
2011年 | 84篇 |
2010年 | 51篇 |
2009年 | 65篇 |
2008年 | 62篇 |
2007年 | 71篇 |
2006年 | 60篇 |
2005年 | 43篇 |
2004年 | 49篇 |
2003年 | 48篇 |
2002年 | 39篇 |
2001年 | 34篇 |
2000年 | 38篇 |
1999年 | 29篇 |
1998年 | 38篇 |
1997年 | 25篇 |
1996年 | 23篇 |
1995年 | 17篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有1142条查询结果,搜索用时 31 毫秒
891.
892.
Jesper H. Andersen Henrik Fossing Jens W. Hansen Ole H. Manscher Ciarán Murray Ditte L. J. Petersen 《Ambio》2014,43(7):906-913
Nutrient enrichment of coastal marine waters caused by losses of nitrate (NO3−) from agriculture is an increasing global problem. In the European Union, the Nitrates Directive (ND) of 1991 was meant to be a cornerstone in reducing eutrophication effects in coastal waters downstream from intensively farmed catchments. Although reductions in losses of nitrate have been attained, very few Member States have yet been able to reduce eutrophication effects caused by inputs of NO3− from agriculture. We report trends in concentrations of NO3− and chlorophyll-a (Chl-a) in Danish coastal and open marine waters during the period from 1996 to 2011 together with an assessment of eutrophication status based on multiple indicators (e.g. nutrient concentrations, Chl-a, submerged aquatic vegetation and benthic macroinvertebrates). Despite decreasing concentrations of both NO3−and Chl-a, Danish coastal waters are not yet to be classified as ‘unaffected by eutrophication’. In order to improve future pan-European evaluations of the effectiveness of the ND, we argue for the added value of including indicators and assessment principles from other European Directives, i.e. the Water Framework Directive and the Marine Strategy Framework Directive.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-014-0514-y) contains supplementary material, which is available to authorized users. 相似文献893.
城市生物质废物中温单级厌氧消化中试研究 总被引:1,自引:1,他引:0
建立了城市生物质废物中温单级厌氧消化中试反应器,对城市生物质废物厌氧消化过程系统稳定性、产甲烷性能及有机物的去除效果进行解析.反应器稳定运行410 d,共经历2.4、3.6、4.8、6.0 kg VS/(m3·d)4个负荷,反应器pH稳定在7.2 ~7.6之间,有机酸浓度<500 mg/L.在负荷6.0 kg VS/(m3·d)时反应器平均容积产气率4.25m3/(m3·d),有机物去除率为63.2%;另外,实验结果表明,厌氧消化过程对蛋白质、脂肪、纤维素及多糖类物质的去除效果有明显差异,其中脂肪类物质去除率为98.2%,产沼气贡献率为38.8%.实现了针对我国城市生物质废物的高负荷高效厌氧消化,为我国城市生物质废物厌氧消化规模化处理提供了基础数据. 相似文献
894.
Trace elements (n = 23) in Irish headwater lakes (n = 126) were investigated to determine their ambient concentrations, fractionation (total, dissolved, and non-labile), and geochemical controls. Lakes were generally located in remote upland, acid-sensitive regions along the coastal margins of the country. Total trace metal concentrations were low, within the range of natural pristine surface waters; however, some lakes (~20 %) had inorganic labile aluminum and manganese at levels potentially harmful to aquatic organisms. Redundancy analysis indicated that geochemical weathering was the dominant controlling factor for total metals, compared with acidity for dissolved metals. In addition, many metals were positively correlated with dissolved organic carbon indicating their affinity (or complexation) with humic substances (e.g., aluminum, iron, mercury, lead). However, a number of trace metals (e.g., aluminum, mercury, zinc) were correlated with anthropogenic acidic deposition (i.e., non-marine sulfate), suggesting atmospheric sources or elevated leaching owing to acidic deposition. As transboundary air pollution continues to decline, significant changes in the cycling of trace metals is anticipated. 相似文献
895.
Winter-flooding of ricefields provides foraging habitat to waterfowl, which in return may bring agronomic benefits to farmers. Our study experimentally tested the effect of mallards (Anas platyrhynchos) on the standing stalks and weed seed bank in the Camargue (France), both of which present major challenges for farmers. Three duck densities were tested: (D1) 5 ducks ha−1 (historical nocturnal density), (D2) 23 ducks ha−1 (present nocturnal density), and (D3) 300 ducks ha−1 (Asian rice-duck farming density). The ducks reduced the stalks significantly: −27 % (D1), −52 % (D2), and −91 % (D3). Conversely, they decreased the number of seeds by only 3 % (D3) and the seed mass by about 21 % (D1 and D3), which was not significant. Besides they had no effect on seed species richness. This study clearly demonstrates that the winter-flooding effect on straw decomposition can be enhanced by waterfowl foraging, hence showing an agronomic benefit from ducks to farmers. However, there was no clear effect in terms of seed bank reduction. 相似文献
896.
Optimization of regional hazardous waste management systems: an improved formulation 总被引:1,自引:0,他引:1
The planning and design of regional hazardous waste management system (RHWMS) involves selection of treatment and disposal facilities, allocation of hazardous wastes and waste residues from generator to the treatment and disposal sites and selection of the transportation routes. An improved formulation based upon multi-objective integer programming approach is presented to arrive at the optimal configuration of RHWMS components. This formulation addresses important practical issues like unique characteristics of the hazardous wastes reflecting on waste–waste and waste–technology compatibility. A utility function approach is presented to integrate both cost and risk related objectives. An illustrative case example is presented to demonstrate the usefulness of the improved formulation as a tool which can be used by environmental planning agencies in regional planning for hazardous waste management. 相似文献
897.
Susumu Shimura Isamu Yokota Yoshitaka Nitta 《Journal of Material Cycles and Waste Management》2001,3(1):48-59
Developing nations have various problems regarding municipal solid waste (MSW). Therefore, to carry out a systematic review
of the MSW problems in the target area and to formulate a well-considered management plan, it is extremely important to understand
the present MSW flow in the region. One of the authors participated in the nine solid waste management (SWM) studies in developing
nations undertaken under the technical cooperation program of the Japan International Cooperation Agency (JICA). Based on
these studies, this paper reviews the results of research in developing countries regarding different MSW streams, the factors
that cause the differences, and the elements considered to have the most impact on those streams. This research identifies
several issues regarding MSW streams in developing nations. The MSW generation rate per capita in developing countries is
generally said to grow in proportion to the GNP. However, the findings of this research show no correlation between the two;
instead, there is a relationship between the GNP and the collection rate. To formulate proper future MSW management plans
in countries with low collection rates, it is very important to forecast the rates of self-disposed and recycled waste, and
their fluctuations. These are affected by urban structure, collection services, etc.
Received: January 27, 2000 / Accepted: July 19, 2000 相似文献
898.
核废物的安全和环境影响 总被引:8,自引:0,他引:8
本论述了核废物特性,核废物安全管理原则,核废物的安全处理、处置技术、废放射源的安全管理、乏燃料的安全管理和核废物的环境影响等6方面问题。特别强调了废物管理9条原则,核废物最少化,豁免和清洁解控,核废物处理、处置技术的发展动向,我国核废物管理40字方针,国际社会关注的废放射源和乏燃料安全处理和处置等,并以我国大亚湾和秦山核电站为例,说明核废物可以被安全地控制和管理,保证环境的安全。 相似文献
899.
成都市各区(市)县城镇生活垃圾处理对策 总被引:2,自引:1,他引:1
介绍了成都市各区(市)县生活垃圾的成分和处理现状,提出了将来成都市各区(市)县城镇垃圾无害化、资源化、减量化的处理方案。 相似文献
900.
This study aimed to investigate the impact of contamination by persistent organic pollutants (POPs) on Brazilian wildlife. The concentrations of certain POPs, including dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs), in the eggs of the brown booby (Sula leucogaster) were measured. The eggs were collected from breeding colonies located on three archipelagos (Saint Peter and Saint Paul, Abrolhos and Cagarras Islands) in the Atlantic Ocean, which are located at different distances from the Brazilian coast (range 4-1010 km). In addition, possible alterations in eggshell characteristics were evaluated. The average values of POPs found in eggs from the archipelago of Saint Peter and Saint Paul (0.05 μg g−1 of ΣPCBs and 0.01 μg g−1 of ΣDDT) and the archipelago of Abrolhos (0.19 μg g−1 of ΣPCBs and 0.03 μg g−1 of ΣDDT) were low compared to the reference values reported in the literature. In contrast, the concentrations measured in eggs from Cagarras (8.4 μg g−1 of ΣPCBs and 1.8 μg g−1 of ΣDDT) were the highest, and this total PCB level is close to the threshold values considered to be harmful to birds. Our findings indicate that the brown booby colony closest to the Rio de Janeiro coast has recently been exposed to DDT. Despite the high pollution levels found on the Cagarras Islands, no alterations in the eggshell weight or the thickness of the analyzed eggs were detected. Hence, more detailed studies are recommended to determine the actual effects of the selected POPs on the Cagarras breeding colony. 相似文献