全文获取类型
收费全文 | 3637篇 |
免费 | 84篇 |
国内免费 | 486篇 |
专业分类
安全科学 | 136篇 |
废物处理 | 199篇 |
环保管理 | 404篇 |
综合类 | 957篇 |
基础理论 | 695篇 |
环境理论 | 5篇 |
污染及防治 | 1265篇 |
评价与监测 | 281篇 |
社会与环境 | 217篇 |
灾害及防治 | 48篇 |
出版年
2024年 | 4篇 |
2023年 | 40篇 |
2022年 | 107篇 |
2021年 | 103篇 |
2020年 | 63篇 |
2019年 | 91篇 |
2018年 | 87篇 |
2017年 | 105篇 |
2016年 | 151篇 |
2015年 | 186篇 |
2014年 | 221篇 |
2013年 | 320篇 |
2012年 | 261篇 |
2011年 | 260篇 |
2010年 | 183篇 |
2009年 | 195篇 |
2008年 | 242篇 |
2007年 | 224篇 |
2006年 | 183篇 |
2005年 | 149篇 |
2004年 | 137篇 |
2003年 | 121篇 |
2002年 | 128篇 |
2001年 | 80篇 |
2000年 | 53篇 |
1999年 | 57篇 |
1998年 | 57篇 |
1997年 | 40篇 |
1996年 | 49篇 |
1995年 | 39篇 |
1994年 | 34篇 |
1993年 | 28篇 |
1992年 | 28篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 13篇 |
1987年 | 5篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1977年 | 4篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1968年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有4207条查询结果,搜索用时 15 毫秒
981.
Jef Van Meensel Ludwig Lauwers Guido Van Huylenbroeck 《Journal of environmental management》2010,91(11):2370-2377
Reducing nitrogen emission from livestock production is usually perceived as costly. Nevertheless, production process related measures addressing the transformation of input(s) into output(s) may result in a cost-saving reduction of nitrogen emission. This paper explores the separate and combined use of traditional key performance indicators and an environmentally adjusted Data Envelopment Analysis (DEA) to reveal firm-specific cost-saving mechanisms for pig-finishing farms. Traditional key performance indicators are easy to communicate but have shortcomings when assessing benchmarks for comparative farm analysis. The environmentally adjusted DEA decomposes both cost and environmental efficiencies into technical and allocative efficiency components, separating the physical production analysis from price and nutrient content information. DEA makes efficiency benchmarks and improvement paths explicit, but the practical value of such efficiency scores is low. This paper proposes to take advantage of both methods: concrete benchmarks and eligible improvement paths are assessed using frontier methods, while the decision variables that steer farmers towards changes are described in terms of traditional key performance indicators. This leads to an improved diagnosis that is easy to communicate to farmers and may therefore facilitate decision support. Our pig-finishing case study shows that farms can achieve economic-environmental win–win situations through improving technical, cost allocative and cost efficiencies, which are mainly driven by feed conversion. Less technical efficient farms are found to require a lower delivery weight in order to minimize costs, which shows the farm-specificity of economic-environmental improvement advice. 相似文献
982.
Ayman Elshkaki Ester van der Voet Mirja Van Holderbeke Veerle Timmermans 《Waste management (New York, N.Y.)》2009,29(6):1916-1928
Substances may enter the economy and the environment through both intentional and non-intentional flows. These non-intentional flows, including the occurrence of substances as pollutants in mixed primary resources (metal ores, phosphate ores and fossil fuels) and their presence in re-used waste streams from intentional use may have environmental and economic consequences in terms of pollution and resource availability. On the one hand, these non-intentional flows may cause pollution problems. On the other hand, these flows have the potential to be a secondary source of substances.This article aims to quantify and model the non-intentional flows of lead, to evaluate their long-term environmental consequences, and compare these consequences to those of the intentional flows of lead. To meet this goal, the model combines all the sources of non-intentional flows of lead within one model, which also includes the intentional flows.Application of the model shows that the non-intentional flows of lead related to waste streams associated with intentional use are decreasing over time, due to the increased attention given to waste management. However, as contaminants in mixed primary resources application, lead flows are increasing as demand for these applications is increasing. 相似文献
983.
André Pelser Nola Redelinghuys Nontombi Velelo 《Environment, Development and Sustainability》2013,15(5):1205-1226
Protected areas in developing countries are increasingly expected to move beyond biodiversity protection so as also to contribute to poverty reduction and the economic development of their surrounding communities. The purpose of this article is to report on the key findings that emerged from the assessment of a poverty alleviation programme at the Golden Gate Highlands National Park in South Africa and the lessons learned from that particular programme. Designed around outcomes analysis as an analytical framework for programme evaluation, a mixed-method approach of semi-structured interviews and focus-group sessions was used to collect data from amongst programme beneficiaries, the park management and members of the park’s advisory board. The findings indicate that although programmes of this kind can indeed impact positively on poverty levels, their direct impacts do however remain limited to a relatively small proportion of households in neighbouring communities. The article concludes that by conceptualising poverty as a multidimensional state of well-being, this allows for the exploration of a much broader range of potential social, cultural and economic benefits available from protected areas. 相似文献
984.
José A. Martínez-Casasnovas María Concepción Ramos Sílvia Espinal-Utgés 《Environmental monitoring and assessment》2010,163(1-4):379-396
The availability of heavy machinery and the vineyard restructuring and conversion plans of the European Union Common Agricultural Policy (Commission Regulation EC no. 1227/2000 of 31 May 2000) have encouraged the restructuring of many vineyards on hillslopes of Mediterranean Europe, through the creation of terraces to favor the mechanization of agricultural work. Terrace construction requires cutting and filling operations that create soil spatial variability, which affects soil properties and plant development. In the present paper, we study the effects of hillslope terracing on the spatial variability of the normalized difference vegetation index (NDVI) in fields of the Priorat region (NE Spain) during 2004, 2005, and 2006. This index was computed from high-resolution remote sensing data (Quickbird-2). Detailed digital terrain models before and after terrace construction were used to assess the earth movements. The results indicate that terracing by heavy machinery induced high variability on the NDVI values over the years, showing significant differences as effect of the cut and fill operations. 相似文献
985.
986.
987.
988.
989.
Hanane Bouchghoul Chloé Quelin Philippe Loget Féréchté Encha-Razavi Marie-Victoire Senat Lorraine Maheut Julie Galimand Sophie Collardeau-Frachon Lydie Da Costa Jelena Martinovic 《黑龙江环境通报》2018,38(10):772-778
We report a multiplex family with a GATA1 gene mutation responsible for a massive fetal cerebral hemorrhage occurring at 36 weeks. Two other stillbirth cousins presented with fetal hydrops and congenital hemochromatosis' phenotype at 37 and 12 weeks of gestation. Molecular screening revealed the presence of a c.613G>A pathogenic allelic variation in exon 4 of GATA1 gene in the 3 male siblings and their carrier mothers. The diagnosis of a GATA1 gene mutation may be suspected in cases of male fetuses with intracerebral bleeding, particularly if a history of prior fetal loss(es) and mild maternal thrombocytopenia are also present. 相似文献
990.