全文获取类型
收费全文 | 1550篇 |
免费 | 85篇 |
国内免费 | 155篇 |
专业分类
安全科学 | 307篇 |
废物处理 | 11篇 |
环保管理 | 277篇 |
综合类 | 592篇 |
基础理论 | 178篇 |
环境理论 | 3篇 |
污染及防治 | 141篇 |
评价与监测 | 28篇 |
社会与环境 | 167篇 |
灾害及防治 | 86篇 |
出版年
2023年 | 10篇 |
2022年 | 59篇 |
2021年 | 65篇 |
2020年 | 71篇 |
2019年 | 49篇 |
2018年 | 49篇 |
2017年 | 74篇 |
2016年 | 76篇 |
2015年 | 64篇 |
2014年 | 64篇 |
2013年 | 132篇 |
2012年 | 100篇 |
2011年 | 93篇 |
2010年 | 85篇 |
2009年 | 86篇 |
2008年 | 87篇 |
2007年 | 112篇 |
2006年 | 116篇 |
2005年 | 79篇 |
2004年 | 56篇 |
2003年 | 57篇 |
2002年 | 58篇 |
2001年 | 33篇 |
2000年 | 28篇 |
1999年 | 11篇 |
1998年 | 13篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1790条查询结果,搜索用时 15 毫秒
911.
Local food networks (LFNs) are growing in popularity, in part as a response to broader criticisms of conventional food production. Municipal policy-makers have the opportunity to work with stakeholders to build LFNs to increase access to healthy foods in cities and ultimately improve population health and well-being. Building opportunities for healthy eating is particularly important in our study area. Flint, Michigan, is a post-industrial shrinking city suffering from the economic and health effects of deindustrialisation. Various stakeholders in Flint have responded to a significant issue with access to food by strengthening collaborations through a food policy council (FPC). Growth in the local food system has been supported by administrators and community advocates alike, through supporting community gardens, farmers' markets, and urban agriculture in a manner similar to nearby Detroit. Participant observation was conducted with stakeholders involved in the development of the LFN and the FPC in Flint. Stakeholders were exposed to existing research on the food system to help inform their policy direction. The group expressed several core concerns and prospects for future work, including a strong emphasis on consensus-based decision-making. Based on the synthesis of stakeholder opinions, policy recommendations are made to aid in continued planning of the LFN. Planning for food is an important first step in improving public health and strengthening local economic development in post-industrial cities. This research highlights the issue by making explicit the challenges and opportunities for policy advocacy in LFNs. 相似文献
912.
Land take and food security: assessment of land take on the agricultural production in Europe 总被引:1,自引:0,他引:1
Ciro Gardi Panos Panagos Marc Van Liedekerke Claudio Bosco Delphine De Brogniez 《Journal of Environmental Planning and Management》2015,58(5):898-912
Soil is a multifunctional, non-renewable natural resource for Europe as clearly expressed in the European Union (EU) Thematic Strategy for Soil Protection (COM (2006)231). Soil carries out multiple functions, including the support of food production. Urban development and its associated land take poses a major threat to soil and could have significant effects on agricultural production. This paper aims to evaluate the potential productivity losses in European agriculture due to land-take processes between 1990 and 2006. Agricultural land take was calculated using CORINE Land Cover maps of 1990, 2000 and 2006. For 21 of the 27 EU member states, agricultural land take was computed to be 752,973 ha for 1990–2000 and 436,095 ha for 2000–2006, representing 70.8% and 53.5%, respectively, of the total EU land take for these periods. The impact of this land take on the production capabilities of the agricultural sector for the period 1990–2006 for 19 of the 21 states was estimated to be equivalent to a loss of more than six million tonnes of wheat. The paper demonstrates that Europe's intense urbanisation has a direct impact on its capability to produce food. 相似文献
913.
古旧建筑经多年使用之后,由于各种原因造成材料劣化、结构损伤等,在抗震性能和结构安全性方面存在一定的隐患。近年来,我国建筑结构检测工作广泛开展,如何更充分地利用这些珍贵的检测成果是一个值得思考的课题。本文针对建于20世纪40年代末的某历史保护建筑物,根据前后相隔10年的2次结构检测鉴定结果,分析了建筑物服役过程中,其材料、构件性能、结构安全性等方面的变化规律,以及造成构件损坏的主要原因。鉴定结果认为,该建筑物整体性依然良好,能满足历史建筑物保护和结构承载能力的要求。同时,结合该建筑物现状,分析了其结构构件时变安全性,为采取合理的加固措施提供了依据。 相似文献
914.
生态风险与生态安全的评价方法及前景 总被引:1,自引:0,他引:1
各种生态环境问题的严重后果引起了人们对环境与生态的重视,并催生了生态风险与生态安全评价.为了更好地进行这两方面的评价,首先分别综述生态风险和生态安全评价的发展进程,突出主要研究方法的介绍,由此总结生态风险评价与生态安全评价的关系以及生态风险与生态安全评价的发展趋势.生态风险评价主要有健康危险度法、环评指数法、景观生态法、空间统计或地统计法、相对风险模型等方法;生态安全评价主要有综合指数法、景观生态法、生态承载力和生态足迹方法、突变级数等方法.生态风险与生态安全评价是从相反的角度研究生态系统的状况和潜在威胁,生态风险评价偏重细节分析,生态安全评价偏重整体分析.空间和时间尺度的扩大、评价方法的改进、评价标准的制定和评价的可信性检验都是生态风险评价与生态安全评价的发展趋势. 相似文献
915.
陈筱 《生态与农村环境学报》1999,(4)
分析了神农架建设绿色食品基地的自然优势条件和农业资源特点,提出了发展山区、河谷、城镇基地,创建名牌资源品种的建设方针。 相似文献
916.
Frans W. A. Brom 《Journal of Agricultural and Environmental Ethics》2000,12(2):127-139
The use of biotechnology in food productiongives rise to consumer concerns. The term ``consumerconcern' is often used as a container notion. Itincludes concerns about food safety, environmental andanimal welfare consequences of food productionsystems, and intrinsic moral objections againstgenetic modification. In order to create clarity adistinction between three different kinds of consumerconcern is proposed. Consumer concerns can be seen assigns of loss of trust. Maintaining consumer trustasks for governmental action. Towards consumerconcerns, governments seem to have limitedpossibilities for public policy. Under current WTOregulations designed to prevent trade disputes,governments can only limit their policies to 1) safetyregulation based upon sound scientific evidence and 2)the stimulation of a system of product labeling. Ananalysis of trust, however, can show that ifgovernments limit their efforts in this way, they willnot do enough to avoid the types of consumer concernsthat diminish trust. The establishment of a technicalbody for food safety – although perhaps necessary –is in itself not enough, because concerns that relatedirectly to food safety cannot be solved by ``pure'science alone. And labeling can only be a good way totake consumer concerns seriously if these concerns arerelated to consumer autonomy. For consumer concernsthat are linked to ideas about a good society,labeling can only provide a solution if it is seen asan addition to political action rather than as itssubstitution. Labeling can help consumers take uptheir political responsibility. As citizens, consumershave certain reasonable concerns that can justifiableinfluence the market. In a free-market society, theyare, as buyers, co-creators of the market, andsocietal steering is partly done by the market.Therefore, they need the information to co-create thatmarket. The basis of labeling in these cases, however,is not the good life of the individual but thepolitical responsibility people have in their role asparticipants in a free-market. Then, public concernsare taken seriously. Labeling in that case does nottake away the possibilities of reaching politicalgoals, but it adds a possibility. 相似文献
917.
Terry Newholm 《Journal of Agricultural and Environmental Ethics》2000,12(2):153-164
Disputes over agriculture and foodproduction have occurred against a background ofdisputed authority with regard to governments,experts, and single issue pressure groups. Consumershave intervened in quite significant ways with manyaltering their buying patterns. The conventionalassessment of consumer ``preferences' throughaggregated purchases fails to reflect the ethicalnature of significant numbers of purchase decisions.Nevertheless, consumers seem to offer a wider basis onwhich to consider ethical issues. The author proposesthat a valuable inclusion of consumer opinion in thedebates would require a move away from neo-classicaleconomics and the selective inclusion of consumeropinion to unravel the complexity of (aggregated)consumer behavior. It is argued that Hirschman'sframework of ``exit, voice, and loyalty' is a moreappropriate tool for the understanding of ethics infood consumption. 相似文献
918.
简述地质灾害现状及防治的重要性,总结分析了地质灾害治理工程施工中安全管理所采取的措施及对策。 相似文献
919.
水环境安全预警系统构建探析 总被引:7,自引:0,他引:7
从水环境安全预警系统相关概念出发,阐述了预警系统建立的作用与意义,提出预警系统构建的总体框架和系统的3个主要组成层面,即技术层、信息层和用户层;指出预警系统构建的关键性问题为指标体系的建立、预警模型的选择以及预警安全阈值的确定;提出水环境安全预警系统研究中值得进一步关注的几个问题。 相似文献
920.
以系统降解效能和产甲烷量最大化为目标,分别考察不同有机负荷(8.93、10.71、13.39 kg·m-3·d-1)及进料频率(1、2、3次·d-1)下厨余垃圾中温厌氧消化系统运行过程中甲烷产量、SCOD、氨氮、pH和挥发性脂肪酸(VFAs)的变化,旨在明确系统负荷边界及进料频率对系统稳定性的影响.结果表明,系统的有机负荷存在最优值,系统累计产甲烷量随负荷的增加而升高,随后降低,有机负荷为10.71 kg·m-3·d-1时获得最大累计产甲烷量37.17 L,VS降解率72.58%.负荷增加系统稳定性下降甚至失稳,各物质出现积累,不利于反应的进行.增加进料频率可优化系统运行参数,显著提高系统产气和产甲烷量,进料频率较高时,运行周期内系统的甲烷产量及产率最高,分别达到45.03 L和0.738 L·g-1,呈线性增长,增加进料频率可提高系统对氨氮的耐受能力,显著提高系统稳定性,明显改善VFA和丙酸积累问题. 相似文献