全文获取类型
收费全文 | 3014篇 |
免费 | 88篇 |
国内免费 | 79篇 |
专业分类
安全科学 | 114篇 |
废物处理 | 23篇 |
环保管理 | 1107篇 |
综合类 | 1102篇 |
基础理论 | 191篇 |
环境理论 | 1篇 |
污染及防治 | 39篇 |
评价与监测 | 35篇 |
社会与环境 | 528篇 |
灾害及防治 | 41篇 |
出版年
2023年 | 19篇 |
2022年 | 41篇 |
2021年 | 50篇 |
2020年 | 53篇 |
2019年 | 44篇 |
2018年 | 49篇 |
2017年 | 80篇 |
2016年 | 87篇 |
2015年 | 68篇 |
2014年 | 72篇 |
2013年 | 118篇 |
2012年 | 123篇 |
2011年 | 156篇 |
2010年 | 111篇 |
2009年 | 93篇 |
2008年 | 102篇 |
2007年 | 157篇 |
2006年 | 127篇 |
2005年 | 156篇 |
2004年 | 159篇 |
2003年 | 147篇 |
2002年 | 121篇 |
2001年 | 91篇 |
2000年 | 129篇 |
1999年 | 139篇 |
1998年 | 85篇 |
1997年 | 73篇 |
1996年 | 55篇 |
1995年 | 69篇 |
1994年 | 50篇 |
1993年 | 54篇 |
1992年 | 50篇 |
1991年 | 36篇 |
1990年 | 25篇 |
1989年 | 9篇 |
1988年 | 14篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 12篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 11篇 |
1972年 | 10篇 |
1971年 | 15篇 |
排序方式: 共有3181条查询结果,搜索用时 15 毫秒
991.
Barbara Ntombi Ngwenya Ketlhatlogile Keta Mosepele Lapologang Magole 《Natural resources forum》2012,36(2):109-122
Fish is a major source of livelihood for the majority of people living around the Okavango Delta in northwestern Botswana. Gender dynamics and governance regimes determine differential access to, and control of, resources between women and men in the area. The purpose of this case study is to critically assess the embeddedness of gendered inequities in the governance of Okavango Delta fishery. Primary data was collected through focus group discussions and face‐to‐face interviews of 96 basket fishers from five villages along the Panhandle area of the Okavango River. The study found that past and present Okavango Delta fishery policy and programme interventions tended to entrench rather than minimize gendered disparities between women and men fishers' access to and control over fish resources, asset accumulation and employment opportunities. Basket fishers have intimate knowledge of flood variability, fish migration and habitat and use this knowledge to make decisions about when and where to harvest what fish species. Women fishers' ecological knowledge, interests and concerns however, have been excluded from current zoning and closed season regulations and co‐management structures. The paper concludes that past and current development interventions as well as the regulatory framework continue to entrench pre‐existing gender relations in the fishery sector which excludes, disempowers and marginalizes women fishers. We recommend innovative co‐management and local based structures which recognize the diversity of interests and interest groups. 相似文献
992.
黄河三角洲土地资源开发对策的探讨 总被引:6,自引:0,他引:6
黄河三角洲是我国三大三角洲之一,面积约5930km2,它拥有丰富的土地资源,但从大农业角度来看,其土地质量较差,生态环境脆弱。当前,其土地资源的合理开发利用具有十分重要的现实意义。 首先,本文将区内土地类型划为 5类和19个亚类。其次,应用二级模糊综合评判,将其土地质量分为8等13级。其中宜农地占28.83%,宜牧地占34.44%,渔业用地占27.98%。最后,应用层次分析法(AHP)对土地资源合理开发利用的对策作了分析探讨。认为:对于黄河三角洲土地资源的开发,必须强调遵循经济效益服从社会效益和生态效益的总原则。在此前提下,提出了以保证工矿业用地为首的6项开发策略,以及以引黄放淤改良盐碱地为首的20项开发措施。 相似文献
993.
The relationship of forests in water quantity and quality has been debated during the past years. At the same time, focus
on climate change has increased interest in ecosystem restoration as a means for adaptation. Climate change might become one
of the key drivers pushing integrated approaches for natural resources management into practice. The National Adaptation Programme
of Action (NAPA) is an initiative agreed under the UN Framework Convention on Climate Change. An analysis was done to find
out how widely ecosystem restoration and integrated approaches have been incorporated into NAPA priority adaptation projects.
The data show that that the NAPAs can be seen as potentially important channel for operationalizing various integrated concepts.
Key challenge is to implement the NAPA projects. The amount needed to implement the NAPA projects aiming at ecosystem restoration
using integrated approaches presents only 0.7% of the money pledged in Copenhagen for climate change adaptation. 相似文献
994.
党的十八大将生态文明建设提升到五位一体总体布局的战略高度,要求把生态文明建设放在突出地位,融入经济建设、政治建设、文化建设、社会建设各方面和全过程。从人类文明转型的高度,分析了推进生态文明建设的历史必然性,探寻了再生资源产业与生态文明建设间的内在联系,剖析了再生资源产业的典型特征,并对生态文明建设与再生资源产业的未来发展进行了展望. 相似文献
995.
围绕废旧物资增值税税征管理政策调整完善工作,论述了其在废旧物资“产废”、“收废”、“利废”三大基础环节的现状及存在的问题,提出合理平衡三大环节的经济利益及打造三大环节税征链扣的建议,为切实做好废旧物资税征政策调整完善工作提供参考。 相似文献
996.
成都冬季典型辐射逆温过程分析 总被引:1,自引:0,他引:1
本文利用测温声雷达的探测结果,借助同期探空和地面观测资料,分析了成都平原典型辐射逆温的生消演变规律,指出了其主要特征。这些结果对气候资源利用、污染气象条件的研究等具有重要意义。 相似文献
997.
998.
试论江苏省国土资源与区域可持续发展 总被引:9,自引:3,他引:6
国土资源是区域可持续发展的基础,国土资源的合理开发利用是区域持发展的必由之路。首先详细地分析了江苏国土资源的优势条件,然后着重阐述了江苏国土资源的劣势,指出 一个资源约束型省份人地关系紧张、气候灾害频敏、环境问题突出已严重制约着区域的可持续发展;最后,根据江苏省情,对江苏可持续发展提出如下建议;加强对地理区位的开发和利用,促进力的合理布局,严格控制人口增长,努力提高人口素质,严格保护耕地,高效利用 相似文献
999.
Damodar S. Airan 《Journal of the American Water Resources Association》1973,9(3):421-432
ABSTRACT Environmental resources can be managed properly only by adopting a comprehensive approach. The whole environment must be considered as a single system, and prior to any action, all types of environmental impacts caused by it should be studied in detail. This paper underlines the close relationship between different environmental problems, analyzes existing management patterns, and proposes new alternatives whenever applicable. The different constraints, which have to be considered in the decision-making process while developing a plan, are also discussed. It is concluded that efforts neglecting the interaction among different aspects of the environment do not upgrade the quality of water, air, and land to any appreciable degree. 相似文献
1000.
The recent versions of nonlinear programming techniques such as the conjugate gradient and the gradient projection algorithms are used to obtain the optimal operating conditions of a multiple reservoirs system with multiple purposes. These algorithms are compared with other techniques in the literature. The conjugate gradient method incorporates the advantages of both the generalized Newton-Raphson, also known as the quasilinearization technique, and the gradient approach while avoiding their major drawbacks. To illustrate the technique, a water resources system with three reservoirs and a tabular objective function is solved by the two algorithms. 相似文献