首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   37672篇
  免费   2825篇
  国内免费   4412篇
安全科学   8888篇
废物处理   586篇
环保管理   7173篇
综合类   17268篇
基础理论   3170篇
环境理论   25篇
污染及防治   2232篇
评价与监测   1689篇
社会与环境   2314篇
灾害及防治   1564篇
  2024年   122篇
  2023年   605篇
  2022年   970篇
  2021年   1261篇
  2020年   1391篇
  2019年   1139篇
  2018年   849篇
  2017年   1423篇
  2016年   1548篇
  2015年   1648篇
  2014年   1596篇
  2013年   2122篇
  2012年   2478篇
  2011年   2751篇
  2010年   1978篇
  2009年   2184篇
  2008年   1599篇
  2007年   2479篇
  2006年   2498篇
  2005年   2073篇
  2004年   1826篇
  2003年   1634篇
  2002年   1456篇
  2001年   1202篇
  2000年   1160篇
  1999年   998篇
  1998年   663篇
  1997年   605篇
  1996年   442篇
  1995年   451篇
  1994年   321篇
  1993年   295篇
  1992年   222篇
  1991年   148篇
  1990年   100篇
  1989年   61篇
  1988年   77篇
  1987年   51篇
  1986年   39篇
  1985年   38篇
  1984年   48篇
  1983年   35篇
  1982年   38篇
  1981年   30篇
  1980年   42篇
  1979年   49篇
  1978年   26篇
  1973年   21篇
  1972年   22篇
  1971年   27篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
11.
/ Why are some environmental risks distributed disproportionately in the neighborhoods of the minorities and the poor? A hypothesis was proposed in a recent study that market dynamics contributed to the current environmental inequity. That is, locally unwanted land uses (LULUs) make the host communities home to more poor people and people of color. This hypothesis was allegedly supported by a Houston case study, whereby its author analyzed the postsiting changes of the socioeconomic characteristics of the neighborhoods surrounding solid waste facilities. I argue that such an analysis of postsiting changes alone is insufficient to test the causation hypothesis. Instead, I propose a conceptual framework for analysis of environmental equity dynamics and causation. I suggest that the presiting neighborhood dynamics and the characteristics of control neighborhoods be analyzed as the first test for the causation hypothesis. Furthermore, I present theories of neighborhood change and then examine alternative hypotheses that these theories offer for explaining neighborhood changes and for the roles of LULUs in neighborhood changes. These alternative hypotheses should be examined when analyzing the relationship between LULUs and neighborhood changes in a metropolitan area. Using this framework of analysis, I revisited the Houston case. First, I found no evidence that provided support for the hypothesis that the presence of LULUs made the neighborhoods home to more blacks and poor people, contrary to the conclusion made by the previous study. Second, I examined alternative hypotheses for explaining neighborhood changes-invasion-succession, other push forces, and neighborhood life-cycle; the former two might offer better explanation.KEY WORDS: Environmental equity and justice; Locally unwanted lane uses; Siting; Market dynamics; Invasion-succession; Neighborhood changes  相似文献   
12.
Abstract:  Broadly conceived and considered in its many usages, sustainability has grave defects as a planning goal, particularly when used by conservationists: it confuses means and ends; it is vague about what is being sustained and who or what is doing the sustaining; it is uninspiring; it is little more than Pinchot-era conservation (and thus ignores the many lessons learned since then); it need not be linked to land, to the land's functioning, or to any ecological science; it need not include a moral component; it is consistent with the view of humans as all-powerful manipulators of the planet; and, in general, it is such a malleable term that its popularity provides only a facade of consensus. When sustainability is defined broadly to include the full range of economic and social aspirations, it poses the particular risk that ecological and biodiversity concerns will be cast aside in favor of more pressing human wants. Given these many defects, the conservation movement should discard the term in favor of a more alluring goal, attentive to nature and its ecological functioning. A sound goal would incorporate and distill the considerable ecological and moral wisdom accumulated since Pinchot's day while giving conservationists the rhetorical tools needed to defend the land against competing pressures. In our view, conservation would be well served by an updated variant of "land health," Aldo Leopold's ecologically grounded goal from the 1940s. Land health as an independent understanding should set the essential terms of how we live and enjoy the earth, providing the framework within which we pursue our many social and economic aims.  相似文献   
13.
报道了利用N,N─二甲基苯胺为偶联试剂的Criess反应以示波极谱法测定NO_2~-的测试方法。在拟定的实验条件下,NO_2~-在4.0×10~-3~4.8×10~-1μg/ml范围内与极谱波波高呈良好的线性关系。环境水测定的相对标准偏差小于l%,回收率在97%~101%之间。  相似文献   
14.
小城镇的生态环境保护   总被引:1,自引:0,他引:1  
在城镇化不断发展的进程中,小城镇的生态环境日益恶化。分析了小城镇生态环境存在的问题,提出了应采取的生态环境保护规划与对策。  相似文献   
15.
湖泊综合治理,单靠行政手段和经济手段是远远不够的,必须发动群众,依靠湖区周边的广大群众,通过广泛深入地进行环境保护宣传教育,提高广大群众的环境保护意识,促使他们自觉自愿地投身于湖泊的治理和建设中去,湖泊治理才能取得预期效果.  相似文献   
16.
以大连市环境监测中心为例,介绍了实验室认可中档案管理人员的设置,人员技术档案、监测业务档案、仪器设备档案、物资采购档案、质量体系文件归档的方法和要求。阐述了实验室认可中档案管理的重要性。  相似文献   
17.
秦皇岛市水环境现状与恢复   总被引:1,自引:0,他引:1  
秦皇岛地区原始自然环境优越,多年来,不正当的人为活动、环境恶化趋势明显,也直接干扰与影响着水的良性循环。现状水环境:河流基流渐小,并季节性断流,坑塘减少,湿地萎缩水土流失,洪径增大。地下水位下降,水量减少,承压水无序开采,污净比失衡,河流承栽力降低。地下水垂直污染面扩大,点、面、垃圾污染源趋重。联通青一洋、石一起,实施水资源再分配。优化配置城乡用水。重视地下水源地建设,联合调度地表、地下水源。谨慎开发承压水。植树造林、涵养水分。注重防风林带建设,改善田间小气候。严控地下水采量,防止土壤旱化。搞好坑塘建设,解决乡镇污水出路与净化。保护湿地,促进水的良性循环。深度处理废污水.使之资源化。从源头抓好城市三大水源地污染源.察勘储备新地下水源地。改良恢复水环境,保障水资源循环利用。  相似文献   
18.
论国家生态安全   总被引:6,自引:0,他引:6  
国家生态安全是一种全新的现代国家安全观,要重视和维护国家生态安全。  相似文献   
19.
论述了用市场化模式解决三峡库区城市污水处理场和垃圾处理场的建设和运营问题,并提出了市场化的总体架构。  相似文献   
20.
本文对水危机及全球水源状况进行了分析,为保护人类水资源与生态环境进行了有益的探索。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号