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   4196篇
  免费   100篇
  国内免费   56篇
安全科学   254篇
废物处理   157篇
环保管理   836篇
综合类   539篇
基础理论   1063篇
环境理论   3篇
污染及防治   974篇
评价与监测   315篇
社会与环境   170篇
灾害及防治   41篇
  2023年   29篇
  2022年   40篇
  2021年   47篇
  2020年   59篇
  2019年   71篇
  2018年   85篇
  2017年   124篇
  2016年   143篇
  2015年   112篇
  2014年   139篇
  2013年   359篇
  2012年   187篇
  2011年   240篇
  2010年   189篇
  2009年   212篇
  2008年   213篇
  2007年   227篇
  2006年   206篇
  2005年   182篇
  2004年   157篇
  2003年   140篇
  2002年   138篇
  2001年   105篇
  2000年   71篇
  1999年   67篇
  1998年   48篇
  1997年   72篇
  1996年   52篇
  1995年   57篇
  1994年   61篇
  1993年   49篇
  1992年   39篇
  1991年   32篇
  1990年   34篇
  1989年   32篇
  1988年   24篇
  1987年   17篇
  1986年   23篇
  1985年   23篇
  1984年   18篇
  1983年   32篇
  1982年   24篇
  1981年   33篇
  1980年   19篇
  1979年   18篇
  1978年   16篇
  1977年   8篇
  1976年   13篇
  1975年   6篇
  1974年   6篇
排序方式: 共有4352条查询结果,搜索用时 174 毫秒
451.
Animal lifespans range from a few days to many decades, and this life history diversity is especially pronounced in ants. Queens can live for decades. Males, in contrast, are often assumed to act as ephemeral sperm delivery vessels that die after a brief mating flight—a view developed from studies of lekking species in temperate habitats. In a tropical ant assemblage, we found that males can live days to months outside the nest, a trait hypothesized to be associated with female calling, another common mating system. We combined feeding experiments with respirometry to show that lifespan can be enhanced over 3 months by feeding outside the nest. In one focal female calling species, Ectatomma ruidum, feeding enhanced male lifespan, but not sperm content. Extended lifespans outside the nest suggest stronger than expected selection on premating traits of male ants, although the ways these traits shape male mating success remain poorly understood.  相似文献   
452.
453.
454.
An inventory of sources of biodegradable municipal soil waste (BMSW) was constructed for urban and rural areas in the EU accession region of Cyprus. Composition analysis was performed on source-separated BMSW collected from households in the rural Ergates Community and an urban area within the Agglanjia Municipality. The data were statistically scrutinized to identify the main factors influencing the quantities of BMSW disposed by urban and rural communities in Cyprus. The results were extrapolated to predict the quantities and types of BMSW disposed by the entire communities. Significantly more BMSW was disposed in the urban area compared to the rural community due to lower diversion rates for green waste and the disposal of food waste from commercial sources. The quantity of food waste collected from households was influenced by socio-economic (household size, income, percentage of children) and behavioural (feeding of food waste to domestic animals, consuming processed 'ready' food) factors, whereas garden size, the type of vegetation, the reuse of trimmings and home composting were the main factors controlling the disposal of green waste.  相似文献   
455.
456.
Some neighbourhood environments have become dumping grounds for locally unwanted land uses (LULUs) that middle-class Americans do not want near their homes. LULUs may combine with other pariah land uses to collectively undermine the quality of the local environment, reduce investment, government services, the proportion of middle-income people and associated businesses. As important neighbourhood attributes are lost, illegal activities, derelict structures, trash-strewn lots and the concentration of poor and unhealthy people may increase. This paper describes the theory behind the impact of pariah land uses through examples of the downward spiral experienced by Camden, New Jersey and the south Bronx, New York. It then documents the experience of one community, Elizabethport, New Jersey, in reversing that downward spiral. Success in Elizabethport came from the synergistic activities of local, state and federal governments, community groups, and not-for-profit organizations as they struggled to regain control through local environmental management, rebuilding, and reducing crime. Social capital was also strengthened by using a local community health concern—that of childhood asthma. Efforts to reverse the downward spiral of urban decay from pariah land uses should be multi-faceted, spurred by local efforts that address local concerns.  相似文献   
457.
458.
459.
460.
Rural regions in post-industrial countries confront significant new challenges, particularly in relation to climate, biodiversity, unconventional resource development and energy. Yet at a time when the contours of these challenges are still being sketched, and preliminary, planned interventions undertaken, the practice of rural planning finds itself at a low ebb. We examine two ‘critical cases’, one each from Australia and the USA, to explore the issues and options for capacity of rural regional planning to surmount these new challenges. Our examination indicates the urgent need for a renewed discourse on rural regional planning.  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