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   892篇
  免费   56篇
  国内免费   22篇
安全科学   276篇
废物处理   5篇
环保管理   110篇
综合类   320篇
基础理论   52篇
环境理论   1篇
污染及防治   20篇
评价与监测   14篇
社会与环境   107篇
灾害及防治   65篇
  2023年   4篇
  2022年   28篇
  2021年   45篇
  2020年   41篇
  2019年   28篇
  2018年   25篇
  2017年   25篇
  2016年   32篇
  2015年   36篇
  2014年   32篇
  2013年   46篇
  2012年   60篇
  2011年   65篇
  2010年   61篇
  2009年   59篇
  2008年   55篇
  2007年   63篇
  2006年   82篇
  2005年   54篇
  2004年   40篇
  2003年   24篇
  2002年   29篇
  2001年   15篇
  2000年   8篇
  1999年   5篇
  1998年   1篇
  1996年   1篇
  1994年   1篇
  1992年   2篇
  1991年   1篇
  1986年   1篇
  1984年   1篇
排序方式: 共有970条查询结果,搜索用时 15 毫秒
871.
建筑施工企业施工安全水平的提高主要取决于其自身重视与努力这一内在因素,但作为外因的政府监督也是不可忽视的。从前人的研究可知政府采用奖罚结合的策略最优,但就现有安全激励机制下,奖励少则施工企业失去激励动力,奖励多则增加政府负担。在这个问题上还鲜有研究。首先通过对政府与施工方在上述两种状况下的博弈对比分析来论证市场激励比政府监管效率更高。其次,通过引入安全信用等级系数来对工程施工招投标机制进行改进。当投标人安全信用等级较高时,在维持原中标概率的基础上,可获得一个利润增量,从而从安全激励上实现对原有政府监管机制的改进。最后,在理论分析的基础上进行了例证分析。  相似文献   
872.
This paper develops an analytical framework to investigate the relationship between water and armed conflict, and applies it to the ‘Summer War’ of 2006 between Israel and Lebanon (Hezbollah). The framework broadens and deepens existing classifications by assessing the impact of acts of war as indiscriminate or targeted, and evaluating them in terms of international norms and law, in particular International Humanitarian Law (IHL). In the case at hand, the relationship is characterised by extensive damage in Lebanon to drinking water infrastructure and resources. This is seen as a clear violation of the letter and the spirit of IHL, while the partial destruction of more than 50 public water towers compromises water rights and national development goals. The absence of pre‐war environmental baselines makes it difficult to gauge the impact on water resources, suggesting a role for those with first‐hand knowledge of the hostilities to develop a more effective response before, during, and after armed conflict.  相似文献   
873.
水安全既是城市生态文明建设的重要内容,也是生态文明建设的重要保障,而水安全评价则是实现水安全的必然途径。本文旨在以生态文明建设为宗旨,以水安全的影响因素为依据,构建水安全评价指标体系。生态文明导向下的城市水安全评价更强调水资源的循环性、效率性、可持续性,水生态与社会发展的和谐性及平衡性。评价指标体系可分为自然生态、社会行为、制度规则和精神意识4个维度,然后根据每个维度下水资源的特征及外部因素对水资源的影响方式设计具体的评价指标,并运用层析分析法为各指标赋权。  相似文献   
874.
发生在2012年1月28日的中水电集团苏丹项目29名中方员工被劫持事件,极大地牵动了国人的心弦,其影响范围之广,关注度之高前所未有。与之相比,中国石油集团公司海外项目所在国家有20多个属于较高风险国家,在这些国家的石油项目同样面临着诸如社区滋扰、绑架劫持、武装袭击、战争等巨大安保风险。如何有效保障海外石油工程项目中方员工人身和资产安全,不得不再次引起我们的思考。本文通过对"1.28"事件这一典型非传统领域社会安全事件的分析,结合海外社会安全管理特点,提出了加强海外石油工程项目社会安全管理的几点思考,以供参考。  相似文献   
875.
安全产业是改善安全生产状况,实现安全发展的重要支撑和保障。本文明确了安全产业的相关概念及分类,对国内外安全产业发展状况进行了较为全面深入的调查,分析了我国安全产业发展的形势和主要问题,研究提出了我国安全产业发展的战略思路、原则及主要目标,明确了安全产业发展主要方向,重点领域、关键技术和重点产品,并提出了安全产业发展的重点工程和政策措施建议,为制定出台我国安全产业发展的政策措施、地方政府制定安全产业园区规划和企业投资发展安全产业提供重要的理论参考。  相似文献   
876.
建设甘肃河西内陆区水资源战略安全体系的构想   总被引:2,自引:0,他引:2  
主要通过对河西内陆区生命支持系统的水资源战略重要性,区域社会经济的发展与问题的分析,依据现有基础条件,提出了建设甘肃河西内陆区水资源战略安全体系的构想:建立三条战略安全防线,形成四套节水技术体系,实施技术集成的示范基地建设,为实现新世纪水-经济-生态系统可持续发展提供坚实基础.  相似文献   
877.
基于GIS格网模型的银川市土地生态安全评价研究   总被引:15,自引:5,他引:10  
为探索市域范围内土地生态安全的粒度特性及其空间效应,论文结合PSR理论框架构建评价指标体系,以公里格网为评价单元,采用熵权法计算区域土地生态安全综合指数。银川市的实证分析表明,2014年整个区域土地生态安全指数为0.488 2,市域范围内土地生态安全存在着空间异质性和结构功能分化的双重特征。从宏观行政区划层面来看,3个中心辖区表现相对较为均衡,2个郊区县差异性较大,仅有贺兰县(0.557 7)高于全市均值;从微观格网尺度来看,北部和城市中心的综合指数较高且呈离散分布,城市边缘区较低且呈集聚分布;从土地利用功能区的角度来看,农业区、城市建城区、湿地和自然保护区的核心区域综合指数较高,而功能边缘区与交叉区较低,土地生态安全和土地利用方式存在耦合关系。通过ESDA空间分析表明,格网尺度下土地生态安全全局Moran’s I指数为0.780 4,生态安全的空间格局表现出空间连续性和聚集效应。因此,从空间建构的视角来看,应充分利用“高高聚集”区的空间扩散和溢出效益,并通过逐步改善影响“低低聚集”区的限制性因子,实现区域内部土地生态安全格局的优化配置。  相似文献   
878.
Numerous resilience measurement frameworks for climate programmes have emerged over the past decade to operationalise the concept and aggregate results within and between programmes. Proxies of resilience, including subjective measures using perception data, have been proposed to measure resilience, but there is limited evidence on their validity and use for policy and practice. This article draws on research on the Decentralising Climate Funds project of the Building Resilience and Adaptation to Climate Extremes and Disasters programme, which supports communities in Mali and Senegal to improve climate resilience through locally controlled adaptation funds. It explores attributes of resilience from this bottom‐up perspective to assess its predictors and alignment with food security, as a proxy of well‐being. We find different patterns when comparing resilience and the well‐being proxy, illustrating that the interplay between the two is still unclear. Results also point to the importance of contextualising resilience, raising implications for aggregating results.  相似文献   
879.
水资源安全的内涵及其评价--以湖北省为例   总被引:9,自引:0,他引:9  
水资源安全作为资源安全的重要组成部分,其内涵在于保障水量的稳定供给、水质的有效保护和水灾害威胁的化解.水资源安全评价可以从水量安全评价、水质安全评价和水灾害防治安全评价三个方面入手.  相似文献   
880.
SUMMARY

A rich diversity of traditional crops occurs generally in the Himalaya and more particularly in Central Himalaya. Over forty species of food grains are grown in traditional agroecosystems of Central Himalaya, which have been managed by the local farming communities since time immemorial. These traditional crop varieties have evolved over centuries and are well adapted to the particular area. A number of edaphic, topographic and climatic factors associated with different selection pressures over centuries of cultivation resulted in immense variations in the crop species.

The grain and by-product yield of the majority of the traditional crops cultivated across an altitudinal gradient were worked out and compared with common food crops (paddy, wheat, mustard) at two points in time (1970-74, 1990–94) and it was found that almost all the traditional crops had slightly higher yields during 1970–74 than between 1990–94. However, common food crops grown during the Kharif season had higher yields during 1990–94 whereas, Rabi season crops exhibited higher yield during 1970–74. The yield of rainfed paddy remained static over the years across the altitudinal gradient. Among the traditional crops cultivated during the Kharif and Rabi seasons in mixed and pure forms at different altitudes were Macrotyloma uniforum (at higher altitude), Parilla frutescens and Vigna mungo (at middle altitude) and Panicum miliaceum (at lower altitude) which were found to be eco-energetically efficient. Avena sativa (oat) and mixed cropping of Fagopyrum esculentum and potato had higher energy efficiency ratios whereas the latter also exhibited a higher monetary output/input ratio. Crops like paddy and wheat with mustard, grown in irrigated land were found to be more eco-energetically efficient than the same crops grown in the rainfed land. In general, traditional crops possess higher nutritive value than the common food crops. The contribution of traditional crops to the local diet (kg/capita/year) and their energy and protein equivalents were higher during both time periods. It was observed that while exporting these traditional crops, the locals of the region are highly exploited by middlemen. Despite having huge potential, traditional crop diversity of this region has been reduced to a great extent during the last two decades. Besides, the area under cultivation with these crops has been declining rapidly. However, many of these crops possess immense potential to meet the growing food demand and ensure food security of an increasing population. Therefore, a comprehensive programme of conservation through various means and improvement of agronomic yield in their natural habitats is urgently needed.  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