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   388篇
  免费   26篇
  国内免费   32篇
安全科学   86篇
废物处理   5篇
环保管理   70篇
综合类   149篇
基础理论   45篇
污染及防治   24篇
评价与监测   19篇
社会与环境   34篇
灾害及防治   14篇
  2024年   3篇
  2023年   2篇
  2022年   5篇
  2021年   8篇
  2020年   6篇
  2019年   7篇
  2018年   2篇
  2017年   9篇
  2016年   16篇
  2015年   16篇
  2014年   10篇
  2013年   16篇
  2012年   33篇
  2011年   35篇
  2010年   19篇
  2009年   17篇
  2008年   23篇
  2007年   34篇
  2006年   24篇
  2005年   26篇
  2004年   23篇
  2003年   14篇
  2002年   17篇
  2001年   18篇
  2000年   17篇
  1999年   5篇
  1998年   8篇
  1997年   6篇
  1996年   3篇
  1995年   5篇
  1994年   3篇
  1993年   6篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1988年   2篇
  1987年   1篇
排序方式: 共有446条查询结果,搜索用时 734 毫秒
131.
Donini A  Minear L  Walker P 《Disasters》2004,28(2):190-204
In late 2003 the Feinstein International Famine Center, in partnership with institutions in London, Geneva and Washington, organised a series of consultations on the future of humanitarian action post-Iraq. This article is based on those discussions. A number of recurring concerns are elaborated, ranging from the perception of humanitarianism as a Northern-driven and Northern-controlled enterprise, through the politicisation of security and the devaluation of the protective power of emblems, to the very nature of how the crisis in Iraq is perceived. The article explores the implications of such issues for humanitarian workers and their institutions. It concludes by framing an agenda for action by the humanitarian sector.  相似文献   
132.
Investing in safety an analytical precautionary principle   总被引:6,自引:0,他引:6  
PROBLEM: Governments and businesses must respond to increasing safety requirements and balance the associated costs with productivity and competing pressures. METHOD: A real options approach has been introduced for decision making in the private sector; this approach is adapted for regulatory decisions that can involve irreversible and uncertain safety impacts, social costs that differ from private costs, and differences in perception among the stakeholders. RESULT AND IMPACT ON INDUSTRY AND GOVERNMENT: The outcome is an economic decision gage that determines if it is optimal to invest in safety even if the estimated costs significantly exceed the estimated benefits. Applications potentially include safety decisions related to aviation, ground transportation, pipelines, nuclear facilities, natural disaster planning, and terrorism, among others.  相似文献   
133.
火灾中温度升高对蛋白质构象影响的计算机模拟(Ⅰ)   总被引:4,自引:3,他引:1  
应用分子力学原理进行了温度对肽链构象影响的计算机模拟,模拟结果显示,火灾中环境温度升高对生物分子的结构和功能是一个很敏感的因素之一,天然生物分子因吸热而使自身构象发生异常变化,进而与特定构象紧密联系的生物活性丧失,发生变性,模拟结果对于从分子水平上揭示火灾对生物体的危害具有重要意义.  相似文献   
134.
Mercury is recognized internationally as an important pollutant since mercury and its compounds are persistent, bioaccumulative and toxic, and pose human and ecosystem risks. A critical aspect of mercury cycling is its bioaccumulation, mainly as methylmercury, along the aquatic food web resulting in high risk of human exposure through contaminated fish consumption. Since lake acidity (pH) and mercury methylation are correlated, control of lake pH through lake liming is a possible option to mitigate mercury bioaccumulation. This work proposes to use optimal control theory to derive time-dependent lake liming strategies for a tighter control of lake pH. Since the behavior of the freshwater ecosystems such as lakes is often associated with considerable uncertainties, a robust and realistic analysis should incorporate such uncertainties. This work models the time-dependent uncertain variations in the basic lake pH value and derives the liming profiles in the presence of such seasonal pH fluctuations. Established techniques from real options theory are employed for modeling the uncertainty as a stochastic process, and stochastic optimal control is used for deriving liming profiles. The approach is critically evaluated through applications to various case study lakes. Considering the substantial costs associated with liming operations, the work formulates a multi-objective problem highlighting the tradeoff between accurate pH control and liming cost. The results of the control problem solution are also compared with heuristics based liming. The results, while highlighting the success of using time-dependent liming, put forth certain interesting aspects that might be helpful to a decision maker. The analysis is expected to make liming operation more reliable, thereby presenting one more tool to manage the harmful effects of mercury pollution.  相似文献   
135.
Powder mixed near dry electrical discharge machining (PMND-EDM) is a novel electrical discharge machining (EDM) process. It is proposed to further improve the machining efficiency of dry EDM. The principle of material removal in PMND-EDM is illustrated and its deionization principle is proposed. The influence of residual heat on MRR is analyzed. The concept of superfluous residual heat is proposed. The material removal rate (MRR), the main index of machining efficiency for PMND-EDM process, is researched. Single factor experiments are performed to get effect of peak current, pulse on time, pulse off time, flow rate, tool rotational speed, air pressure and powder concentration on MRR under different material combinations of tool electrode and workpiece electrode. Thermal phenomena in PMND-EDM are illustrated. Effect of each process parameter on MRR of PMND-EDM is gotten and analyzed based on the deionization principle of PMND-EDM. Differences in MRR under different material combinations are found out. Brass tool electrode and W18Cr4V workpiece gain higher MRR under most of discharge conditions, while the superiority of copper tool electrode and 45 carbon steel workpiece in MRR arise when there is improper heat dissipation. The difference is analyzed based on the deionization principle of PMND-EDM.  相似文献   
136.
油库是储存易燃易爆油品的专用场所,雷电是油库安全生产的重大隐患,油库防雷已成为关系到经济建设、社会发展和人民生命财产安全的重大课题。针对目前我国油库雷击事故频繁发生的问题,在对大量事故资料研究的基础上,分析了油库雷击火灾爆炸事故的原因,指出雷电产生的火花引燃油气是导致油库火灾爆炸的主要原因。并重点从安全管理学的角度,运用事故预防与控制的"3E"对策,分别从安全技术、安全管理、安全教育三个方面探讨了油库雷击事故的预防与控制措施。  相似文献   
137.
根据生态学的基本原理,结合我国国情,推导出污泥处置技术的选取和判定原则:一致性匹配原则、能级稳定原则及资源循环最短原则;并用这些原则对现有污泥处置技术进行了评判。  相似文献   
138.
环境风险预防原则是应对环境风险日益凸显的重要原则。通过对环境风险预防原则的分析,发现环境风险预防原则在我国确立中还存在着对其研究程度不够、混同于"预防为主,防治结合"原则以及仍惯于事后执法的传统思维等问题。面对挑战,应多措并举推进环境风险预防原则建设,例如确立环境风险预防原则作为环境法基本原则,转变举证责任主体的机制、建立信息公开等与风险预防原则相关的法律制度,拟采过错责任为风险预防的归责原则,从而预防和遏制环境风险的产生与扩散。  相似文献   
139.
21世纪中国城市化方式转变与对策研究   总被引:2,自引:0,他引:2  
21世纪之初 ,中国的城市化发展正面临一些新形势 ,必须重新定位城市化战略。本文指出加快城市化步伐 ,重视发展大城市 ,促进城市群的形成与发展 ,有重点地发展小城市 ,是未来中国城市化战略的正确选择  相似文献   
140.
环境规划是环境管理工作的重要内容之一,环境规划的目标是环境保护与经济协调发展的具体结合点。为使制定的规划能够可行,在规划的整个过程中公众参与是非常重要的。文章基于对中国目前环境规划中的公众参与存在的不足之处的简要论述,对影响环境规划公众参与有效性的因素进行了初步的探讨,指出公众参与的制度、对象、时间、形式、内容的设计、解决矛盾的能力、参与公众的热情等是影响中国环境规划公众参与有效性的主要因素,并提出了一些提高中国环境规划公众参与有效性的建议。  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