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   486篇
  免费   23篇
  国内免费   30篇
安全科学   119篇
废物处理   11篇
环保管理   104篇
综合类   160篇
基础理论   46篇
污染及防治   17篇
评价与监测   24篇
社会与环境   20篇
灾害及防治   38篇
  2022年   5篇
  2021年   8篇
  2020年   8篇
  2019年   11篇
  2018年   6篇
  2017年   8篇
  2016年   9篇
  2015年   8篇
  2014年   16篇
  2013年   29篇
  2012年   16篇
  2011年   35篇
  2010年   17篇
  2009年   26篇
  2008年   15篇
  2007年   23篇
  2006年   25篇
  2005年   24篇
  2004年   22篇
  2003年   31篇
  2002年   25篇
  2001年   24篇
  2000年   20篇
  1999年   12篇
  1998年   8篇
  1997年   13篇
  1996年   11篇
  1995年   4篇
  1994年   10篇
  1993年   6篇
  1992年   9篇
  1991年   4篇
  1990年   7篇
  1989年   2篇
  1988年   3篇
  1987年   2篇
  1985年   1篇
  1984年   1篇
  1981年   4篇
  1980年   5篇
  1979年   5篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   4篇
  1971年   5篇
  1970年   2篇
排序方式: 共有539条查询结果,搜索用时 250 毫秒
411.
群体心理行为模拟的探讨   总被引:2,自引:0,他引:2  
谭芸 《安全与环境工程》2006,13(3):87-89,94
目前群体心理行为的计算机模拟的重要性日益显现,研究工作取得了一定成就.面临的巨大困难是如何建立一个可信的群体心理模型。笔者对群体心理行为模拟现状进行了介绍和分析。  相似文献   
412.
变频恒压供水控制技术在泵站供水系统中的应用   总被引:1,自引:0,他引:1  
初步讨论变频恒压供水的基本原理及其在泵站中的应用.通过介绍泵站供水工艺系统的组成、自动化及仪表系统的配置、变频恒压供水的控制原理及监控系统的构成等的泵站供水自动化控制工程实例说明变频恒压供水在泵站中的应用.  相似文献   
413.
介绍了C语言格式式化输出类操作函数,对该类函数的实现方式和C语言可变参数的工作原理进行了较为详细的阐述,同时,构造了一个方便通用的格式化输出函数,为数据数据格式化操作提供了一条灵活便捷有效的处理途径.  相似文献   
414.
The objective of this research was the implementation of tools for the evaluation of solvents trough property screening in the early stages of process development. An important feature of the tools is that the implementation of indexes, scores, or weights is avoided. Information already available from the literature was stored in a database in order to turn raw data into decision making information. As a result, a solvent radar chart, a solvent representation table, and a solvent telescopying tool were developed in an ASP.NET application. The synthesis of Propranolol was used as study case in order to explore the selection of solvents in the early stages of process development. The replacement of diethyl ether was possible in the extraction step, while solvent choices were detected for potential telescoping for extraction and crystallisation steps. Solubility was found as a critical parameter in telescoping analysis. The methodology proposed enhanced the view towards a more holistic perspective and a more robust solvent screening process. As a consequence, the next steps into solvent evaluation and process development can be reduced.  相似文献   
415.
为研究火源对人员疏散的影响,在现有场域模型的基础上进行扩展,结合元胞自动机提出1种考虑多出口吸引、人员从众行为与火源威胁3者耦合作用的场域疏散模型。此模型综合考虑心理和环境等因素,定量描述人员之间、人与环境之间的相互影响,将出口吸引、从众心理与火源威胁3个影响行人疏散决策的元素归一化,以静态场和动态场耦合作用确定的转移概率作为行人移动的准则。采用此模型,分别对火源位置、火源威胁范围扩散速度在疏散中的影响进行模拟研究。结果表明:模型在一定程度上能够反映火源威胁下行人的疏散过程,再现了行人躲避和趋众行为,能为火源威胁下行人疏散提供理论借鉴。  相似文献   
416.
阐述了化学合成类制药工业污染排放自行监测方案的编制依据,分析了化学合成制药的生产工艺与污染排放特征,在此基础上提出了自行监测方案的主要内容,以及监测点位、监测指标、监测频次设定的注意事项,并明确了特殊情况监测方案的设计原则及自行监测信息记录的相关内容。  相似文献   
417.
Integrated assessment (IA) can be defined as a structured process of dealing with complex issues, using knowledge from various scientific disciplines and/or stakeholders, such that integrated insights are made available to decision makers (J. Rotmans, Enviromental Modelling and Assessment 3 (1998) 155). There is a growing recognition that the participation of stakeholders is a vital element of IA. However, only little is known about methodological requirements for such participatory IA and possible insights to be gained from these approaches. This paper summarizes some of the experiences gathered in the ULYSSES project, which aims at developing procedures that are able to bridge the gap between environmental science and democratic policy making for the issue of climate change. The discussion is based on a total of 52 IA focus groups with citizens, run in six European and one US city. In these groups, different computer models were used, ranging from complex and dynamic global models to simple accounting tools. The analysis in this paper focuses on the role of the computer models. The findings suggest that the computer models were successful at conveying to participants the temporal and spatial scale of climate change, the complexity of the system and the uncertainties in our understanding of it. However, most participants felt that the computer models were less instrumental for the exploration of policy options. Furthermore, both research teams and participants agreed that despite considerable efforts, most models were not sufficiently user-friendly and transparent for being accessed in an IA focus group. With that background, some methodological conclusions are drawn about the inclusion of the computer models in the deliberation process. Furthermore, some suggestions are made about how given models should be adapted and new ones developed in order to be helpful for participatory IA. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
418.
以上海和苏南地区农村生活污水治理的10个示范工程为例,评估研究了农村生活污水治理技术方案的合理性。文章认为,在技术合理性方面,现有示范工程的处理模式选择和工艺设计基本实现了因地制宜,但在成本的有效性方面,现有示范工程还存在较大的成本下降空间。  相似文献   
419.
随着现代信息网络技术的不断发展和广泛使用,使用电子阅览室查阅各种文献的读者迅速增加,电子阅览室的安全问题也愈发突出。从计算机及辅助设备的安全管理和维护、加强对计算机病毒的防治、加强对用户的管理等方面探讨了在网络环境下如何实现对电子阅览室日常的安全管理。  相似文献   
420.
Underground nuclear weapons testing at the Nevada Test Site introduced numerous radionuclides that may be used subsequently to characterize subsurface hydrologic transport processes in arid climates. In 1965, a unique, 16-year pumping experiment designed to examine radionuclide migration away from the CAMBRIC nuclear test, conducted in the saturated zone beneath Frenchman Flat, Nevada, USA, gave rise to an unintended second experiment involving radionuclide infiltration through the vadose zone, as induced by seepage of pumping effluents beneath an unlined discharge trench. The combined experiments have been reanalyzed using a detailed, three-dimensional numerical model of transient, variably saturated flow and mass transport in a heterogeneous subsurface, tailored specifically for large-scale and efficient calculations. Simulations have been used to estimate tritium travel and residence times in various parts of the system for comparison with observations in wells. Model predictions of mass transport were able to clearly demonstrate radionuclide recycling behavior between the trench and pumping well previously suggested by isotopic age dating information; match travel time estimates for radionuclides moving between the trench, the water table, and monitoring and pumping wells; and provide more realistic ways in which to interpret the pumping well elution curves. Collectively, the results illustrate the utility of integrating detailed numerical modeling with diverse observational data in developing more accurate interpretations of contaminant migration processes.  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