全文获取类型
收费全文 | 413篇 |
免费 | 9篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 169篇 |
废物处理 | 1篇 |
环保管理 | 36篇 |
综合类 | 97篇 |
基础理论 | 15篇 |
环境理论 | 1篇 |
污染及防治 | 5篇 |
评价与监测 | 2篇 |
社会与环境 | 8篇 |
灾害及防治 | 97篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 16篇 |
2019年 | 11篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 9篇 |
2015年 | 20篇 |
2014年 | 7篇 |
2013年 | 30篇 |
2012年 | 32篇 |
2011年 | 51篇 |
2010年 | 30篇 |
2009年 | 31篇 |
2008年 | 22篇 |
2007年 | 27篇 |
2006年 | 19篇 |
2005年 | 21篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1977年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有431条查询结果,搜索用时 781 毫秒
201.
Summary The major objective of the design of safe crowded transmitting antenna sites is not only to determine a safe zone around each
individual antenna; rather, to establish safety areas at the antenna site itself, as well as, at the neighboring areas. The
requirement is to ascertain the safety regions by considering the following parameters at each Test Point (TP) (or area segment):
the contribution of N co-located radiating antennas to the total radiation incident at the TP, the radiation pattern of each antenna, the near/far
field region of each antenna, and most importantly, the different Permissible Exposure Limits (PELs) associated with each
operating frequency at the antenna site. Implementation of all the above-mentioned aspects in a suitable computer requires
resources that only expert knowledgeable organizations possess. The graphically aided tool presented in this paper facilitates
the calculation of a “safety zone” for RADHAZ around a crowded antenna site from the knowledge of the “safety ranges” which
correspond to the individual transmitting antennas comprising it. 相似文献
202.
基于神经网络的重大危险源分级研究 总被引:6,自引:0,他引:6
利用人工种经网络系统理论,对重大危险源进行分级研究,介绍了危险源分级网络系统的结构、学习过程和分级方法,并在计算机上进行网络实现与模拟。实例结果表明,利用神经网络方法对重大危险源进行分级是合理可行的,具有一定的实用价值。 相似文献
203.
This paper describes a heuristic model which helps to relate a developing nation's environmental risk to the level of sophistication appropriate in adjusting management strategy to dealing with environmental hazards. The model takes into account three factors: the degree of risk, the stage of economic growth, and the sophistication of adjustment. The interrelationship of these factors is examined, and the role of international cooperation in establishing strategies is outlined. 相似文献
204.
George R. Phippen 《Journal of the American Water Resources Association》1970,6(4):640-647
Flooding and the susceptibility to flood damage inherent in all land uses constitute the flood hazard. Resolution of the hazard while properly recognizing flood plain environmental attributes within the context of overall community or area needs is the essence of comprehensive flood plain management. The traditional approach–flood control–has effected modification of only the flooding component of the hazard whether it be coastal or inland. Until recently Federal programs have overlooked the possibilities of modifying the susceptibility component, for which the major responsibility lies with non-Federal interests. Beginning with actions in the TVA area, the latter is now being strongly encouraged through Federal programs and actions notably the Flood Plain Management Services and Survey Programs of the Corps of Engineers, those stemming from Executive Order 11296, and those required for eligibility under the National Flood Insurance Act of 1968. Flood plain management objectives must be stated in planning, e.g., economic efficiency, reduction in threat to life and health, environmental improvement, and regional development, to permit proper evaluation of the optional means and approaches for achieving them. 相似文献
205.
关于土木基础设施系统的基础研究 总被引:2,自引:0,他引:2
论述了土木基础设施系统对社会经济发展和人民生活质量提高所起的重要作用,总结了国内外土木基础设施系统的现状和研究趋势,指出了针对我国基础设施建设和更新改造中的重大科学问题开展多学科交叉研究的重要意义。同时建议重点开展以下几方面的研究:1.土木基础设施系统性能检测与寿命评估技术;2.土木基础设施系统的防灾减灾研究;3.材料性能研究;4.土木基础设施系统的维修和更新改造技术开发;5.土工技术基础问题研究 相似文献
206.
试论长江中游防洪减灾的工程对策 总被引:4,自引:1,他引:3
长江中游洪患自古乃中华民族的心腹大患,数百年来不得治愈的根本原因是没有做到对症下药。从洪患形成的地学环境分析和数百年抗洪经验总结来看,行洪不畅,泥沙淤积和长期以堵为主的抗洪方式是长江中游洪患得不倒根除的主要。疏-疏水和疏水是根治长江洪患的唯一出路,开辟分洪河道,疏沙淤垸降和蓄水分洪是长江中游共减灾的重要措施。 相似文献
207.
208.
209.
箱形长钢梁内焊接危害分析与对策 总被引:2,自引:0,他引:2
大跨度起重机箱形梁,因结构强度的要求,需要从两端进入梁内施焊。由于截面小、长度大,作业中产生大量烟尘、毒气,不能及时排出,严重损害工人身体健康。特别在高温季节,焊接热又使梁内温度增高,操作者闷热难忍,危害身心健康,影响工作效率。本文在实验研究基础上,分析了箱形长钢梁内多人焊接时,产生的烟尘、毒气及其分布情况,并“以人为中心”,剖析各种解决焊接危害技术的特点,提出适用于截面在1~2m~2、长度在30~50m范围的钢梁内多人施焊时的排烟降温对策。 相似文献
210.
James K. Boyce 《Environmental management》1990,14(4):419-428
A major flood control initiative has been launched in Bangladesh under the coordination of the World Bank. The bank's five-year
Action Plan is intended to initiate a long-term investment program, the specifics of which remain to be determined. Long-term
proposals under consideration include the construction of massive embankments along the great rivers of the Bangladesh delta.
The wisdom of such a “structural solution” to Bangladesh's flood problems can be questioned on economic, environmental, and
technical grounds. Regrettably, the decision-making process has not encouraged wide debate on these questions. 相似文献