全文获取类型
收费全文 | 251篇 |
免费 | 8篇 |
国内免费 | 22篇 |
专业分类
安全科学 | 73篇 |
废物处理 | 5篇 |
环保管理 | 58篇 |
综合类 | 81篇 |
基础理论 | 19篇 |
污染及防治 | 10篇 |
评价与监测 | 10篇 |
社会与环境 | 6篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 20篇 |
2012年 | 4篇 |
2011年 | 15篇 |
2010年 | 6篇 |
2009年 | 13篇 |
2008年 | 5篇 |
2007年 | 11篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 11篇 |
2003年 | 19篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 1篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 2篇 |
排序方式: 共有281条查询结果,搜索用时 15 毫秒
191.
内集-外集模型的计算机仿真检验 总被引:1,自引:0,他引:1
基于信息分配方法建立的内集 -外集模型 ,用于计算可能性 -概率风险 ,可以表达概率估计的模糊性。实践证明 ,用这一模型计算出来的自然灾害模糊风险能对减灾方案进行合理的筛选 ;实验证明 ,我们还可以用这一模型替代专家依据给定的样本进行模糊概率估计。本文用计算机仿真技术 ,在期望值的意义上 ,检验这一模型的可靠性。仿真结果显示 ,用内集 -外集模型计算出来的可能性 -概率分布的均值甚至比传统直方图分布的均值更靠近真实概率分布的期望值。这一研究表明 ,内集-外集模型用于自然灾害模糊风险评估 ,在期望值的意义上是一个可靠的模型。 相似文献
192.
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
193.
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
194.
195.
196.
滚筒设计参数对粉尘爆炸率影响的研究 总被引:2,自引:0,他引:2
李晓豁 《中国安全科学学报》2007,17(6):103-107
利用所建立的数学模型,以国产某型滚筒式采煤机为例,采用计算机模拟的方法,得到了采煤机最大切屑厚度、每线齿数、牵引速度、截线间距、滚筒转速、滚筒直径、叶片头数以及煤岩破碎性能指标与粉尘爆炸率之间的关系曲线,通过分析,确定了各参数对粉尘爆炸率的影响,为预测采煤机工作对粉尘爆炸率的影响、完善采煤机工作性能的评价体系,为改进机器设计、减小采煤机的截割粉尘、降低粉尘爆炸率、提高煤炭生产的安全性提供理论依据。 相似文献
197.
孙景民 《中国环境管理干部学院学报》2002,12(1):68-70
随着科学技术的日新月异和计算机应用的广泛普及,学术期刊编辑工作应用计算机已势在必行。学术期刊编辑工作现代化,就是将编辑出版过程中的手工操作变成由计算机控制的信息处理。 相似文献
198.
用计算机仿真技术检验自然灾害模糊风险模型 总被引:1,自引:6,他引:1
自然灾害模糊风险是用模糊集对自然灾害风险的一种近似表达.本文建议了一种计算机仿真方法,用来检验计算模糊风险的模型是否可靠.假定真实的概率风险可以用某个概率密度函数来表达,当用某种模型依据小样本来估计这个函数时,必然会存在误差.设给定概率密度函数的其望值为E, 用传统模型估计得到的概率密度函数的期望值为E,用某种模糊数学方法计算出来的模糊概率分布的期望值为E.如果E与E的差小于E与E的差,则说明模糊风险模型比较可靠.本文给出了计算E的公式,对计算机仿真实验进行设计.并给出了产生随机数的3个重要程序. 相似文献
199.
Walter M. Grayman Richard M. Males Robert M. Clark 《Journal of the American Water Resources Association》1988,24(6):1311-1316
ABSTRACT: Information on raw water quality, treatment process removal efficiency, and distribution system monitoring is essential to the proper management and operation of a water utility system. Microcomputer hardware and software systems using commercially available data base management systems (DBMS) have emerged within the last few years as an effective means of managing, analyzing, and displaying water quality data. Understanding hardware, software, and training requirements is essential to the proper use of these systems. Three types of data base design are common: relational, hierarchical, and network. Only the relational type of data base architecture is widely implemented on microcomputer DBMS. In this paper two examples of the application of DBMS to water utility problems are presented. One example deals with collection and analysis of data concerning the water quality of the Mississippi River. The second example deals with the DBMS as a means of analyzing water quality data in the North Penn Water Authority (NPWA) distribution system. 相似文献
200.
John F. Walker Susan A. Pickard William C. Sonzogni 《Journal of the American Water Resources Association》1989,25(1):139-147
ABSTRACT: Although several sophisticated nonpoint pollution models exist, few are available that are easy to use, cover a variety of conditions, and integrate a wide range of information to allow managers and planners to assess different control strategies. Here, a straightforward pollutant input accounting approach is presented in the form of an existing model (WATERSHED) that has been adapted to run on modern electronic spreadsheets. As an application, WATERSHED is used to assess options to improve the quality of highly eutrophic Delavan Lake in Wisconsin. WATERSHED is flexible in that several techniques, such as the Universal Soil Loss Equation or unit-area loadings, can be used to estimate nonpoint-source inputs. Once the model parameters are determined (and calibrated, if possible), the spreadsheet features can be used to conduct a sensitivity analysis of management options. In the case of Delavan Lake, it was concluded that, although some nonpoint controls were cost-effective, the overall reduction in phosphorus would be insufficient to measurably improve water quality. 相似文献