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   85309篇
  免费   1216篇
  国内免费   1065篇
安全科学   3648篇
废物处理   3033篇
环保管理   13311篇
综合类   20887篇
基础理论   25578篇
环境理论   74篇
污染及防治   12162篇
评价与监测   5129篇
社会与环境   3288篇
灾害及防治   480篇
  2022年   779篇
  2021年   781篇
  2020年   640篇
  2019年   853篇
  2018年   1061篇
  2017年   1080篇
  2016年   2085篇
  2015年   1814篇
  2014年   2555篇
  2013年   9204篇
  2012年   1958篇
  2011年   2055篇
  2010年   3149篇
  2009年   3288篇
  2008年   1544篇
  2007年   1357篇
  2006年   1889篇
  2005年   1969篇
  2004年   2289篇
  2003年   2107篇
  2002年   1667篇
  2001年   1867篇
  2000年   1776篇
  1999年   1410篇
  1998年   1341篇
  1997年   1324篇
  1996年   1448篇
  1995年   1540篇
  1994年   1440篇
  1993年   1292篇
  1992年   1273篇
  1991年   1252篇
  1990年   1198篇
  1989年   1168篇
  1988年   1007篇
  1987年   956篇
  1986年   982篇
  1985年   1049篇
  1984年   1143篇
  1983年   1157篇
  1982年   1168篇
  1981年   1087篇
  1980年   933篇
  1979年   905篇
  1978年   812篇
  1977年   706篇
  1976年   632篇
  1975年   591篇
  1973年   615篇
  1972年   619篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Most of the mitigation measures against natural hazards can not be perfectly allocated via the common market mechanism, given their principle character of being a public good. Thus, different instruments need to be applied to retrieve their values. Economic valuation tools are one alternative to estimate preferences of individuals towards these goods. These methods are often difficult to operationalise and are not a feasible task for every single project. An alternative is offered by direct preference representation through involving affected interest groups actively in decisions. A critical question is whether the decision on protection measures can be left to public participation or should remain in the experts’ decision responsibility. It can be observed that the latter mode shows inefficiencies. In this paper, it is argued that participation could be one way to bring about the desired goal of increasing efficiency. The present work offers a discussion of the relevant political economic concepts in order to introduce the idea that participation can increase efficiency through achieving the Pareto criterion claimed in the realm of constitutional economics. Furthermore it will be shown that decision aiding tools, namely multi-criteria analysis, can integrate participation into actual decision making processes in a structured way.  相似文献   
992.
Escaping is natural in the case of accidents in underground mines. Determining the optimal escape route is one of the most important factors for relief of miners in the emergency cases. This paper aims at developing a mathematical method to determine the shortest escape time from a given point to alternative points of an underground mine network. It also aims to find the shortest routes between each pair of the given points. The first point refers to the place of the accident where some miners may exist, and the alternative points show the safe places that the miners can escape to. After determining the shortest escape time and its corresponding route between each pair of mine work junctions, it is possible to set an electronic board that shows the access route to the nearest safe location by an arrow sign in each mine work. In this paper, Floyd–Warshall and π algorithms are used to determine the shortest escape time between the place of accident and safe places as well as their corresponding routes. Those algorithms are rigorous since they are supported by mathematical proof. Finally, the algorithms are implemented on the network of a certain underground coal mine and the results are presented.  相似文献   
993.
This paper presents an agent-based approach for error detection in incident management organizations. The approach consists of several parts. First, a formal approach for the specification and hierarchical verification of both traces and properties. Incomplete traces are enriched by enrichment rules. Furthermore, a classification mechanism is presented for the different properties in incident management that is based on psychological literature. Classification of errors provides insight in the functioning of the agents involved with respect to their roles. This insight enables the provision of dedicated training sessions and allows software support to give appropriate warning messages during incident management.  相似文献   
994.
995.
In this paper the purpose is to discuss a concept of technology that can explain how the transfer of technology implies the risk of new failures, misuse, accidents and unhealthy workplaces. Production technologies are often transformed through a steady stream of incremental changes appropriate to their social context, and the technology will therefore gradually acquire some contextually dependent preconditions for use. These preconditions will most probably be revealed when a technology is transferred from one context to another. Thus, a technology transfer project may trigger a long process of re-innovations just to make the technology fully operational in its new context. In a transfer process, technological risks may arise due to incomplete transfer of mastering capacity; mismatch between transferred technology and the environment; transfer of latent conditions for failure; and the transformation of latent conditions or known risks when the technology is installed in a new environment. Longitudinal data from the Norwegian petroleum industry indicates that the first phases in a transfer process will create high technological risks. It will take many years before the transferred technologies are adapted to the new context and the risk level has been normalised.  相似文献   
996.
Is protection of equipment the only consideration when setting the relieving pressures of safety relief valves? I will show you a case where other factors should have been considered and suggest that you might give your safety valve set pressures a second thought.Do you have side-by-side pieces of identical equipment? If so, you must consider that operating or maintenance personnel may become confused, and the results maybe catastrophic. A PVC reactor incident will demonstrate this point.Does your process contain materials that could decompose? After thirty years of safe operation in butadiene units, there was a vinyl acetylene decomposition. Could it happen to you?It is my hope that these three unique and unusual cases will provide valuable information for operations and maintenance personnel, managers, safety professionals, and engineers.  相似文献   
997.
998.
999.
1000.
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