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   20734篇
  免费   1434篇
  国内免费   3327篇
安全科学   2725篇
废物处理   368篇
环保管理   3663篇
综合类   11281篇
基础理论   2100篇
环境理论   58篇
污染及防治   1722篇
评价与监测   988篇
社会与环境   1595篇
灾害及防治   995篇
  2024年   89篇
  2023年   425篇
  2022年   631篇
  2021年   792篇
  2020年   810篇
  2019年   676篇
  2018年   597篇
  2017年   821篇
  2016年   951篇
  2015年   920篇
  2014年   940篇
  2013年   1261篇
  2012年   1395篇
  2011年   1513篇
  2010年   1067篇
  2009年   1177篇
  2008年   884篇
  2007年   1360篇
  2006年   1307篇
  2005年   1113篇
  2004年   994篇
  2003年   938篇
  2002年   816篇
  2001年   699篇
  2000年   667篇
  1999年   622篇
  1998年   405篇
  1997年   350篇
  1996年   225篇
  1995年   212篇
  1994年   178篇
  1993年   182篇
  1992年   108篇
  1991年   62篇
  1990年   49篇
  1989年   24篇
  1988年   31篇
  1987年   21篇
  1986年   12篇
  1985年   19篇
  1984年   22篇
  1983年   21篇
  1982年   17篇
  1981年   11篇
  1980年   17篇
  1979年   16篇
  1977年   7篇
  1973年   7篇
  1972年   6篇
  1971年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
我国民爆行业安全管理存在的主要问题及其对策   总被引:4,自引:0,他引:4  
今年以来,民爆企业重、特大事故多发,安全生产日趋严峻。随着我国国民经济的快速发展,民爆行业安全问题已日益成为社会关注的热点,也成为安全监管的重点。本文从政府行业监管职责、企业主体责任两个层面存在的突出问题的剖析入手,为进一步强化民爆行业安全监督管理工作,在实施产业技术政策,落实政府监管责任,推进企业技术进步,加强企业基础管理,完善法律法规标准,深化安全专项整治,强化安全许可工作等方面提出了对策建议。  相似文献   
82.
据国际国内关于油品储罐的事故统计和分析,拱顶储油罐的事故率最高,可见该类型储罐风险大,由于影响储罐安全运行的因素很多,任何一个环节出问题,都可能引发重大事故。本文就凝析油罐运行6年来,从储罐腐蚀、浮盘质量及安全环保方面所发现和整改的实际情况,在设计和施工中遗留的问题进行深入分析,提出改进措施,为类似的储罐设计施工及管理提供参考。  相似文献   
83.
当代大学生思想政治状况分析及对策   总被引:1,自引:0,他引:1  
根据高校大学生思想教育工作和公共理论课教学工作问卷调查统计,分析了当代大学生的思想政治状况及特点,指出了其成因,提出了加强大学生思想政治工作的方法和途径,为做好高校学生工作提供了借鉴。  相似文献   
84.
论述了为实现全面建设小康社会的发展目标,必须走跨越式发展之路。  相似文献   
85.
This article develops a practical proposal for progress on sustainable development law. It examines the prospects for an international sustainable development law to provide a framework for more effective, coherent governance. Sustainable development law is briefly defined and an analytical framework is provided. Different degrees of integration between economic, social and environmental law are described. Certain principles of international law related to sustainable development are also highlighted. It is argued that these principles may serve to guide law‐makers and jurists where social, economic and environmental law and policy conflict or overlap. Continuing, underlying questions of sustainable development governance are addressed and its global frameworks analysed. The article also focuses on the 2002 World Summit on Sustainable Development, held in Johannesburg in August‐September 2002, and its specific mandate for the United Nations Commission on Sustainable Development (UNCSD) to take related legal developments into account. The article advances a proposal: that governments, economic, social and environmental intergovernmental organizations and other actors establish a ‘network of inquiry’ with members from relevant groups, including legal and academic organizations, and other expert groups, in order to follow, research, analyse and debate legal developments in a balanced way.  相似文献   
86.
ABSTRACT: The objective of this study was to examine the chemistry of Coalbed Methane (CBM) discharge water reacting with semi‐arid ephemeral stream channels in the Powder River Basin, Wyoming. The study area consisted of two ephemeral streams: Burger Draw and Sue Draw. These streams are tributaries to the perennial Powder River. Samples were collected bimonthly from three CBM discharge points and seven channel locations in Burger Draw and Sue Draw. Samples were also collected bimonthly from the Powder River above and below the confluence of Burger Draw. Before sample collection, the pH and electrical conductivity (EC) were measured in the field. Samples were transported to the laboratory and analyzed for alkalinity, major cations, and anions. From the measurement of sodium (Na), calcium (Ca), and magnesium (Mg), practical sodium adsorption ratio (SARp) and true sodium adsorption ratio (SARt) were calculated. Results suggest pH and EC of CBM discharge water was 7.1 and 4.3 dS/m, respectively. The CBM discharge water consisted of higher concentrations of sodium and alkalinity compared to other components. The pH of CBM discharge water increased significantly (p = 0.000) in the downstream channel of Burger Draw from 7.1 to 8.84 before it joined with the Powder River. Dissolved calcium concentration of CBM discharge water decreased significantly (p = 0.000) in the downstream channel water. Subsequently, SARp increased approximately from 24 to 29. The SARt also increased significantly (p = 0.001) in the downstream channel water. For instance, SARt of CBM discharge water increased from 32.93 to 45.5 downstream channels after the confluence of Sue Draw with the Burger Draw. The only significant difference in water chemistry above and below the confluence of Burger Draw with the Powder River was pH, which increased from 8.36 to 8.52. The significant increase in SAR values of CBM discharge water in Burger Draw and Sue Draw tributaries suggest a careful monitoring of salinity and sodicity is needed if CBM discharge water is used for irrigation in semi‐arid environments. Results discussed in this study will be useful to downstream water users who depend on water for irrigation.  相似文献   
87.
ABSTRACT: Increasing demands on western water are causing a mounting need for the conjunctive management of surface water and ground water resources. Under western water law, the senior water rights holder has priority over the junior water rights holder in times of water shortage. Water managers have been reluctant to conjunctively manage surface water and ground water resources because of the difficulty of quantification of the impacts to surface water resources from ground water stresses. Impacts from ground water use can take years to propagate through an aquifer system. Prediction of the degree of impact to surface water resources over time and the spatial distribution of impacts is very difficult. Response functions mathematically describe the relationship between a unit ground water stress applied at a specific location and stream depletion or aquifer water level change elsewhere in the system. Response functions can be used to help quantify the spatial and temporal impacts to surface water resources caused by ground water pumping. This paper describes the theory of response functions and presents an application of transient response functions in the Snake River Plain, Idaho. Transient response functions can be used to facilitate the conjunctive management of surface and ground water not only in the eastern Snake River Plain basin, but also in similar basins throughout the western United States.  相似文献   
88.
基于CAN总线的分布式安全报警系统   总被引:4,自引:5,他引:4  
CAN总线是一种多主站局部网络 ,支持分布式控制系统或实时控制系统的通信功能 ,具有检错功能强 ,抗干扰 ,传输速率高等优点 ,广泛应用于工业控制领域。笔者以CAN总线技术为基础 ,用单片机和个人计算机组成分布式安全报警系统 ,该系统具有开放性、全分散体系结构、安装维护简单等特点。笔者介绍了该系统的总体构成及其软件和硬件设计。试验结果表明 ,该系统实现了事故现场、住户与住宅小区三者联系的安全报警功能。系统稳定性好 ,实时性强 ,报警准确。  相似文献   
89.
中美煤矿安全比较与借鉴   总被引:8,自引:4,他引:8  
中国和美国都是煤炭生产和消费大国,但是中国的煤矿安全却与美国存在巨大差距。笔者首先从两国历年来煤矿安全数据分析入手,认为:美国煤矿安全经历了严重恶化、小幅波动和安全稳定3个阶段;而中国的煤矿经历了改革开放前大起大落和其后的小幅波动两个阶段,迄今为止,还没有进入安全稳定时期。然后从法规、监察、采矿权、安全投入、矿工及工会、教育及培训、科技进步等7个方面对两国的煤矿安全进行了比较。最后,借鉴美国进入第3阶段的成功经验,提出一些改善中国煤矿安全的相应对策建议,如完善法规、加强监管、明晰采矿权、设立安全投入预算资金、改善矿工的弱势地位、加强教育与培训、依靠科技进步等。  相似文献   
90.
结合对“社会弱势群体”含义、产生原因的分析以及对我国社会弱势群职业卫生与安全法律保护现状的总结,本文指出了法律对社会弱势群体职业卫生与安全给予倾斜性保护的重要意义,并进一步提出了加强对社会弱势群体职业卫生与安全法律保护具体措施的设想。  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