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   22881篇
  免费   251篇
  国内免费   149篇
安全科学   590篇
废物处理   1009篇
环保管理   2988篇
综合类   3788篇
基础理论   6284篇
环境理论   11篇
污染及防治   5960篇
评价与监测   1489篇
社会与环境   1010篇
灾害及防治   152篇
  2022年   201篇
  2021年   231篇
  2020年   148篇
  2019年   167篇
  2018年   324篇
  2017年   341篇
  2016年   503篇
  2015年   368篇
  2014年   562篇
  2013年   1739篇
  2012年   684篇
  2011年   955篇
  2010年   763篇
  2009年   745篇
  2008年   911篇
  2007年   951篇
  2006年   824篇
  2005年   766篇
  2004年   787篇
  2003年   759篇
  2002年   695篇
  2001年   828篇
  2000年   599篇
  1999年   355篇
  1998年   275篇
  1997年   300篇
  1996年   291篇
  1995年   347篇
  1994年   316篇
  1993年   292篇
  1992年   286篇
  1991年   290篇
  1990年   301篇
  1989年   285篇
  1988年   254篇
  1987年   249篇
  1986年   228篇
  1985年   210篇
  1984年   263篇
  1983年   219篇
  1982年   275篇
  1981年   224篇
  1980年   184篇
  1979年   207篇
  1978年   186篇
  1977年   156篇
  1974年   159篇
  1973年   162篇
  1972年   149篇
  1971年   147篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
491.
Epidemiological procedures can be organised under disaster conditions by means of a simple surveillance system and with few personnel.
In the aftermath of the 4 February 1976 earthquake in Guatemala, an information system was organized by which the requisite information for decision-making was obtained with adequate speed and promptness.
The initial epidemiologic informution was based on reports collected during the early days on symptoms observed at hospitals and health centers and in localities and villages in the stricken area.
At a second, post-emergency stage a more elaborate surveillance system was instituted to provide guidance in the investigntwn of outbreaks, evaluate the health activities and establish basic criteria for preventive and control measures.  相似文献   
492.
493.
The development of traceability in low-level radioactivity measurements is discussed. The role that the development of large quantities of natural matrix standards can play is also discussed.  相似文献   
494.
Although oil spill cleanup requirements have existed in the United States for years, recent increases in oil imports and marine transportation of petroleum products as well as growing environmental concern have exposed a new industry, the Oil Spill Cleanup Industry. This paper explores some of the microeconomic aspects of this industry which has come under increased scrutiny by the general public, big business, and the federal government.In addition to a brief history and definition, several basic questions about the economic viability of the oil spill cleanup industry are raised and explored, and the impact on the industry of cleanup from government sources is examined, both from the perspective of present operations and from apparent future increases in federal participation. The primary dilemma facing the industry, that of providing continued and immediate supply while confronted with stochastic demand, is discussed. The effects of the large spill on the industry both in terms of revenue and ability to meet cleanup requirements is also considered.Information for the paper is drawn from past and continuing involvement in the U.S. Coast Guard's Marine Environmental Protection Program by both authors. The statistical evidence presented here was compiled through personal interviews and from two computerized Coast Guard information systems; PIRS (the Pollution Incident Reporting System), and SKIM (the Spill Cleanup Equipment Inventory System).  相似文献   
495.
496.
497.
498.
Random rubble     
Hughes R 《Disasters》1982,6(2):154-154
  相似文献   
499.
500.
Results of a recent intercomparison on the determination of trace elements in simulated air filter samples are reported. A large scatter of results is obtained for some elements and systematic differences between laboratories are observed. The performance of different methods, in particular neutron activation analysis and atomic absorption spectrophotometry, used by the various laboratories is discussed (air filter analysis; intercomparison; trace elements; control charts).  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