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   50926篇
  免费   547篇
  国内免费   626篇
安全科学   1568篇
废物处理   2094篇
环保管理   6684篇
综合类   8378篇
基础理论   14016篇
环境理论   36篇
污染及防治   13181篇
评价与监测   3233篇
社会与环境   2565篇
灾害及防治   344篇
  2022年   441篇
  2021年   439篇
  2020年   349篇
  2019年   437篇
  2018年   757篇
  2017年   729篇
  2016年   1112篇
  2015年   896篇
  2014年   1306篇
  2013年   3969篇
  2012年   1621篇
  2011年   2266篇
  2010年   1834篇
  2009年   1882篇
  2008年   2248篇
  2007年   2341篇
  2006年   2050篇
  2005年   1720篇
  2004年   1668篇
  2003年   1695篇
  2002年   1568篇
  2001年   2038篇
  2000年   1419篇
  1999年   889篇
  1998年   666篇
  1997年   670篇
  1996年   679篇
  1995年   752篇
  1994年   748篇
  1993年   636篇
  1992年   656篇
  1991年   615篇
  1990年   653篇
  1989年   641篇
  1988年   559篇
  1987年   495篇
  1986年   423篇
  1985年   478篇
  1984年   478篇
  1983年   495篇
  1982年   482篇
  1981年   440篇
  1980年   360篇
  1979年   407篇
  1978年   358篇
  1977年   278篇
  1976年   285篇
  1975年   290篇
  1974年   257篇
  1972年   288篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
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   
163.
164.
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   
165.
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   
166.
167.
168.
169.
Sharlin SA  Mor-Barak M 《Disasters》1983,7(2):142-147
This paper describes the help given by the social services department of a shipping company to bereaved families following a shipping disaster. In the absence of clear, factual and prompt information from an authoritative source, there is a tendency for bereaved individuals to deny their loss and thereby delay the process of mourning and eventual recovery. Appropriate intervention and support can help to overcome this tendency as was seen in the Madasa case.  相似文献   
170.
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