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   98900篇
  免费   1286篇
  国内免费   1334篇
安全科学   3974篇
废物处理   3622篇
环保管理   15027篇
综合类   21878篇
基础理论   27593篇
环境理论   76篇
污染及防治   18564篇
评价与监测   5863篇
社会与环境   4259篇
灾害及防治   664篇
  2022年   848篇
  2021年   855篇
  2020年   720篇
  2019年   883篇
  2018年   1267篇
  2017年   1314篇
  2016年   2284篇
  2015年   1879篇
  2014年   2643篇
  2013年   9364篇
  2012年   2601篇
  2011年   3214篇
  2010年   3487篇
  2009年   3645篇
  2008年   2793篇
  2007年   2733篇
  2006年   2877篇
  2005年   2698篇
  2004年   3001篇
  2003年   2824篇
  2002年   2393篇
  2001年   2831篇
  2000年   2281篇
  1999年   1637篇
  1998年   1423篇
  1997年   1420篇
  1996年   1546篇
  1995年   1629篇
  1994年   1520篇
  1993年   1362篇
  1992年   1364篇
  1991年   1340篇
  1990年   1295篇
  1989年   1252篇
  1988年   1104篇
  1987年   1016篇
  1986年   1006篇
  1985年   1094篇
  1984年   1185篇
  1983年   1186篇
  1982年   1188篇
  1981年   1111篇
  1980年   960篇
  1979年   956篇
  1978年   837篇
  1977年   735篇
  1976年   664篇
  1974年   647篇
  1973年   671篇
  1972年   684篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
261.
262.
263.
Four small- to medium-sized municipalities in the south-east of Sweden were chosen for a 5-year study of their Local Agenda 21 (LA21) processes. The study shows that the LA21 processes have instigated many new ideas, brought fields together and introduced new subjects into the municipal world. In the decisions of the local governments environmental considerations are treated seriously. There are signs of an extended dialogue and of public influence, especially within fields where citizens are directly involved. LA21 does not seem to have great influence on which natural resources are dealt with, but does on how they are dealt with. New stakeholders within and outside the municipal organization have been identified through the LA21 processes, and more comprehensive ways of solving problems and a positive climate for testing new ideas have been created. In these respects LA21 has been and will be a significant support to the development of appropriate natural resource management at the local level.  相似文献   
264.
265.
266.
267.
In a 1981 survey of 436 Florida citrus growers, 27 pesticide related poisoning incidents were reported that were to have taken place within one year of the interview date. From these reports it is possible to estimate that there are 376 citrus fieldworker related poisonings per year in Florida. This number of estimated poisonings may be developed into an incidence rate of 113 fieldworker poisonings per 10,000 fieldworkers.  相似文献   
268.
Community evacuation following a chlorine release, Mississippi   总被引:1,自引:0,他引:1  
On 7th September 1986, four miles north of Collins, Mississippi, a train transporting chlorine derailed. Two cars ruptured and gas escaped. As a result, 100 families were evacuated. To study the evacuation process, we conducted person-to-person interviews with sixty-two families staying in the evacuation center. Only 52.5% of the families received their first directive to evacuate directly from police or other officials. Delays in evacuating tended to be shorter when people were warned by the police and were told the reason for evacuating. Lack of personal transportation and preexisting health problems resulted in delays in evacuation. Concerns about evacuation included fear of looting, lack of a place to go, lack of transportation, difficulty in moving with children and elderly persons, and the need to take care of pets. One third of the interviewees reported feeling panic. Community evacuation procedures would be improved if: (1) officials contact all households directly; (2) the warning message addresses people's concerns; and (3) transportation is provided.  相似文献   
269.
After several years of experimentation and demonstration, photovoltaic (PV) power is now firmly established for certain applications where reliable power is required in remote locations. The technology has recently matured to the point where PV is now an appropriate, cost-effective technology for village use. This paper reviews experience and presents economic comparisons between photovoltaic and conventional power systems. It is concluded that PV is cost-effective for individual home lighting and small loads such as radios, when compared with kerosene lamps and batteries. For mutiple uses PV is cost-effective compared with diesel generators for daily electricity demands up to around 20 kWh, depending on local conditions.  相似文献   
270.
ABSTRACT: This paper describes the formulation of an Index of Water Quality to evaluate the level of pollution in fresh water. A Four-Round Delphi equation, using a panel of seven nationally recognized water scientists, was performed to ascertain the pollutants to be included in the index, the relationship between the quantity of these pollutants in the water and the resulting quality of the water, and the importance of each pollution variable to each water use as well as to overall pollution. A multiplicative index was used to bring the pollutants together into one system.  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