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   44175篇
  免费   468篇
  国内免费   605篇
安全科学   1348篇
废物处理   2078篇
环保管理   5444篇
综合类   6945篇
基础理论   11608篇
环境理论   22篇
污染及防治   11609篇
评价与监测   3208篇
社会与环境   2704篇
灾害及防治   282篇
  2023年   202篇
  2022年   461篇
  2021年   467篇
  2020年   336篇
  2019年   400篇
  2018年   701篇
  2017年   715篇
  2016年   1100篇
  2015年   801篇
  2014年   1234篇
  2013年   3582篇
  2012年   1502篇
  2011年   2000篇
  2010年   1685篇
  2009年   1709篇
  2008年   2014篇
  2007年   2108篇
  2006年   1843篇
  2005年   1529篇
  2004年   1468篇
  2003年   1551篇
  2002年   1397篇
  2001年   1817篇
  2000年   1263篇
  1999年   778篇
  1998年   549篇
  1997年   540篇
  1996年   560篇
  1995年   608篇
  1994年   613篇
  1993年   516篇
  1992年   520篇
  1991年   494篇
  1990年   531篇
  1989年   490篇
  1988年   442篇
  1987年   395篇
  1986年   319篇
  1985年   348篇
  1984年   389篇
  1983年   373篇
  1982年   387篇
  1981年   326篇
  1980年   272篇
  1979年   309篇
  1978年   271篇
  1977年   206篇
  1976年   192篇
  1975年   200篇
  1974年   187篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Community response to hazard information   总被引:1,自引:0,他引:1  
McKay JM 《Disasters》1984,8(2):118-123
The impact of flood hazard information on public acceptance of a selected flood mitigation strategy was assessed by an analysis of the content of newspaper reports of community reaction and letters to the editor. The impact of personal delivery of a flood hazard map on individual perception of risk and attitude to such information was assessed using personal interviews. The results indicated that media coverage of the flood hazard information reduced public criticism of the works. This result must be partially attributable to the dramatic style of media coverage and the fact that the media only emphasized the positive value of the works. The interview demonstrated that personal delivery of the information raised perception of risk, improved comprehension of flood risk, had no impact on acceptability of risk but discouraged some respondents from seeking such information in the future. Factors to explain the last negative change were identified to be the format of the map sheet and low salience of flood hazard. On the basis of all results, methods to improve community response to hazard information are provided.  相似文献   
132.
Davey  J. T.  Gee  J. M.  Moore  S. L. 《Marine Biology》1978,45(4):319-327
The population dynamics of Mytilicola intestinalis Steuer in mussels (Mytilus edulis L.) from the River Lynher, Cornwall, England, have been studied over 3 years. By transplanting uninfested mussels from the River Erme, South Devon, into the Lynher mussel bed, the study was extended to the growth and development of new infestations under natural conditions. Female Mytilicola intestinalis are shown to breed twice, and two generations of parasites coexist for most of the year, with recruitment taking place in summer and autumn. One generation contributes its first brood to the autumn recruits before overwintering and contributing its second brood to the following summer's recruits. The other generation overwinters as juvenile and immature stages to contribute its two broods successively to the summer and autumn recruits. Environmental temperatures are believed to control the rates of development at all stages rather than acting as triggers in the onset or cessation of breeding at specific times. There is no evidence to support the contention that heavily infested mussels are killed, and parasite mortality is shown to be density-independent.  相似文献   
133.
134.
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   
135.
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   
136.
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   
137.
138.
139.
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   
140.
Much of the forest wealth on the plains and in the hilly areas of India has been foolishly destroyed, and the rich heritage of wildlife has been slaughtered mostly for only temporary gain. The wanton axing of the larger indigenous trees and the uprooting of other floristic elements in the hills and on the lower slopes of the mountains, gradually impoverishes them, and may be followed by erosion that ultimately leaves the slopes barren. These alarming threats to the chir (Pinus roxburghii) and fir (Abies pindrow) forests of Kashmir will have disastrous consequences. Once densely-forested, the mountain slopes in Kashmir have become largely naked through too-heavy tapping and cutting of the trees; with concomitant landslides, frequent floods, and loss of fertile topsoil. Unfortunately, the people living in the areas of the chir and fir trees, do not play a proper part in their protection, and the last two decades have witnessed, year by year, the rapid march of urbanization and manifold destructive activities which have taken a heavy toll on these precious species. Urgent conservation measures are essential to preserve these endangered trees in Kashmir.  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