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   17156篇
  免费   201篇
  国内免费   145篇
安全科学   454篇
废物处理   732篇
环保管理   2158篇
综合类   2707篇
基础理论   4762篇
环境理论   9篇
污染及防治   4381篇
评价与监测   1171篇
社会与环境   1013篇
灾害及防治   115篇
  2022年   158篇
  2021年   148篇
  2020年   119篇
  2019年   145篇
  2018年   237篇
  2017年   291篇
  2016年   393篇
  2015年   306篇
  2014年   514篇
  2013年   1332篇
  2012年   571篇
  2011年   805篇
  2010年   679篇
  2009年   671篇
  2008年   769篇
  2007年   804篇
  2006年   680篇
  2005年   560篇
  2004年   566篇
  2003年   561篇
  2002年   528篇
  2001年   672篇
  2000年   517篇
  1999年   269篇
  1998年   191篇
  1997年   211篇
  1996年   224篇
  1995年   253篇
  1994年   253篇
  1993年   190篇
  1992年   204篇
  1991年   190篇
  1990年   208篇
  1989年   199篇
  1988年   163篇
  1987年   172篇
  1986年   162篇
  1985年   166篇
  1984年   153篇
  1983年   150篇
  1982年   137篇
  1981年   133篇
  1980年   118篇
  1979年   129篇
  1978年   105篇
  1977年   117篇
  1975年   91篇
  1974年   88篇
  1973年   96篇
  1972年   87篇
排序方式: 共有10000条查询结果,搜索用时 935 毫秒
381.
382.
383.
384.
Melville CP 《Disasters》1983,7(2):107-117
The disastrous floods of July 1934 in Tabriz are examined in the context of the history of floodinginthe city, which is crossed by a dry stream bed liable to sudden Inundation by mountain torrents from the southeast. Few details of past events have survived, suggesting that relatively little significance has been attached to them. Typically, flood dykes were inadequately maintained. This neglect, combined with a radical alteration in urban topography after 1925, when broad straight avenues were constructed through the old heart of the city, led to serious losses from flooding twice in 1929 and again in 1934. Enhanced perception of the flood risk finally found expression in the adoption of large scale engineering measures to mitigate future events, including strengthening protective dykes and widening the river channel through the city. These works have reduced vulnerability to flooding from river overflow. No long-term detrimental Impact of the 1934 flood has been observed. Some of the physical and social parameters that have influenced the vulnerability of Tabrizinthe past continue to be present both there and elsewhere in Iran, and they may be characteristic also of other regions with comparable natural environments or in a similar stage of socio-economic development.  相似文献   
385.
386.
387.
388.
This article examines the role of economic development agencies in strengthening the environmental performance of industry within rapidly industrialising East Asian economies. Three case-study examples are considered, namely, the role of the Industrial Development Board in reducing industrial pollution in Taiwan, pollution control in the palm oil industry in Malaysia, and the role of the Economic Development Board in influencing environmental performance of industry in Singapore. The concept of embedded autonomy is developed to consider the ways in which agencies of economic development can work with firms and industries while simultaneously remaining autonomous from these firms with respect to setting and enforcing performance standards. The three cases suggest that a form of policy integration that more directly integrates economic and environmental goals within agencies of economic development may be feasible, but only where there exists a strong autonomous government bureaucracy and where there is strong societal commitment to improving the environmental performance of industry.  相似文献   
389.
There is a growing recognition that knowledge of indigenous communities, based on accumulated observations and experience over time, is significant for sustainable environmental management in collaboration with modern scientific knowledge. A number of innovative policy initiatives are currently being implemented in New Zealand to enable indigenous Maori tribes and sub-tribes to rehabilitate and manage their local fisheries in accordance with customary values and practices. These policies are an important milestone from an historical perspective as they are meant to recognise and empower the role of Maori as Treaty partners. The fisheries management regime in New Zealand now provides for Maori representation at the local level within a co-management framework that enables local Maori communities to exercise their customary rights. These institutional arrangements have been crafted to facilitate Maori input, based on customary values and practices, to complement modern Western management practices for sustainable harvesting of marine resources. Nevertheless, the degree to which these initiatives constitute an adequate response to Maori Treaty aspirations is debatable. A major constraint in this respect is that the government is compelled to recognise the needs of other, economically and politically more dominant, non-Maori user-groups in allocating and managing access to fishery resources and the marine environment.  相似文献   
390.
ABSTRACT: This paper presents the results of a study on the use of continuous stage data to describe the relation between urban development and three aspects of hydrologic condition that are thought to influence stream ecosystems—overall stage variability, stream flashiness, and the duration of extreme‐stage conditions. This relation is examined using data from more than 70 watersheds in three contrasting environmental settings—the humid Northeast (the metropolitan Boston, Massachusetts, area); the very humid Southeast (the metropolitan Birmingham, Alabama, area); and the semiarid West (the metropolitan Salt Lake City, Utah, area). Results from the Birmingham and Boston studies provide evidence linking increased urbanization with stream flashiness. Fragmentation of developed land cover patches appears to ameliorate the effects of urbanization on overall variability and flashiness. There was less success in relating urbanization and streamflow conditions in the Salt Lake City study. A related investigation of six North Carolina sites with long term discharge and stage data indicated that hydrologic condition metrics developed using continuous stage data are comparable to flow based metrics, particularly for stream flashiness measures.  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