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   24248篇
  免费   249篇
  国内免费   197篇
安全科学   595篇
废物处理   1020篇
环保管理   2953篇
综合类   4637篇
基础理论   5979篇
环境理论   9篇
污染及防治   6281篇
评价与监测   1581篇
社会与环境   1548篇
灾害及防治   91篇
  2022年   203篇
  2021年   189篇
  2019年   160篇
  2018年   330篇
  2017年   321篇
  2016年   501篇
  2015年   377篇
  2014年   549篇
  2013年   1720篇
  2012年   660篇
  2011年   986篇
  2010年   775篇
  2009年   877篇
  2008年   1040篇
  2007年   1066篇
  2006年   946篇
  2005年   800篇
  2004年   789篇
  2003年   821篇
  2002年   755篇
  2001年   1034篇
  2000年   671篇
  1999年   465篇
  1998年   300篇
  1997年   324篇
  1996年   337篇
  1995年   362篇
  1994年   342篇
  1993年   302篇
  1992年   297篇
  1991年   303篇
  1990年   308篇
  1989年   292篇
  1988年   250篇
  1987年   233篇
  1986年   212篇
  1985年   230篇
  1984年   247篇
  1983年   245篇
  1982年   245篇
  1981年   212篇
  1980年   182篇
  1979年   187篇
  1978年   167篇
  1977年   159篇
  1976年   146篇
  1975年   150篇
  1974年   166篇
  1973年   141篇
  1971年   132篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
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   
102.
103.
104.
105.
106.
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   
107.
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   
108.
In the UK for the period 1994-99, a broad range of environmental projects were given financial support through the European Agriculture Guidance and Guarantee Fund under the Objective 1 and Objective 5b programmes. This paper is concerned with the ex-post evaluation of these projects set within a Sustainable Development framework. The aim was to identify project types or characteristics that offered the greatest return on investment. A classification of six broad project types was adopted. The evaluation revealed that there were significant differences between individual projects with respect to the type and scale, and temporal and social distribution of the benefits they delivered. In particular, as well as delivering environmental and economic benefits, many projects made a significant contribution to the development of human and social capital. The paper concludes that it is possible to improve the basis for future project selection in order to maximise the returns on environmental investments in the context of sustainable development.  相似文献   
109.
Urban atmospheric environment contains many trace organic pollutants that are related to the incomplete fuel combustion in domestic heating, industrial plants and automobile traffic. Removal of these pollutants from the atmosphere takes place through wet and dry deposition as well as chemical transformations. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs) in wet deposition samples were determined at an urban site of Turkey. Wet and dry deposition samples were collected using Andersen Rain Sampler. The sampler was modified accordingly for the collection of organic pollutants. Collected samples were preconcentrated by using solid phase extraction (SPE) disks and consecutively analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). Among the 13 compounds quantified in this study, anthracene, fluoranthene, and pyrene were found more frequently and at elevated concentrations (202, 271 and 260 ng L-1 mean concentrations, respectively).Concentrations of PAHs were found to be high in winter period.  相似文献   
110.
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