全文获取类型
收费全文 | 24248篇 |
免费 | 249篇 |
国内免费 | 197篇 |
专业分类
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 |
出版年
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.
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.
Occurence and Distribution of Polycyclic Aromatic Hydrocarbons in Ankara Precipitation 总被引:1,自引:0,他引:1
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.