全文获取类型
收费全文 | 41589篇 |
免费 | 443篇 |
国内免费 | 539篇 |
专业分类
安全科学 | 1218篇 |
废物处理 | 1869篇 |
环保管理 | 5080篇 |
综合类 | 7787篇 |
基础理论 | 10483篇 |
环境理论 | 23篇 |
污染及防治 | 10693篇 |
评价与监测 | 2759篇 |
社会与环境 | 2445篇 |
灾害及防治 | 214篇 |
出版年
2022年 | 393篇 |
2021年 | 388篇 |
2020年 | 279篇 |
2019年 | 356篇 |
2018年 | 616篇 |
2017年 | 602篇 |
2016年 | 959篇 |
2015年 | 733篇 |
2014年 | 1103篇 |
2013年 | 3212篇 |
2012年 | 1323篇 |
2011年 | 1847篇 |
2010年 | 1477篇 |
2009年 | 1569篇 |
2008年 | 1833篇 |
2007年 | 1901篇 |
2006年 | 1668篇 |
2005年 | 1393篇 |
2004年 | 1345篇 |
2003年 | 1410篇 |
2002年 | 1278篇 |
2001年 | 1642篇 |
2000年 | 1107篇 |
1999年 | 703篇 |
1998年 | 479篇 |
1997年 | 512篇 |
1996年 | 519篇 |
1995年 | 586篇 |
1994年 | 598篇 |
1993年 | 504篇 |
1992年 | 504篇 |
1991年 | 503篇 |
1990年 | 527篇 |
1989年 | 455篇 |
1988年 | 418篇 |
1987年 | 388篇 |
1986年 | 345篇 |
1985年 | 360篇 |
1984年 | 388篇 |
1983年 | 377篇 |
1982年 | 383篇 |
1981年 | 329篇 |
1980年 | 278篇 |
1979年 | 296篇 |
1978年 | 279篇 |
1977年 | 212篇 |
1975年 | 224篇 |
1974年 | 215篇 |
1972年 | 202篇 |
1971年 | 212篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
181.
182.
183.
184.
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
185.
186.
187.
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
188.
Gunavant M. Oza 《The Environmentalist》2003,23(2):189-192
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
189.
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
190.