全文获取类型
收费全文 | 387篇 |
免费 | 54篇 |
国内免费 | 146篇 |
专业分类
安全科学 | 27篇 |
废物处理 | 4篇 |
环保管理 | 47篇 |
综合类 | 289篇 |
基础理论 | 89篇 |
环境理论 | 1篇 |
污染及防治 | 36篇 |
评价与监测 | 9篇 |
社会与环境 | 69篇 |
灾害及防治 | 16篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 28篇 |
2021年 | 29篇 |
2020年 | 21篇 |
2019年 | 29篇 |
2018年 | 24篇 |
2017年 | 26篇 |
2016年 | 30篇 |
2015年 | 33篇 |
2014年 | 22篇 |
2013年 | 30篇 |
2012年 | 37篇 |
2011年 | 22篇 |
2010年 | 31篇 |
2009年 | 22篇 |
2008年 | 17篇 |
2007年 | 20篇 |
2006年 | 25篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 17篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1979年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有587条查询结果,搜索用时 24 毫秒
151.
152.
Can Labor Out-Migration Reduce Firewood Consumption by Rural Households in Western Mountainous China
Marcus W.Feldman 《中国人口.资源与环境(英文版)》2012,(2):110-119
The relationship between out-migration of labor in the Qinling mountain area and households’ firewood consumption is explored. Migration and remittances reduce households’ firewood consumption due to increases in both income and opportunity cost of firewood collection. Previous studies have been equivocal because they ignored uncertainty in household economy, which is widespread in forest areas of less developed countries. This study provides additional insight by considering vulnerability and subjective assessment of poverty generated by unstable income and an uncertain future. We provide evidence that the amount of firewood consumed depends on income and opportunity cost of firewood collection, but also on a prudent consumption strategy, due to farmers’ subjective assessment of their future possible poverty. We also find out-migration of labor can reduce per capita firewood consumption but subjective poverty also acts against reduction of firewood consumption. 相似文献
153.
Qin Hua 《中国人口.资源与环境(英文版)》2012,10(3):9-17
Abstract: Migration process has become increasingly important in recent research on population and the environment. A majority of the existing migration and environment literature has focused on the en... 相似文献
154.
吸附分离辅助电渗透脱水过程中污泥的特性 总被引:1,自引:1,他引:0
电渗透技术对于城市污水厂污泥的深度脱水是非常有效的,但相对较高的能耗制约了它的广泛应用。为此,针对污泥电渗透脱水过程中阴极排水困难引起能耗高的问题,提出了吸附分离辅助电渗透脱水,同时考察了吸附分离辅助电渗透脱水过程中污泥中水分的运动特点、pH的变化以及离子的迁移规律。结果显示,吸附分离可以极大地提高污泥电渗透脱水的效果。且脱水过程中阳极附近污泥的含水率、pH均迅速减小;阴极附近污泥的含水率稍有减少,但pH却迅速增大;而中间层污泥的含水率及pH均没有发生变化。此外,电渗透脱水技术对于污泥中目标离子的去除非常有效,但同时容易导致非目标离子的去除。 相似文献
155.
Legarda F Romero LM Herranz M Barrera M Idoeta R Valiño F Olondo C Caro A 《Journal of environmental radioactivity》2011,102(6):589-597
In this study the total activity of 137Cs deposited per unit area over the Spanish peninsular territory was analysed using a 150 × 150 km2 mesh grid, with samples taken from 29 points. The deposited activities ranged between 251 and 6074 Bq/m2. A linear relationship was obtained between these values and the mean annual rainfall at each sampling point which allowed a map to be drawn, using GIS software, which shows the distribution of total deposited 137Cs activity across the Spanish mainland. At twelve of these sampling points the vertical migration profile of 137Cs was obtained. These profiles are separated into two groups with different behaviour, one of which includes clay and loam soils and the other containing sandy soils. For both groups of profiles the parameters of the convective-diffusive model, which describes the vertical migration of 137Cs in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) were calculated. 相似文献
156.
Patrick J. Dugan Chris Barlow Angelo A. Agostinho Eric Baran Glenn F. Cada Daqing Chen Ian G. Cowx John W. Ferguson Tuantong Jutagate Martin Mallen-Cooper Gerd Marmulla John Nestler Miguel Petrere Robin L. Welcomme Kirk O. Winemiller 《Ambio》2010,39(4):344-348
The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin’s fisheries and the people who depend upon them for food and income. We find no evidence that current moves towards dam construction will stop, and consider two scenarios for the future of the fisheries and other ecosystems of the basin. We conclude that major investment is required in innovative technology to reduce the loss of ecosystem services, and alternative livelihood strategies to cope with the losses that do occur. 相似文献
157.
持久性有机污染物的环境分布与生物危害 总被引:2,自引:0,他引:2
介绍了国内外持久性有机物的研究进展,分析了中国典型地区中的持久性有机污染物的分布情况,其中淮河中下游的PAHs含量较高,而大连湾检测出的DDTs和PCBs含量均高于其他地区。持久性有机污染物可以在动植物体内不断富集,据分析,有机污染物在鱼类的富集因子可高达1124.1,持久性有机污染物通过食物链的富集逐级放大,对全球生态构成潜在巨大的威胁。近年来,由于持久性有机污染物的影响,在世界各地出现了动物的死亡、甚至灭绝的现象,而且有机污染物在人体内的蓄积,会对人体产生极大的的影响。最后,就当前存在的问题,提出了对策与建议,指出了该领域的发展方向。 相似文献
158.
随着烧结工艺的发展,排放标准的提高,对机头电除尘器的要求越来越严格。然而高碱度烧结和高负压操作法等生产工艺却对机头电除尘器造成严重影响。本文针对烧结机头电除尘器的烟气、烟尘特点,充分讨论机头电除尘器在选型时应该考虑的几个问题,以满足机头工艺除尘的要求,以达到净化烟气的目的。 相似文献
159.
160.
An Assessment of Invasion Risk from Assisted Migration 总被引:4,自引:0,他引:4
Abstract: To reduce the risk of extinction due to climate change, some ecologists have suggested human-aided translocation of species, or assisted migration (AM), to areas where climate is projected to become suitable. Such intentional movement, however, may create new invasive species if successful introductions grow out of control and cause ecologic or economic damage. We assessed this risk by surveying invasive species in the United States and categorizing invaders based on origin. Because AM will involve moving species on a regional scale within continents (i.e., range shifts), we used invasive species with an intracontinental origin as a proxy for species that would be moved through AM. We then determined whether intracontinental invasions were more prevalent or harmful than intercontinental invasions. Intracontinental invasions occurred far less frequently than invasions from other continents, but they were just as likely to have had severe effects. Fish and crustaceans pose a particularly high threat of intracontinental invasion. We conclude that the risk of AM to create novel invasive species is small, but assisted species that do become invasive could have large effects. Past experience with species reintroductions may help inform policy regarding AM. 相似文献