全文获取类型
收费全文 | 3557篇 |
免费 | 218篇 |
国内免费 | 255篇 |
专业分类
安全科学 | 98篇 |
废物处理 | 16篇 |
环保管理 | 847篇 |
综合类 | 1281篇 |
基础理论 | 658篇 |
环境理论 | 51篇 |
污染及防治 | 159篇 |
评价与监测 | 205篇 |
社会与环境 | 540篇 |
灾害及防治 | 175篇 |
出版年
2024年 | 9篇 |
2023年 | 68篇 |
2022年 | 82篇 |
2021年 | 114篇 |
2020年 | 105篇 |
2019年 | 159篇 |
2018年 | 150篇 |
2017年 | 186篇 |
2016年 | 221篇 |
2015年 | 192篇 |
2014年 | 135篇 |
2013年 | 298篇 |
2012年 | 220篇 |
2011年 | 272篇 |
2010年 | 179篇 |
2009年 | 208篇 |
2008年 | 168篇 |
2007年 | 210篇 |
2006年 | 167篇 |
2005年 | 128篇 |
2004年 | 112篇 |
2003年 | 103篇 |
2002年 | 86篇 |
2001年 | 72篇 |
2000年 | 93篇 |
1999年 | 75篇 |
1998年 | 38篇 |
1997年 | 44篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 30篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有4030条查询结果,搜索用时 262 毫秒
951.
C. Calfapietra B. Gielen R. Ceulemans 《Environmental pollution (Barking, Essex : 1987)》2010,158(4):1095-1104
The use of agroforestry crops is a promising tool for reducing atmospheric carbon dioxide concentration through fossil fuel substitution. In particular, plantations characterised by high yields such as short rotation forestry (SRF) are becoming popular worldwide for biomass production and their role acknowledged in the Kyoto Protocol. While their contribution to climate change mitigation is being investigated, the impact of climate change itself on growth and productivity of these plantations needs particular attention, since their management might need to be modified accordingly. Besides the benefits deriving from the establishment of millions of hectares of these plantations, there is a risk of increased release into the atmosphere of volatile organic compounds (VOC) emitted in large amounts by most of the species commonly used. These hydrocarbons are known to play a crucial role in tropospheric ozone formation. This might represent a negative feedback, especially in regions already characterized by elevated ozone level. 相似文献
952.
基于2008年及2009年分4个季节对北京市3种类型道路(开阔型、交叉路口型和峡谷型)空气中的NOx的现场监测结果,分析了3种类型道路空气中NOx的污染现状和时空变化规律及影响因素。实验结果表明,昼间北京市各类型街道空气中NOx浓度呈早晚浓度高、中午浓度低的变化规律,NOx浓度随季节和车流量变化较明显。交通道路空气中NO占NOx的分担率高,且有较好的相关性,而NO2分担率较低,与NOx相关性较差。 相似文献
953.
Haixiao Wu 《中国人口.资源与环境(英文版)》2016,14(1):11-15
There is an increasing number of “mass events” in mainland China. My study extends the current studies to the context of China and tries to examine the potential impacts of climate changes on human conflicts in China. The results suggest a strong linkage between the deviation of monthly mean temperature from the historical mean and the number of mass events in a province. If the current trend of warming persists, in the next 6–8 decades, the number of mass events in China will increase by over 8.8%. 相似文献
954.
955.
安徽地区近45年蒸发皿蒸发量变化特征及影响因素初探 总被引:1,自引:0,他引:1
利用线性倾向性估计和Mann Kendal检验方法,研究了过去的45年(1963~2007年)安徽地区32个代表站 20 cm 口径蒸发皿蒸发量的变化特征。结果表明:(1)安徽地区蒸发皿蒸发量呈现明显下降趋势(-65.3 mm/10 a,信度001),年蒸发总量在1976年发生突变,1982年显著减少,夏季突变最为明显;(2)32个代表台站中24个台站蒸发皿蒸发量表现为显著下降趋势,仅1个表现为上升趋势(信度005),在空间上减少趋势基本呈现“北多南少”的态势。结合其它气候要素研究发现:气温显著升高,蒸发量明显减少,即安徽地区存在“蒸发悖论”规律,但气温与蒸发量之间相关性不明显;日照,日较差和风速存在显著减少趋势,相关性〖JP+1〗分析表明它们是影响蒸发皿蒸发量减少的最重要因子;低云量,降水量和相对湿度等要素本身没有明显变化趋势但对蒸发皿蒸发量的减少作用也不可忽视。 相似文献
956.
David Manuel-Navarrete Gilberto C. Gallopín Mariela Blanco Martín Díaz-Zorita Diego O. Ferraro Hilda Herzer Pedro Laterra María R. Murmis Guillermo P. Podestá Jorge Rabinovich Emilio H. Satorre Filemón Torres Ernesto F. Viglizzo 《Environment, Development and Sustainability》2009,11(3):621-638
Assessing the sustainability of complex development processes requires multi-causal and integrated analyses. We develop a
system-based methodology, rooted in interdisciplinary discussion and consensus building between 15 experts, to construct a
multi-causal diagram which examines the sustainability of the Argentine Pampas′ process of agriculturization. The resulting
diagram includes 25 factors and provides a big-picture of the multiple dimensions and interrelations affecting sustainability.
According to this examination, the increasing concentration of production and the incorporation of technological innovations,
triggered by economic and institutional factors, are the cause of environmental distresses and social changes, whose consequences
for sustainability are still highly disputed. Nevertheless, the symptoms of both environmental and social unsustainability
are more evident in the case of the extra-Pampean regions than in the Pampas. This suggests that the Pampean agriculture model
should not be transferred to these regions without substantial modifications. The experts did not reach consensus on whether
the agriculturization process is overall sustainable or unsustainable. Lack of consensus revolved mainly around opposing perspectives
regarding the significance of the threats to environmental sustainability. The magnitude of socio-distributive unbalance and
loss of rural jobs were also contentious. Yet, the paper shows how the exercise of building a joint causal diagram was undoubtedly
helpful for linking piece-meal disciplinary facts, brought in from all fronts, into a comprehensive and coherent picture.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
957.
Land Use and Land Cover Change Analysis and Prediction in the Upper Reaches of the Minjiang River,China 总被引:2,自引:1,他引:1
Scientists have aimed at exploring land use and land cover change (LUCC) and modeling future landscape pattern in order to
improve our understanding of the causes and consequences of these phenomena. This study addresses LUCC in the upper reaches
of Minjiang River, China, from 1974 to 2000. Based on remotely sensed images, LUCC and landscape pattern change were assessed
using cross-tabulation and landscape metrics. Then, using the CLUE-S model, changes in area of four types of land cover were
predicted for two scenarios considering forest polices over the next 20 years. Results showed that forestland decreased from
1974 to 2000 due to continuous deforestation, while grassland and shrubland increased correspondingly. At the same time, the
farmland and settlement land increased dramatically. Landscape fragmentation in the study area accompanied these changes.
Forestland, grassland, and farmland take opposite trajectories in the two scenarios, as does landscape fragmentation. LUCC
has led to ecological consequences, such as biodiversity loss and lowering of ecological carrying capacity. 相似文献
958.
959.
Ingemar Renberg Christian Bigler Richard Bindler Matilda Norberg Johan Rydberg Ulf Segerström 《Journal of environmental management》2009
Establishment of plans for environmental planning and management requires that a number of natural and societal factors must be taken into consideration. Insights into the inherent dynamics of nature as well as the role that past human activities have played for establishing the current condition of the landscape and the natural environment in general are essential. Many natural and man-made changes occur over time scales of decades or centuries, and these are difficult to comprehend without a historical perspective. Such a perspective can be obtained using palaeoecological studies, i.e. by geochemical and biological analyses of lake sediment and peat deposits. To illustrate the long-term dynamics of nature and particularly the role of man, we present here five case studies from Sweden concerning pollution, lake acidification, lake eutrophication, biodiversity, and landscape dynamics and conservation – topics of broad interests – and discuss benefits of including a longer time perspective in environmental management. 相似文献
960.
Reaching the economic, environmental and sustainability objectives of all societies requires overcoming several major energy challenges; it necessitates rapid progress in multiple areas. The scenario pathways presented in this paper describe transformative changes toward these goals, taking a broad view of the four main energy challenges faced by society in the 21st century: providing universal access to modern energy for all; reducing the impacts of energy production on human health and the environment; avoiding dangerous climate change; and enhancing energy security. The overarching objective of the paper is to provide policy guidance on how to facilitate the transformation of the energy system to achieve these multiple energy objectives. Particular focus is given to the required pace of the transformation at both the global and regional levels, and to the types of financial and policy measures that will be needed to ensure a successful transition. Synergies and trade‐offs between the objectives are identified, and co‐benefits quantified. The paper makes an important contribution to the scenario literature by approaching the global transition toward sustainable development in a more integrated, holistic manner than is common in other studies. 相似文献