全文获取类型
收费全文 | 20904篇 |
免费 | 238篇 |
国内免费 | 127篇 |
专业分类
安全科学 | 545篇 |
废物处理 | 891篇 |
环保管理 | 2849篇 |
综合类 | 3435篇 |
基础理论 | 5853篇 |
环境理论 | 11篇 |
污染及防治 | 5386篇 |
评价与监测 | 1292篇 |
社会与环境 | 871篇 |
灾害及防治 | 136篇 |
出版年
2021年 | 138篇 |
2019年 | 130篇 |
2018年 | 239篇 |
2017年 | 256篇 |
2016年 | 409篇 |
2015年 | 308篇 |
2014年 | 475篇 |
2013年 | 1648篇 |
2012年 | 581篇 |
2011年 | 827篇 |
2010年 | 677篇 |
2009年 | 673篇 |
2008年 | 842篇 |
2007年 | 881篇 |
2006年 | 778篇 |
2005年 | 668篇 |
2004年 | 658篇 |
2003年 | 634篇 |
2002年 | 616篇 |
2001年 | 766篇 |
2000年 | 575篇 |
1999年 | 330篇 |
1998年 | 265篇 |
1997年 | 282篇 |
1996年 | 283篇 |
1995年 | 335篇 |
1994年 | 305篇 |
1993年 | 286篇 |
1992年 | 278篇 |
1991年 | 279篇 |
1990年 | 296篇 |
1989年 | 285篇 |
1988年 | 250篇 |
1987年 | 242篇 |
1986年 | 232篇 |
1985年 | 204篇 |
1984年 | 259篇 |
1983年 | 215篇 |
1982年 | 272篇 |
1981年 | 222篇 |
1980年 | 189篇 |
1979年 | 205篇 |
1978年 | 194篇 |
1977年 | 155篇 |
1976年 | 139篇 |
1975年 | 144篇 |
1974年 | 162篇 |
1973年 | 163篇 |
1972年 | 149篇 |
1971年 | 146篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
471.
Management of an Agroecosystem 总被引:4,自引:0,他引:4
Agroecosystems (AESs) are autotrophic ecosystems managed by man. The goal of the management is to obtain the maximum possible amount of high-quality agricultural products while preserving agricultural resources, primarily the soils and biodiversity. The main components of the management of AES structures and functions, including primary and secondary biological production, the ratio between the energy flows in the plant–man and plant–livestock–man food chains, the efficiency of energy transfer in the plant–livestock link, and conservation of agricultural resources, are considered. 相似文献
472.
A pilot survey of blood lead levels in various types of workers in the United Arab Emirates. 总被引:1,自引:0,他引:1
The aim of the present study is to determine the effect of blood lead on the health of industrial workers in United Arab Emirates (UAE). This is a cross-sectional pilot survey of blood lead levels (BLL) of 100 industrial workers (exposed) and 100 non-industrial workers (nonexposed), matched for age, sex and nationality selected from Al-Ain, Abu-Dhabi Emirate. Industrial workers had significantly higher mean of BLL (77.5+/-42.8 microg/dl and median 80.9 microg/dl) than non-industrial workers (19.8+/-12.3 microg/dl and median 11.0 microg/dl). In the present study, reported symptoms among industrial workers were strongly associated with BLL nausea/vomiting, muscular symptoms, dizziness, fatigue, irritability, memory disturbances, insomnia and allergic conjuctivitis, rhinitis and dermatitis. Furthermore, the present study revealed that industrial workers had higher prevalence of respiratory symptoms for phlegm, shortness of breath and diagnosed asthma. In conclusion, this study determined that occurrence of certain symptoms might be associated with lead exposure among industrial workers. 相似文献
473.
474.
475.
476.
The ecosystem services (ES) concept is being increasingly incorporated into environmental policy formulation and management approaches. The Corporate Ecosystem Services Review (ESR) is a framework used to assess the dependence and impact that a business has on ES. The success of the corporate experience of ES assessment provides an opportunity for adaption for local authority decision making. In this paper, the ESR tool was adapted to the South African setting at a local government level, and tested at two sites in the Msunduzi Municipality, KwaZulu-Natal. In testing the tool and gathering feedback from key stakeholders, it was found that there are both opportunities and challenges to this approach. Overall, however, it provides an opportunity for the systematic inclusion of ES assessment into existing regulatory frameworks for land-use planning and Integrated Environmental Management, whether in a strategic application, at a broader spatial (municipal) scale or in a specific locale within the municipality. 相似文献
477.
478.
479.
480.
Poulomi Ganguli Auroop R. Ganguly 《Journal of the American Water Resources Association》2016,52(1):138-167
We examine the robustness of a suite of regional climate models (RCMs) in simulating meteorological droughts and associated metrics in present‐day climate (1971‐2003) over the conterminous United States (U.S.). The RCMs that are part of North American Regional Climate Change Assessment Program (NARCCAP) simulations are compared with multiple observations over the climatologically homogeneous regions of the U.S. The seasonal precipitation, climatology, drought attributes, and trends have been assessed. The reanalysis‐based multi‐model median RCM reasonably simulates observed statistical attributes of drought and the regional detail due to topographic forcing. However, models fail to simulate significant drying trend over the Southwest and West. Further, reanalysis‐based NARCCAP runs underestimate the observed drought frequency overall, with the exception of the Southwest; whereas they underestimate persistence in the drought‐affected areas over the Southwest and West‐North Central regions. However, global climate model‐driven NARCCAP ensembles tend to overestimate regional drought frequencies. Models exhibit considerable uncertainties while reproducing meteorological drought statistics, as evidenced by a general lack of agreement in the Hurst exponent, which in turn controls drought persistence. Water resources managers need to be aware of the limitations of current climate models, while regional climate modelers may want to fine‐tune their parameters to address impact‐relevant metrics. 相似文献