全文获取类型
收费全文 | 12856篇 |
免费 | 1144篇 |
国内免费 | 1809篇 |
专业分类
安全科学 | 1818篇 |
废物处理 | 173篇 |
环保管理 | 2218篇 |
综合类 | 7179篇 |
基础理论 | 1393篇 |
环境理论 | 7篇 |
污染及防治 | 580篇 |
评价与监测 | 1003篇 |
社会与环境 | 953篇 |
灾害及防治 | 485篇 |
出版年
2024年 | 66篇 |
2023年 | 235篇 |
2022年 | 309篇 |
2021年 | 408篇 |
2020年 | 472篇 |
2019年 | 375篇 |
2018年 | 338篇 |
2017年 | 474篇 |
2016年 | 560篇 |
2015年 | 589篇 |
2014年 | 643篇 |
2013年 | 866篇 |
2012年 | 896篇 |
2011年 | 1063篇 |
2010年 | 732篇 |
2009年 | 762篇 |
2008年 | 606篇 |
2007年 | 873篇 |
2006年 | 836篇 |
2005年 | 675篇 |
2004年 | 573篇 |
2003年 | 522篇 |
2002年 | 488篇 |
2001年 | 394篇 |
2000年 | 405篇 |
1999年 | 335篇 |
1998年 | 218篇 |
1997年 | 232篇 |
1996年 | 148篇 |
1995年 | 175篇 |
1994年 | 89篇 |
1993年 | 114篇 |
1992年 | 66篇 |
1991年 | 57篇 |
1990年 | 38篇 |
1989年 | 22篇 |
1988年 | 24篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 16篇 |
1980年 | 9篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1975年 | 4篇 |
1971年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
851.
Ying Guo Huan-Yun Yu Eddy Y. Zeng 《Environmental pollution (Barking, Essex : 1987)》2009,157(6):1753-1763
This review summarizes and analyzes available data in the literature (mostly after 2000) on the occurrence of dichlorodiphenyltrichloroethane (DDT) and its main metabolites, dichlorodiphenyldichloroethane (DDD) and chlorodiphenyldichloroethylene (DDE), in the environment of the Pearl River Delta (PRD), South China. Generally, the concentration levels of the sum of DDT, DDD, and DDE, designated as DDTs thereafter, have not significantly declined since 1983. However, the composition of DDTs residues has changed with time. DDTs in soil, freshwater sediment and freshwater fish species were mainly residues from chronological use. There is evidence that new point sources, such as dicofol and anti-fouling paint, may have contributed DDTs to various environmental compartments. Risk assessment against existing criteria indicated that the levels of DDTs in water and some fish species may pose adverse effects to humans or wildlife, and those in sediment/soil may also cause negative impacts to the eco-environment of the PRD. 相似文献
852.
The majority of Australian weeds are exotic plant species that were intentionally introduced for a variety of horticultural and agricultural purposes. A border weed risk assessment system (WRA) was implemented in 1997 in order to reduce the high economic costs and massive environmental damage associated with introducing serious weeds. We review the behaviour of this system with regard to eight years of data collected from the assessment of species proposed for importation or held within genetic resource centres in Australia. From a taxonomic perspective, species from the Chenopodiaceae and Poaceae were most likely to be rejected and those from the Arecaceae and Flacourtiaceae were most likely to be accepted. Dendrogram analysis and classification and regression tree (TREE) models were also used to analyse the data. The latter revealed that a small subset of the 35 variables assessed was highly associated with the outcome of the original assessment. The TREE model examining all of the data contained just five variables: unintentional human dispersal, congeneric weed, weed elsewhere, tolerates or benefits from mutilation, cultivation or fire, and reproduction by vegetative propagation. It gave the same outcome as the full WRA model for 71% of species. Weed elsewhere was not the first splitting variable in this model, indicating that the WRA has a capacity for capturing species that have no history of weediness. A reduced TREE model (in which human-mediated variables had been removed) contained four variables: broad climate suitability, reproduction in less or than equal to 1year, self-fertilisation, and tolerates and benefits from mutilation, cultivation or fire. It yielded the same outcome as the full WRA model for 65% of species. Data inconsistencies and the relative importance of questions are discussed, with some recommendations made for improving the use of the system. 相似文献
853.
854.
The Western Forest Complex (WEFCOM) of Thailand is comprised of many protected areas and has one of the highest wildlife populations in the country. Populations of wildlife in the WEFCOM have decreased dramatically over recent years. Rapid economic development has resulted in the conversion of forest into agricultural and pastoral land, which has directly and indirectly impacted the wildlife community. This research aimed to evaluate populations of domesticated cattle (Bos indicus) and buffalo (Bubalus bubalis) in the WEFCOM and their possible impacts on the wildlife community. Domesticated cattle and buffalo keepers from 1561 (or 3.3%) of houses in and near WEFCOM were interviewed. The average number of animals per household was 15.6 cattle and 8.5 buffalo. Most villagers released domesticated cattle and buffalo to forage in the protected areas. This tended to have a high impact on the wildlife community in Huai Kha Khaeng Wildlife Sanctuary and Tungyai Naresuan Wildlife Sanctuary. The least impacted areas were Luam Khlong Ngu National Park, Thong Pha Phum National Park and Chaleam Ratanakosin National Park. With a high risk to the wildlife community, law enforcement should be used in combination with a certain level of co-management with local communities. 相似文献
855.
The influence of use-related,environmental, and managerial factors on soil loss from recreational trails 总被引:2,自引:0,他引:2
Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding “fall-line” alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes. 相似文献
856.
Warmer, drier summers brought by climate change increase the potential risk of wildfires on the moorland of the Peak District of northern England. Fires are costly to fight, damage the ecosystem, harm water catchments, cause erosion scars and disrupt transport. Fires release carbon dioxide to the atmosphere. Accurate forecasts of the timing of fires help deployment of fire fighting resources. 相似文献
857.
Sustainability assessment (SA) is a holistic and long-range strategic instrument capable of assisting policy-making in electing,
and deciding upon, future development priorities. The outcomes of an SA process become more relevant and strengthened when
conducted with multi-stakeholder engagement, which provides for multiple dialogues and perspectives. This was the object of
research of the SA team in the context of BioScene (Scenarios for Reconciling Biodiversity Conservation with Declining Agriculture Use in Mountain Areas in Europe), a three-year project (2002–2005) funded by the European Union 5th Framework Program, which aimed to investigate the implications
of agricultural restructuring and decline for biodiversity conservation in the mountain areas of Europe, using three distinct
methodological streams: the ecological, the socio-economic, and the SA approaches. The SA approach drew on the previous two
to assess the importance for biodiversity management of different scenarios of agri-environmental change and rural policy
in six countries (France, Greece, Norway, Slovakia, Switzerland, and the United Kingdom), develop causal chains, include stakeholder
views, and identify potential contributions for, or conflicts with, sustainability. This article tells how SA was used, what
sustainability meant in each study area through different objectives of sustainability considered, discusses the methods used
in SA, and the benefits arising. The SA was conducted by a team independent of any study area, who developed and oversaw the
application of the SA methodology, assisting national teams, and developing a cross-country understanding of the sustainability
of proposed scenarios in the different geographical and social contexts, and their implications for policy-making. Finally,
it reflects on the persistent challenges of interdisciplinary research, compounded by multi-cultural teams, and concludes
on the BioScene’s lessons for the further development and application of SA.
相似文献
William R. SheateEmail: |
858.
Allen CD 《Environmental management》2009,43(2):346-356
Characterized by expensive housing, high socioeconomic status, and topographic relief, Upper Sonoran Lifestyle communities
are found primarily along the Wildland-Urban Interface (WUI) in the Phoenix, Arizona metro area. Communities like these sprawl
into the wildlands in the United States Southwest, creating a distinct urban fringe. This article, through locational comparison,
introduces and evaluates a new field assessment tool for monitoring anthropogenic impact on soil–vegetation interactions along
the well-maintained multi-use recreational trails in Upper Sonoran Lifestyle region. Comparing data from randomly selected
transects along other multi-use trails with data from a control site revealed three key indicators of anthropogenic disturbances
on soil–vegetation interactions: soil disturbance, vegetation disturbance, and vegetation density. Soil and vegetation disturbance
displayed an average distance decay exponent factor of −0.60, while vegetation density displayed a reverse decay average of
0.60. Other important indicators of disturbance included vegetation type, biological soil crusts, and soil bulk density. The
predictive ability of this new field tool enhances its applicability, offering a powerful rapid ecological assessment method
for monitoring long-term anthropogenic impact in the Upper Sonoran Lifestyle, and other sprawling cities along the WUI. 相似文献
859.
Three geomorphic considerations that underpin the design and implementation of realistic and strategic river conservation
and rehabilitation programs that work with the nature are outlined. First, the importance of appreciating the inherent diversity
of river forms and processes is discussed. Second, river dynamics are appraised, framing the contemporary behavioral regime
of a reach in relation to system evolution to explain changes to river character and behavior over time. Third, the trajectory
of a reach is framed in relation to downstream patterns of river types, analyzing landscape connectivity at the catchment
scale to interpret geomorphic river recovery potential. The application of these principles is demonstrated using extensive
catchment-scale analyses of geomorphic river responses to human disturbance in the Bega and Upper Hunter catchments in southeastern
Australia. Differing implications for reach- and catchment-scale rehabilitation planning prompt the imperative that management
practices work with nature rather than strive to ‘fight the site.’ 相似文献
860.
Alan T. Herlihy Jean Sifneos Chris Bason Amy Jacobs Mary E. Kentula M. Siobhan Fennessy 《Environmental management》2009,44(2):369-377
We sampled 92 wetlands from four different basins in the United States to quantify observer repeatability in rapid wetland
condition assessment using the Delaware Rapid Assessment Protocol (DERAP). In the Inland Bays basin of Delaware, 58 wetland
sites were sampled by multiple observers with varying levels of experience (novice to expert) following a thorough training
workshop. In the Nanticoke (Delaware/Maryland), Cuyahoga (Ohio), and John Day (Oregon) basins, 34 wetlands were sampled by
two expert teams of observers with minimal protocol training. The variance in observer to observer scoring at each site was
used to calculate pooled standard deviations (SDpool), coefficients of variation, and signal-to-noise ratios for each survey. The results showed that the experience level of
the observer had little impact on the repeatability of the final rapid assessment score. Training, however, had a large impact
on observer to observer repeatability. The SDpool in the Inland Bay survey with training (2.2 points out of a 0–30 score) was about half that observed in the other three basins
where observers had minimal training (SDpool = 4.2 points). Using the results from the survey with training, we would expect that two sites assessed by different, trained
observers who obtain DERAP scores differing by more than 4 points are highly likely to differ in ecological condition, and
that sites with scores that differ by 2 or fewer points are within variability that can be attributed to observer differences. 相似文献