全文获取类型
收费全文 | 727篇 |
免费 | 34篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 50篇 |
废物处理 | 24篇 |
环保管理 | 164篇 |
综合类 | 87篇 |
基础理论 | 246篇 |
环境理论 | 1篇 |
污染及防治 | 125篇 |
评价与监测 | 37篇 |
社会与环境 | 25篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 28篇 |
2017年 | 25篇 |
2016年 | 37篇 |
2015年 | 23篇 |
2014年 | 33篇 |
2013年 | 60篇 |
2012年 | 43篇 |
2011年 | 60篇 |
2010年 | 34篇 |
2009年 | 39篇 |
2008年 | 49篇 |
2007年 | 44篇 |
2006年 | 31篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 16篇 |
2002年 | 34篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有772条查询结果,搜索用时 359 毫秒
281.
From disaster to development: a systematic review of community‐driven humanitarian logistics
下载免费PDF全文
![点击此处可从《Disasters》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A plethora of untapped resources exist within disaster‐affected communities that can be used to address relief and development concerns. A systematic review of the literature relating to community participation in humanitarian logistics activities revealed that communities are able to form ad hoc networks that have the ability to meet a wide range of disaster management needs. These structures, characterised as Collaborative Aid Networks (CANs), have demonstrated efficient logistical capabilities exclusive of humanitarian organisations. This study proposes that CANs, as a result of their unique characteristics, present alternatives to established humanitarian approaches to logistics, while also mitigating the challenges commonly faced by traditional humanitarian organisations. Furthermore, CANs offer a more holistic, long‐term approach to disaster management, owing to their impact on development through their involvement in humanitarian logistics. This research provides the foundation for further theoretical analysis of effective and efficient disaster management, and details opportunities for policy and practice. 相似文献
282.
Removal of predators can have strong indirect effects on primary producers through trophic cascades. Crustose coralline algae (CCA) are major primary producers worldwide that may be influenced by predator removal through changes in grazer composition and biomass. CCA have been most widely studied in Caribbean and temperate reefs, where cover increases with increasing grazer biomass due to removal of competitive fleshy algae. However, each of these systems has one dominant grazer type, herbivorous fishes or sea urchins, which may not be functionally equivalent. Where fishes and sea urchins co-occur, fishing can result in a phase shift in the grazing community with subsequent effects on CCA and other substrata. Kenyan reefs have herbivorous fishes and sea urchins, providing an opportunity to determine the relative impacts of each grazer type and evaluate potential human-induced trophic cascades. We hypothesized that fish benefit CCA, abundant sea urchins erode CCA, and that fishing indirectly reduces CCA cover by removing sea urchin predators. We used closures and fished reefs as a large-scale, long-term natural experiment to assess how fishing and resultant changes in communities affect CCA abundance. We used a short-term caging experiment to directly test the effects of grazing on CCA. CCA cover declined with increasing fish and sea urchin abundance, but the negative impact of sea urchin grazing was much stronger than that of fishes. Abundant sea urchins reduced the CCA growth rate to almost zero and prevented CCA accumulation. A warming event (El Ni?o Southern Oscillation, ENSO) occurred during the 18-year study and had a strong but short-term positive effect on CCA cover. However, the effect of the ENSO on CCA was lower in magnitude than the effect of sea urchin grazing. We compare our results with worldwide literature on bioerosion by fishes and sea urchins. Grazer influence depends on whether benefits of fleshy algae removal outweigh costs of grazer-induced bioerosion. However, the cost-benefit ratio for CCA appears to change with grazer type, grazer abundance, and environment. In Kenya, predator removal leads to a trophic cascade that is expected to reduce net calcification of reefs and therefore reduce reef stability, growth, and resilience. 相似文献
283.
Pregitzer KS Zak DR Talhelm AF Burton AJ Eikenberry JR 《Ecology》2010,91(12):3456-62; discussion 3503-14
In order to better understand the nitrogen (N) cycle, a pulse of 15NO3- was applied in 1998 to a sugar maple (Acer saccharum) dominated northern hardwood forest receiving long-term (1994-2008) simulated atmospheric N deposition. Sugar maple leaf litter and live fine-root 15N were quantified for four years prior to labeling and for 11 subsequent years. Continuous sampling of 15N following addition of the tracer enabled calculation of leaf litter and fine-root N pool turnover utilizing an exponential decay function. Fine-root 15N recovery peaked at 3.7% +/- 1.7% the year the tracer was applied, while leaf litter 15N recovery peaked in the two years following tracer application at approximately 8%. These results suggest shoots are primarily constructed from N taken up in previous years, while fine roots are constructed from new N. The residence time of N was 6.5 years in leaf litter and 3.1 years in fine roots. The longer residence time and higher recovery rate are evidence that leaves were a stronger sink for labeled N than fine roots, but the relatively short residence time of tracer N in both pools suggests that there is not tight intra-ecosystem cycling of N in this mature forest. 相似文献
284.
Chaochung Tsai Sylvia Yang Alan C. Trimble Jennifer L. Ruesink 《Marine Biology》2010,157(9):1929-1936
Dwarf eelgrass (duckgrass; Zostera japonica) and Manila clams (Ruditapes philippinarum) are two introduced species that co-occur on intertidal flats of the northeast Pacific. Through factorial manipulation of
clam (0, 62.5, 125 clams m−2) and eelgrass density (present, removed by hand, harrowed), we examined intra- and interspecific effects on performance,
as well as modification of the physical environment. The presence of eelgrass reduced water flow by up to 40% and was also
observed to retain water at low tide, which may ameliorate desiccation and explain why eelgrass grew faster in the presence
of conspecifics (positive feedback). Although shell growth of small (20–50 mm) clams was not consistently affected by either
treatment in this 2-month experiment, clam condition improved when eelgrass was removed. Reciprocally, clams at aquaculture
densities had no effect on eelgrass growth, clam growth and condition, or porewater nutrients. Overall, only Z. japonica demonstrated strong population-level interactions. Interspecific results support an emerging paradigm that invasive marine
ecosystem engineers often negatively affect infauna. Positive feedbacks for Z. japonica may characterize its intraspecific effects particularly at the stressful intertidal elevation of this study (+1 m above mean
lower low water). 相似文献
285.
Jennifer Sumner 《Local Environment》2016,21(10):1230-1242
The struggle for healthy eating is a nascent social movement that represents active resistance to the hostile food environments created by multinational food and beverage corporations. Using a political economy approach and leveraging Winson's [2013. The industrial diet: the degradation of food and the struggle for healthy eating. Vancouver: UBC Press] concepts of dietary regimes and the industrial diet, this paper will examine the strengths and limitations of Brazil's new dietary guidelines and discuss its role as a precursor to a new dietary regime that incorporates social justice and sustainability. 相似文献
286.
Fabio Boschetti Claire Gaffier Magnus Moglia Iain Walke Jennifer Price 《Sustainability Science》2017,12(3):345-364
How well does the general public understand the concept of urban resilience? We address this question via an online survey of 500+ citizens living in three large Australian cities (Sydney, Melbourne and Perth). The majority of respondents claim not to know what urban resilience means. Of the remaining respondents, understanding ranges from poor to sophisticated. To circumvent this stated lack of understanding, we cast the concept of urban resilience into a more familiar framework consisting of risk and ability to cope with threats. This allows us to assess perceptions about what may challenge the resilience of Australian cities. Two concerns clearly emerge: (1) violence and social unrest and (2) environmental threats. Analysing a number of constructs from the social psychology literature reveals that these two concerns hold different cognitive signatures, whose understanding may facilitate discussion and communication within a public engagement process. 相似文献
287.
This study investigated bioamplification of polychlorinated biphenyls (PCBs) in yellow perch (Perca flavescens) eggs resulting from nutrient utilization by developing embryos during incubation. Newly fertilized eggs containing trace levels of PCBs via maternal deposition were collected from an aquaculture pond in which adult broodstock had been reared over their natural lives. The eggs were incubated using a flow through system that received the same pond water at in-situ temperatures from which they were spawned. Replicate samples of eggs were collected at six time points throughout incubation, ranging from day 0 (newly fertilized eggs) to post-hatch larvae (2-d old). Congener specific PCB fugacities in pooled egg samples showed increases over the incubation period. Just prior to hatching, incubated eggs averaged 2.7-fold higher PCB fugacities compared to fresh eggs. The increase in PCB fugacity with egg incubation time was independent of chemical KOW. After hatching, PCB residues were lost from the larvae, attenuating the maximum chemical fugacity achieved in late-incubated eggs. However, the rate of PCB elimination in the early larvae stages was KOW dependent such that a significant larvae/egg fugacity ratio was still evident for intermediate and highly hydrophobic compounds 2 d post-hatching. This study provides the first evidence of in-ovo PCB bioamplification in eggs of an aquatic species and suggests that incubating fish embryos are exposed to higher chemical fugacities in-ovo than would be predicted by maternal deposition alone. 相似文献
288.
289.
Energy efficiency and conservation for individual Americans 总被引:1,自引:0,他引:1
D. Pimentel Jennifer Gardner Adam Bonnifield Ximena Garcia Julie Grufferman Claire Horan Julia Schlenker Emily Walling Emily Rochon 《Environment, Development and Sustainability》2009,11(3):523-546
Americans make up only 4% of the world population, yet currently consume 25% of the world’s fossil fuels. The U.S. imports
63% of its oil and it is predicted that by 2020 the U.S. will be importing 95% of its oil resources. Over the past century,
ample and affordable supplies of fossil fuels have powered the growth and prosperity of the economies of the US and other
countries. Within this century, world oil supplies will decline while demand is projected to continue to increase, suggesting
that we will have to transition to different fuels or become much more energy efficient or both. Looking ahead to the near
decades, estimates are that consumers will have to reduce their energy use by at least 50%. This reduction will be necessary
in large part due the decline in the availability of conventional oil and gas, but also because the U.S. population will continue
to grow in number. Although government action is important, individuals too often discount their ability to make significant
contributions to solving such major problems. This investigation identifies how informed and concerned individuals can collectively
conserve fossil energy.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.
An erratum to this article can be found at 相似文献
290.
Photocatalytic purification of volatile organic compounds in indoor air: A literature review 总被引:1,自引:0,他引:1
Jinhan Mo Yinping Zhang Qiujian Xu Jennifer Joaquin Lamson Rongyi Zhao 《Atmospheric environment (Oxford, England : 1994)》2009,43(14):2229-2246
Volatile organic compounds (VOCs) are prevalent components of indoor air pollution. Among the approaches to remove VOCs from indoor air, photocatalytic oxidation (PCO) is regarded as a promising method. This paper is a review of the status of research on PCO purification of VOCs in indoor air. The review and discussion concentrate on the preparation and coating of various photocatalytic catalysts; different kinetic experiments and models; novel methods for measuring kinetic parameters; reaction pathways; intermediates generated by PCO; and an overview of various PCO reactors and their models described in the literature. Some recommendations are made for future work to evaluate the performance of photocatalytic catalysts, to reduce the generation of harmful intermediates and to design new PCO reactors with integrated UV source and reaction surface. 相似文献