首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   221篇
  免费   9篇
  国内免费   2篇
安全科学   7篇
废物处理   8篇
环保管理   44篇
综合类   45篇
基础理论   66篇
环境理论   1篇
污染及防治   34篇
评价与监测   10篇
社会与环境   8篇
灾害及防治   9篇
  2023年   5篇
  2022年   8篇
  2021年   6篇
  2020年   7篇
  2019年   15篇
  2018年   8篇
  2017年   12篇
  2016年   10篇
  2015年   17篇
  2014年   12篇
  2013年   17篇
  2012年   8篇
  2011年   22篇
  2010年   8篇
  2009年   9篇
  2008年   11篇
  2007年   4篇
  2006年   6篇
  2005年   2篇
  2004年   7篇
  2003年   5篇
  2002年   8篇
  2001年   5篇
  2000年   7篇
  1999年   3篇
  1998年   1篇
  1997年   1篇
  1995年   1篇
  1994年   1篇
  1992年   2篇
  1982年   1篇
  1981年   3篇
排序方式: 共有232条查询结果,搜索用时 0 毫秒
191.
192.
The increasing popularity of local food consumption can be attributed to the heightened awareness of food safety concerns, carbon emissions produced from food transportation, and an understanding of how large corporations’ obtain their food supplies. Although there is increasing discussion on both the local and organic food movement independently, there is not a wide availability of literature examining the motivations and perceptions of consumers with regard to farmers’ markets. Issues such as perceptions about what type of food consumers are purchasing at markets, nor the main motivations for frequenting such establishments are discussed. Therefore the purpose of this study was to determine consumer motivations, benefits, and perceptions of farmers’ markets. Using the case study location of Toronto, Canada, this study surveyed 300 participants during the fall of 2011. Findings indicated that the main purpose for visiting famers’ markets is not solely to fulfill grocery needs. Quality of products offered and the ability to support the local community were the primary motivators to visit the markets.  相似文献   
193.
Regionally specific sustainability processes that account for diverse environments and populations and that integrate social, economic, political and ecological spheres are being developed in Western Australia. A coordinated commitment to sustainability principles and a participatory philosophy by the state and local governments is necessary. This requires a transformation of the public service, from a director of passive programmes and laws to a facilitator of community projects and outcomes, towards an enabling state. An international participatory paradigm provides an array of concepts and methods for local and regional communities in partnership with government and industry to achieve this. Participatory methodologies are utilised successfully around the globe to create an institutional framework that facilitates a process of dialogue, partnership, networking, learning and managing change. This paper examines the potential contribution of a participatory approach to improve the participatory capacity of regional communities and both local and state governments towards the facilitation of regional sustainability processes.  相似文献   
194.
US policies for securing the border with Mexico are driven by multiple political concerns, including the desire to control illegal trade and immigration in a way that conveys “border security” to a national audience. Highly visible border enforcement near urban centres and via the border fence has pushed migrants into far less visible and remote wilderness areas, driving both ecological degradation and a humanitarian crisis. This study employed ethnographic methods to explore how natural resource agency employees and humanitarian volunteers in Altar Valley Arizona perceived and responded to the production of border security. We found that both groups recognised human rights and environmental concerns, although they assigned different priorities and addressed them through conflicting means. As in other cases where consumers are separated from production practices, there was a general consensus among informants that it was important to raise the consciousness of the national audience about the negative externalities of producing border security.  相似文献   
195.
196.
Conservation biologists recognize that a system of isolated protected areas will be necessary but insufficient to meet biodiversity objectives. Current approaches to connecting core conservation areas through corridors consider optimal corridor placement based on a single optimization goal: commonly, maximizing the movement for a target species across a network of protected areas. We show that designing corridors for single species based on purely ecological criteria leads to extremely expensive linkages that are suboptimal for multispecies connectivity objectives. Similarly, acquiring the least‐expensive linkages leads to ecologically poor solutions. We developed algorithms for optimizing corridors for multispecies use given a specific budget. We applied our approach in western Montana to demonstrate how the solutions may be used to evaluate trade‐offs in connectivity for 2 species with different habitat requirements, different core areas, and different conservation values under different budgets. We evaluated corridors that were optimal for each species individually and for both species jointly. Incorporating a budget constraint and jointly optimizing for both species resulted in corridors that were close to the individual species movement‐potential optima but with substantial cost savings. Our approach produced corridors that were within 14% and 11% of the best possible corridor connectivity for grizzly bears (Ursus arctos) and wolverines (Gulo gulo), respectively, and saved 75% of the cost. Similarly, joint optimization under a combined budget resulted in improved connectivity for both species relative to splitting the budget in 2 to optimize for each species individually. Our results demonstrate economies of scale and complementarities conservation planners can achieve by optimizing corridor designs for financial costs and for multiple species connectivity jointly. We believe that our approach will facilitate corridor conservation by reducing acquisition costs and by allowing derived corridors to more closely reflect conservation priorities.  相似文献   
197.
Congress repealed OSHA's Ergonomics Program Standard. But ergonomics remains an important health and safety issue for businesses. Moreover, additional regulation in this area is likely to come in the future. © 2001 John Wiley & Sons, Inc.  相似文献   
198.
Regional Environmental Change - This article provides a review of recent scientific literature on social vulnerability to climate change, aiming to determine which social and demographic groups,...  相似文献   
199.
The dairy industry in the Texas High Plains has experienced rapid expansion in the past two decades. This study assesses the impact of the increased presence of dairies on overall water use, crop composition, and the local economy. The increase in water use related to the dairy industry from 2000 to 2015 was primarily due to an increase in demand for drinking by the cows (direct water) as well as an increased demand for silage (indirect water). However, a comparative analysis (dairy presence vs. no dairy presence) from a single year indicates minimal impacts on total water use due to dairies. During the same time period, the number, size, and employment of related local business establishments have increased economic activity in rural areas. Editor's note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.  相似文献   
200.
Predators are often confronted with a broad diversity of potential prey. They rely on cues associated with prey quality and palatability to optimize their hunting success and to avoid consuming toxic prey. Here, we investigate a predator’s ability to assess prey cues during capture, handling, and consumption when confronted with conflicting information about prey quality. We used advertisement calls of a preferred prey item (the túngara frog) to attract fringe-lipped bats, Trachops cirrhosus, then offered palatable, poisonous, and chemically manipulated anurans as prey. Advertisement calls elicited an attack response, but as bats approached, they used additional sensory cues in a sequential manner to update their information about prey size and palatability. While both palatable and poisonous small anurans were readily captured, large poisonous toads were approached but not contacted suggesting the use of echolocation for assessment of prey size at close range. Once prey was captured, bats used chemical cues to make final, post-capture decisions about whether to consume the prey. Bats dropped small, poisonous toads as well as palatable frogs coated in toad toxins either immediately or shortly after capture. Our study suggests that echolocation and chemical cues obtained at close range supplement information obtained from acoustic cues at long range. Updating information about prey quality minimizes the occurrence of costly errors and may be advantageous in tracking temporal and spatial fluctuations of prey and exploiting novel food sources. These findings emphasize the sequential, complex nature of prey assessment that may allow exploratory and flexible hunting behaviors.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号