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   201篇
  免费   39篇
  国内免费   2篇
安全科学   2篇
环保管理   53篇
综合类   7篇
基础理论   160篇
污染及防治   8篇
评价与监测   5篇
社会与环境   7篇
  2023年   11篇
  2022年   13篇
  2021年   14篇
  2020年   19篇
  2019年   10篇
  2018年   12篇
  2017年   12篇
  2016年   19篇
  2015年   9篇
  2014年   13篇
  2013年   13篇
  2012年   7篇
  2011年   6篇
  2010年   6篇
  2009年   6篇
  2008年   6篇
  2007年   5篇
  2006年   12篇
  2005年   11篇
  2004年   2篇
  2003年   6篇
  2002年   2篇
  2001年   2篇
  2000年   5篇
  1999年   3篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1971年   1篇
排序方式: 共有242条查询结果,搜索用时 15 毫秒
91.
We introduced a multilevel model of value shift to describe the changing social context of wildlife conservation. Our model depicts how cultural-level processes driven by modernization (e.g., increased wealth, education, and urbanization) affect changes in individual-level cognition that prompt a shift from domination to mutualism wildlife values. Domination values promote beliefs that wildlife should be used primarily to benefit humans, whereas mutualism values adopt a view that wildlife are part of one's social network and worthy of care and compassion. Such shifts create emergent effects (e.g., new interest groups) and challenges to wildlife management organizations (e.g., increased conflict) and dramatically alter the sociopolitical context of conservation decisions. Although this model is likely applicable to many modernized countries, we tested it with data from a 2017–2018 nationwide survey (mail and email panel) of 43,949 residents in the United States. We conducted hierarchical linear modeling and correlational analysis to examine relationships. Modernization variables had strong state-level effects on domination and mutualism. Higher levels of education, income, and urbanization were associated with higher percentages of mutualists and lower percentages of traditionalists, who have strong domination values. Values affected attitudes toward wildlife management challenges; for example, states with higher proportions of mutualists were less supportive of lethal control of wolves (Canis lupus) and had lower percentages of active hunters, who represent the traditional clientele of state wildlife agencies in the United States. We contend that agencies will need to embrace new strategies to engage and represent a growing segment of the public with mutualism values. Our model merits testing for application in other countries.  相似文献   
92.
Abstract:  The European wild rabbit ( Oryctolagus cuniculus ) is a staple prey species in Mediterranean ecosystems. The arrival and subsequent spread of rabbit hemorrhagic disease throughout southwestern Europe, however, has caused a decline in rabbit numbers, leading to considerable efforts to enhance wild rabbit populations, especially through habitat management. Because rabbit population dynamics depend on habitat suitability and changes in habitat structure and composition subsequent to habitat management, I evaluated the effects of population dynamics on the long-term impact of rabbit hemorrhagic disease on rabbit populations. I used an age-structured model with varying degrees of population productivity and turnover and different habitat carrying capacities, and I assumed the existence of a unique, highly pathogenic virus. My results suggest that disease impact may be highly dependent on habitat carrying capacity and rabbit population dynamics, and the model provided some insight into the current abundance of wild rabbits in different locations in southwestern Europe. The highest disease impact was estimated for populations located in habitats with low to medium carrying capacity. In contrast, disease impact was lower in high-density populations in habitats with high carrying capacity, corresponding to a lower mean age of rabbit infection and a resulting lower mortality from rabbit hemorrhagic disease. The outcomes of the model suggest that management strategies to help rabbit populations recover should be based on improving habitats to their maximum carrying capacity and increasing rabbit population productivity. In contrast, the use of strategies based on temporary increases in rabbit density, including vaccination campaigns, translocations, and temporal habitat improvements at medium carrying capacities, may increase disease impact, resulting in short-term decreases in rabbit population density.  相似文献   
93.
Donor countriesare providing financial and technicalsupport for global climate change countrystudies to help African nations meet theirreporting needs under the United NationsFramework Convention on Climate Change(UNFCCC). Technical assistance to completevulnerability and adaptation assessmentsincludes training of analysts, sharing ofcontemporary tools (e.g. simulationmodels), data and assessment techniques,information-sharing workshops and aninternational exchange programme foranalysts. This chapter summarizes 14African country studies (Botswana, Côted'Ivoire, Egypt, Ethiopia, the Gambia,Kenya, Malawi, Mauritius, Nigeria, SouthAfrica, Tanzania, Uganda, Zambia andZimbabwe) assessing vulnerabilities toglobal climate change and identifyingadaptation options. The analysis revealedthat the participating African countriesare vulnerable to global climate change inmore than one of the followingsocio-economic sectors: coastal resources,agriculture, grasslands and livestock,water resources, forests, wildlife, andhuman health. This vulnerability isexacerbated by widespread poverty,recurrent droughts, inequitable landdistribution, environmental degradation,natural resource mismanagement anddependence on rain-fed agriculture. Arange of practical adaptation options wereidentified in key socio-economic sectors ofthe African nations analysed. However,underdeveloped human and institutionalcapacity, as well as the absence ofadequate infrastructure, renders manytraditional coping strategies (rooted inpolitical and economic stability)ineffective or insufficient. FutureAfrican country studies should be moreclosely coordinated with development ofnational climate change action plans  相似文献   
94.
Mass media worldwide has contributed to increasing awareness of the illegal wildlife trade and its significant impact on wildlife conservation. We used mass media coverage as a proxy for macro-level public opinion to analyze the media framing of elephant ivory in 6394 Chinese newspaper articles published from 2000 to 2021 and thus determine the effects of wildlife policies on public opinion. We focused on 2 events: the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) approval of China as a trading partner in the purchase and import of ivory stockpiles from Africa in July 2008 and the Chinese government's announcement of a domestic ivory ban in December 2016. Using latent Dirichlet allocation topic modeling, we identified 8 topics about elephant ivory and grouped them into 3 frames: ivory arts and culture, ivory crimes, and elephant conservation. Over the last 2 decades, topics related to ivory crimes remained the most prevalent in news articles. Topics about ivory arts and culture showed a significant shift in media salience before and after the 2 events (from 0.44 to 0.19 and from 0.08 to 0.15, respectively, p < 0.05), whereas the other 2 frames did not change significantly. Contrary to popular belief, our results indicated that Chinese macro-level public opinion on ivory had become more negative following the CITES approval of ivory importation and less negative after the ivory ban announcement, at least for certain periods. The relationship between mass media, public opinion, and wildlife trade policies is complex and requires further examination of the sociopolitical dynamics that influence media narratives. Our results showed the value of topic modeling in monitoring and assessing media representations of wildlife issues in the era of big data. Conservationists should remain vigilant of mass media coverage and collaborate with media practitioners to produce comprehensive narratives on wildlife issues if resources permit.  相似文献   
95.
当前野生食用菌资源经营权转让已成为促进集体经济增长和资源持续利用的主要措施,但在这种有偿转让的情况下,最关键和最基本的问题是协调好转让过程中涉及的关键利益相关者。通过对云南省小哨村的8个村小组进行实地调研,从转让模式、过程和模式的选择,关键利益相关者及其收益分配与利用,以及农户参与机制几个方面进行了深入分析,并就如何促进大部分农户参与并从中获益,以及保障关键利益相关者的利益提出了优化措施。  相似文献   
96.
Illegal hunting of African elephants (Loxodonta africana) for ivory is causing rapid declines in their populations. Since 2007, illegal ivory trade has more than doubled. African elephants are facing the most serious conservation crisis since 1989, when international trade was banned. One solution proposed is establishment of a controlled legal trade in ivory. High prices for ivory mean that the incentives to obtain large quantities are high, but the quantity of tusks available for trade are biologically constrained. Within that context, effective management of a legal ivory trade would require robust systems to be in place to ensure that ivory from illegally killed elephants cannot be laundered into a legal market. At present, that is not feasible due to corruption among government officials charged with implementing wildlife‐related legislation. With organized criminal enterprises involved along the whole commodity chain, corruption enables the laundering of illegal ivory into legal or potentially legal markets. Poachers and traffickers can rapidly pay their way out of trouble, so the financial incentives to break the law heavily outweigh those of abiding by it. Maintaining reliable permitting systems and leak‐proof chains of custody in this context is challenging, and effective management breaks down. Once illegal ivory has entered the legal trade, it is difficult or impossible for enforcement officers to know what is legal and illegal. Addressing corruption throughout a trade network that permeates countries across the globe will take decades, if it can ever be achieved. That will be too late for wild African elephants at current rates of loss. If we are to conserve remaining wild populations, we must close all markets because, under current levels of corruption, they cannot be controlled in a way that does not provide opportunities for illegal ivory being laundered into legal markets. Comercio Legal de Marfil en un Mundo Corrupto y su Imapacto sobre Poblaciones de Elefantes  相似文献   
97.
Hibernating bats have undergone severe recent declines across the eastern United States, but the cause of these regional‐scale declines has not been systematically evaluated. We assessed the influence of white‐nose syndrome (an emerging bat disease caused by the fungus Pseudogymnoascus destructans, formerly Geomyces destructans) on large‐scale, long‐term population patterns in the little brown myotis (Myotis lucifugus), the northern myotis (Myotis septentrionalis), and the tricolored bat (Perimyotis subflavus). We modeled population trajectories for each species on the basis of an extensive data set of winter hibernacula counts of more than 1 million individual bats from a 4‐state region over 13 years and with data on locations of hibernacula and first detections of white‐nose syndrome at each hibernaculum. We used generalized additive mixed models to determine population change relative to expectations, that is, how population trajectories differed with a colony's infection status, how trajectories differed with distance from the point of introduction of white‐nose syndrome, and whether declines were concordant with first local observation of the disease. Population trajectories in all species met at least one of the 3 expectations, but none met all 3. Our results suggest, therefore, that white‐nose syndrome has affected regional populations differently than was previously understood and has not been the sole cause of declines. Specifically, our results suggest that in some areas and species, threats other than white‐nose syndrome are also contributing to population declines, declines linked to white‐nose syndrome have spread across large geographic areas with unexpected speed, and the disease or other threats led to declines in bat populations for years prior to disease detection. Effective conservation will require further research to mitigate impacts of white‐nose syndrome, renewed attention to other threats to bats, and improved surveillance efforts to ensure early detection of white‐nose syndrome.  相似文献   
98.
East European food self-provisioning (FSP) has fascinated scholars of post-socialism ever since the early 1990s. In keeping with its predominantly economic and cultural conceptualisations, much of this research has been concerned with FSP’s role in household economy and with the social profile of its practitioners. In contrast to western conceptualisations of FSP as an opportunity to expand food activism and foster social justice and environmental sustainability, post-socialist FSP has rarely been considered as such. In Czechia, FSP is practised by 43% of citizens and many of them do so in a relatively environmentally friendly way. Yet, most food-related campaigns run by environmental NGOs (ENGOs) pay little attention to FSP and focus on market-based ethical consumerism and alternative food networks instead. Using insights from actor-network theory, this paper discusses how Czech ENGO activists engage with FSP through discourse and in practice. Based on ethnographic fieldwork and interviews with leading activists, we show that FSP does figure in non-food-related campaigns and that the FSP practised by activists themselves or the FSP carried out by relatives and relatives’ friends are not the same as the FSP on which they are reluctant to campaign. These differences, which include controllability and the time-consuming nature of practising FSP according to some of the activists’ ideals, help this paper to come to an initial understanding of why Czech ENGOs do not run campaigns explicitly focused on FSP at the moment and shed some light on how this could change in the future.  相似文献   
99.
ABSTRACT: Today most rivers are not freely flowing but are highly regulated to meet both human and wildlife needs. Several models allow the determination of instream flows that are needed to meet wildlife demands. However, these models are based on assumptions that limit their applicability to certain types of rivers. While these limitations do not preclude the use of the models on other types of rivers, like the Platte River in Nebraska, their limitations should be considered and accommodated by those making instream flow planning and management decisions. Other factors affecting channel morphology and its associated wildlife habitat, such as threshold values and vegetation are not adequately considered by current concepts. If rivers are to be managed to provide wildlife habitat, these factors will have to be addressed.  相似文献   
100.
Stakeholder engagement processes have sought to ensure that state government meets public trust and good governance obligations to citizens. As the expectations of stakeholders and state agencies change, and management focuses on landscape-level interventions, a change in the level at which agencies engage the public is needed. This involves tradeoffs, as different levels call for different engagement design and implementation considerations. To understand how these differences affect decision making, we examine a regional engagement model for deer management in New York that was piloted to replace a sub-regional model. We identify concerns with the old model, objectives for the redesigned model, and explain the logistical and good governance considerations that informed its design. We share our evaluation of the model's process and outcomes, including implications for program design and scale. Overall, despite the pilot model's attention to design components aimed at addressing potential barriers to regional engagement as well as limitations of the previous engagement model, the pilot did not meet many of its objectives, especially those related to representation, resulting in some of the same concerns associated with the model it was intended to enhance and replace. Implications of this for regional-level engagement efforts are discussed.  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