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   628篇
  免费   6篇
安全科学   29篇
废物处理   5篇
环保管理   177篇
综合类   89篇
基础理论   246篇
环境理论   5篇
污染及防治   27篇
评价与监测   13篇
社会与环境   23篇
灾害及防治   20篇
  2023年   4篇
  2022年   7篇
  2021年   12篇
  2020年   2篇
  2019年   17篇
  2018年   14篇
  2017年   18篇
  2016年   32篇
  2015年   18篇
  2014年   21篇
  2013年   31篇
  2012年   6篇
  2011年   23篇
  2010年   18篇
  2009年   64篇
  2008年   55篇
  2007年   51篇
  2006年   46篇
  2005年   22篇
  2004年   24篇
  2003年   12篇
  2002年   10篇
  2001年   9篇
  2000年   20篇
  1999年   13篇
  1998年   11篇
  1997年   8篇
  1996年   11篇
  1995年   10篇
  1994年   11篇
  1993年   7篇
  1992年   5篇
  1991年   3篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   4篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1980年   2篇
  1979年   1篇
  1977年   1篇
  1973年   1篇
排序方式: 共有634条查询结果,搜索用时 15 毫秒
391.
The occasion for this forum was sparked by a front-page story in the New York Times by John M. Broder entitled, “Seeking to Save the Planet, with a Thesaurus” (May 1, 2009, p. A11). The article focused on the non-profit EcoAmerica's report, “Climate and Energy Truths: Our Common Future,” which shares research on communication approaches to engaging climate change and energy issues. The Broder article included commentary from Robert J. Brulle, Professor of Sociology and Environmental Science at Drexel University. In response, George P. Lakoff, Professor of Cognitive Science and Linguistics at UC-Berkeley, published an essay in The Huffington Post, “Why Environmental Understanding, or ‘Framing,’ Matters: An Evaluation of the EcoAmerica Summary Report” (May 19, 2009). The discussion about this report and differing approaches to environmental communication continued on blogs, in emails, and through various other forums. The editorial leadership team of this journal thought such prominent attention to environmental communication in the nexus of so many disciplines and professional investments was exciting. We are pleased the following scholars and practitioners are willing to elaborate on the stakes of this discussion in this forum.  相似文献   
392.
Until recently, few studies have used social network theory (SNT) and metrics to examine how social network structure (SNS) might influence social behavior and social dynamics in non-human animals. Here, we present an overview of why and how the social network approach might be useful for behavioral ecology. We first note four important aspects of SNS that are commonly observed, but relatively rarely quantified: (1) that within a social group, differences among individuals in their social experiences and connections affect individual and group outcomes; (2) that indirect connections can be important (e.g., partners of your partners matter); (3) that individuals differ in their importance in the social network (some can be considered keystone individuals); and (4) that social network traits often carry over across contexts (e.g., SN position in male–male competition can influence later male mating success). We then discuss how these four points, and the social network approach in general, can yield new insights and questions for a broad range of issues in behavioral ecology including: mate choice, alternative mating tactics, male–male competition, cooperation, reciprocal altruism, eavesdropping, kin selection, dominance hierarchies, social learning, information flow, social foraging, and cooperative antipredator behavior. Finally, we suggest future directions including: (1) integrating behavioral syndromes and SNT; (2) comparing space use and SNS; (3) adaptive partner choice and SNS; (4) the dynamics and stability (or instability) of social networks, and (5) group selection shaping SNS. This contribution is part of the special issue “Social networks: new perspectives” (Guest Editors: J. Krause, D. Lusseau and R. James).  相似文献   
393.
In the face of fundamental land‐use changes, the potential for trophy hunting to contribute to conservation is increasingly recognized. Trophy hunting can, for example, provide economic incentives to protect wildlife populations and their habitat, but empirical studies on these relationships are few and tend to focus on the effects of benefit‐sharing schemes from an ex post perspective. We investigated the conditions under which trophy hunting could facilitate wildlife conservation in Ethiopia ex ante. We used a choice experiment approach to survey international trophy hunters’ (n = 224) preferences for trips to Ethiopia, here operationalized as trade‐offs between different attributes of a hunting package, as expressed through choices with an associated willingness to pay. Participants expressed strong preferences and, consequently, were willing to pay substantial premiums for hunting trips to areas with abundant nontarget wildlife where domestic livestock was absent and for arrangements that offered benefit sharing with local communities. For example, within the range of percentages considered in the survey, respondents were on average willing to pay an additional $3900 for every 10 percentage points of the revenue being given to local communities. By contrast, respondents were less supportive of hunting revenue being retained by governmental bodies: Willingness to pay decreased by $1900 for every 10 percentage points of the revenue given to government. Hunters’ preferences for such attributes of hunting trips differed depending on the degree to which they declared an interest in Ethiopian culture, nature conservation, or believed Ethiopia to be politically unstable. Overall, respondents thus expressly valued the outcomes of nature conservation activities—the presence of wildlife in hunting areas—and they were willing to pay for them. Our findings highlight the usefulness of insights from choice modeling for the design of wildlife management and conservation policies and suggest that trophy hunting in Ethiopia could generate substantially more financial support for conservation and be more in line with conservation objectives than is currently the case.  相似文献   
394.
Saltwater fishing tournaments in the United States are generally not regulated nor are there different fishing regulations for tournament and nontournament anglers. Although much is known about those who participate in fishing tournaments in terms of their fishing motivations, attitudes, and characteristics, much less is known at the angler population level regarding their preferences for tournament opportunities. Using a stated preference choice model with hypothetical scenarios to simulate participation choices and understand preferences, study objectives were to identify angler preferences for various types of tournament fishing “products.” Four tournament policy characteristics were investigated: promotion of catch and release, bait restrictions, whether a percentage of the tournament entrance fee should go to support fishery management activities, and whether a tournament should be a nonprofit or profit-making venture. Three expectation attributes were inserted: tournament size, trip cost per day, and whether a tournament is family friendly. We sent seven different versions of the mail questionnaire to 1,633 anglers. Of 795 returns, 648 were used for estimating conditional logit models. Analysis indicated that a scenario with no management interventions was not most preferred. Anglers most preferred a conservation-oriented option that introduced additional management measures. Overall, scenarios with management interventions were more favored than the status quo situation (with no management interventions). Although respondents showed reluctance to adopt other management-related options, results generally indicated they were increasingly concerned with sustainability of fish stocks and potential conflicts between tournament and nontournament users and preferred tournament products that reflect these concerns.  相似文献   
395.
The household-recycling rate in the Borough of Burnley, England in 2001/2002 was only half the national average of 12%. This research employed both quantitative and qualitative surveys in order to ascertain whether householders’ attitudes to recycling were contributory factors to the generally poor recycling performance and to investigate other social, cultural and structural influences. The Borough has a large Asian–British population concentrated in two deprived wards where recycling rates are particularly low, so special attention was given to ascertaining their attitudes towards recycling.The quantitative survey comprised a postal questionnaire sent to a random sample of 360 households drawn from the electoral register. The qualitative survey consisted of group interviews with the Asian–British population at local community centres and focus groups attended by volunteers from the quantitative study.The findings suggest that householders are very willing to participate in recycling, as shown by the almost 80% claiming to recycle paper, but that local recycling services are too unreliable and inconvenient to allow them to do so comprehensively. Asian–British attitudes to recycling were found to be no different to those of the wider population, with their low participation being linked to the higher priorities imposed upon them by economic deprivation. The findings are broadly in line with those of the literature in that recycling participation tends to be higher among more affluent and older people, but lower among less affluent and younger households, probably due in part to the availability of both storage space and time, with the implication that the Borough's preponderance of terraced housing militates against a high recycling rate. Policy recommendations to local authorities include the provision of bespoke recycling services to suit the variety of residential conditions across the UK, and the provision of regular feedback to householders regarding recycling services and performance.Further research is needed to identify non-recyclers and to explore how householders’ underlying psychological, cultural and social attitudes to recycling impinge upon recycling and participation rates.  相似文献   
396.
200 years of sustainability in forestry: Lessons from history   总被引:4,自引:0,他引:4  
Since the end of the 1980s the concept of sustainable development has gained general acceptance, but much uncertainty still exists on how to operationalize this concept. In forestry the concept of sustainability has been an accepted principle since the 18th century. The experiences with its application in forestry may contribute towards obtaining a better insight into the implications and operational significance of the concept of sustainability. This article describes the history of sustainability in forestry, including the various social values on which its interpretation has been based. The original principle of sustained yield has gradually been broadened to a more inclusive principle of sustainable forest management. The dynamics in social valuation of forest resources resulted in various attempts at practical operationalization of the principle. Notwithstanding 200 years of efforts to operationalize the concept of sustainability, its exact application in forestry remains troublesome. Three lessons are drawn: (1) the need to recognize the different nature of ecological limits and social dynamics, (2) the role of dynamic social values with respect to forest resources, and (3) the significance of operational experiences in trying to attain sustainability within a concrete context.  相似文献   
397.
China’s government is now promoting the Nomad Sedentarization Project (NSP) in large areas of grassland as a solution for ecological restoration and poverty alleviation. To examine the effects of this policy, we conducted in-depth interviews at two of the project’s sites and examined the social and ecological systems at village, county, and catchment scales in Jinghe County of Xinjiang. We found that (1) the NSP in one village greatly improved the household standard of living and changed their resource utilization modes; (2) the success in this village can be attributed to resources imported from the social and ecological systems at larger scales, and could not be repeated in a second nearby village with different constraints; and (3) the NSP is poorly adapted to local ecosystem characteristics, and may therefore have negative impacts at larger scales. To avoid these problems, holistic assessments are necessary to judge the NSP’s impacts on social and ecological systems at multiple scales, and the program must be implemented cautiously to account for the potential risks in ecologically vulnerable areas.  相似文献   
398.
We used interdemic variation in the tendency to form mixed-species groups to examine the costs and benefits of association among the primates of Kibale National Park, Uganda. A year-long survey of six sites revealed that the amount of time that the five common diurnal primates [red colobus (Procolobus tephrosceles), black-and-white colobus (Colobus guereza), redtail monkeys (Cercopithecus ascanius), blue monkeys (Cercopithecus mitis), and grey-cheeked mangabeys (Lophocebus albigena)] spent in mixed-species groups varied dramatically among sites. In many cases, the proportion of time that species associated was positively related to their densities. By using detailed behavioral observations of redtail monkeys and red colobus made over 4 years (2660 h) at four sites, we were able to reject the null hypothesis that associations occur by chance for only one of four sites. However, a correlative approach exploring the costs and benefits of association suggests that ecological variables do influence association patterns. We found that redtail monkeys and red colobus overlapped in diet (19.2% of their foraging effort) and traveled further when in mixed-species groups than when alone. Having demonstrated this, we examined the applicability of the ecological constraints model for predicting the proportion of the time spent in mixed-species groups based on food availability. For this analysis we concentrated on red colobus from the site with 35 months of observation and demonstrated that their tendency to be in mixed- species groups was related to food availability. We used two methods to examine if mixed-species associations function to decrease predation risk. First, chimpanzees are known to prey heavily on red colobus, but rarely kill other primates. The time red colobus spent in mixed-species groups was correlated to chimpanzee density, but it was not for the other monkey species, suggesting that mixed-species groups serve to decrease predation risk. Second, when red colobus groups contain more infants and are presumably at the greatest risk of predation, they form mixed-species groups most often. These results demonstrate that the costs and benefits of mixed-species associations vary dramatically over small spatial and temporal scales. If such variation is generally the case, then studies conducted at different locations or different times could easily highlight the importance of difference selective agents in favoring mixed-species associations. Received: 10 February 1999 / Received in revised form: 16 September 1999 / Accepted: 2 October 1999  相似文献   
399.
Real world observations suggest that social norms of cooperation can be effective in overcoming social dilemmas such as the joint management of a common pool resource—but also that they can be subject to slow erosion and sudden collapse. We show that these patterns of erosion and collapse emerge endogenously in a model of a closed community harvesting a renewable natural resource in which individual agents face the temptation to overexploit the resource, while a cooperative harvesting norm spreads through the community via interpersonal relations. We analyze under what circumstances small changes in key parameters (including the size of the community, and the rate of technological progress) trigger catastrophic transitions from relatively high levels of cooperation to widespread norm violation—causing the social–ecological system to collapse.  相似文献   
400.
The function of the conspicuous pre-roost gathering in communally roosting birds is poorly known. We studied movement and social cohesion of radio-tagged hooded crows (Corvus corone cornix) from their daytime location via pre-roost to roost in autumn and winter. With increasing snowfall the previous 24 h, the crows attended pre-roosts farther from the territory, and moved longer from pre-roost to roost. The crows became more likely to roost communally as distance to their territory increased. Attending a pre-roost on average almost doubled the travel distance to a communal roost. Crows were much more likely to join the same roost when they had attended the same pre-roost than otherwise. Breeding mates were more likely to keep together from pre-roost to roost than were other assigned pairs of a territorial male and female. For assigned pairs of non-mates, cohesion from pre-roost to roost decreased with increasing distance to roost, and was higher when both crows roosted communally compared to when at least one of them roosted in its territory. When both roosted communally, cohesion decreased with increasing snowfall and increasing number of crows attending the pre-roost, increased with increasing snow depth, and became higher among two females, compared to other combinations of two crows, with increasing number of crows attending the pre-roost. These patterns may be interpreted as supporting several of the current hypotheses on the function of pre-roost gathering. Electronic Publication  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