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   300篇
  免费   8篇
  国内免费   21篇
安全科学   7篇
环保管理   110篇
综合类   73篇
基础理论   52篇
环境理论   1篇
污染及防治   29篇
评价与监测   20篇
社会与环境   20篇
灾害及防治   17篇
  2023年   3篇
  2022年   8篇
  2021年   6篇
  2020年   7篇
  2019年   4篇
  2018年   19篇
  2017年   5篇
  2016年   14篇
  2015年   14篇
  2014年   6篇
  2013年   23篇
  2012年   8篇
  2011年   27篇
  2010年   11篇
  2009年   32篇
  2008年   18篇
  2007年   20篇
  2006年   15篇
  2005年   4篇
  2004年   9篇
  2003年   10篇
  2002年   6篇
  2001年   6篇
  2000年   8篇
  1999年   6篇
  1998年   3篇
  1997年   2篇
  1996年   4篇
  1995年   3篇
  1994年   4篇
  1992年   2篇
  1991年   2篇
  1990年   4篇
  1989年   2篇
  1987年   3篇
  1985年   2篇
  1984年   4篇
  1983年   1篇
  1982年   2篇
  1979年   1篇
  1977年   1篇
排序方式: 共有329条查询结果,搜索用时 31 毫秒
321.
ABSTRACT

Central Appalachia's historical dependence on natural resource extraction industries has contributed to a long history of under- and uneven development, including trends of persistent poverty, cycles of unemployment, weakened local governance, environmental degradation, and severe social inequalities relative to the rest of the nation. Though these trends have been well documented at structural and community-levels, scholarship is more limited in assessing how the conditions of natural resource dependency may shape the everyday experiences of those who live in such regions and how those everyday experiences may illuminate challenges for future development. Employing an embedded case study design, this study examines how everyday environmental injustices may be experienced via community gardening activities, a sustainable development-oriented activity celebrated in urban locations but largely unexplored in rural environments. Drawing upon in-depth interviews with 43 gardening programme coordinators and participants, the findings demonstrate that everyday environmental injustices are experienced across four distinct, yet overlapping and mutually reinforcing, dimensions: natural, built, human health, and socioeconomic environments. These factors in turn constrain programme participation and beneficial programme outcomes, particularly for more disadvantaged households that are affected by chronic illness, geographic isolation, and environmental hazards. Although the interviewees viewed many of these challenges as further justification for pursuing grassroots initiatives like community gardening programmes, these constraints also interacted in a way that limited the success of these locally-oriented sustainable development efforts, particularly for individuals who are the most socially, economically, and environmentally marginalised.  相似文献   
322.
An effective response to global environmental challenges requires analysis of communication patterns, processes and approaches. In addition, improving communication through emerging information and communication technologies (ICT) also must be explored. Understanding recipients’ perception of the innovations used in information diffusion is also necessary. This study, using a sample of 120 subjects, examined attitudes of leaders of community-based natural resources organizations toward two approaches used in public instructional communication in the Okavango Delta, Botswana. The quasi-experimental study also explored the effect of demographic variables on subjects’ attitudes. The results demonstrated more favorable attitudes toward the visualized method than the traditional verbal method, suggesting subjects’ preference and acceptance for the visualized public instructional communication approaches. Results also indicated a differential effect of age on attitude toward methods of communication. The results of the study highlight the importance for practitioners to use integrated communication approaches in the public sphere. Suggestions for future research are offered.  相似文献   
323.
Impacts of atrazine in aquatic ecosystems   总被引:26,自引:0,他引:26  
A portion of all herbicides applied to forests, croplands, road sides, and gardens are inevitably lost to water bodies either directly through runoff or indirectly by leaching through groundwater into ephemeral streams and lakes. Once in the aquatic environment, herbicides may cause stress within aquatic communities and radically alter community structure. Atrazine is one of the most effective and inexpensive herbicides in the world and is consequently used more frequently than any other herbicide. Atrazine is frequently detected in aquatic waters, and has been known to affect reproduction of aquatic flora and fauna, which in turn impacts on the community structure as a whole. This paper presents a summary of the reported direct and indirect impacts of atrazine on aquatic organisms and community structure. The information can be used for developing improved management guidelines and legislation. It is concluded that a single universal maximum limit on the atrazine application in catchments, as suggested by many regulatory authorities, does not provide adequate protection of the aquatic environment. Rather, it is advocated that flexible limits on the application of atrazine be developed in line with the potential risk of contamination to surface and subsurface water and fragility of the aquatic environment.  相似文献   
324.
Resource consumption in developing countries has been the focus of a considerable amount of research. What has been understudied however, has been the feedback affects of resource consumption on resource availability to both households and communities. Heavy reliance on natural resources and intensive smallholder agriculture common to many rural communities in developing countries has forced people to fulfill short-term needs to the detriment of long-term ecological and livelihood sustainability. This paper introduces a conceptual framework to examine how individuals and households fulfill daily caloric needs and the aggregate effects on resource availability and consumption. Data were collected from a large number of published case studies of rural land-use dynamics, growth and yield models, and human livelihoods were reviewed from scientific journals, reports published by NGOs, and government reports. Using inputs defined by the user, the model tracks annual fuelwood and agricultural land use based on meeting individual energy demands. A case-study-based analysis was patterned after smallholder agriculturalists at the family and community level. Three scenarios are presented in this paper using data from Uganda to illustrate the application of this model.  相似文献   
325.
农药污染对土壤动物群落影响的实验研究   总被引:28,自引:0,他引:28  
通过敌敌畏农药污染的模拟实验,研究了农药污染对土壤动物的影响。结果表明:随着敌敌畏农药处理浓度的提高,土壤动物种类数从低浓度(0.04mL/L)的53属(科)减少至高浓度(10mL/L)的26属(科);个体数则从低浓度占全捕量的14.1%减少到高浓度仅占全捕量的2%;而随处理时间的延长,对土壤动物的影响不太明显;大型土壤动物蚯蚓的染毒实验表明:蚯蚓可作为农药污染的重要指示动物。   相似文献   
326.
连云港市泥砂质潮间带大型底栖动物群落调查   总被引:1,自引:0,他引:1       下载免费PDF全文
于2013年9月对连云港市某泥砂质潮间带3个站位的大型底栖动物进行调查,结果表明,有大型底栖动物57种,其中多毛类23种,甲壳类18种,软体动物10种,其他类群6种。该潮间带大型底栖动物的总平均丰度为2 119.1 m-2,总平均生物量为66.34 g/m2,其中光滑狭口螺(Stenothyra glabar)在高潮带的丰度高达3 082.7 m-2,整个潮间带丰度呈现由高潮带向低潮带逐渐降低的趋势。潮间带Shannon-Wiener多样性指数平均值3.26;整个调查潮间带的沉积物环境较清洁。  相似文献   
327.
于2021年5月对淮安境内淮河主要干支流8个点位的水质状况和着生藻类群落结构采样调查,应用3种多样性指数模型评价区域水生态健康状况,并探究影响着生藻类多样性的因素。结果表明:采样期间淮河流域淮安市域共检出着生藻类3门23科32属(种),由硅藻门、蓝藻门和绿藻门组成,硅藻门占绝对优势;多样性指数计算结果显示,流域水生态状况良好,整体表现为清洁-轻污型水体,淮河上游水质稍差于其他水域;结合水质监测数据与卫星遥感影像分析,认为生境状况是影响着生藻类群落分布的主要因素。  相似文献   
328.
以南京市环境监测中心站的实践为例,初步探讨了地市级环境监测站转型发展的优势和困难、总体思路和分步措施。针对转型中存在的人力不足、人才培养滞后、制度和机制与发展需求不匹配等问题,引入社会检测力量,释放人力,促进人员初步转型,并建立组织管理体系、资金管理体系和质控管理体系,试行人员持证上岗制,为顺利转型提供保障。提出强化人才转型、对外的质控与监管、对内的精细化管理、监测成果的挖掘分析,以及对区县站的扶持,进一步深化转型发展。  相似文献   
329.
● Riverine microbiomes exhibited hyperlocal variation within a single transect. ● Certain family-level taxa directionally associated with river center and bank. ● Taxon accumulation curves within a transect urges more nuanced sampling design. Microbial communities inhabiting river ecosystems play crucial roles in global biogeochemical cycling and pollution attenuation. Spatial variations in local microbial assemblages are important for detailed understanding of community assembly and developing robust biodiversity sampling strategies. Here, we intensely analyzed twenty water samples collected from a one-meter spaced transect from the near-shore to the near-center in the Meramec River in eastern Missouri, USA and examined the microbial community composition with 16S rRNA gene amplicon sequencing. Riverine microbiomes across the transect exhibited extremely high similarity, with Pearson’s correlation coefficients above 0.9 for all pairwise community composition comparisons. However, despite the high similarity, PERMANOVA revealed significant spatial differences between near-shore and near-center communities (p = 0.001). Sloan’s neutral model simulations revealed that within-transect community composition variation was largely explained by demographic stochasticity (R2 = 0.89). Despite being primarily explained by neutral processes, LefSe analyses also revealed taxa from ten families of which relative abundances differed directionally from the bank to the river center, indicating an additional role of environmental filtering. Notably, the local variations within a river transect can have profound impacts on the documentation of alpha diversity. Taxon-accumulation curves indicated that even twenty samples did not fully saturate the sampling effort at the genus level, yet four, six and seven samples were able to capture 80% of the phylum-level, family-level, and genus-level diversity, respectively. This study for the first time reveals hyperlocal variations in riverine microbiomes and their assembly mechanisms, demanding attention to more robust sampling strategies for documenting microbial diversity in riverine systems.  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