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   74篇
  免费   4篇
  国内免费   2篇
安全科学   7篇
废物处理   3篇
环保管理   8篇
综合类   7篇
基础理论   24篇
污染及防治   20篇
评价与监测   3篇
社会与环境   8篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   4篇
  2017年   4篇
  2016年   2篇
  2015年   6篇
  2014年   2篇
  2013年   2篇
  2012年   6篇
  2011年   1篇
  2010年   4篇
  2009年   4篇
  2008年   2篇
  2007年   4篇
  2006年   3篇
  2005年   4篇
  2004年   1篇
  2003年   2篇
  2002年   1篇
  2001年   4篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1989年   2篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1978年   1篇
排序方式: 共有80条查询结果,搜索用时 125 毫秒
41.
The North Water (NOW) polynya is one of the most productive marine areas of the Arctic and an important breeding area for millions of seabirds. There is, however, little information on the dynamics of the polynya or the bird populations over the long term. Here, we used sediment archives from a lake and peat deposits along the Greenland coast of the NOW polynya to track long-term patterns in the dynamics of the seabird populations. Radiocarbon dates show that the thick-billed murre (Uria lomvia) and the common eider (Somateria mollissima) have been present for at least 5500 cal. years. The first recorded arrival of the little auk (Alle alle) was around 4400 cal. years bp at Annikitsoq, with arrival at Qeqertaq (Salve Ø) colony dated to 3600 cal. years bp. Concentrations of cadmium and phosphorus (both abundant in little auk guano) in the lake and peat cores suggest that there was a period of large variation in bird numbers between 2500 and 1500 cal. years bp. The little auk arrival times show a strong accord with past periods of colder climate and with some aspects of human settlement in the area.  相似文献   
42.
This article addresses the role of Atlantic walrus (Odobenus rosmarus rosmarus) in present-day Avanersuaq from anthropological and biological perspectives, and asks whether or not sustainable resource utilisation is a useful concept in northwest Greenland. We describe the relations that unfold around walrus and walrus hunting, in the communities living adjacent to the North Water polynya on the eastern side of Smith Sound. We examine the interplay of walrus population abundance, hunting practices, uses, and formal (governmental) and informal (traditional) ways of regulating the hunt, and we analyse how walruses acquire multiple values as they circulate in different networks. Sustainable resource utilisation, we conclude, is a concept that is relevant in Avanersuaq and beyond, because it works as a biological standard, and hence organises laws, norms, and practices of formal management. Simultaneously, the term is problematic, because it ignores manifold levels of human and societal values connected to walrus.  相似文献   
43.
Current observed as well as projected changes in biodiversity are the result of multiple interacting factors, with land use and climate change often marked as most important drivers. We aimed to disentangle the separate impacts of these two for sets of vascular plant, bird, butterfly and dragonfly species listed as characteristic for European dry grasslands and wetlands, two habitats of high and threatened biodiversity. We combined articulations of the four frequently used SRES climate scenarios and associated land use change projections for 2030, and assessed their impact on population trends in species (i.e. whether they would probably be declining, stable or increasing). We used the BIOSCORE database tool, which allows assessment of the effects of a range of environmental pressures including climate change as well as land use change. We updated the species lists included in this tool for our two habitat types. We projected species change for two spatial scales: the EU27 covering most of Europe, and the more restricted biogeographic region of ‘Continental Europe’. Other environmental pressures modelled for the four scenarios than land use and climate change generally did not explain a significant part of the variance in species richness change. Changes in characteristic bird and dragonfly species were least pronounced. Land use change was the most important driver for vascular plants in both habitats and spatial scales, leading to a decline in 50–100% of the species included, whereas climate change was more important for wetland dragonflies and birds (40–50 %). Patterns of species decline were similar in continental Europe and the EU27 for wetlands but differed for dry grasslands, where a substantially lower proportion of butterflies and birds declined in continental Europe, and 50 % of bird species increased, probably linked to a projected increase in semi-natural vegetation. In line with the literature using climate envelope models, we found little divergence among the four scenarios. Our findings suggest targeted policies depending on habitat and species group. These are, for dry grasslands, to reduce land use change or its effects and to enhance connectivity, and for wetlands to mitigate climate change effects.  相似文献   
44.
Landscape fragmentation affects wildlife population viability, in part, through the effects it has on individual dispersal. In addition, some forms of human disturbance impinge on dispersal without physically fragmenting habitats. Here, we use the term "landscape resistance" to capture constraints to dispersal that cannot be linked directly to fragmentation. The extent to which landscape resistance can influence population persistence is not well understood. Agricultural development over the past 60?years has resulted in considerable habitat fragmentation in the Riding Mountain National Park (RMNP) region in southwestern Manitoba, Canada. We examined how park boundaries, roads outside park boundaries and negative human attitudes have altered dispersal success and population persistence. We examined whether stochastic disturbance, representing infectious disease epidemics, further reduced long-term population persistence for various scenarios. Finally, we assessed whether the simultaneous occurrence of the three features had additive effects. We simulated dispersal using HexSim, a spatially explicit individual-based population model, parameterised with data on wolves (Canis lupus) in the RMNP region. Simulations that separately accounted for negative human attitudes and roads outside the park boundaries exhibited lower mean population size than those that ignored these details. Increasing deflection from park boundaries did not appear to have significant impacts. Our results did not indicate the presence of additive effects, and scenarios incorporating all three features had similar results as that of roads. Stochastic disturbance further reduced mean population size. Our results do illustrate how less-visible human disturbances (i.e. those that do not clearly alter landscape characteristics) can significantly limit dispersal and population persistence.  相似文献   
45.
The radiation protection community has only recently started the important work of preparedness for long-term post-accidental management of radioactively contaminated areas, like for instance the EC projects STRATEGY, FARMING and EURANOS and the French authorities' CODIRPA and PAREX programmes. There are, however, different views concerning how long a long-term management might last. Based on the Norwegian and former Soviet Union experience after the Chernobyl accident, it is clear that a nuclear accident can entail decades of necessary management and rehabilitation of living conditions. The time period is dependent on a number of factors, e.g. amount of fallout, type of radionuclides, land use of contaminated area, number and density of people affected and available techniques and resources for implementing countermeasures. This paper discusses the management strategy implemented in Norway after the Chernobyl accident, the need for changing strategy over time and the important involvement of affected groups. Careful planning and reflections should be undertaken before actions are taken in the recovery phase, keeping in mind the possibility of decades with problems.  相似文献   
46.
PROBLEM: Fresh market berry production workers are exposed to physical risk factors for musculoskeletal injury. METHOD: We disseminated information through trade publications and other sources to berry managers in seven U.S. states about five prevention through design practices that were both safer and more profitable than traditional methods. We administered mail evaluation questionnaires prior to the intervention and after each of four intervention years to rolling, independent U.S. samples and to comparison New Zealand berry farm manager samples after years one through three. RESULTS: U.S. manager self-reports of reading trade publication information increased compared to baseline values for two of five practices and self-reported awareness increased for four of five practices. There were no increases in adoption. More U.S. than New Zealand managers reported getting information about two practices from trade publications and about four practices from public events. No U.S. versus New Zealand differences were observed in reported awareness or adoption for any practice. IMPACT ON INDUSTRY: This study showed that even a modest campaign can build awareness of safer practices fairly quickly in three to four years among small agricultural firms but that increasing adoption apparently requires more time. Widespread adoption of safer practices could help keep operators in business longer as they age by reducing the workload and musculoskeletal strain associated with labor intensive crop production for them and their workforce. Adoption of practices that also improve profits, like the five practices featured in this study, could also help managers stay in business.  相似文献   
47.
Drei neue Nickelenzyme aus anaeroben Bakterien   总被引:2,自引:0,他引:2  
Until recently nickel was not considered to be an element of biological importance. Nutritional studies have shown, however, that many eucaryotic and procaryotic organisms are dependent on the transition metal for growth. Four enzymes are presently known to contain nickel: urease from plants and from bacteria; methyl CoM reductase from methanogenic bacteria; all “uptake” hydrogenases investigated so far; and carbon monoxide dehydrogenase from anaerobic bacteria. The prosthetic group of the methyl CoM reductase has been identified as a nickel tetrapyrrole, the structure of which has been elucidated.  相似文献   
48.
Geographical Range Size and the Conservation of Mexican Mammals   总被引:2,自引:0,他引:2  
Range was estimated for the 423 noninsular mammals of Mexico to identify those species with more restricted distributions and to detect priority areas for conservation based on the presence of such species. Thirty-eight percent of nonvolant mammals and 15.4% of bats are restricted in Mexico to areas of less than 114,000 km2. Restricted species were defined as those occurring in ranges smaller than the median for bats and for nonvolant species. Following this criterion, most nonvolant species with restricted distribution in Mexico are either endemic to the country or are shared with the United States, whereas endemic chiropteran species are few, and most Mexican bats with restricted distribution also occur in South America. Nonvolant mammals with restricted distribution in Mexico tend to be of small body size, herbivore or granivore, and fossorial or semifossorial. Among bats, gleaners are significantly more restricted than aerial insectivores. Species with restricted distribution are inadequately represented in the current official list of endangered species, particularly in the case of nonvolant mammals. Similarly, some areas of Mexico that harbor several species with restricted distribution are not represented in the Mexican system of protected areas. Therefore, rarity, in this case measured by the area of distribution, should be included as an additional criterion for conservation of the Mexican mammal fauna.  相似文献   
49.
The paper presents a methodology that guided several ethnoentomological research projects and goes on to examine and compare the results from two independent research locations in Asia. The first location is in the Philippines, a Green Revolution area that has been heavily impacted by extension messages and insecticide use. The second location is in Nepal which has a traditional subsistence orientation and has remained widely unaffected by agricultural modernization. The paper emphasizes the differences and similarities of the results from the two sites and discusses the role of the methodology and methods used in capturing ethnoentomological knowledge, particularly with regard to insect pests in rice. The results of both investigations share the importance of agronomic criteria among farmers in insect classification and sorting criteria, thus highlighting the relevance of functional criteria. Farmers at both research sites have difficulties in identifying the lifecycles of insects. We discuss the issues of tradition and change in farmer entomological knowledge and providing support to the knowledge base of farmers though programs like IPM-Farmer Field Schools as opposed to broad-based recommendations for crop pest management.Article type: MS-ENVI-SI ETHNOSCI MS04 Contribution to Environment, Development & Sustainability, special issue ‘Bridging the gap between natural resources and their human management for the future using ethnoscience’.  相似文献   
50.
If resource consumption is to be reduced through economic “de-growth”, individuals in industrialized countries may have to accept a reduction in their consumption levels. In democratic societies, implementing this process requires the consent of a majority of the population. However, as long as people have high reference levels of consumption, lower consumption will induce feelings of loss, and hence evoke resistance. This paper summarizes recent experimental evidence on some of the factors that determine the utility costs involved in decreasing consumption. The results suggest that the acceptance of economic de-growth would be facilitated if people's material aspirations were moderated, and the extent to which material achievements are emphasized in our daily environment were reduced.An analysis of the financial and economic crisis that developed during 2008 suggests that it will not contribute to either of these points. Rather, by increasing the public's focus on the economic sphere even beyond pre-crisis levels, it may lead to a further decrease in the acceptance of de-growth policies in the population.  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