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   76篇
  免费   0篇
安全科学   11篇
废物处理   2篇
环保管理   23篇
综合类   11篇
基础理论   17篇
环境理论   1篇
污染及防治   7篇
评价与监测   2篇
社会与环境   2篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2019年   2篇
  2018年   1篇
  2017年   2篇
  2015年   6篇
  2014年   1篇
  2013年   3篇
  2012年   2篇
  2011年   5篇
  2010年   4篇
  2009年   3篇
  2008年   3篇
  2007年   5篇
  2006年   4篇
  2005年   3篇
  2004年   1篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1987年   1篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
排序方式: 共有76条查询结果,搜索用时 0 毫秒
61.
ABSTRACT: Few water budgets exist for specific types of wetlands such as peatlands, even though such information provides the basis from which to investigate linkages between wetlands and upland ecosystems. In this study, we first determined the water budget and then estimated nutrient loading from an upland farm field into a 1.5 ha, kettle-block peatland. The wetland contains highly anisotropic peat and has no distinct, active layer of groundwater flow. We estimated the depth of the active layer using Fick's law of diffusion and quantified groundwater flow using a chemical mass balance model. Evapotranspiration was determined using MORECS, a semi-physical model based on the Penman-Monteith approach. Precipitation and surface outflow were measured using physical means. Groundwater provided the major inflow, 84 percent (44,418 m3) in 1993 and 88 percent (68,311 m3) in 1994. Surface outflow represented 54 percent (28,763 m3) of total outflows in 1993 and 48 percent (37,078 m3) in 1994. A comparison of several published water budgets for wetlands and lakes showed that error estimates for hydrologic components in this study are well within the range of error estimates calculated in other studies. Groundwater inflow estimates and nutrient concentrations of three springs were used to estimate agricultural nutrient loading to the site. During the study period, nutrient loading into the peatland via groundwater discharge averaged 24.74 kg K ha-1, 1.83 kg total inorganic P had, and 21.81 kg NO3-N ha-1.  相似文献   
62.
The Journal of Safety Research has partnered with the Injury Center at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, USA, to briefly report on some of the latest findings in the research community. This report is the third in a series of CDC articles. Look for other such articles in future issue of the Journal of Safety Research.  相似文献   
63.

Problem

Falls are the leading cause of non-fatal injuries in the United States. This study assessed the prevalence of fall injuries associated with cats and dogs in the United States and describes the types of injuries sustained, the location, activity, and circumstances under which they occurred.

Methods

Data were from a nationally representative sample of emergency department visits from January 1, 2001 to December 31, 2006, available through the National Electronic Injury Surveillance System All Injury Program (NEISS-AIP).

Results

Based on 7,456 cases, an estimated 86,629 fall injuries each year were associated with cats and dogs, for an injury rate of 29.7. There were 7.5 times as many injuries involving dogs as cats and females were 2.1 times more likely to be injured than males. Injury rates were highest among people aged ≥ 75, but pets were a fall hazard for all ages. Fractures and contusions or abrasions were the most common injuries; the highest rates were for injuries to the extremities. About 66.4% of falls associated with cats and 31.3 % of falls associated with dogs were caused by falling or tripping over the pet. An additional 21.2% of falls related to dogs were caused by being pushed or pulled.

Summary

Although pets were associated with fall injuries, this risk can be reduced by increasing public awareness about situations that can lead to falls, such as dog-walking and chasing pets, and by calling attention to the importance of obedience training for dogs to minimize hazardous behaviors such as pulling and pushing.

Impact on industry

Fall injuries represent a burden to individuals, our society and our health care system. Increasing public awareness and implementing basic prevention strategies can help people of all ages enjoy their pets, reduce their chances of experiencing pet-related falls, and lessen the impact of fall injuries on our health care system.  相似文献   
64.

Problem

Information about where nonfatal unintentional injuries occur is limited, but bathrooms commonly are believed to be a hazardous location.

Methods

Data from a nationally representative sample of hospital emergency departments (ED) was used to quantify and characterize nonfatal unintentional bathroom injuries among people aged ≥ 15 years.

Results

In 2008, an estimated 234,094 nonfatal bathroom injuries were treated in EDs. Most injuries (81.1%) were caused by falls and 37.3% of injuries occurred when bathing, showering, or getting out of the tub or shower. Both injury and hospitalization rates increased with age.

Summary

These results suggest that bathrooms tend to be most hazardous for persons in the oldest age groups.

Impact on Industry

Bathroom injuries among all household members might be reduced by increasing awareness about potentially hazardous activities in the bathroom combined with simple environmental changes such as adding grab bars inside and outside the tub or shower.  相似文献   
65.
Understanding the dynamics of population recovery is particularly complex when an organism has multiple, remote breeding and feeding grounds separated by one of the longest known migration routes. This study reports on the most comprehensive assessment of humpback whale (Megaptera novaeangliae) movements between remote Antarctic waters south of New Zealand and east Australia (EA), and the migratory corridors and breeding grounds of Australia and Oceania. A total of 112 individual whales were identified; 57 from microsatellites and 61 by fluke with 23 % (n = 26) matched to sites outside Antarctica. Despite large datasets from other southern regions being included in the comparison, the whales were predominantly linked to EA (n = 24). Only two matches to the Oceania catalogues directly north was surprising; therefore the primary feeding grounds of these endangered whales still remain unknown. The confirmation of the Balleny Islands as an important feeding ground for EA whales could provide an insight into reasons behind the rapid recovery of this population. Determining the feeding grounds of Oceania’s whales may explain whether prey energetics or migration length are limiting factors to their recovery and will allow an understanding of future ecosystem changes in these whales.  相似文献   
66.
We report the prenatal diagnosis of trisomy 6 mosaicism via amniocentesis, in which trisomy 6 cells were identified in three of five culture vessels with 33% (5/15) of colonies showing trisomic cells. The pregnancy was electively terminated and examination revealed minor abnormalities (shortening of the femurs, micrognathia, posterior malrotation of the ears, and bilateral camptomelia of the second digit of the hands and fifth digits of the feet). Cytogenetic analysis of the placenta showed trisomy 6 in 100% of 20 cells studied. Karyotype was 46,XX in 100 cells examined from fetal skin. There are relatively few prenatally diagnosed cases of mosaic trisomy 6 at amniocentesis. Confined placental mosaicism (CPM) has been postulated in other cases where follow-up cytogenetic studies were not available. The present case differs from those previously reported, as it appears to represent CPM of chromosome 6 with phenotypic effects to the fetus. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
67.
68.
Soil properties are well known to affect vegetation, but the role of soil heterogeneity in the patterning of vegetation dynamics is poorly documented. We asked whether the location of an ecotone separating grass-dominated and sparsely vegetated areas reflected only historical variation in degradation or was related to variation in inherent soil properties. We then asked whether changes in the cover and spatial organization of vegetated and bare patches assessed using repeat aerial photography reflected self-organizing dynamics unrelated to soil variation or the stable patterning of soil variation. We found that the present-day ecotone was related to a shift from more weakly to more strongly developed soils. Parts of the ecotone were stable over a 60-year period, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (<40 m2) patches throughout the study area. The probability that patches were presently vegetated or bare, as well as the probability that vegetation persisted and/or established over the 60-year period, was negatively related to surface calcium carbonate and positively related to subsurface clay content. Thus, only a fraction of the landscape was susceptible to vegetation change, and the sparsely vegetated area probably featured a higher frequency of susceptible soil patches. Patch dynamics and self-organizing processes can be constrained by subtle (and often unrecognized) soil heterogeneity.  相似文献   
69.
Australia is experiencing mounting pressures related to processes of urbanisation, biodiversity loss and climate change felt at large in cities. At the same time, it is cities that can take the leading role in pioneering approaches and solutions to respond to those coupling emergencies. In this perspective piece we respond to the following question: What are the required transformations for prioritising, valuing, maintaining and embracing nature in cities in Australia? We adopt the mission framework as an organising framework to present proposed pathways to transform Australian cities as nature-positive places of the future. We propose three interconnected pathways as starting actions to steer urban planning, policy and governance in Australian cities: First, cities need to establish evidence-based planning for nature in cities and mainstream new planning tools that safeguard and foreground urban nature. Second, collaborative planning needs to become a standard practice in cities and inclusive governance for nature in cities needs to prioritise Aboriginal knowledge systems and practices as well as look beyond what local governments can do. Third, for progressing to nature-positive cities, it is paramount to empower communities to innovate with nature across Australian cities. Whilst we focus on Australian cities, the lessons and pathways are broadly applicably globally and can inspire science-policy debates for the post COP15 biodiversity and COP26 climate change implementation processes.  相似文献   
70.
A company highlighted in the last issue of Environmental Quality Management offers an update on its continuing environmental accomplishments. © 2000 John Wiley & Sons, Inc.  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