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   92篇
  免费   1篇
安全科学   3篇
废物处理   2篇
环保管理   32篇
综合类   22篇
基础理论   7篇
环境理论   1篇
污染及防治   13篇
评价与监测   9篇
社会与环境   3篇
灾害及防治   1篇
  2022年   3篇
  2019年   2篇
  2018年   3篇
  2017年   2篇
  2016年   5篇
  2015年   2篇
  2014年   4篇
  2013年   4篇
  2012年   5篇
  2011年   3篇
  2010年   6篇
  2009年   5篇
  2008年   3篇
  2007年   5篇
  2006年   3篇
  2005年   3篇
  2004年   4篇
  1998年   1篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1985年   3篇
  1984年   2篇
  1983年   5篇
  1982年   1篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1977年   2篇
  1967年   1篇
  1965年   2篇
  1964年   1篇
  1962年   2篇
  1936年   1篇
排序方式: 共有93条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
Many fields of study have employed geophysical islands in experimental design with a great deal of success. An island is a closed and bounded system in many respects and presents a manageable unit of study. The island microcosm has been the basis for significant advances in areas such as evolutionary biology, ecosystem ecology and physical anthropology. The same properties that make islands so useful to scientists present island populations with pressing sustainability challenges of limited resource availability and natural carrying capacity. This paper discusses the characteristics of the island context to show the severity and immediacy of these challenges. Based on this discussion, it is apparent that new approaches are needed to address sustainable development on islands. Island systems and the study of industrial ecology, which examines industry embedded within the finite natural environment, have much to gain from one another in this respect. Several industrial ecology case studies, primarily drawn from research in Puerto Rico, are presented to illustrate the compatibility of islands as a study unit in this field. Industrial ecology presents new solutions to the challenges of sustainable island development, while well‐defined island systems offer a unique opportunity for the approach of industrial ecology.  相似文献   
75.
The response of corticolous lichens, bryophytes, and vascular plants to anthropogenic edges in northern hardwood forest preserves is compared in east-coast and mid-west (NW Minnesota) sites, using micro-epiphytes on red oak (Quercus rubra) and sugar maple (Acer saccharum). The drastically attenuated lichen flora in the east, apparently due to regional air pollution, restricts the usefulness of these bioindicators, even 120 km from New York City. The forest edge is not necessarily equated with increased light. Established edges may have pronounced shoot growth that shades epiphytes. In the absence of air pollution, lichen and bryophyte species exhibit individual responses to light, humidity, and substrate chemistry. Thus summary variables such as total cover or species richness have limited value as bioindicators of forest integrity.  相似文献   
76.
In a recent article (Tilton et al., 2011), we argue that even when investor stocks are declining an increase in investor demand can cause a commodity's price to rise, a conclusion that is both contrary to conventional wisdom and counter-intuitive. In his comment on our article, Olle Östensson (2011) challenges this finding. After assessing his concerns in this reply, we maintain that our original finding is valid: investor demand can be driving commodity prices higher even when investor stocks are falling.  相似文献   
77.
Considering growing population and decreasing mineral resource reserves, the issue of undermining has been and shall remain very topical. This study aims to identify the mutual connections between mined out panels of a deposit and the final manifestations on the ground surface related to deep black coal mining. On the grounds of the identified connections, the study describes a method to simplify a common evaluation of undermined areas according to building site categories. Within the study, a demarcation of the areas was conducted in two localities in Czech Republic influenced by the effects of undermining in the Upper-Silesian Basin. In the allotment of the CSM Mine, an area unsuitable for founding structures was defined from the centre of the worked out workings to the distance of 175 m from the panel's edge, for which the corresponding break angle is 78.3°. Similarly, in the allotment of the Paskov Mine, an area unsuitable for founding structures was determined to the distance of 500 m from the panel's edge, for which the corresponding break angle is 50.2°. This demarcation may be implemented prior to deposit mining being aware of several physical-mechanical parameters of rocks in the deposit's overburden. Having mined out a particular section of a deposit, it is recommended to verify the values of break angle using the method described herein. The study may be applied as a relatively fast and effective method to evaluate future land use for planning.  相似文献   
78.
Atmospheric particulate matter (PM) is hypothesized to increase the risk of myocardial infarction (MI). However, the epidemiological evidence is inconsistent. We identified 33 studies with more than 4 million MI patients and applied meta-analysis and meta-regression to assess the available evidence. Twenty-five studies presented the effects of the PM level on hospitalization for MI patients, while eight studies showed the effects on mortality. An increase in PM10 was associated with hospitalization and mortality in myocardial infarction patients (RR per 10 μg/m3?=?1.011, 95 % CI 1.006–1.016; RR per 10 μg/m3?=?1.008, 95 % CI 1.004–1.012, respectively); PM2.5 also increased the risk of hospitalization and mortality in MI patients (RR per 10 μg/m3?=?1.024, 95 % CI 1.007–1.041 for hospitalization and RR per 10 μg/m3?=?1.012, 95 % CI 1.010–1.015 for mortality). The results of the cumulative meta-analysis indicated that PM10 and PM2.5 were associated with myocardial infarctionwith the addition of new studies each year. In conclusion, short-term exposure to high PM10 and PM2.5 levels revealed to increase risk of hospitalization and mortality for myocardial infarction. Policy support of pollution control and individual protection was strongly recommended.  相似文献   
79.
Underground mining activities may potentially play a role on the initiation and reactivation of the slope movements. However, an adequate attention has not yet been paid to these problems; in this study, the possible influence of present and former mining activities on the selected set of model slope deformations in the Ostrava-Karviná Coalfield (Opliji, Repiste and Orlova Lazy District) was analysed and a methodology for their observation for application to similar conditions and influence was described. Isocatabase maps, terrain deformation parameters calculated for the point lying on the slope deformation surface, length measurement by zone extensometer and dilatometer measurement in cracks was also provided for evaluation of the underground mining impact. It was found that inclinations of both boreholes were evidence of underground mining impact, and localization of inclinometer measurement on boreholes in the active part as well as in the near vicinity was very important as an important result of this study. Analysis of underground mining activity influence on model localities in relation to performed mining operations, subsidence and other influences on the ground surface was also determined. Thus, the study will contribute to a more objective knowledge of these problems of interest for the professional public and also for the state administration to solve problems associated with the utilisation and settlement of such affected areas.  相似文献   
80.
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