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   157篇
  免费   0篇
  国内免费   3篇
安全科学   8篇
废物处理   7篇
环保管理   33篇
综合类   24篇
基础理论   35篇
污染及防治   36篇
评价与监测   9篇
社会与环境   6篇
灾害及防治   2篇
  2022年   2篇
  2021年   1篇
  2020年   4篇
  2019年   3篇
  2018年   1篇
  2017年   5篇
  2016年   3篇
  2015年   3篇
  2014年   8篇
  2013年   14篇
  2012年   5篇
  2011年   11篇
  2010年   8篇
  2009年   9篇
  2008年   7篇
  2007年   17篇
  2006年   7篇
  2005年   4篇
  2004年   2篇
  2003年   1篇
  2002年   8篇
  2001年   3篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1981年   2篇
  1977年   1篇
  1968年   1篇
  1967年   1篇
  1962年   1篇
  1957年   1篇
  1955年   2篇
  1952年   1篇
排序方式: 共有160条查询结果,搜索用时 238 毫秒
1.
2.
3.
4.
Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Córdoba city, Argentina. The study area receives regional pollutants and was categorized taking into account traffic level, industrial density, type of industry, location of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur, soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins, pigments, HPCD, and MDA as they are responsible for the major variability of data.  相似文献   
5.
6.
Postpartum women ≧ 33 years were interviewed about their attitudes to and knowledge and use of prenatal diagnosis. Overall, 68 per cent had heard of prenatal diagnosis; nevertheless, only 30 per cent of those ≧ 35 had actually been tested. The only significant difference between eligible women who were tested and those who were not was maternal age. Of those tested, half requested it for themselves; conversely, only two-thirds of women requesting the procedure actually received it. Among women not tested, 82 per cent were never offered the procedure by the physician. Expressed attitudes to prenatal diagnosis were strongly positive among all women, with 75 per cent continuing to want testing after learning both their age-specific risk of having an affected child and the possible risks of amniocentesis. The data document a potential demand for amniocentesis far in excess of current use and present service facilities. They suggest, moreover, that underuse may reflect professional hesitation and underreferral more than consumer lack of demand or reluctance to be tested.  相似文献   
7.
Emission inventory is one of the required inputs to air quality models. To assist in the urban and regional modeling efforts, United States Environmental Protection Agency (EPA) has compiled a National Emission Inventory (NEI) for criterion pollutants, and the precursors of ozone and particulate matter (PM). In December 2002, EPA released the 1999 NEI estimates (NEI99), which represent the most recent national emission data. However, the data sets are not in model-ready format for air quality simulations. This present work converts the NEI99 Final Version 2 data sets into Inventory Data Analyzer (IDA) format and processes the data using the Sparse Matrix Operator Kernel Emissions (SMOKE) modeling system to generate a gridded emission inventory in a domain covering the west Gulf Coast Region, USA. The spatial and diurnal emission characteristics of the gridded emission inventories are then assessed and compared with those of the National Emission Trend 1996 (NET96). The NEI99 database contains more complete emission records in both area and point sources. It is also found that NEI99 data exhibit greater emissions with respect to point and mobile sources but smaller emissions with respect to area sources when compared to the corresponding gridded NET96 data in the same study domain. The most distinct differences between the NEI99 and NET96 databases are CO emission of mobile sources, SO2 emissions of point sources, and VOC/PM/NH3/NOx emissions of area and non-road sources. The gridded NEI99 data show low VOC/NOx ratios (<2-5) in the urban areas of the study domain.  相似文献   
8.
Costa Rica is internationally recognized for its abundant biodiversity and being a leader in the promotion of education strategies for biodiversity conservation. We interviewed staff from 16 institutions developing key environmental communication, education, and participation projects for biodiversity conservation in the country. Through content analysis, hierarchical cluster analysis and Chi-square tests, we examined the characteristics of the projects carried out by these institutions and developed a typology of four categories derived from six variables: primary audience, content, project purpose, location, scale, and facility. Then, we designed a conceptual model describing the integration of conservation and economic development in the educational projects. We found two key approaches related to this integration: vision of nature protection which aims to inform audiences of ecological concepts and focuses on schoolchildren and vision of sustainability which engages adult audiences and is management-oriented. Education for community-based environmental management may serve as a good example of educational projects which integrate conservation and economic development, implementing a vision of sustainability.  相似文献   
9.
Anticoagulants are biocides widely used as pest control agents in agriculture, urban infrastructures, and domestic applications for the control of rodents. Other anticoagulants such as warfarin and acenocoumarol are also used as drugs against thrombosis. After use, anticoagulants are discharged to sewage grids and enter wastewater treatment plants (WWTPs). Our hypothesis is that WWTP effluents can be a source of anticoagulants to receiving waters and that these can affect aquatic organisms and other nontarget species. Therefore, the objective of the present study was to determine the occurrence of 11 anticoagulants in WWTPs receiving urban and agricultural wastewaters. Warfarin was the most ubiquitous compound detected in influent waters and was partially eliminated during the activated sludge treatment, and low nanograms per liter concentration were found in the effluents. Other detected compounds were coumatetralyl, ferulenol, acenocoumarol, flocoumafen, brodifacoum, bromadiolone, and difenacoum at concentrations of 0.86–87.0 ng L?1. Considering water volumes of each WWTP, daily emissions were estimated to be 0.02 to 21.8 g day?1, and thus, WWTPs contribute to the loads of anticoagulants to receiving waters. However, low aquatic toxicity was observed using Daphnia magna as a model aquatic organism.  相似文献   
10.
Many professionals in the environmental industry have questioned whether the rapid expansion in shale gas development, particularly in the Marcellus Shale Play, is providing business opportunities. While gas production is a routine practice, the development of shale gas requires a process (fracturing, or, more commonly, “fracing'') that uses chemicals and is far more intrusive to the subsurface environment than traditional gas production. In this Editor's Perspective, we evaluate the environmental issues surrounding shale gas development, with a specific focus on the Marcellus Shale Play because it is currently the most active play in the United States, from both the drilling and political perspectives. In addition, we examine where the business opportunities are likely to be for environmental professionals relative to shale gas development. © 2011 Wiley Periodicals, 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