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   450篇
  免费   5篇
  国内免费   11篇
安全科学   26篇
废物处理   17篇
环保管理   95篇
综合类   51篇
基础理论   83篇
污染及防治   123篇
评价与监测   42篇
社会与环境   26篇
灾害及防治   3篇
  2023年   5篇
  2022年   12篇
  2021年   16篇
  2020年   4篇
  2018年   11篇
  2017年   9篇
  2016年   15篇
  2015年   12篇
  2014年   14篇
  2013年   48篇
  2012年   10篇
  2011年   24篇
  2010年   19篇
  2009年   16篇
  2008年   20篇
  2007年   22篇
  2006年   19篇
  2005年   11篇
  2004年   16篇
  2003年   17篇
  2002年   17篇
  2001年   7篇
  2000年   5篇
  1999年   4篇
  1998年   9篇
  1997年   10篇
  1996年   7篇
  1995年   3篇
  1993年   8篇
  1992年   6篇
  1991年   5篇
  1990年   4篇
  1989年   3篇
  1987年   3篇
  1986年   2篇
  1985年   5篇
  1984年   4篇
  1983年   2篇
  1982年   4篇
  1981年   2篇
  1979年   4篇
  1978年   2篇
  1975年   2篇
  1973年   2篇
  1964年   2篇
  1963年   2篇
  1958年   2篇
  1957年   2篇
  1956年   3篇
  1955年   3篇
排序方式: 共有466条查询结果,搜索用时 46 毫秒
351.
Rice farming sustainability assessment in Bangladesh   总被引:1,自引:0,他引:1  
Farming sustainability is primordial to long-term socioeconomic development. This study assesses rice farming sustainability in Bangladesh by developing a composite indicator (CI) under the four pillars of sustainability and examines the main determining factors. The assemblage of top-down and bottom-up approaches were applied to generate an essential set of indicators and data were collected through a household survey from 15 villages of three major rice growing ecosystems. The results revealed that less than half of the rice growers were sustainable in terms of economical viability, ecological benefits, and quality of life. By category, Boro rice farming was found to be the most sustainable, followed by Aman and Aus rice farming. Human capital development, increasing land productivity, use of resource conserving practices and technologies, and information availability and accessibility were the main factors promoting rice farming sustainability. The findings indicated that the construction of CI by employing several methodologies such as normalisation provide straightforward and clear-cut policy inputs. The major policy implications that emerged from the findings of the study are outlined to actualise rice farming sustainability, which contributes to sustainable development in Bangladesh.  相似文献   
352.
Abstract

Ceratophyllum demersum exposed to a constant 1 μg/rnl aminocarb exhibited a large capacity for the sorption of the pesticide, up to 400 μg/g fresh weight in the dark and 1000 μg/g fresh weight in the light. Smaller, actively growing sprigs sorbed 5 times more pesticide per gm fresh weight than larger, older sprigs, although total uptake per plant was greater in the larger plants. Membrane conformation and integrity appear to be important factors in determining the capacity of this aquatic plant for pesticide sorption.  相似文献   
353.
An instrumented single engine aircraft is being used to characterize plumes from large emission sources. By cross sectioning these plumes at a number of points we hope to describe the character and concentration of pollution as it ages and travels downwind under known meteorological conditions. This paper reports experimental work thus far completed on aerosol measurement. Flights have been made through plumes from a large coal-fired power station, forest fires, and a gravel plant. Particle counts in various size classifications were made with a Bausch and Lomb 40–1 Dust Counter which was carried in the aircraft. Selected meteorological parameters were recorded. Results show the aerosol concentrations in various size classifications that are found at successive distances downwind from these sources for distances up to 32 miles. Background aerosol concentrations are also reported, and variations in these can be noted with respect to time, location and altitude.  相似文献   
354.
Atmospheric sulfates are currently a topic of considerable interest. This arises primarily from their possible association with adverse health effects,1 and from their undoubted importance in the acid rain problem.2

Knowledge of the sulf ate species present in airborne particulates is essential to a full appreciation of the sources of aerosol sulfate constituents and to an understanding of respiratory health hazards. Charlson and coworkers3 have recently reviewed the current state of knowledge of the chemical nature of tropospheric Sulfur aerosols. It is clear from Charlson’s review that firm evidence exists for the presence of only a very few specific sulfate compounds in the atmosphere, and that much of our current thought is based upon inference and supposition.3  相似文献   
355.
The article reports on the first year of the Blackstone Project, a joint pilot project of the Massachusetts Department of Environmental Protection (DEP) and the Department of Environmental Management (DEM). The project is being used to test the best approach to promoting toxics use reduction (similar to ”source reduction“ as defined by EPA). In the project, the two state agencies are testing different methods of inspecting compliance across media (i.e. compliance to air, water, hazardous waste, and Right-to-Know requirements), biasing enforcement actions towards toxics use reduction, and coordinating regulatory activity with technical assistance activity. The Blackstone Project Team finds that the approach tested in the Blackstone Project was successful in its setting. A wide range of environmental protection objectives was cost effectively met through the Blackstone approach. In FY91, DEP will test the approach in the other DEP Regional Offices, with more facilities of a wider variety.  相似文献   
356.
We explore how the impact of seeking feedback from different sources (i.e., feedback source variety) on employee creativity is shaped by perceptions of the work environment. Specifically, we argue that two contextual factors, namely, performance dynamism (Study 1) and creative time pressure (Study 2), moderate the relationship between feedback source variety and creativity such that under conditions of high performance dynamism and low creative time pressure, individuals benefit from diverse feedback information. In Study 1 (N = 1,031), the results showed that under conditions of high performance dynamism, the relationship between feedback source variety and self‐reported creativity was nonlinear, with employee creativity exponentially increasing as a function of feedback source variety. Similarly, in Study 2 (N = 181), we found that under conditions of low creative time pressure, the relationship between feedback source variety and employee creativity was nonlinear, with supervisor‐rated creative performance exponentially increasing at higher levels of feedback source variety. Such results highlight that the relationship between feedback source variety and creative performance is affected by the perceptions of the work environment in which feedback is sought.  相似文献   
357.
The Marcellus Shale is one of the largest natural gas reserves in the United States; it has recently been the focus of intense drilling and leasing activity. This paper describes an air emissions inventory for the development, production, and processing of natural gas in the Marcellus Shale region for 2009 and 2020. It includes estimates of the emissions of oxides of nitrogen (NOx), volatile organic compounds (VOCs), and primary fine particulate matter (≤2.5 µm aerodynamic diameter; PM2.5) from major activities such as drilling, hydraulic fracturing, compressor stations, and completion venting. The inventory is constructed using a process-level approach; a Monte Carlo analysis is used to explicitly account for the uncertainty. Emissions were estimated for 2009 and projected to 2020, accounting for the effects of existing and potential additional regulations. In 2020, Marcellus activities are predicted to contribute 6–18% (95% confidence interval) of the NOx emissions in the Marcellus region, with an average contribution of 12% (129 tons/day). In 2020, the predicted contribution of Marcellus activities to the regional anthropogenic VOC emissions ranged between 7% and 28% (95% confidence interval), with an average contribution of 12% (100 tons/day). These estimates account for the implementation of recently promulgated regulations such as the Tier 4 off-road diesel engine regulation and the U.S. Environmental Protection Agency's (EPA) Oil and Gas Rule. These regulations significantly reduce the Marcellus VOC and NOx emissions, but there are significant opportunities for further reduction in these emissions using existing technologies.

Implications: The Marcellus Shale is one of the largest natural gas reserves in United States. The development and production of this gas may emit substantial amounts of oxides of nitrogen and volatile organic compounds. These emissions may have special significance because Marcellus development is occurring close to areas that have been designated nonattainment for the ozone standard. Control technologies exist to substantially reduce these impacts. PM2.5 emissions are predicted to be negligible in a regional context, but elemental carbon emissions from diesel powered equipment may be important.  相似文献   

358.
Sensory and certain microbial analyses were applied to assess the quality of raw fish sold at a market in Siliguri cityof West Bengal, India. In regular surveys undertaken during June to August 2008, a particular fish species was randomly selected, its source was noted and a sensory analysis, the quality index method (QIM) was applied to assess its quality Raw fish samples were also collected and a small quantity (about 1 g) of scales oran upper layer of the skin surface (forscale-less fish samples), gill, liverand a portion of gut with gut-contents were aseptically removed for enumeration of the total aerobic heterotrophic bacteria, Aeromonas spp., Pseudomonas spp., Salmonella spp. and coliform counts. Oreochromis mossambicus and Tenulosa ilisha recorded significantly higher QIM scores, compared to other species (p<0.05). Riverine fish, Lepidocephalichthys guntea and Channa punctatus scored the lowest QIM scores (0) while scores for Puntius ticto and Mystus vittatus and pond cultured species like Cirrhinus mrigala, Catla catla, Labeo rohita, Labeo bata and Cyprinus carpio were very marginal (p<0.05). Aeromonas spp., Salmonella spp. and total coliforms were recorded from all the studied species while Pseudomonas spp. was isolated from only seven species. Among the tissues examined, the lowest counts of total heterotrophic bacteria, Aeromonas spp., Pseudomonas spp., Salmonella spp. and total coliforms were recorded from the skin in every fish species. Highest counts of pathogenic bacteria (except Pseudomonas spp.) were recorded in Tenulosa ilisha for all the tissues except liver. Since fish are properly cooked in Bengali households, the risk of disease from fish consumption is relatively less. However, some tribes residing in the region are known to consume undercooked fish and proper cooking methods should be followed in view of the present findings to avoid health risks. Besides, utmost care should be taken while handling fish.  相似文献   
359.
Louisiana (LA) ranks fifth in the United States in cancer mortality rate. LA's infamous “cancer alley” is a well evidenced region near the southeast part of the Mississippi river surrounding the petrochemical hub of the state. LA has also experienced a high COVID-19 death rate and incidences compared to other states during the recent pandemic. In this study we analyzed publicly available datasets related to health and socio-economic parameters in LA to determine the factors triggering high incidences and deaths caused by COVID-19. Correlation analysis was performed to find the impact of different parameters on the outcome of COVID-19. Our analysis showed higher COVID-19 incidences in the parishes which are in and around the “cancer alley” with a correlation of r = 0.9. Interestingly, results also indicated a strong correlation (r = 0.9) between the death rates caused by asbestos toxicity to COVID-19 caused death rate. Furthermore, we found that office-administration related employment has a positive correlation to COVID-19 incidences in the “cancer alley.” However, we also found both white and black races are equally affected by the COVID-19 pandemic in the “cancer alley” region. In conclusion, our analysis strongly suggests that inhabiting “cancer alley” could significantly enhance the chances of getting affected by SARS-CoV-2 virus compared to other regions in LA.  相似文献   
360.
This article examines how small and medium enterprises (SMEs) can improve their capital investment decisionmaking process for both environmental and general capital projects. It proposes a framework that helps integrate environmental impacts into capital investment decisions, while recognizing SMEs' specific management practices, unique culture, and constraints. The framework presented here is also applicable to independent strategic business units of larger organizations where the capital investment decision process is decentralized. ©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