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   70篇
  免费   0篇
  国内免费   1篇
安全科学   2篇
废物处理   1篇
环保管理   3篇
综合类   21篇
基础理论   13篇
污染及防治   23篇
评价与监测   6篇
社会与环境   2篇
  2022年   1篇
  2021年   5篇
  2019年   2篇
  2018年   1篇
  2017年   2篇
  2016年   3篇
  2015年   1篇
  2014年   3篇
  2013年   5篇
  2012年   3篇
  2011年   4篇
  2010年   3篇
  2009年   1篇
  2008年   4篇
  2007年   2篇
  2006年   2篇
  2005年   3篇
  2004年   1篇
  2003年   2篇
  2002年   1篇
  1996年   1篇
  1987年   1篇
  1985年   1篇
  1977年   1篇
  1975年   1篇
  1965年   2篇
  1963年   1篇
  1962年   2篇
  1961年   1篇
  1960年   1篇
  1959年   1篇
  1958年   3篇
  1957年   1篇
  1956年   2篇
  1955年   3篇
排序方式: 共有71条查询结果,搜索用时 15 毫秒
1.
Environmental Fluid Mechanics - In this study, we explore several integral and outer length scales of turbulence which can be formulated by using the dissipation of temperature fluctuations (...  相似文献   
2.
Objective: India has been slow in implementing a central emergency medical services (EMS) system across the country. “108 services” is one of the most popular services that is functional under the public–private partnership model. Limited available literature shows that despite access to services, many traffic crash victims are transported using private vehicles. The objective of this study is to understand the effectiveness of 108 services from a traffic safety perspective.

Method: A questionnaire survey is conducted to understand the awareness of EMS and their function. Using traffic-related fatalities as the dependent variable, a fixed effect panel data model is developed to analyze the effectiveness of the 108 services in improving the traffic safety.

Results: The results from the survey show that, in general, people are not aware of the 108 services. A majority of the population prefers taking victims to the hospital using their personal vehicles or any other vehicles available compared to calling an ambulance. Results from panel data analysis show that despite having an efficient system, these services failed to make significant improvement in the safety of road users in the states in which their services were subscribed.

Discussion: The lack of awareness of an important safety service is alarming. This could be a major reason for lower utilization of 108 services for transporting victims of traffic crashes. This article shows the importance of having efficient awareness campaigns to improve the efficiency of any similar programs that are aimed to enhance the safety of a region.  相似文献   

3.
Multi-route risk assessment from trihalomethanes in drinking water supplies   总被引:3,自引:0,他引:3  
The USA is entering an era of energy diversity, and increasing nuclear capacity and concerns focus on accidents, security, waste, and pollution. Physical buffers that separate outsiders from nuclear facilities often support important natural ecosystems but may contain contaminants. The US Nuclear Regulatory Commission (NRC) licenses nuclear reactors; the applicant provides environmental assessments that serve as the basis for Environmental Impact Statements developed by NRC. We provide a template for the types of information needed for safe siting of nuclear facilities with buffers in three categories: ecological, fate and transport, and human health information that can be used for risk evaluations. Each item on the lists is an indicator for evaluation, and individual indicators can be selected for specific region. Ecological information needs include biodiversity (species, populations, communities) and structure and functioning of ecosystems, habitats, and landscapes, in addition to common, abundant, and unique species and endangered and rare ones. The key variables of fate and transport are sources of release for radionuclides and other chemicals, nature of releases (atmospheric vapors, subsurface liquids), features, and properties of environmental media (wind speed, direction and atmospheric stability, hydraulic gradient, hydraulic conductivity, groundwater chemistry). Human health aspects include receptor populations (demography, density, dispersion, and distance), potential pathways (drinking water sources, gardening, fishing), and exposure opportunities (lifestyle activities). For each of the three types of information needs, we expect that only a few of the indicators will be applicable to a particular site and that stakeholders should agree on a site-specific suite.  相似文献   
4.
5.
6.
Analytical solutions, describing the time-dependent DNAPL source-zone mass and contaminant discharge rate, derived previously in Part I [Falta, R.W., Rao, P.S., Basu, N., this issue. Assessing the impacts of partial mass depletion in DNAPL source zones: I. Analytical modeling of source strength functions and plume response. J. Contam. Hydrol.] are used as a flux-boundary condition in a semi-analytical contaminant transport model. These analytical solutions assume a power relationship between the flow-averaged source concentration, and the source DNAPL mass; the empirical exponent (gamma) is a function of the flow field heterogeneity, DNAPL architecture, and the correlation between them. The DNAPL source strength terms can account for partial source remediation, either at time zero, or at some later time after the DNAPL release. The transport model considers advection, retardation, three-dimensional dispersion, and sequential first-order decay/production of several species. A separate solution is used to compute the time-dependent mass of each contaminant in the plume. A series of examples using different values of gamma shows how the benefits of partial DNAPL source remediation can vary with site conditions. In general, when gamma>1, relatively large short-term reductions in the plume concentrations and mass occur, but the source longevity is not strongly affected. Conversely, when gamma<1, the short-term reductions in the plume concentrations and mass are smaller, but the source longevity can be greatly reduced. In either case, the source remediation effort is much more effective if it is undertaken at an early time, before much contaminant mass has entered the plume. If the remediation effort is significantly delayed, the leading parts of the plume are not affected by the source remediation, and additional control or remediation of the plume itself is required.  相似文献   
7.
We measured the levels of ortho-substituted polychlorinated biphenyls (PCB), organochlorinated pesticides (OCP), and polybrominated diphenyl ethers (PBDE) in the cerebral cortex of river otters (Lontra canadensis) trapped from Ontario and Nova Scotia between 2002 and 2004. The mean concentration of total PCBs was 70.9+/-12.1 ng/g l.w., and congeners 153, 180 and 138 accounted for nearly 60% of the sum. The mean concentration of total OCPs was 21.2+/-3.7 ng/g l.w., and hexachlorobenzene (32.6% of total) and DDE (28.1%) accounted for the majority. The mean concentration of total PBDEs was 3.2+/-0.6 ng/g l.w., and congeners 99 (44.9%), 153 (30.5%), and 100 (24.7%) were measured at the indicated percentages. There was no relationship between these residue data and concentrations of brain mercury or neurochemical receptors and enzymes as determined in earlier studies on these same animals.  相似文献   
8.
Four simplified dense non-aqueous phase liquid (DNAPL) source depletion models recently introduced in the literature are evaluated for the prediction of long-term effects of source depletion under natural gradient flow. These models are simple in form (a power function equation is an example) but are shown here to serve as mathematical analogs to complex multiphase flow and transport simulators. The spill and subsequent dissolution of DNAPLs was simulated in domains having different hydrologic characteristics (variance of the log conductivity field=0.2, 1 and 3) using the multiphase flow and transport simulator UTCHEM. The dissolution profiles were fitted using four analytical models: the equilibrium streamtube model (ESM), the advection dispersion model (ADM), the power law model (PLM) and the Damkohler number model (DaM). All four models, though very different in their conceptualization, include two basic parameters that describe the mean DNAPL mass and the joint variability in the velocity and DNAPL distributions. The variability parameter was observed to be strongly correlated with the variance of the log conductivity field in the ESM and ADM but weakly correlated in the PLM and DaM. The DaM also includes a third parameter that describes the effect of rate-limited dissolution, but here this parameter was held constant as the numerical simulations were found to be insensitive to local-scale mass transfer. All four models were able to emulate the characteristics of the dissolution profiles generated from the complex numerical simulator, but the one-parameter PLM fits were the poorest, especially for the low heterogeneity case.  相似文献   
9.
10.
The Gangetic delta is a century-old cholera endemic belt where the role of riverine–estuarine ecosystem in cholera transmission has never been elucidated. Seasonality, distribution, and abundance of environmental Vibrio cholerae O1/O139 and vibriophage in Hooghly riverine–estuarine environment and their correlation with cholera incidence pattern in West Bengal, India, have been analyzed for the first time across summer, monsoon, and winter months. A total of 146 water samples collected from two sites of the Hooghly River (Howrah and Diamond Harbour) were analyzed physicochemically along with cultivable Vibrio count (CVC), V. cholerae O1/O139, and vibriophages. V. cholerae O1 was detected in 56 (38.3 %) samples, while 66 (45.2 %) were positive for V. cholerae O1 phages. Flood tide, water temperature (31?±?1.6 °C), and turbidity (≥250 nephelometric turbidity unit (NTU)) significantly stimulated V. cholerae and vibriophage abundance in riverine ecosystem. Solitary existence of V. cholerae O1 and phages (p?V. cholerae O1 or V. cholerae O1 Φ) on the other. Significant association (p?V. cholerae O1 in aquatic environment implies the role of riverine–estuarine ecosystem in cholera transmission. A “biomonitoring tool” of physicochemical stimulants, tidal, and climatic variants has been proposed collating V. cholerae and phage dynamics that can forewarn any impending cholera outbreak.  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