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   180篇
  免费   1篇
  国内免费   13篇
安全科学   10篇
废物处理   23篇
环保管理   18篇
综合类   18篇
基础理论   35篇
污染及防治   48篇
评价与监测   29篇
社会与环境   12篇
灾害及防治   1篇
  2023年   3篇
  2022年   21篇
  2021年   15篇
  2020年   6篇
  2019年   9篇
  2018年   15篇
  2017年   9篇
  2016年   9篇
  2015年   7篇
  2014年   5篇
  2013年   26篇
  2012年   16篇
  2011年   12篇
  2010年   8篇
  2009年   4篇
  2008年   3篇
  2007年   5篇
  2005年   5篇
  2003年   2篇
  2000年   1篇
  1999年   1篇
  1997年   3篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1965年   1篇
排序方式: 共有194条查询结果,搜索用时 15 毫秒
41.
Overcrowding that happens in places like concerts, stadiums or pilgrimage locations might sometimes cause injury or loss of life. Maintaining the safety of crowd in these places is therefore very important. In addition, increasing the performance of the buildings and structures has always been an important concern. Most of the previous work focused on using new devices and methods for monitoring and management of the crowd but they rarely focus on a comprehensive and structured approach with the purpose of increasing efficiency and safety. In this paper, we explore a Russian “Theory of Inventive Problem Solving”, TRIZ, to see whether its principles can help us to solve or improve overcrowding issues. More specifically we find the contradictions that arise in the context of crowd management and we observe which of the categorical solutions suggested by TRIZ might possibly be useful for our problem. Increasing the crowd capacity in a relatively small area, which leads to overcrowding, is one of the common contradictions in crowd management. TRIZ has been suggested as a good method for solving problems which involve contradiction and thus, chosen for this purpose.  相似文献   
42.
Planetary Stewardship in an Urbanizing World: Beyond City Limits   总被引:1,自引:0,他引:1  
Cities are rapidly increasing in importance as a major factor shaping the Earth system, and therefore, must take corresponding responsibility. With currently over half the world’s population, cities are supported by resources originating from primarily rural regions often located around the world far distant from the urban loci of use. The sustainability of a city can no longer be considered in isolation from the sustainability of human and natural resources it uses from proximal or distant regions, or the combined resource use and impacts of cities globally. The world’s multiple and complex environmental and social challenges require interconnected solutions and coordinated governance approaches to planetary stewardship. We suggest that a key component of planetary stewardship is a global system of cities that develop sustainable processes and policies in concert with its non-urban areas. The potential for cities to cooperate as a system and with rural connectivity could increase their capacity to effect change and foster stewardship at the planetary scale and also increase their resource security.  相似文献   
43.
Nanoscale silica is an important industrial material and extensively used in medicines. The objective of this study was to determine potential cytotoxicity and genotoxic effects attributed to nanosilica exposure in mouse embryonic fibroblasts (L929) cells. Nanosilica produced mild cytotoxicity in L929 cells. Results showed that nanosilica increased thiobarbituric acid reactive substance levels and enhanced superoxide dismutase activity but decreased levels of glutathione. This was accompanied by a concomitant generation of reactive oxygen species, loss of mitochondrial membrane potential, and activation of caspase-3 activity. In addition, in the single-cell gel test, nanosilica (50–300 μg/ml) at two treatment times 24 and 48 hr produced concentration- and time-dependent increase of DNA damage. Therefore, the obtained results indicate that nanosilica may induce genotoxic effects in cultured L929 cells associated with induction of oxidative stress.  相似文献   
44.
ABSTRACT: Due to the spread of Islam in the seventh century the number of pilgrims to the City of Makkah increased sharply, resulting in an acute water shortage. To solve this problem, galleries were built to collect water from the upstream of Wadi Naaman and transfer it to Makkah. Expansion of Makkah and the absence of any mapping of the galleries have resulted in the destruction of a part of the galleries. This caused a discontinuity of flow in the galleries and, consequently, the ground water table is rising at a rate of 0.48 m/yr, causing environmental problems. Research was conducted to rehabilitate the destructed part of the galleries, and to find an appropriate use for the ground water. The study found that the quality of the ground water is suitable for landscaping purposes, that is, for the irrigation of trees and ornamental plants.  相似文献   
45.
In assessing and deciding the prediction schemes of solar irradiation countrywide, better the accuracy means better the management of energy transition toward renewables. Consequently, the present study is on the development of new models to make the most accurate possible estimations of the global and diffuse solar irradiation based on ground measurements. Such analysis produces the most accurate estimations for the input of solar energy systems. This is utmost significant for deciding the investments on solar energy systems and their design periods. Turkey is a high-potent country whose solar energy market has been growing rapidly. She doesn’t have adequate reliable measurement network and there is no estimation methodology developed for each and every point within its territory. Moreover, installing such a measurement system network doesn’t seem to be economically feasible and technically possible, inter alia. Accordingly, this study defines a methodology to make the most accurate estimations of monthly mean daily solar irradiation on horizontal surface and its diffuse and beam components. For the global and diffuse estimations, new methodologies in linear and quadratic forms are developed, compared, and discussed. The comparison is applied by using mean bias error and root mean square error statistical comparison methods. The measured data values used for modeling and comparisons are provided from the State Meteorological Service of Turkey responsible authority for solar irradiation measurements. The results revealed that the methodologies explained in this study give very high accurate values of total solar irradiation on a horizontal surface and its diffuse component.  相似文献   
46.
47.
Journal of Polymers and the Environment - The aim of this study was to investigate the effect of polar and aprotic solvents when used as solvents separately on the antimicrobial activity of nascent...  相似文献   
48.
Environmental Science and Pollution Research - This study estimated unbalanced panel data analysis to investigate the relationship among CO2 emissions, GDP, renewable and non-renewable energy...  相似文献   
49.
The leaves of Robinia pseudo-acacia L. (Fabaceae) were evaluated as a biomonitors of heavy metal contamination in Denizli city, Turkey. Concentrations of Fe, Zn, Pb, Cu, Mn and Cd were determined in washed and unwashed leaves and soils collected from a wide range of sites with different degrees of metal pollution (industry, urban roadside, suburban) and from a rural (control) site by atomic absorption spectrometry. All the elements that measured were found to be at high levels in samples collected at industrial sites, except for lead and copper which were found at high levels in samples collected from urban roadsides that associated with the road traffic. The strong correlation between the degree of contamination and concentrations in all plant leaves assessed display that the leaves of R. pseudo-acacia reflect the environmental changes accurately, and that they seem as an effective biomonitor of environmental quality in areas subjected to industrial and traffic pollutions.  相似文献   
50.
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