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   454篇
  免费   32篇
  国内免费   94篇
安全科学   8篇
废物处理   4篇
环保管理   89篇
综合类   243篇
基础理论   68篇
污染及防治   27篇
评价与监测   30篇
社会与环境   88篇
灾害及防治   23篇
  2024年   3篇
  2023年   7篇
  2022年   15篇
  2021年   22篇
  2020年   19篇
  2019年   17篇
  2018年   10篇
  2017年   17篇
  2016年   24篇
  2015年   21篇
  2014年   14篇
  2013年   43篇
  2012年   35篇
  2011年   34篇
  2010年   23篇
  2009年   27篇
  2008年   23篇
  2007年   39篇
  2006年   27篇
  2005年   27篇
  2004年   16篇
  2003年   18篇
  2002年   14篇
  2001年   14篇
  2000年   7篇
  1999年   14篇
  1998年   9篇
  1997年   8篇
  1996年   3篇
  1994年   6篇
  1993年   4篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1987年   2篇
  1985年   2篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有580条查询结果,搜索用时 46 毫秒
241.
The purpose of this study was to establish the relation between resiliency and the level of positive changes, comprising posttraumatic growth in a group of firefighters experiencing job-related traumatic events and the mediating role of stress appraisal in this relation. The study was performed on a group of 100 firefighters from firefighting and rescue brigades, out of which 75 admitted to experiencing a traumatic event. Firefighters covered by the study were on average 31.51 years old (SD?=?6.34). A Polish version of Posttraumatic Growth Inventory, the Resiliency Assessment Scale and Stress Appraisal Questionnaire were used in the study. The results have shown that 22.7% of firefighters displayed low, 58.6% average and 18.7% high intensity of positive changes resulting from a traumatic event. Resiliency poorly correlates with posttraumatic growth expressed in changes in self-perception, and strongly correlates with stress appraisal, negatively correlates with threat and harm/loss and positively correlates with challenge. Appraisal of stress as a threat and challenge appeared to be mediators of the relationship between resiliency and posttraumatic growth.  相似文献   
242.
以松花江流域省界缓冲区典型监测断面数据(2007-2014年)为基础,利用内梅罗污染指数法对流域水质情况进行综合评价,结合年变异系数和相关系数探究水质年际、年内变化趋势.根据监测断面数量和Ⅲ类及以上水比例变化情况分析省界缓冲区水质状况.根据水质特点确定主要超标项目,结合单因子评价法分析主要监测断面的水质类型、年际变化情况,并对监测指标相关性和超标率进行分析.根据上述分析结果,提出针对松花江省界缓冲区的监管对策及建议.  相似文献   
243.
244.
C. Niessen  K. Eyferth 《Safety Science》2001,37(2-3):187-202
This paper reviews the development of a model of the air traffic controller's mental image, ‘picture’, or situation awareness, used for controlling air traffic. The computerised model's development, origins and theoretical basis are outlined, and the model is described in some detail in the context of current air traffic operations. The model can be utilised to explore the potential impacts of future automation on the cognitive performance of the air traffic controller. The general potential contributions of the area of cognitive modelling to system design and training in accelerating industries such as air traffic control, are also discussed.  相似文献   
245.
246.
Fuelwood is one of the major sources of energy in the domestic sector across the rural areas, especially in the developing regions across the world. The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area. The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region, thus indicating the livelihood conditions. Since land-use land-cover change is the key driver to the change in resource availability of a region, the present study has tried to analyze the land-cover changes over a period 28 years. The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics, which directly affect the resource production. Based on the existing consumption pattern, the total consumption of fuelwood in the watershed ranges from a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year. Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system.  相似文献   
247.
Abstract

This paper takes poverty-stricken county as the basic unit, and selects net income per peasant to study the poverty status in Hebei Province during 1986–2000. Temporal and spatial changes of poverty-stricken areas are analyzed. The result shows that poverty-stricken areas in Hebei Province distributed concentratedly and the areas decreased during 1986–2000, the net income per peasant was on the rise with an increasing speed in off-poverty counties being slightly higher than that in poverty-stricken counties, but the growth rate was extremely unstable, rising slowly in off-poverty counties while dropping in poverty-stricken counties. The main driving forces that influenced temporal and spatial changes were economic development of the whole province, ecological environment quality, infrastructure conditions and radiation of the key city. On this basis, some anti-poverty countermeasures suitable to local conditions are proposed.  相似文献   
248.
This paper tries to identify the characters that might affect interprovincial migrants’ decisions and examine how and why the influence of these characters changed over time individually and synthetically in China during 1985–2005. We have investigated six types of factors, namely, distance, population density, income, employment structure, house price, and migration stock. In addition, we apply the identified factors with a multiple stepwise regression model to a longitudinal dataset, which consists of interprovincial migration flows over the last two decades in China. It is found that different factors have disparate impacts on migration in China, and they can be decomposed into push force in origin area and pull force in destination area. Factors shaping China’s interprovincial migration have shifted from traditional factors such as distance to economic factors such as income and employment structure. This paper suggests that more attention should be paid to obtain detailed migration data with spatial information and develop applicable models for migration processes. Our analysis provides references for development planners and policymakers to develop sound population policies to achieve regional sustainable development in China.  相似文献   
249.
综合应用型人才培养是当前经济社会发展人才需求的迫切需要.安全工程是一门综合性很强的学科,基础理论和实践环节两者缺一不可,是输送综合应用型人才的重要学科之一.实验教学是安全工程学科教育培养体系中的重要组成部分,是工程人才技能培养的基础.实验教学改革研究对激发学生的探索能力、实践能力和主观能动性意义重大.笔者综述了我国安全工程实验教学现状及存在的问题;分析了面向培养综合应用型工程人才的积极意义;介绍了福州大学安全工程实验教学改革的四“转变”模式,为我国安全工程实验教学改革指出了方向.从以往几届毕业生反馈得知,很好地提高了学生的综合素质和动手能力.  相似文献   
250.
Boomer, Kathleen M.B., Donald E. Weller, Thomas E. Jordan, Lewis Linker, Zhi‐Jun Liu, James Reilly, Gary Shenk, and Alexey A. Voinov, 2012. Using Multiple Watershed Models to Predict Water, Nitrogen, and Phosphorus Discharges to the Patuxent Estuary. Journal of the American Water Resources Association (JAWRA) 1‐25. DOI: 10.1111/j.1752‐1688.2012.00689.x Abstract: We analyzed an ensemble of watershed models that predict flow, nitrogen, and phosphorus discharges. The models differed in scope and complexity and used different input data, but all had been applied to evaluate human impacts on discharges to the Patuxent River or to the Chesapeake Bay. We compared predictions to observations of average annual, annual time series, and monthly discharge leaving three basins. No model consistently matched observed discharges better than the others, and predictions differed as much as 150% for every basin. Models that agreed best with the observations in one basin often were among the worst models for another material or basin. Combining model predictions into a model average improved overall reliability in matching observations, and the range of predictions helped describe uncertainty. The model average was not the closest to the observed discharge for every material, basin, and time frame, but the model average had the highest Nash–Sutcliffe performance across all combinations. Consistently poor performance in predicting phosphorus loads suggests that none of the models capture major controls. Differences among model predictions came from differences in model structures, input data, and the time period considered, and also to errors in the observed discharge. Ensemble watershed modeling helped identify research needs and quantify the uncertainties that should be considered when using the models in management decisions.  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