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   1929篇
  免费   226篇
  国内免费   130篇
安全科学   283篇
废物处理   16篇
环保管理   425篇
综合类   732篇
基础理论   196篇
污染及防治   87篇
评价与监测   379篇
社会与环境   93篇
灾害及防治   74篇
  2024年   3篇
  2023年   32篇
  2022年   66篇
  2021年   86篇
  2020年   80篇
  2019年   65篇
  2018年   47篇
  2017年   89篇
  2016年   113篇
  2015年   68篇
  2014年   95篇
  2013年   110篇
  2012年   111篇
  2011年   144篇
  2010年   85篇
  2009年   115篇
  2008年   89篇
  2007年   143篇
  2006年   99篇
  2005年   70篇
  2004年   64篇
  2003年   69篇
  2002年   51篇
  2001年   58篇
  2000年   53篇
  1999年   34篇
  1998年   37篇
  1997年   31篇
  1996年   26篇
  1995年   14篇
  1994年   18篇
  1993年   18篇
  1992年   14篇
  1991年   9篇
  1990年   8篇
  1989年   6篇
  1988年   7篇
  1987年   6篇
  1986年   5篇
  1985年   6篇
  1984年   2篇
  1983年   2篇
  1981年   5篇
  1980年   7篇
  1979年   2篇
  1978年   4篇
  1977年   4篇
  1974年   2篇
  1973年   6篇
  1971年   3篇
排序方式: 共有2285条查询结果,搜索用时 15 毫秒
991.
高危作业预警计算机系统设计   总被引:6,自引:2,他引:4  
为了利用计算机技术对高危作业有害因素的预防控制水平进行动态评估和预警,在对现有的安全预警系统进行分析总结的基础上,根据高危作业的特点,给出了高危作业预警系统的设计方案.  相似文献   
992.
The 26 December 2004 tsunamis around the Indian Ocean exposed the vulnerability of many coastal communities, including those serving tourists. To draw conclusions regarding disaster risk reduction for tourism in coastal areas, this study surveyed international tourists who survived the tsunami regarding their perceptions and experiences of the disaster. Semi-structured interviews were completed between January and June 2005 of 55 primary interviewees who were international tourists in locations affected by the tsunami. The qualitative data from the interviews yielded commonalities across four main themes with relevance to disaster risk reduction: information and awareness, warning systems, personal preparation, and livelihoods. Three areas are suggested as topics to highlight for further investigation: the connections between sustainable tourism and disaster vulnerability, the role of tourists in disasters, and disaster risk reduction education.  相似文献   
993.
由于跨界和跨部门等原因导致的流域水环境数据信息标准不一,无法有效共享、综合利用等问题,是目前水环境信息使用过程中的主要问题之一.基于信息资源规划理论,充分调研水环境监测管理、政府规划与决策、科学技术研究和社会公众使用等对水环境监测信息的需求,以太湖流域为例,分析与水环境相关各种数据资源,研究流域水环境信息的数据体系及数据库体系,设计并建立流域水环境数据中心,初步完成太湖流域水环境数据的管理、分析及共享服务平台设计,为流域水环境监测信息综合管理做出了示范.  相似文献   
994.
Abstract

Monitoring observations made on 60 operators involved in pesticide application work in godowns and warehouses and 60 matched control workers are reported. Occupational exposure history and medical history are noted. Biochemical investigations, plasma and RBC cholinesterase estimations are included along with medical examination of the workers. Workers were found to be mostly exposed to Celphos, DDVP, Malathion, Pyrethrum, etc, and the use of protective devices were very limited. Cases of significant reduction in plasma and RBC cholinesterase activity were found. Frequency of symptoms like dizziness, headache, lachrymation, burning sensation in eyes, nausea and anorexia, etc, were much more in the exposed workers. No cases of clinical poisoning attributable to occupational exposure to pesticides were reported by the workers.  相似文献   
995.
ITS数据质量控制技术及应用研究   总被引:8,自引:1,他引:7  
通过总结智能交通系统 (ITS)数据质量控制中所涉及的数据属性 ,提出了ITS数据质量控制算法 :根据阈值理论和交通流理论 ,针对错误数据、丢失数据和不精确数据设计相应的判别规则 ,利用数值计算方法对其进行修正 ,并提出了针对数据中的不规则时间点的修正算法。在对北京市和美国圣安东尼奥市的两组不同时间序列的ITS数据进行实践应用后 ,比较质量控制前后的数据特征 ,证明所提出的算法能够有效地解决数据质量问题 ,提高数据的精确度。最后 ,对国内外ITS数据进行质量控制后的结论和经验作了总结。  相似文献   
996.
介绍了目前对环境监测异常数据研究状况,简述了环境监测异常数据的辨识方法,分析了环境监测异常数据产生的原因,提出在建设项目环保验收监测过程中异常数据的处理,以及防止产生异常数据的措施.  相似文献   
997.
简述目前环境监测发展的基本形势,回顾了江苏省环境监测发展历程,分析目前江苏省环境监测面临的挑战和压力,提出了江苏环境监测战略目标和战略重点,并对江苏环境监测发展采取的战略措施提出了建议。  相似文献   
998.
In this paper, we construct a model in which the impact of pollution on health is exerted through both direct and indirect channels. The indirect channel is captured by a production function in which the principal health-improving factor, income growth, can be realized only in the cost of pollution increase. This model is then tested by the aggregated chronicle disease data in over 78 Chinese counties. Our results show, after attaining the threshold of 8 μ g/m^2, continuous increase in industrial SO2 emission density will lead the ratio of population suffering chronicle diseases, among which respiratory diseases occupy a significant proportion, to rise. However, owing to technological progress in pollution control activities, the needed SO2 emission to produce one unit of GDP diminishes with time. Therefore, the negative effect from pollution augmentation on public health seems to be recompensed more and more by the positive effect of economic growth.  相似文献   
999.

Introduction

In this paper, we show that FARS data can be a comparable alternative to observational NOPUS data in estimating seat belt use in the United States once we correct for sample selection bias.

Results

Based on assumptions of independence for seatbelt choice, we establish a lower and upper bound for seatbelt usage rates, and find that once we correct for sample selection bias, the seatbelt usage estimates from the corrected FARS emerge at least as a comparable alternative to NOPUS estimates.

Impact on Industry

This implies that researchers can use corrected FARS to complement NOPUS, thus being able to utilize the rich cross-sectional details available in FARS data to analyze various relevant research questions.  相似文献   
1000.
This paper analyses the cut flower market as an example of an invasion pathway along which species of non-indigenous plant pests can travel to reach new areas. The paper examines the probability of pest detection by assessing information on pest detection and detection effort associated with the import of cut flowers. We test the link between the probability of plant pest arrivals, as a precursor to potential invasion, and volume of traded flowers using count data regression models. The analysis is applied to the UK import of specific genera of cut flowers from Kenya between 1996 and 2004.There is a link between pest detection and the Genus of cut flower imported. Hence, pest detection efforts should focus on identifying and targeting those imported plants with a high risk of carrying pest species. For most of the plants studied, efforts allocated to inspection have a significant influence on the probability of pest detection. However, by better targeting inspection efforts, it is shown that plant inspection effort could be reduced without increasing the risk of pest entry. Similarly, for most of the plants analysed, an increase in volume traded will not necessarily lead to an increase in the number of pests entering the UK. For some species, such as Carthamus and Veronica, the volume of flowers traded has a significant and positive impact on the likelihood of pest detection. We conclude that analysis at the rank of plant Genus is important both to understand the effectiveness of plant pest detection efforts and consequently to manage the risk of introduction of non-indigenous species.  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