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   476篇
  免费   28篇
  国内免费   55篇
安全科学   60篇
废物处理   1篇
环保管理   43篇
综合类   263篇
基础理论   119篇
环境理论   1篇
污染及防治   23篇
评价与监测   14篇
社会与环境   10篇
灾害及防治   25篇
  2023年   4篇
  2022年   6篇
  2021年   18篇
  2020年   11篇
  2019年   13篇
  2018年   11篇
  2017年   8篇
  2016年   9篇
  2015年   8篇
  2014年   12篇
  2013年   26篇
  2012年   11篇
  2011年   35篇
  2010年   15篇
  2009年   19篇
  2008年   18篇
  2007年   23篇
  2006年   33篇
  2005年   28篇
  2004年   24篇
  2003年   21篇
  2002年   20篇
  2001年   19篇
  2000年   11篇
  1999年   12篇
  1998年   7篇
  1997年   5篇
  1996年   6篇
  1995年   15篇
  1994年   18篇
  1993年   6篇
  1992年   11篇
  1991年   17篇
  1990年   4篇
  1989年   14篇
  1988年   12篇
  1987年   15篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1981年   4篇
排序方式: 共有559条查询结果,搜索用时 15 毫秒
51.
现代生物力学在煤矿安全科技中的应用研究   总被引:1,自引:1,他引:0  
笔者根据国内外现代生物力学的发展情况 ,结合我国煤矿安全的现状 ,探讨现代生物力学在煤矿安全方面的应用 ,并提出了现代生物力学在安全科技两个方面的应用 :①研究人体结构在冲击事故的破坏极限 ,对安全帽的防护性能做简略的生物力学分析 ;②骨力———电性质的研究对骨折愈合与康复的意义。笔者提出随着现代科学技术的迅猛发展 ,煤矿安全方面的研究能否从现代生物力学在人体安全保护、骨折治疗与康复、职业病防治机理等方面的应用去研究的新思想和新方法 ,使煤矿安全的研究达到一个新的水平。  相似文献   
52.
PROBLEM: People with dizziness caused by vestibular (i.e., inner ear) disorders complain of difficulty driving. Physicians occasionally warn their patients with vestibular disorders not to drive. Few studies have asked patients about their driving performance, so little data are available. METHOD: Using the Driving Habits Questionnaire, the authors did structured interviews with people with several different vestibular disorders and with normal subjects. The self-reported crash rate and rate of citations for moving violations did not differ between the subject groups. RESULTS: Patients report reduced driving skills, particularly in situations when visual information is reduced, rapid head movements are used, and specific path integration or spatial navigation skills are needed.  相似文献   
53.
Geographically explicit analysis tools are needed to assess forest health indicators that are measured over large regions. Spatial scan statistics can be used to detect spatial or spatiotemporal clusters of forests representing hotspots of extreme indicator values. This paper demonstrates the approach through analyses of forest fragmentation indicators in the southeastern United States and insect and pathogen indicators in the Pacific Northwest United States. The scan statistic detected four spatial clusters of fragmented forest including a hotspot in the Piedmont and Coastal Plain region. Three recurring clusters of insect and pathogen occurrence were found in the Pacific Northwest. Spatial scan statistics are a powerful new tool that can be used to identify potential forest health problems.  相似文献   
54.
The following paper examines the main factors determining long-run agricultural land expansion in Latin America compared to other tropical regions. Given the importance of natural resource-based sectors for most economies in Latin America, the impact of price-induced "resource booms" on economic growth in the region is explored. In addition, the paper examines whether there is an inherent "boom and bust" pattern of economic development associated with agricultural land expansion in Latin America, and the extent to which economic policies in the region exacerbate this problem. The paper concludes by examining the role of targeted policies in alleviating the structural obstacles to Latin American agricultural and economic development.  相似文献   
55.
Sub-Saharan Africa is by far and away the most disadvantaged of the world's three main developing regions. Worse, its situation has mostly been deteriorating for much of the past several decades. Its agriculture is severely under-productive, and per capita food supplies have been steadily dwindling. Its environments and natural-resource base, characterised by water deficits, soil erosion, fuelwood shortages, rudimentary agro-practices, and grossly inadequate infrastructure, are generally unfavourable for sustainable agriculture. The population has expanded until it far exceeds carrying capacity, yet its growth rate is the highest in the world. The region also suffers from more disease than any other region. There is widespread and deepening poverty. As a result of these and other problems, and despite major food imports, two-thirds of the people are malnourished, one-quarter of whom endure outright hunger, even semi-starvation. Both these proportions appear set to keep on increasing both relatively and absolutely. Were these problems to persist with their decades-long trends, there could eventually arrive a stage when much larger numbers of people would succumb to terminal malnutrition, precipitating a human tragedy of unprecedented proportions. Fortunately, success stories demonstrate that solutions are available, on the part of both governments concerned and international agencies. Because of ignorance, or rather ignore-ance of the potential mortality disaster ahead, however, not nearly enough has been done to address the challenge with the energy and urgency to match its scale.  相似文献   
56.
ABSTRACT: Medical geography studies both areal patterns of human health and disease and the environmental and cultural factors that contribute to such conditions. In such studies water resources are of major importance, not only because they are essential for life and their scenic beauty is of inspirational value, but also because they are involved, directly or indirectly, in more than 80 percent of all disease. The direct involvements result from various disease causing agents sometimes found in surface or ground water organic ones such as bacteria, worms, etc., which are known as pathogens, and inorganic ones such as trace elements and synthetic toxic chemicals. Surface waters may have indirect effects also, for they may serve as habitats or breeding places for organisms that do not themselves cause human disease but that serve as vectors or hosts for such pathogens. This paper will discuss these various roles of water resources in both endemic and epidemic disease occurrences and ways in which various human activities domestic, economic, recreational, or religious — increase or reduce our exposure to such diseases.  相似文献   
57.
58.
59.
60.
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