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   119篇
  免费   2篇
  国内免费   25篇
安全科学   12篇
废物处理   3篇
环保管理   20篇
综合类   43篇
基础理论   33篇
环境理论   1篇
污染及防治   20篇
评价与监测   4篇
社会与环境   7篇
灾害及防治   3篇
  2021年   3篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   3篇
  2016年   4篇
  2015年   4篇
  2014年   7篇
  2013年   17篇
  2012年   1篇
  2011年   4篇
  2010年   4篇
  2009年   6篇
  2008年   9篇
  2007年   12篇
  2006年   7篇
  2005年   10篇
  2004年   5篇
  2003年   5篇
  2002年   6篇
  2001年   5篇
  2000年   3篇
  1999年   4篇
  1998年   4篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1979年   1篇
  1977年   1篇
排序方式: 共有146条查询结果,搜索用时 640 毫秒
81.
The dominant view of calling among management scholars is that it is a stable construct that does not change. This view has resulted in a research void about calling's early development and subsequent evolution. Insight into the dynamic process through which callings develop is fundamental to understanding its role in people's careers and lives. In this study, I focus on the antecedents of calling, a consuming, meaningful passion people can experience toward a domain. I propose a dynamic model in which calling can change over time and can be shaped by antecedent factors, specifically, through people's ability, behavioral involvement, and social comfort in the area toward which they feel a calling. I tested these ideas in a seven‐year, four‐wave prospective longitudinal survey study of 450 amateur musicians. Multilevel analyses indicate individuals who were more behaviorally involved and felt higher social comfort in the calling domain (e.g., music) experienced higher levels of calling early on but experienced a decline in calling over time. Individuals' ability in the calling domain was not related to initial calling or change in calling. I discuss the implications for theory and research on calling, meaning of work, and the dynamics of careers. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
82.
A support tool system comprising risk and priority analyses was illustrated in a geographical information system environment and also tested with data from two forest protection areas for comparison of the system output. The system is recommended as a management monitoring tool for areas where village forest protection at a local level is taking place. The geographical area in the eastern part of India is subject to scarcity of forest resources and is representative in the context of widespread occurrence of local forest protection. Data used were topography, hectares protected, population census, distance to forest and other villages, degree of forest regeneration, presence of plantations, age of protection, surrounding forest resources, and population mix. Methods used were digitizing information for the systems' different layers, analyses of satellite information, field work, gathering of local information, and the application of five risk/priority analyses: erosion, ecological and institutional sustainability, conflict, and degree of dependency. Questions asked were how the different analyses should be interpreted and how the system could be kept updated. The results show that the system needs resource-demanding and field assistance to be kept dynamic. The system is also dependent on the interpretations of the analyses. The limits or levels of assistance for forest management depend on the resources available. The system illustrates how a tool can be utilized for decisions regarding input of resources. It can further be very useful in defining and comparing different areas in order to detect areas in need of assistance and the type of help needed.  相似文献   
83.
Households’ recycling effort is often argued to be of an insignificant size. It is also frequently argued that this contribution, if significant, is not a cost to households, since it is voluntary. Thus households’ use of time and energy are frequently disregarded in cost-benefit analyses of stricter recycling targets. In this survey, based on 1162 interviews, we find that sorting at source involves significant extra use of time and energy in the households. On average, each of those asked reported that they use close to half an hour a week for cleaning, sorting and transporting recyclable waste. On average, 185 h is used per tonne of waste. Four out of ten reported that they use warm or hot water to clean the materials. When investigating the motives for sorting waste, we find that many perceive sorting as mandatory, while some in fact find it a pleasant activity in itself. Moral motives for sorting at source are also widespread. A majority would prefer that a company took over the sorting if this were possible, and on average, the respondents are willing to pay US$ 20/year for this service.  相似文献   
84.
Oriental lacquer film was prepared and exposed to a fluorescent lamp. The color difference and gloss of the surface of the film decreased compared to those of film kept in a dark place by irradiation with the fluorescent light. The percentage of discoloration was 7.0% on a relative scale with an irradiation of 3600 h. The surface of the film was characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The oxygen content of the surface increased considerably with the decrease in triene groups with exposure time. These changes were also observed when the film was exposed in a glass or acrylic plate box. The change of the above properties was not observed when the film was kept in a dark place for more than 4800 h. The results suggest that oriental lacquer film deteriorates even under irradiation with visible light.  相似文献   
85.
本文用统计学方法,分析研究了《海洋环境科学》近5a的抽样载文及引文情况。从中析出:本刊已拥有一批热心于海洋环保事业的科研队伍,形成了以辽宁、山东等地为核心的的海洋环境科研核心地区和相对稳定的研究体系。所载论文的内容广泛,几乎覆盖了海洋环境科学研究的各处领域。引文量高,比我国行业性技术行业性技术刊物篇均引文量2.8篇高5.27篇。  相似文献   
86.
对大庆水库的总氮在线监测仪与同步实验室分析进行了比对实验,结果表明:SERES2000型总氮在线监测仪采用的分析方法与实验室采用的国家标准分析方法为同一分析方法;总氮在线监测仪的自动监测结果和实验室分析结果均具有准确度高、精密度好的特点,二者之间的相对误差范围为-11.8%~14.1%,均在允许的相对误差范围内,满足比对分析要求;总氮在线监测仪能实时掌握水源地水质变化趋势,它的投入使用为完善水质预警系统、保证监测数据的真实有效提供了科学依据.  相似文献   
87.
某公路滑坡的变形机理与稳定性分析   总被引:1,自引:0,他引:1  
通过对某公路边坡的变形破坏机理分析,表明滑坡的发生是由于坡脚的小规模开挖引发的局部变形破坏了坡体中原有的地下水排泄通道,使地下水水位抬升,从而使边坡稳定性进一步降低,造成变形破坏向坡体的上部发展,最终导致整体的滑动。稳定性计算表明,此滑坡整体稳定性差,需要作加固处理。综合分析地质条件后,选择抗滑桩和坡面护坡的方法来治理滑坡,并达到了较好的效果。  相似文献   
88.
洛阳市城市生活垃圾成份分析   总被引:3,自引:0,他引:3  
对洛阳市城市生活垃圾按季节进行了分类,分析了垃圾中碳、硫、挥发分、灰分及水分的含量,测定了垃圾发热量及部分化学元素的含量,为城市生活垃圾的处理提供了科学数据。  相似文献   
89.
塔里木河下游应急输水前后胡杨年轮生长差异   总被引:1,自引:0,他引:1  
1972年塔里木河下游大西海子水库建成,下游365km河道彻底断流。为拯救沿河植被,2000年5月启动了塔里木河下游应急输水工程,迄今已经完成了7次应急输水。文章通过对塔里木河中游英巴扎和下游输水河畔英苏、喀尔达依、阿拉干断面胡杨(Populus euphratica)一级枝年轮取样调查,运用统计方法比较不同离河距离输水前后胡杨生长量差异的大小,分析了下游应急输水河畔胡杨种群对输水的响应。结果表明:1)英苏断面和喀尔达依断面在离河0~1000m输水前后胡杨生长量差异极显著。阿拉干断面在离河0~300m输水前后胡杨生长量差异极显著,离河300~700m生长量差异显著,700~1000m生长量差异不显著。由输水前后胡杨年轮生长量均值差可得,同一断面不同离河距胡杨年均生长量随离河距增大而降低。2)输水后下游3个调查断面在离河0~300m胡杨生长量增长由大到小顺序为:喀尔达依>英苏>阿拉干;离河300~700m由大到小顺序为:喀尔达依>阿拉干>英苏。3)以中游胡杨同年生长量作为参照对下游胡杨生长量进行相关比较的结果表明:应急输水前输水河畔各离河距离胡杨生长量均小于中游参照河段的生长量。应急输水后,输水河畔离河0~300m生长量已超过中游的生长量;离河300~700m输水河畔的生长量接近中游生长量;离河700~1000m生长量小于中游参照河段生长量,应急输水明显地促进了胡杨生长。  相似文献   
90.
Abstract:  Although sacred groves are important for conservation in India, the landscape that surrounds them has a vital influence on biodiversity within them. Research has focused on tree diversity inside these forest patches. In a coffee-growing region of the Western Ghats, however, landscape outside sacred groves is also tree covered because planters have retained native trees to provide shade for coffee plants. We examined the diversity of trees, birds, and macrofungi at 58 sites—10 forest-reserve sites, 25 sacred groves, and 23 coffee plantations— in Kodagu district. We measured landscape composition and configuration around each site with a geographic information system. To identify factors associated with diversity we constructed multivariate models by using a decision-tree technique. The conventional measures of landscape fragmentation such as patch size did not influence species richness. Distance of sacred groves from the forest reserve had a weak influence. The measures of landscape structure (e.g., tree cover in the surroundings) and stand structure (e.g., variability in canopy height) contributed to the variation in species richness explained by multivariate models. We suggest that biodiversity present within sacred groves has been influenced by native tree cover in the surrounding landscape. To conserve this biodiversity the integrity of the tree-covered landscape matrix will need to be conserved.  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