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   169篇
  免费   6篇
  2023年   1篇
  2021年   1篇
  2020年   5篇
  2019年   6篇
  2018年   10篇
  2017年   6篇
  2016年   7篇
  2015年   8篇
  2014年   5篇
  2013年   26篇
  2012年   7篇
  2011年   4篇
  2010年   3篇
  2009年   2篇
  2008年   3篇
  2007年   3篇
  2005年   1篇
  2004年   3篇
  2003年   9篇
  2002年   1篇
  2000年   4篇
  1999年   5篇
  1998年   2篇
  1997年   4篇
  1996年   3篇
  1995年   3篇
  1994年   6篇
  1993年   2篇
  1992年   9篇
  1991年   4篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   2篇
  1969年   1篇
  1966年   1篇
  1947年   1篇
排序方式: 共有175条查询结果,搜索用时 46 毫秒
91.
For the seismic isolation of light structures, the use of laminated rubber bearings is neither economical nor, for most cases, technically suited. For the isolation of this type of structure a new system, consisting of steel balls rolling on rubber tracks, has been developed at TARRC (Tun Abdul Razak Research Centre).

This article presents the results of experimental tests carried out for the characterization of the behavior of this new device. A numerical model is also proposed that can be used to assess the seismic response of structures with this isolation system.

Comparison of the predictions of the numerical model with the experimental data shows that the model is adequate to perform the correct assessment of the seismic response of isolated structures. The results of the experimental campaign of shaking-table tests, as well as the numerical simulations, show that there is an effective reduction of the acceleration levels induced in the isolated structures.  相似文献   
92.
This paper challenges policy discourses that frame children's independent movement as intrinsically exploitative and threatening to their development. Drawing on research with children and adults in Benin and Ethiopia, two countries caught up in current efforts to eradicate child migration and the trafficking with which it has become associated, the paper critiques assumptions about children's vulnerability and physical dependence and contests the idea that appropriate childhood is necessarily fixed spatially within stable family structures. It, thus, situates children's migration within socio-cultural and economic contexts and suggests that it should be understood as part of a moral economy that confounds simplistic paradigms that conflate migration with trafficking. Policy suggestions are offered for how best to secure children's well-being through acknowledgement of the important relationship between mobility and child maturation.  相似文献   
93.
Fred T. Plog. The Study of Prehistoric Culture Change. New York: Academic Press, 1974. xii + 199 pp. Figures, tables, appendices, references, and index. $11.50.  相似文献   
94.
Much of the early literature on downshifting proposed that reduced hours at work would lead to reduced levels of consumption, increased hours of leisure, and a more sustainable and fulfilling life, and yet recent survey research has challenged these assumptions. Our study contributes knowledge on the differentially lived experience of contemporary downshifting and its relationship to sustainable and/or thrifty consumption. We undertook qualitative interviews with Australians of working age who had voluntarily reduced their hours of work in order to explore the everyday experience of downshifting and its links with consumption practices in the domains of food, leisure, and transport. These downshifters focused on thrift rather than sustainability and consequently did not reduce their consumption in a straightforward way. We found the everyday experience of downshifting was significantly shaped by caring responsibilities and financial and housing security. Moreover, differential levels of financial security affected consumption levels. Although those with lower levels of wealth closely managed discretionary expenditure, financially secure downshifters did not reduce their consumption overall. We argue that reduced working hours are unlikely to lead to reduced consumption in the absence of an ideological commitment to sustainability and without mainstream support for changing consumption mindsets and practices.  相似文献   
95.
Timber-framed wall buildings are seen all over Europe, especially in seismic regions, given its adequacy to resist earthquakes. The “Pombalino” buildings, developed after the great 1755 earthquake that destroyed Lisbon, constitute one of the best examples of historic seismic-resistant structures based on timber-framed masonry walls. The research presented in this article aimed at experimentally evaluating the seismic behavior of the “Pombalino” buildings. The experimental program was based on extensive dynamic testing on sub-structures of typical “Frontal” walls (the timber masonry walls), carried out at the LNEC (the Portuguese National Laboratory of Civil Engineering) shaking table. The tests comprised (a) seismic tests, in which the seismic action was applied with increasing amplitude in one direction; and (b) dynamic identification tests, aiming at evaluating the dynamic properties of the sub-structures and their evolution with damage accumulation.  相似文献   
96.
Within a full-scope modernization program of Portuguese secondary schools, technical inspections were conducted in order to: 1) identify the main degradation processes that affect different types of school buildings, and 2) provide recommendations for the rehabilitation projects. This article presents the constructive characteristics and a statistical analysis of the degradation condition of a particular type of Portuguese secondary schools, the Liceu, comprising a set of buildings with an invaluable historical and cultural importance and that is very iconic in terms of the historical period in which they were built—the Estado Novo. To that end, a database was designed in order to organize information gathered in the inspection of 15 secondary schools of Liceu typology. The aim of the database was to analyze the most frequent anomalies in this type of school buildings, taking into account the constructive solutions used and establishing statistical relationships between anomalies, probable causes and recommended rehabilitation works. Results obtained allowed concluding that the overall condition of these buildings which, in average, were 60 years old, was severe. The most frequent anomalies in both the buildings envelope and interior are mainly due to design and execution errors, water infiltration, and lack of maintenance. Although the school buildings analyzed are to some extent unique, most lessons learned from this study can be extrapolated to other countries, mostly Mediterranean, where during most of the 20th century, buildings were designed and constructed according to the same architectural and constructive principles, and were subjected to the same type of maintenance.  相似文献   
97.
Fire safety is an important issue of building safety, especially when the building’s fire load contents enhance the risks of fire deflagration. When existing timber structures are involved, the most usual way to improve its reaction to fire is to treat wood with fire retardants. This study focuses on the surface protection of existing timber roof structures against fire, through the use of fire retardant (FR) treatments applied on site. An experimental investigation was carried out to study the effect of FR treatments on timber reaction to fire, with a special emphasis on timber members with biological deterioration and previously treated with preservative products. The behaviour and effectiveness of intumescent and non-intumescent treatments was also investigated. The study showed that the application of FR treatments improved the reaction to fire of timber, even in the presence of previous preservative treatments. However, the choice of the specific FR treatment should take into account the substrate conditions. In addition, test results suggest that protection systems involving multi layers (intumescent and non-intumescent) with different functioning modes each are likely to have a good global performance on the protection of timber elements against fire.  相似文献   
98.
This paper presents the carbon (13C/12C), nitrogen (15N/14N), oxygen (18O/16O), hydrogen (2H/1H) and sulfur (34S/32S) stable isotope values measured in the hair of a female individual from north-western Argentina. The analysis of segments of this tissue allows for the recording of the diet and migratory changes with a short time resolution. The sample is from a mummified young female individual discovered in Chuscha mount, Salta province. It was found at more than 5000 masl, in a mountain sanctuary of the Inca expansion (capacochas). The paper discusses the paleodiet and mobility patterns of this individual in the period before her death, focusing on the isotopic variations in a limited time scale. The results indicate that the individual moved from a different region to the place where she was sacrificed. Furthermore, in the last year the individual was alive, a shift in the isotopic composition of the food consumed is detected: a variation in the importance of C4 over C3 resources is evident. The results are compared with the isotopic estimations for other children and young people recovered in archaeological contexts associated with capacochas to infer variability in the geographical trajectories covered during their last months of life.  相似文献   
99.
Is it possible for an anthropologist to decide whether an individual or a collectivity can or cannot be characterized as « indigenous », and then proceed to establish the limits of the territory which should be assigned (or recognized) by the state? Does his role as a scientist furnish him with the conceptual and methodological instruments necessary for such a task? In epistemological and ethical terms, is this something which he should endeavour to do? The purpose of this paper is to discuss how these questions are being put to Brazilian anthropologists since the 1980s. Torn between an « indianist » and an « indigenist » discourse, between romanticism and political mediation, the anthropologist must define an appropriate posture for dealing with policy-making; one which will simultaneously safeguard the scientific quality of his work while addressing the specific demands of each situation.  相似文献   
100.
South Africa was once notorious for an extreme system of racial inequality known as apartheid. It is still a world leader in economic inequality, but the racial situation is confused. In the meantime something like apartheid has become universal. The Southern African regional economy has some features that point to a more humane alternative to unequal society, to a “human economy”. The world needs a new free trade movement that would begin to dismantle the institutions of national privilege and insist on movement as a human right.  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