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   69篇
  免费   7篇
  2023年   4篇
  2020年   6篇
  2019年   3篇
  2018年   5篇
  2017年   4篇
  2016年   7篇
  2015年   4篇
  2014年   1篇
  2013年   12篇
  2012年   3篇
  2011年   6篇
  2010年   3篇
  2009年   2篇
  2008年   3篇
  2006年   5篇
  2005年   1篇
  2003年   2篇
  2002年   1篇
  1998年   1篇
  1997年   1篇
  1993年   1篇
  1987年   1篇
排序方式: 共有76条查询结果,搜索用时 15 毫秒
1.
While food allergy prevalence has been studied at the national level, we know little of food allergy prevalence or perceptions of prevalence/management at the local level. This paper uses Waterloo Region as a case study to 1) document self-reported individual and household food allergy and sensitivity prevalence at the local level; 2) investigate perceptions of food allergy prevalence; and 3) explore perceived confidence in anaphylaxis management. Survey data were collected from January to March 2019. Respondents (n = 500) self-reported individual and household food allergy and sensitivity, estimated the percentage of Canadians with food allergy, and were queried about their knowledge of food allergy management. Prevalence estimates were weighted to the structure of the 2016 Canadian Census, and univariate and bivariate analysis were conducted. Prevalence of self-reported food allergy was 12.1% (95%CI, 8.8%-15.3%), and prevalence of self-reported food sensitivity was 26.3% (95%CI, 21.9%-30.7%). When asked to estimate the percentage of Canadians with food allergy, the mean perceived percentage was 35.1% (SD = 22.96). Self-reported prevalence of food allergy appears higher in Waterloo Region, and the estimated percentage of Canadians with food allergy is inflated. Understanding prevalence and perceptions at the local level is important for targeted allocation of public health resources to ensure safe spaces for individuals with food allergy.  相似文献   
2.
ABSTRACT

This paper reports on results of nonlinear analyses performed within the RINTC project on an RC building isolated with different systems (High Damping Rubber Bearings, High Damping Rubber Bearings and Flat Sliding Bearings, Friction Pendulum System) and designed according to the Italian design code. The seismic response has been evaluated under different seismic input levels of two sites with different hazard and by considering two Limit States: Global Collapse and Usability-Preventing Damage. The influence of seismic stoppers and modelling uncertainties is also evaluated. Results permit to compute the implicit collapse risk and to identify critical aspects of current design procedures.  相似文献   
3.
In Argentine Patagonia, the type of archaeological burial “in pit” has been only identified on the coast of Lángara Bay. This modality is characterized by the presence of single and multiple primary burials. Studies on five human burials in pits are presented in this article. The aim is to compare the contexts of burials in pit at the site level and the spatial characteristics of their distribution in the Lángara Bay locality from a diachronic perspective. The approach focuses on mortuary practices and social relations of hunter-gatherer groups during the Late Holocene. A characterization of the burials, their chronologies, bioarchaeological determinations, stable isotope studies, and their spatial distribution are included. The results allow us to chronologically place the contexts between ca. 3000 and 2000 cal BP. A spatial pattern in the distribution of burials in the coastal landscape was identified. Finally, it is proposed that this part of the Patagonian coast was a persistent place of burials in pit.  相似文献   
4.
This article systematically reviews and synthesises academic, peer‐reviewed literature to assess the state of knowledge concerning socio‐economic vulnerability to climate change impacts and environmental hazards in New South Wales and Queensland, Australia. It focuses upon empirical research that identifies socio‐economic factors associated with vulnerable subpopulations. Using systematic review methods, 35 articles met the inclusion criteria. These articles are analysed according to their general characteristics, the methods used, and the factors reported to be associated with socio‐economic vulnerability. This body of evidence reveals that (1) the majority of the knowledge about socio‐economic vulnerability in New South Wales and Queensland has only recently emerged; (2) more knowledge has been published about Queensland; and (3) extreme temperature is the most researched environmental hazard. Despite increased research activity over time, the number of factors repeatedly demonstrated to influence socio‐economic vulnerability is small. Age, gender, place of residence, and pre‐existing illness were the most commonly reported factors, although the influence of these factors upon socio‐economic vulnerability is complex. There is scope to extend the empirical research base across a broader range of climate‐related hazards and to better link findings from the domains of climate change vulnerability and population health.  相似文献   
5.
Through the assistance of trace element and petrographic analyses on 14 samples of mortar aggregates from Roman monuments, including the Porticus Aemilia, the Temple of Concordia, the Temple of the Dioscuri, Temple B and other structures of the Area Sacra di Largo Argentina, and the Villa di Livia, we establish the source area and we investigate the chronological employment of the volcanic materials used in ancient Rome's masonry. In contrast to previous inferences, the petrochemical data presented here show that systematic exploitation of the local ‘Pozzolane Rosse’ pyroclastic deposit has occurred since the early development of concrete masonry, at the beginning of the second century bc , through the early Imperial age. Subsequently, exploitation was extended to the overlying Pozzolane Nere and Pozzolanelle deposits. Only during the early phase of development of the concrete masonry in Rome, volcaniclastic sediments outcropping near the construction sites were mixed with the sieved remains of the tuff employed as the coarse aggregate, to produce the fine aggregate. The results of the study on the investigated monuments suggest the possibility of establishing the chronological identification of three different types of mortars, as a function of the composition of the volcanic material employed in the fine aggregate, which, when implemented by future studies, may contribute to the dating of monuments and archaeological structures.  相似文献   
6.
A 19th‐century dog burial uncovered from a historical homelot in Toronto, Canada, provided a unique opportunity to reconstruct the individual's osteobiography. Of particular interest are the dog's very large size and a suite of skeletal pathologies. Recovery of a nearly complete skeleton combined with the use of X‐rays and micro‐computed tomography (micro‐CT) allowed for a discriminating differential diagnoses. Stable isotope analyses were applied to investigate questions of diet. Results reveal an individual who suffered greatly from disease towards the end of his life and hint at its owners attitudes towards dogs. The interdisciplinary approach applied to this case study highlights the potential information obtainable from pet burials. We argue that better analyses and reporting of pet burials will help address research questions targeting broader themes related to human–animal relationships. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
7.
This paper is a brief investigation of one of the outstanding problems in Chalcolithic archaeology in the Negev desert of Israel: that of the spatial distribution of sites and the possible relationships between these sites that may be inferred. Although the region is rich in archaeological data for the Chalcolithic period, very little work has thus far been undertaken in terms of the quantification of the archaeological data – a necessary prerequisite for complex spatial analysis. Nevertheless, simple analysis of settlement patterns using the data presently available for 403 Chalcolithic sites in the Negev is given as an example. Autocorrelation tests measuring clustering and dispersion of sites show that the overall impression of clustering is a factor of access to farming land, water, grazing and Mediterranean maquis, but that smaller scale analysis suggests that settlement patterns were essentially random. This makes it difficult to argue in favour of settlement hierarchies or structured settlement of any kind.  相似文献   
8.
Historical park visitation and weather data, taken at the daily time scale from 2000 to 2009 for Pinery Provincial Park in southern Ontario (Canada), were analysed as an objective measure of the weather sensitivity, temperature thresholds, and potential impacts of projected climate change for park visitation. Three seasonal weather-visitation models were constructed using multivariable linear regression (peak, shoulder, off-season). To account for both natural and institutional seasonality, the weather-visitation models included both climatic (temperature, precipitation) and social (weekends, holidays) variables, which demonstrated equably comparable effects on visitation across the three models. Critical temperature thresholds were identified for each season using one-way analysis of variance to determine the range of temperatures within which the threshold was evident; the specific degree of temperature associated with the threshold was identified within the seasonal regression models. Temperatures over 33 °C during the peak season and over 29 °C during the shoulder season indicated critical thresholds at which point conditions that were ‘too hot’ for some caused a decline in visitation. Furthermore, temperatures below 11 °C indicated another critical threshold, where conditions were ‘too cold’ for most and therefore park visitation was less sensitive to temperature variability below this threshold. A partial sensitivity analysis for the impact of a warmer, wetter climate on park visitation was conducted, illustrating the effect of a 1 °C to 5 °C warming in maximum temperatures, coupled with a 5% to 15% increase in total precipitation. In response to projected climate change, the weather-visitation models suggested that for each additional degree of warming experienced, despite the negative effects of increasing precipitation and more frequent heat extremes, annual park visitation could increase by 3.1%, annually. The projected increase in park visitation as a result of rising temperatures was mainly associated with shoulder season visitation, with only minor increases in peak season visitation.  相似文献   
9.
Easter Island, or Rapa Nui, has been the focus of much research and speculation, particularly with reference to the island’s hundreds of giant, enigmatic statues and the set of conditions that supported their construction and transportation. In this paper, we analyze an abundant class of lithic artifacts, mata’a, to study of patterns of cultural transmission with implications for the evolution of groups, competition, and scale of socio-political organization among this island population. While these kinds of studies often draw upon assemblages of decorated ceramics, here we show how analysis of variability unconstrained by performance allows us to measure aspects of inheritance related to the manufacture of these artifacts. In the case of mata’a from Rapa Nui, we demonstrate that it is possible to reach falsifiable conclusions about the evolutionary dynamics that shaped the remarkable archaeological record on Rapa Nui.  相似文献   
10.
Despite its worldwide use as a stone tool raw material, quartz is known to be a difficult material for archaeologists. The main reason for this is the tendency of quartz flakes to fragment during detachment, which complicates the use of traditional lithic analyses. In this article we present an experimental study of quartz flake fragmentation. We evaluate the method called fracture analysis that has been developed and used explicitly for the study of quartz assemblages. The method assumes high predictability of quartz flake fragmentation, but our experiments show that there is significant variation in fragmentation that fracture analysis does not take into account. Our results indicate that this variation is partly explained by indenter hardness, the relative thickness of the detached flake, as well as individual knapper-related factors. These results undermine the applicability of quartz fracture analysis in its current form. In addition, we discuss the effects of flake fragmentation on the technological organisation of prehistoric quartz users and suggest that it has affected reduction strategies as well as blank and tool dimensions. We also suggest that there should be mobility-related differences in archaeological assemblages in terms of the quality of the quartz raw material and that the curation of quartz should be low in relation to better quality raw materials used parallel with it.  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