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   117篇
  免费   3篇
  2023年   9篇
  2022年   1篇
  2020年   11篇
  2019年   4篇
  2018年   9篇
  2017年   10篇
  2016年   8篇
  2015年   3篇
  2014年   12篇
  2013年   20篇
  2012年   11篇
  2011年   11篇
  2010年   2篇
  2009年   2篇
  2008年   2篇
  2005年   1篇
  2003年   1篇
  1997年   1篇
  1994年   1篇
  1991年   1篇
排序方式: 共有120条查询结果,搜索用时 15 毫秒
61.
Many studies conducted in the last few years in Poland indicate that the results of thermoluminescence dating of loess are reliable and correspond well to their geological ages. They can form the basis for determination of the chronology of changes of palaeoenvironmental conditions. In this paper we report dating results from the Halych IIC profile (Halych Prydnistrov’ja region, Ukraine). Thermoluminescence dating of this profile gives new information about the influence of local conditions on the results of TL analysis. As much as 75% of the obtained results are distinctly overestimated, even by several hundred per cent, that is untypical of regional loess profiles. However, in the Halych Prydnistrov’ja region it is the second loess site in which such incompatibility of the expected age and thermoluminescence age is found. This fact indicates how this region is unique among the loess areas of SE Poland and NW Ukraine in respect of the conditions of mineral material transport and deposition. Further investigations are necessary to identify the reasons for regular overestimating of the TL results obtained for loess deposits of the Halych Prydnistrov’ja region.  相似文献   
62.
In this paper I try to explain why the potassium-argon dating method was developed much later than other radiometric methods (like U-He and U-Pb), which were established at the beginning of the 20th century. In fact the pioneering paper by Aldrich and Nier (1948) was published 50 years after the discovery of polonium and radium, when nearly all the details concerning potassium isotopes and radioactivity of potassium-40 had been investigated. The role of Marie Curie’s concept of the nature of radioactivity in the discovery of the radioactivity of potassium is emphasized.  相似文献   
63.
Metasequoia glyptostroboides is considered to be a species highly resistant to harmful environmental factors. For this reason it has been introduced to the cities. The climate of Krakow differs from that in its natural range in China. The research was focused on 40-year-old trees, planted in Kraków on fertile alluvial soils with a low level of ground water, in the vicinity of the steelworks. During the period of the highest level of air pollution in the 1970s and 1980s, the radial increment of investigated trees showed an increasing trend. At the end of the 1980s, when the emissions were reduced, a decreasing trend in radial growth was recorded. Throughout the entire period of their life the investi-gated trees have shown high homogeneity of short-term growth reactions. The sensitivity chronology of the trees was characterized by a high representativeness and a strong high-frequency signal. This may indicate that the investigated trees have shown a large sensitivity to climatic factors. The positive effect on the radial growth of Metasequoia had a cold September in the previous year, and also a cold January, April and May in the year of ring formation. Positive impact on the growth of trees had also the high precipitation occurring in April and August, as well as high air humidity in the spring of the year of ring formation. In the period 1974–2011 fifteen signature years were found. The analysis of the climatic conditions in these years confirms the results of the statistical analyses.  相似文献   
64.
The frequency and chronological distribution of enamel hypoplasias were assessed in a Roman Period population of the Wielbark culture from Rogowo, northern Poland, dated to the 2nd century ad . Hypoplasias were recorded on permanent incisors, canines, and premolars of 52 skeletons. The position of linear defects on the crown surface was measured and then converted to the age of occurrence using two methods: a conventional method that employs the chart of enamel development for the permanent teeth, constructed by Massler et al. (1941) in Swärdstedt's (1966) modification, and the method by Goodman & Song (1999), which corrects for hidden cuspal enamel. Hypoplastic defects were found in 48.1% of examined cases. Linear defects [linear enamel hypoplasias (LEH)] were observed in 38.5% of individuals and in 22% of investigated teeth. The chronological distribution of LEH according to the conventional method revealed two peaks of defects: one at 2.6–3.0 years of age and the other at 4.1–4.5 years of age. The method that accounts for hidden cuspal enamel also provided two peaks, but they occurred at later ages: 3.0–4.0 and 4.6–5.0 years of age. The prevalence of hypoplasia in the Rogowo population in comparison with other European populations of the Roman Period seems to be rather low for both individuals and teeth affected. This may indicate advantageous living conditions, which are supported by archaeological data that suggest general well‐being of the Wielbark people. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
65.
The thermoluminescence (TL) dating method has a significant measurement error margin reaching almost 10%. Due to this fact it could be considered as little effective in case of such sites from the Roman period as burial grounds with many artefacts useful for archaeological dating. However, for many settlements from this period, where pottery is the only kind of artefacts, the TL method can give notable results. The main purpose of the study was to make an attempt at TL dating of pottery and clay daub samples from the Nieszawa Kolonia and Kręcieszki sites and to compare the obtained dates with the results of archaeological dating of selected features from the Przeworsk Culture settlements. In the Kręcieszki site the fragments of burnt clay daub were dated by the TL method for the first time in the Lublin laboratory. It turned out that clay daub is an equally good dating material as pottery. It can be found that the TL dating of pottery from Nieszawa Kolonia confirms two stages of settlement. The first settlement stage is related to the phases B2-B2/C1-C1a of the Roman period, i.e. from the beginning of the 2nd to the beginning of the 3rd century. The second group of TL dates corresponds to the phases C2D that is to the second stage of settlement, from the second half of the 3rd century to the half of the 5th century AD. The results of TL dating of pottery and clay daub in the Kręcieszki site are rather similar and correspond to the phase B1/B2 of the period of Roman influence, determined from pottery style, but can also indicate the phase B2/C1.  相似文献   
66.
67.
68.
This article aims to compare the biographical experiences and individual memories of child deportees and migrants from Eastern Europe. The analysis is based on a field study of over 100 biographical interviews in two local communities situated in the borderland regions which were particularly exposed to post-war displacement, resettlement and population exchange: Ukrainian Galicia and Western Poland. The author claims that although the history of these two distant communities was totally different, contemporary memory of being a refugee/deportee/forced migrant, losing one's home/homeland and watching the deportation of the previous inhabitants of one's new place of residence bear many similarities. While analysing autobiographical narratives, I attempt to find common threads and topics generated by their experiences as children, as well as explain the differences by exploring the social context of individual memory, with a special accent on post-war socialisation and the Polish and Ukrainian memory culture. The author also strives to show how and why the children's memories differ from those of their parents.  相似文献   
69.
Surface damage to bird bones from pellets of three species of owls (S. aluco, A. otus and B. bubo) was compared with that of bird bones exposed to weathering and soil corrosion (Záskogo Cave in the Western Balkan Mountains, Bulgaria and Ciemna Cave, southern Poland). Scanning electron microscopy and light microscope examinations indicate that the effects of weathering of bird bones (extensive pitting and flaking away on whole bones, holes with sharp edges, depressions with rough bottoms and sharp edges of breakage) are distinguishable from those of digestion (rounding of hole edges on articular ends and sometimes on shafts, rounding of breakage). However, soil corrosion may produce similar rounding to that of digestion, which may hamper taphonomic interpretations of fossil assemblages. Two stages of weathering in bird bone are distinguished. Generally, the kind of damage done to bird bones is similar to that done to mammalian remains. Taphonomic studies of fossil bird remains should take into account a combination of features, including surface damage, fragmentation and possible chemical alterations of bone tissues. © 1997 John Wiley & Sons, Ltd.  相似文献   
70.
The number and geographical distribution of the aged, and how the distribution changes over time, have captured the attention of geographical gerontologists; the complexity and spatially differentiated nature of ageing is of considerable practical and theoretical import. This article seeks to link the traditional concerns of population geography to the social and spatial relations between old people, their health and places of residence and care. It does presuppose, however, that patterns and processes at the sub‐national level are also taken into account. Therefore, the aim of the article is to identify the aged and the localities or regions where they reside, within the particular context of a Polish post‐socialist society that has recently become integrated into the European mainstream. As such it is potentially subject to a double transition, where the political and economic changes cross path with the second demographic transition. To identify interrelationships between ageing and post‐socialist transition, areas vulnerable to ageing are defined using ageing indices. Projections of the share of elderly up to 2030, based on a component cohort method, are made with a view to identifying future change in the spatial patterns of ageing. Regional patterns of ageing are presented in social, political or economic context, to show their relation to the structural changes that societies such as Poland have been passing through during the period of transition to democracy and a market economy or are likely to go through in the near future.  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