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   261篇
  免费   24篇
  2023年   6篇
  2021年   2篇
  2020年   10篇
  2019年   9篇
  2018年   27篇
  2017年   22篇
  2016年   22篇
  2015年   6篇
  2014年   13篇
  2013年   52篇
  2012年   7篇
  2011年   8篇
  2010年   8篇
  2009年   11篇
  2008年   10篇
  2007年   4篇
  2006年   2篇
  2005年   5篇
  2004年   3篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  2000年   3篇
  1999年   3篇
  1998年   6篇
  1997年   5篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   4篇
  1987年   3篇
  1986年   1篇
  1981年   1篇
  1979年   1篇
  1972年   1篇
  1969年   1篇
排序方式: 共有285条查询结果,搜索用时 15 毫秒
41.
42.
The study of Near Eastern Neolithic villages provides a unique means of tracing subsistence strategy, population growth, health, and emerging social inequality associated with agricultural origins. However, disentangling these patterns requires a detailed comprehension of the chronological placement of individual households in the site. In this paper, we present a test to determine the reliability and applicability of the fluoride dating method (a relative dating method) on human dentition of 40 samples from 28 Pre-Pottery Neolithic B (or PPNB) burials from the site of Tell Halula, in Syria. This method, applied here for the first time on a Neolithic Near East case study, is an alternative when other dating methods, like radiocarbon dates, do not provide the required temporal resolution to address particular research problems. Nonetheless, the results obtained in the fluoride analysis show how both the age at death of individuals, and the integrity of the burial plug enormously affect the amount of fluoride absorbed by teeth, so that only a small subset of the full dataset was suitable for fluoride dating. Although the distribution of fluoride values of dentine from the small sample of burials from suitable contexts matches the expected chronology, and corroborates the hypothesis that the occupation at Halula extends from the Middle to the Late PPNB, our analysis illustrates the need for a better understanding of the different sources of error in fluoride dating to improve the method itself, and to obtain more reliable fluoride chronologies.  相似文献   
43.
44.
45.
Dr. Haakon Sæthre was a leader of Norwegian neurology and psychiatry. He was resourceful, compassionate and had immense pride in his independent homeland. He described Sæthre-Chotzen syndrome (acrocephalosyndactyly type III). When Nazi Germany occupied Norway during World War II, Sæthre fearlessly and actively resisted, from revoking his medical association membership, to hiding persecuted Jews as patients in his psychiatric ward and aiding in their escape to Sweden, to managing the largest “illegal” food warehouse in Oslo with Danish humanitarian aid. As a prominent and noticeable citizen, he was arrested and executed by the Nazis in reprisal for the resistance's assassination of a hated Norwegian Nazi. His legacy lives on in Norway, where he was honored by a scholarship fund, a portrait and multiple plaques at Ullevål Hospital, and a street and memorial statue in his hometown. He was a hero and should be remembered by all who practice neurology.  相似文献   
46.
Summary: Mummified human remains have been preserved in the cool, well-ventilated crypts of old Finnish churches, which were popular burial sites among the elite of the early modern period. Here, the authors present the results of a computed tomography study of the remains of an early 17th-century vicar of Keminmaa. They examined the preservation of his remains and made several pathological findings; the causes of the latter possibly had a severe impact on his health. He was a large man who achieved relative longevity for his time, although he suffered from conditions related to obesity. There were also potential indications of tuberculosis. Inflammatory changes, for example, had afflicted his spine.  相似文献   
47.
48.
After the last Holocene sea level rise (about 6900 BP), the Gulf of Tartessos extended over the south-western area of the nowadays Guadalquivir Valley (Spain). With the development of some depositional littoral landforms and the progressive infill, the system evolved towards an inland lagoon. The first political system in the area emerged and collapsed from the fourth to the second millennium BC. Around the first millennium BC the culture of Tartessos flourished in this area under the Phoenician influence, but it vanished by the sixth century BC. The quest of its lost capital, the city of Tartessos, has been one of the most exciting archaeological enterprises in the past century. The former coastline and the bathymetry of the gulf can be reasonably reconstructed from geo-archaeological studies, and it can be used for the numerical modeling of tide and tsunami propagation in this water body. Models, with a spatial resolution of 30 s of arc, are based on the 2D non-linear hydrodynamic equations and have been previously validated under nowadays conditions. Computed tidal elevations and currents can provide some insight on the ancient trades for ship traffic and fisheries. The simulation of tsunami propagation, like the catastrophic one of 1755, allows estimating their potential hazardous effects on ancient coastal cities.  相似文献   
49.
Marsola, J.C.A., Grellet-Tinner, G., Montefeltro, F.C., Sayão, J.M., Hsiou, A.S. & Langer, M.C., 2014. The first fossil avian egg from Brazil. Alcheringa 38, 563–567. ISSN 0311-5518.

In contrast to the rich record of eggs from non-avian dinosaurs, complete eggs attributable to Mesozoic birds are relatively scarce. Nevertheless, several well-preserved specimens have been discovered over the last three decades revealing functional and phylogenetic characters that shed light on the breeding strategies of extinct birds. Here we report the first fossil avian egg from Brazil, which was discovered in Upper Cretaceous strata of São Paulo in the southeastern part of the country. The taxonomic identity and structural features of the biomineralized tissues were determined using a combination of Scanning Electron Microscopy, Wave Dispersion Energy analyses and Computed Tomography. These show that the 125.5-μm-thick shell of the 31.4?×?19.5?mm egg incorporates three structural layers of similar thickness with both prismatic and aprismatic boundaries. Close similarity between the Brazilian bird egg and those of enantiornithines from the Upper Cretaceous Bajo de la Carpa Formation (Río Colorado Subgroup) of Argentina advocates affinity with basal Ornithothoraces. Furthermore, coherency of their depositional contexts might imply a compatible preference for breeding and nesting environments.

Júlio Cesar de A. Marsola [], Annie Schmaltz Hsiou [] and Max C. Langer [], Laboratório de Paleontologia de Ribeirão Preto, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, São Paulo state, 14040-901, Brazil. Gerald Grellet-Tinner [], Centro Regional de Investigaciones La Rioja—Consejo Nacional de Investigaciones Científicas y Técnicas, Entre Ríos y Mendoza s/n, 5301 Anillaco, Argentina; Orcas Island Museum, PO Box 134, 181 North Beach Road, Eastsound, WA 98245. Felipe C. Montefeltro [], Departamento de Zoologia, Universidade Estadual Paulista, Avenida 24A 1515, Rio Claro, São Paulo State, 13506-900, Brazil. Juliana M. Sayão [], Laboratório de Diversidade do Nordeste, Núcleo de Biologia, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Rua do Alto do Reservatório s/n, Bela Vista, Vitória de Santo Antão, Pernambuco state, 52050-480, Brazil. Received 18.12.2013; revised 30.4.2014; accepted 18.5.2014.  相似文献   
50.
The article discusses the significance of the concept of gender for historical analysis, particularly on the basis of the importance of different types of ego-documents for the self-expression of the sexes. Attention is focused mainly on the status of autobiographies as a historical source, with some consideration of other types of life writing. It is shown how the form of this genre affects the sexes’ access to self-expression and how their differing ‘cultural space’ opens up opportunities for people's self-creation. The development is viewed in an international light, with reference to both ego-documents and history in general, and it is shown how sources of this kind and women's perspectives are necessary preconditions for the humanities to be able to achieve an important reinterpretation of older historical arguments. Each can provide scholars with opportunities to investigate material that has previously defied their analysis.  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