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   1995篇
  免费   424篇
  2023年   10篇
  2022年   21篇
  2021年   36篇
  2020年   51篇
  2019年   184篇
  2018年   145篇
  2017年   130篇
  2016年   159篇
  2015年   140篇
  2014年   132篇
  2013年   297篇
  2012年   197篇
  2011年   138篇
  2010年   119篇
  2009年   81篇
  2008年   105篇
  2007年   110篇
  2006年   76篇
  2005年   71篇
  2004年   54篇
  2003年   50篇
  2002年   36篇
  2001年   35篇
  2000年   27篇
  1999年   5篇
  1998年   1篇
  1997年   1篇
  1996年   2篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1983年   1篇
排序方式: 共有2419条查询结果,搜索用时 15 毫秒
101.
"文革"中的知识青年上山下乡运动研究述评   总被引:3,自引:0,他引:3  
"文革"中的知青上山下乡运动是当代中国的重大事件之一.中外学者对这场运动进行了深入的探讨研究,取得了不少成果,发表了一批论文及专著,整理和公布了许多资料,目前在许多问题上已达成共识,与此同时也存在很大分歧,如关于"文革"中的知识青年上山下乡运动的基本动因问题、历史进程及其评价问题,对知青"返城风"及上山下乡运动终止原因等等,这些都有待研究者进行深入细致的研究.此外,在研究中还存在资料收集困难、研究力量薄弱、研究方法单一等困难与不足.  相似文献   
102.
Archaeological research on disasters has increased substantially since Sheets's 1980 review of the topic, and with heightened media coverage and funding for the study of such events, archaeological interest will continue to grow. This paper examines how prehistorians have incorporated disasters into their research since 1980, using the literature on El Niño as an illustrative case, and assesses this work in relation to geographical approaches to disaster as well as concepts that have been developed within the new ecologies.  相似文献   
103.
Examining recently excavated burnt burials, we explore the potential of spatial analysis to contribute to the understanding of changes that human body goes through during burning and relocation to the place of secondary deposition. Artificial heat decomposition of a body is a complex process that consists of several stages of intentional manipulation with the body. Each stage can be biased by several accidental factors which then significantly change the final archaeological record. We focussed on the post‐burning stage, especially the pathways of bone fragments to secondary deposition. We investigated spatial distribution and weight of bones in urns and pits and asked whether it is possible to observe their intentional arrangement. The trend of bone arrangement could be distinguished in most cases. Bones of peripheral parts of body were typically situated at the bottom; skull bones were usually concentrated in the upper part. However, the weight underrepresentation of all investigated burials was apparent. Deposition of selected burnt bones suggests their careful collection from the pyre and complex post‐mortem manipulation. Our detailed analysis aims to reconstruct particular steps executed during funeral rites of past populations. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
104.
大数据背景下国内人文地理研究进展与方法审视   总被引:3,自引:0,他引:3  
通过梳理人文地理领域杂志近年大数据文章解释其与大数据应用的关系,强调其应用给人文地理学研究带来机遇和挑战:①大数据作为研究方法,不能代替传统人文地理研究范式,而是对现研究方法的补充。大数据和小数据需对话交流;②大数据本身是一种话语权,嵌入人文地理研究系统。保证人文地理学多样性,避免过度依赖大数据,需在批判角度审视和运用;③需关注大数据对于人文地理学研究方法和思想的影响;④运用大数据解读地理和空间过程复杂性的同时,应看到大数据应用对公共服务的潜力,思考其结果如何更好的服务社会。  相似文献   
105.
One of the main factors involved in entheseal changes (EC) aetiology may be related to the physiological limits of biomechanical loading fixed during bone development, such that higher load during childhood and the adolescent growth spurt leads to a lower frequency of EC during adulthood. In this sense, it is possible that ECs may be related to overloading beyond an individual's normal physiological limits as established during childhood and adolescence. This meta‐analysis tested this aetiological possibility by studying the influence of terrain on the entheses of the lower extremities. The hypothesis is that individuals who inhabited rugged terrain have lower EC than those living in flat terrain. This is because biomechanical loads associated with rugged terrain will lead to a higher normal capacity (defined during skeletal development) mitigating the probability of overloading compared to those living in flat terrain who will therefore have a higher frequency of ECs. To test this, papers reporting EC frequencies in the lower limbs were analysed alongside the local terrain. Terrain was defined into two categories: flat or rugged based on altimetry profile, i.e. the average elevation gains and losses along four specific paths (North‐South, East‐West, Northwest‐Southeast, Southwest‐Northeast). Odds ratios were calculated to compare rugged and flat terrain. The overall results are consistent with the hypothesis that overloading is a factor in EC aetiology. However, when the analysis is conducted by sex and side, this general trend does not always occur. Limitations such as the lack of standardized age ranges could be affecting the outcome, i.e. older individuals have a higher frequency of ECs. The findings of this analysis suggest that the theoretical assumptions associated with the cause of ECs require further testing and evaluation. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
106.
It is believed on the basis of archaeozoological research that the domestic cat appeared in Central Europe during the Roman Period. In Poland, the domestic cat is a common species in medieval deposits. Only a few finds of cat remains of pre‐medieval age have been reported from Poland to date, including several specimens from deposits older than the Roman Period, dated to the pre‐Roman Period and even the Bronze Age. To clarify the earliest history of the domestic cat in Poland, the paper presents a review of the available published cat remains and adds some data about newly discovered remains. Combined methods of morphometry and ancient DNA were applied to enable distinction of wildcats and domestic cats. The domestic cat remains were radiocarbon dated. In six cases of domesticated cat reported in the literature, five were positively taxonomically verified, both by morphology and by genetic analysis, and one was recognised as a European wildcat. According to radiocarbon chronology, the oldest studied find is dated to the fourth–third century bc and represents a wildcat. Only two individuals of domestic cat – skeletons from Łojewo and Sławsko Wielkie, both from Kuyavia region (central‐northern Poland) – represent the Roman Period (first–third century ad ), and they are the oldest confirmed domestic cats in Poland. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
107.
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   
108.
A. Tarriño 《Archaeometry》2015,57(5):928-948
A new classification system is proposed to describe the volumetric formats of clastic lithic products of geological and archaeological origin. In order to build this operative classification, the rectangular block or cuboid is established as the standard geometric format to represent their three‐dimensional format (the X‐axis being length or long diameter, the Y‐axis being the width or intermediate diameter, and the Z‐axis being the thickness or short diameter) on a two‐dimensional diagram. To obtain this graph, each absolute coordinate (X, Y, Z) defining the prisms is projected on to an auxiliary plane with a new set of relative coordinates (x, y, z), expressed as the percentage of their sum. The projection generates a triangular diagram on which the indices of elongation and flatness are represented. A geometric transformation converting the triangular diagram into a quadrangular diagram has been produced in order to better represent the scatter points. Then, a double scale is necessary: (i) an absolute scale to quantify the indices, and (ii) a relative scale to calculate where the graphic locus is projected. This new graph also allows us to work with statistical parameters. Finally, two classic examples of applications selected from the literature are shown.  相似文献   
109.
In the present study, the fragments of wall painting found in the Roman Temple Complex at Horvat Omrit were analysed for the first time using the non‐destructive techniques of X‐ray diffraction (XRD) and scanning electron microscopy (ESEM) equipped with energy‐dispersive X‐ray spectroscopy (EDS). The application of these methods enabled unambiguous identifications of the pigments and plaster components of the samples. Quantitative information on mineral composition, crystallite size and elemental composition of each studied paint layer and plaster was collected. Based on the results of the XRD and EDS analyses, the green pigment was identified as celadonite. It was revealed that the Egyptian blue pigment does not contain impurities of tin and lead, and this excludes the use of bronze scrap in its synthesis. Comparison of the mineral composition of the paint layers indicates that a wider palette of colours was obtained by mixing the available mineral pigments. The study of cross‐sections of painted specimens revealed the usage of slaked lime for plastering. The obtained results give a new insight into the wall painting technique employed by ancient artists at Horvat Omrit, in northern Israel.  相似文献   
110.
Voltammetry of microparticles using a paraffin‐impregnated graphite electrode (VMP/PIGE) was applied as a very local and non‐invasive analytical technique in order to investigate the presence of remains of metallic plating on two ferrous and one cuprous artefact from the medieval period. The analyses have been performed locally and selectively on regions presenting particular features, such as texture, cohesion and colour differences. The results confirm local differences in chemical composition, leading to conclusions about the presence of metallic plating on these artefacts.  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