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   1484篇
  免费   90篇
  2024年   8篇
  2023年   40篇
  2022年   16篇
  2021年   19篇
  2020年   62篇
  2019年   77篇
  2018年   90篇
  2017年   82篇
  2016年   74篇
  2015年   57篇
  2014年   58篇
  2013年   189篇
  2012年   115篇
  2011年   86篇
  2010年   82篇
  2009年   73篇
  2008年   80篇
  2007年   75篇
  2006年   60篇
  2005年   30篇
  2004年   18篇
  2003年   28篇
  2002年   20篇
  2001年   12篇
  2000年   17篇
  1999年   9篇
  1998年   6篇
  1997年   7篇
  1996年   7篇
  1995年   5篇
  1994年   4篇
  1993年   7篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1987年   2篇
  1985年   9篇
  1984年   6篇
  1983年   9篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1979年   9篇
  1978年   3篇
排序方式: 共有1574条查询结果,搜索用时 15 毫秒
941.
This paper is a preliminary overview of the main characteristics of the archaeological resource of Oman from a management perspective. It looks at the resource in terms of form, space and time. It covers a pilot statistical analysis of the archaeological data so far input into the proposed National Archaeological Database of Oman (NADO). The main findings of this analysis show that the management of Omani archaeological resource lacks a well‐defined strategic research plan, and that there are large research gaps in many geographical and chronological areas. It also shows that the governmental organisations responsible for the management of the country's archaeological resource are not taking into consideration the potential benefits of archaeological records in their management practices.  相似文献   
942.
It has been argued that the corporate kin-group was the main form of socioeconomic organization at the Turkish site of Çatalhöyük during the Pre-Pottery Neolithic B (PPNB). This hypothesis is linked to a claim of long-term repetitive patterning in the use of household space. Çatalhöyük's corporate kin-groups, it is suggested, would have been maintained by social memory, and social memory would have been created by the repeated rebuilding of houses with the same floor plan and by the burial of important members of the corporate kin-groups under house floors. This hypothesis been taken up by a number of authors in recent years. However, it is not clear how much confidence should be invested in the hypothesis as the use of household space at Çatalhöyük during the PPNB has not been subject to formal evaluation. With this in mind, we carried out a study in which we examined the relationship between continuity in house floor plans and the percentage of houses that contain burials. To assess the co-variation between these variables, we developed a GIS-based method of quantifying house wall continuity, and then subjected the resulting index and a number of other variables, including the percentage of houses that contain burials, to factor analysis. The results of the analyses do not support the hypothesis. The house-wall continuity index and the percentage of houses that contains burials load on different factors, which indicates that they do not co-vary through time. This is contrary to the predictions of the corporate kin-group hypothesis. Thus, claims that during the PPNB Çatalhöyük's occupants formed corporate kin groups that were maintained by social memory and “history houses” should be curtailed and interpretations built on this hypothesis should be viewed with suspicion.  相似文献   
943.
When prehistoric archaeological sites yield non-carbonised wood, one of the ways to test for management practices consisting of pollarding and coppicing is analysis of branch diameter and age. However, the interpretation of such data is often based on assumptions. To test whether it is in fact possible to identify past woodland management on the basis of age/diameter analysis in archaeological wood assemblages, this paper presents models that predict the expected age and diameter distribution of branches from unmanaged and managed trees. The models have been tested using data on modern-day Alnus glutinosa, Fraxinus excelsior and species of the genus Salix. Branches of modern-day unmanaged and managed trees with a diameter up to approx. 2 cm (not an absolute limit) have a comparable age. Branches with a diameter of approx. 2–6 cm from unmanaged trees are older than similar branches from managed trees. The age distribution in the latter also ends abruptly. The age/diameter data from the modern-day trees indicate that the models can be used to discern management in the past, if branches up to approx. 2 cm in diameter are avoided and if, critically, taxon, sample size, growing conditions, natural disturbance/opportunistic wood collection and the possibility of diameter selection are taken into account. Archaeological datasets mainly from prehistoric sites are then reinterpreted by means of comparison with the models. Indications of management in prehistory as demonstrated by age/diameter are scarce but available. There is thus a clear need for further research in this field. Practical suggestions are provided for improving the quality of future research on woodland management practices by means of branch age/diameter analysis.  相似文献   
944.
For archaeologists, metallic artifacts are key materials to assess Middle Bronze Age production areas and cultural exchanges. Here, a set of 629 bronze palstaves excavated in northern France, belonging to Breton and Norman typological groups, was treated by (open) outline-based morphometrics with orthogonal polynomial regression. Using robust statistics developed for outlier detection, these Norman and Breton palstave outlines can be divided into two groups: those for which the shape fluctuates close to the standard shape, called “congruent” axes, and those which are far enough from this standard to be considered as “non-congruent”, although they possess most of the features of the typological group. The highest density of discovery (whether congruent and non-congruent in shape) is in the extreme east of Brittany for the Breton axes, while the Norman axes are concentrated in northern Normandy, hence the choice of names. However, the distribution of congruent and non-congruent artifacts appears to be spatially dependent for the Norman group, and to a lesser extent for the Breton group, as there are proportionally more congruent specimens inside the supposed production areas than outside. This contradicts the generally accepted archaeological scheme which hypothesizes that all axes in a group originate from the same production center, and that some items were exported from there to supply neighboring regions. Other minor production centers probably existed, copying the original model with greater shape variation.  相似文献   
945.
Levallois cores and products were manufactured by hominin populations distributed across wide regions of Africa and Eurasia. Levallois technology remains an important focus for research in Palaeolithic archaeology, yet quantitative morphological comparisons of Levallois core morphology from different regions remain rare. Here, utilizing Levallois cores from Africa, the Near East, Europe, and the Indian subcontinent, patterns of morphological variability in the shape of the Levallois flaking surface and core outline (margin) shape were examined for patterns of variability and stability across regions using 3D geometric morphometrics. The multivariate statistical shape analyses undertaken revealed a clear pattern: that is, the greatest levels of shape variability in Levallois cores is evident in the form of their outline (planform) shape. Conversely, the geometrical relationship between the margin of the Levallois cores and their topological surface morphology was relatively uniform. This pattern of variability was evident in terms of variation both across regions and between cores from the same locality. These results indicate that the outline form of such cores was a less important variable than the geometric/topological properties of the surface morphology and, in particular, the relationship between the margin of the core and those variables. These results have implications for why it has been reported that replicating such cores in modern experiments is a particularly difficult task. The specific interrelationship between the geometric properties of the core and the core margin provide further evidence that Levallois core technology would be unlikely to emerge from the context of opportunistic migrating platform reduction strategies (such as those seen in many Mode 1 industries). If, as is widely suggested, Levallois cores were deliberate products in Pleistocene contexts, these results also hint that relatively sophisticated means of social transmission (i.e. teaching) may have been required to sustain their production over time and space.  相似文献   
946.
The late Holocene archaeofaunal record of the San Francisco Bay Area demonstrates temporal declines in the abundance of low-cost, high-ranked marine and terrestrial resources. During later periods of occupation, faunal assemblages are often dominated by lower-ranked, higher-cost resources, suggesting an increase in diet breadth through time. Archaeological resource intensification models argue that this marks a late Holocene decline in foraging efficiency in the Bay Area, driven by human-induced harvest pressure. This study examines dietary change in the region using stable carbon and nitrogen isotope data from 65 human burials, spanning two temporal components (cal AD 55–890 and cal AD 762–1550) at the Ellis Landing site (CA-CCO-295). The strong linear relationship between collagen carbon and nitrogen isotope values reflects both marine and terrestrial food consumption, with individuals showing a high level of dietary variability at the site. No temporal trend or meaningful sex differences were found in isotope values. The widening of diet breadth predicted by the archaeofaunal record occurred prior to the occupation of the Ellis Landing shellmound site. The trend in exploiting a greater amount of terrestrial resources during the Middle and Late Period in central California was supported by isotopic evidence.  相似文献   
947.
The nature of long bone formation and the pathways of interaction between bone samples and the burial environment suggest that portions of the bones disconnected from the arterial system are resistant to diagenetic alteration. Preliminary work on femurs from Early Bronze Age hunter-gatherers in Cis-Baikal, Siberia shows that the nature and progression of chemical changes in the bone matrix due to microbial attack can be analyzed using laser ablation inductively coupled plasma mass spectrometry. Intra-osteon variability in elemental concentrations and strontium isotope ratios (87Sr/86Sr) indicate the presence of unaltered portions of bone within diagenetically modified bone and suggest that useful data remain accessible. These biogenic signals can potentially be useful for mobility research in broad terms and the smaller timescales within an individual's lifetime (months, years), accessible therein. Laser ablation micro-sampling of femur specimens showed that intra-osteon elemental composition of Ba, Re, and Cs varied within and was correlated between multiple osteons of a single bone. Portions of chemically unaffected bone were identified within, and effectively discriminated from diagenetically altered bone tissue. Areas showing visual alterations and erratic or uncorrelated Ca and Sr elemental results also had anomalous Sr isotope ratios, suggesting diagenetic alteration in those places. Compositional and isotopic analysis of intact portions of bone supports the hypothesis that hunter-gatherer groups in Cis-Baikal made numerous major movements during their lives. Microscopic analysis of long bones clarifies aspects of biodeterioration and correlations between trace elemental results and diagenetic alteration. Micro-sampling of intact portions of bone expands the scope of available materials for research on mobility and other aspects of human past behavior.  相似文献   
948.
The aim of this research was the understanding of a peculiarly expanded soil sequence in Bologna (i.e., Roman Bononia, Etruscan Felsina), one of the most important archaeological poles for Etruscan colonisation and settlement in northern Italy. The uppermost part of the chronological sequence dating from the Bronze Age up to medieval and modern times was analysed for the first time from geochemical and pedological viewpoints. The integration of archaeological, stratigraphical and pedological data supported by soil chemical analysis, a fundamental key for reconstructing a correct evolutionary sequence, made it possible to recognise seventeen buried Soil Units (ancient Technosols, Anthrosols and Cambisols) characterised by different kinds and degrees of intensity of anthropogenic influence. In some cases, the results show a relatively severe element concentration (Cu, Sn) mainly characterising the Iron Age (Etruscan and Villanovan) stratigraphic units, representing an ancient industrial pollution linked to local dispersal of melting activity dump products generated in near-site surrounding areas. Therefore, a comparison was possible between natural blank and anthropogenically polluted geochemical values for some local soils.  相似文献   
949.
Three Santacrucian borhyaenoids, Cladosictis patagonica, Pseudonotictis pusillus and Sipalocyon gracilis, are analyzed from a functional-adaptive perspective. Five extant placentals and one marsupial model are also examined in order to interpret the locomotor adaptations of these fossils. Pseudonotictis pusillus is the smallest of the Santacrucian borhyaenoids and is known from fragmentary remains; from its small size, dental specializations and elbow anatomy, this species was certainly not far ecologically from an extant weasel. The postcranium of Sipalocyon gracilis, although poorly known, suggests climbing capabilities, and the pseudo-opposable pollex indicates skilful manipulative behaviour. Cladosictis patagonica was an active predatory form, short-legged and able to climb, although it was a less specialized arboreal form than the contemporaneous Prothylacinus patagonicus; the proportions of its limbs recall that of a living South American marten, the tayra. The pseudo-opposable pollex of Cladosictis, as in Sipalocyon, indicates skilful manipulative behaviour.  相似文献   
950.
This oological analysis supports Palaeognathae monophyly, and places Dromornithidae within Neognathae, the sister clade of Paleognathae. This Dromornithidae relationship is congruent with a recent phylogenetic hypothesis, based on cranial characters, that differs from the original assignment of this group of extinct birds to the Palaeognathae. Minor differences exist between previous palaeognath phylogenetic hypotheses and that obtained from this research. Some of the topological disparities might be influenced solely by inclusion of more fossil taxa in this analysis compared with those considering either molecular or skeletal characters. Surprisingly, oological data differentiate the Australasian palaeognath taxa from those of Africa and South America; this phylogenetic topology conforms to the paleognath geographic distribution.

Regardless of the issues related to Paleognathae, results show that oological characters permit the differentiation of groups at a generic level, thus validating the use of eggs and eggshells as a source of evolutionary characters.  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