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   195篇
  免费   5篇
  2024年   2篇
  2021年   1篇
  2020年   1篇
  2019年   6篇
  2018年   5篇
  2017年   1篇
  2016年   4篇
  2015年   5篇
  2014年   3篇
  2013年   48篇
  2012年   7篇
  2011年   7篇
  2010年   10篇
  2009年   4篇
  2008年   4篇
  2007年   3篇
  2006年   7篇
  2005年   3篇
  2004年   2篇
  2003年   6篇
  2002年   4篇
  2001年   2篇
  2000年   2篇
  1999年   3篇
  1998年   1篇
  1997年   3篇
  1996年   2篇
  1995年   4篇
  1994年   4篇
  1993年   1篇
  1992年   3篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   4篇
  1986年   7篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
  1958年   1篇
  1957年   2篇
  1950年   1篇
排序方式: 共有200条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Summary Now, for the first time, it is possible to place in an exact archaeological context the polished tools which have been collected for many years on the surface in the savanna immediately to the south of the equatorial forest. In Lower Zaïre, in an area of 6000 km2, polished tools have been found systematically associated with a particular type of pottery. This pottery, which was previously known as Groupvi pottery and which we propose calling Ngovo group pottery is very distinctive.Although faunal remains associated in one case were of wild animals, someElaeïs andCanarium nuts could indicate the beginnings of agriculture. A series of dates in good agreement place these polished tools and this pottery within the last two centuries bc.At the present time, iron-working in Lower Zaïre has not been dated prior to the second century ad. This Early Iron Age is associated with the Kay Ladio group pottery which is possibly derived from the Ngovo group.
Résumé Pour la première fois, il est possible de préciser le contexte archéologique des outils polis que depuis longtemps on recueillait en surface dans les savanes immédiatement au sud de la forêt équatoriale.Au Bas-Zaïre, dans une zone de plus de 6000 km2, des outils polis ont été trouvés systématiquement en association avec une céramique d'un type particulier. Cette céramique, connue précédemment sous le nom de céramique du groupevi et que l'on propose d'appeler dorénavant groupe de Ngovo, est très caractéristique.Bien que les restes de faune qui y sont associés dans une grotte soient ceux d'animaux sauvages, des noix d'Elaeïs et deCanarium indiquent peut-être un début d'agriculture.Une série de datations remarquablement convergentes placent ces outils polis et cette céramique durant les deux derniers siècles bc.La métallurgie n'est jusqu'à présent pas datée au Bas-Zaïre avant le 2e siècle ad. Cet âge du fer ancien est associé à la céramique du groupe Kay Ladio qui dérive peut-être du groupe de Ngovo.
  相似文献   
5.
6.
7.
Geographical variables generally show spatially structured patterns corresponding to intrinsic characteristics of the environment. The size of the sampling unit has a critical effect on our perception of phenomena and is closely related to the variance and correlation structure of the data. Geostatistical theory uses analytical relationships for change of support (change of sampling unit size), allowing prediction of the variance and autocorrelation structure that would be observed if a survey was conducted using different sampling unit sizes. To check the geostatistical predictions, we use a test case about tree density in the tropical rain forest of the Pasoh Reserve, Malaysia. This data set contains exhaustive information about individual tree locations, so it allows us to simulate and compare various sampling designs. The original data set was reorganized to compute tree densities for 5 times 5-, 10 times 10-, and 20 times 20-meter quadrat sizes. Based upon the 5 times 5-meter data set, the spatial structure is modeled using a nugget effect (white noise) plus an exponential model. The change of support relationships, using within-quadrat variances inferred from the variogram model, predict the spatial autocorrelation structure and new variances corresponding to 10 times 10-meter and 20 times 20-meter quadrats. The theoretical and empirical results agreed closely, whereas neglecting the autocorrelation structure would have led to largely underestimating the variance. As the quadrat size increases, the range of autocorrelation increases, while the variance and the proportion of noise in the data decrease.  相似文献   
8.
The investigation of a simple behavior, child naming, can provide insights into the varying reactions of families confronted by the extraordinary war losses of the First World War. The current study analyses names given in a large cohort of French orphans born 1914–1916, constructed thanks to the linkage of civil registers with a nationwide database of soldiers who died during the War. It shows that a prenatal loss of father was associated with a strong increase in father's name transmission. The phenomenon was twice as intense in officers' offspring. Regression analysis suggests the precise timing of the father's death controlled this change in naming behavior: father's name transmission was at a maximum when the father died at the very beginning of pregnancy.  相似文献   
9.
A sailing replica based on the archaeological remains and structural analysis of the 6th‐century archaic Greek sewn boat Jules‐Verne 9 was built in Marseille as part of the city's European Capital of Culture 2013 programme. Full‐scale reconstruction allowed investigation of specific aspects of the methods used to build a shell‐first, sewn‐plank, and lashed‐frame vessel, as well as learning the gestures and know‐how of the original shipbuilders. The first two seasons of sailing trials, including short journeys in the Bay of Marseille and longer, coast‐hopping expeditions, reflecting the uses of the original vessel have taken place and are reported here.  相似文献   
10.
Following the exceptional discovery of Neolithic engravings on a boulder at Vallée aux Noirs in the Fontainebleau forest, south of Paris, an excavation trench was opened in order to access the buried part of the decorated rock panel and explore the stratigraphic context of the artwork. A palaeosol was found two metres below the modern ground level, underneath multiple layers of sterile sandy soil forming a very compact sequence from which only one archaeological artefact was recovered – an Iron Age fibula (c.200–300 BC). Dating of the palaeosol was attempted through two different methods: AMS dates from charcoal suggest a significant span from the Early Bronze Age to the Iron Age, while two more consistent OSL dates point to formation of the palaeosol during the Late Neolithic (3500–3000 cal BC). The entire engraved rock surface (16 m2), including its buried part, was fully recorded. Four main semiotic groups were identified: a typical fifth‐millennium crook‐hafted axe with a ring, two boats with steering oars, and a central, very tall human figure dominating the composition from its 3.5‐metre height.  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