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   998篇
  免费   69篇
  国内免费   13篇
  2024年   1篇
  2023年   15篇
  2022年   19篇
  2021年   46篇
  2020年   25篇
  2019年   31篇
  2018年   31篇
  2017年   40篇
  2016年   25篇
  2015年   28篇
  2014年   31篇
  2013年   77篇
  2012年   23篇
  2011年   28篇
  2010年   25篇
  2009年   42篇
  2008年   55篇
  2007年   65篇
  2006年   51篇
  2005年   27篇
  2004年   30篇
  2003年   29篇
  2002年   28篇
  2001年   22篇
  2000年   18篇
  1999年   15篇
  1998年   9篇
  1997年   13篇
  1996年   18篇
  1995年   17篇
  1994年   12篇
  1993年   14篇
  1992年   16篇
  1991年   18篇
  1990年   2篇
  1989年   10篇
  1988年   14篇
  1987年   8篇
  1986年   20篇
  1985年   15篇
  1984年   16篇
  1983年   2篇
  1982年   11篇
  1981年   7篇
  1980年   5篇
  1979年   7篇
  1978年   4篇
  1977年   10篇
  1976年   4篇
  1974年   1篇
排序方式: 共有1080条查询结果,搜索用时 15 毫秒
261.
晚侏罗世摇蚊科新属、种   总被引:3,自引:0,他引:3  
张俊峰 《古生物学报》1991,30(5):556-569
本文描述了我国冀北和鲁东上侏罗统摇蚊科化石3属、3种,其中,1新属和3新种。冀北大北沟组中不存在Chironomaptera gregaria种化石,以前被鉴定为幽蚊科的这个种实际上应为摇蚊科的1个新种。并对如何区分上侏罗统这两个科成虫化石作了简述。  相似文献   
262.
本文描述了山西太原西山煤田太原组7号煤层煤核中的3种石化科达植物雄性繁殖器官的解剖构造特征。Cordaianthus ramcnt-rarus sp. nov. 具螺旋状排列的苞片及生殖短枝,生殖短枝呈扁状,不育鳞片数目很少。C. ximinensis sp. nov. 的苞片及生殖短枝呈四列状着生于主轴上,主轴横切面呈菱形或四边形。C. cf. concinnus Delevoryas与欧美植物区的C. concinnus Delevoryas的区别在于其鳞片排列较紧密。欧美植物区的Cordaianthus的苞片及生殖短枝几乎都是呈二列状着生于主轴上。本文报道的C. rament-rarus sp. nov. 的苞片及生殖短枝在主轴上则以螺旋状排列,代表一种新的类型,其进化程度可能比二列状排列的类型要高。  相似文献   
263.
The paper deals with a Neanderthal human femur, recovered during excavations in Santa [corrected] Croce Cave, Bisceglie. The cave also yielded Mousterian lithic industry and fauna indicating a paleoclimate condition with dry-warm tendency and savannah landscape. Metrical, morphometrical, and morphological analysis, and the comparison with Neanderthal specimens show that the femur belonged to an adult individual. It particularly shows great affinities with the analogous specimens from La Ferrassie 1 and 2, Spy 2, and Fond de Forêt, which are similar in size and, above all, show similar archaic morphological traits.  相似文献   
264.
Upper pleistocene fossil hominids from Sri Lanka   总被引:2,自引:0,他引:2  
Between 1978 and 1983 hominid skeletal remains were collected from the cave sites of Batadomba lena and Beli lena Kitulgala in Sri Lanka (formerly Ceylon). These are the most ancient specimens of anatomically modern Homo sapiens found thus far in South Asia, radiocarbon dates placing them in the Upper Pleistocene. Morphometric analysis of the remains of some 38 individuals from the two sites indicates that these populations were characterized by medium stature, moderate to pronounced cranial and postcranial robusticity, medium-size permanent tooth crown measurements, prognathic alveolar facial proportions, and low incidence of osseous and dental pathological conditions. Comparisons of these ancient Sri Lankans with other prehistoric skeletal series from South Asia and elsewhere support the hypothesis that muscular-skeletal robusticity was a significant physical adaptation of earlier hunting-foraging populations. A trend towards reduction of sexual dimorphism and development of more gracile body form and smaller teeth appears to have accelerated with the socioeconomic transition to food-production strategies involving agriculture and pastoralism and refinement of technologies for food procurement and preparation, as documented by morphometric studies of later prehistoric inhabitants of South Asia.  相似文献   
265.
Fossil hominid remains dating to the Upper Pleistocene in Yugoslavia are reviewed. Particular emphasis is placed on the assessment of a hominid frontal from the site of Velika Pe?ina in northwestern Croatia. This specimen represents the earliest absolutely-dated hominid associated with the Upper Paleolithic in Europe. Also the hominid material from the site of Veternica is discussed, and data are presented on the new remains from ?andalja. It is concluded that no Neandertal remains, except for Krapina, have been found in Yugoslavia.  相似文献   
266.
《L'Anthropologie》2022,126(3):103049
Stone and bone artefacts serving as expedient food-procurement and processing implements are the principal and most frequent findings at Palaeolithic sites. Utilitarian art items, often aesthetically fashioned artefacts, are much less common. Emergence of cognitive art within the broader Ural region was determined by progressive cultural developments and adaptations of anatomically modern human beings to mosaic mountain settings and parkland-steppes. At the Urals’ Late Pleistocene cave sites, objects, which were made frequently of unusual and rare materials and are presumed to be of a ritual nature, are represented by adornments and artworks bearing stylized pictorial images. Zoomorphic figurines produced from flint and mammoth ivory document the high skills of Stone Age artisans. The earliest, utilitarian, art-related works of the Urals include sculptures using natural pre-forms such as river pebbles and animal bones, occasionally ochre-painted or ornamented by incising or engraving. Personal decorations are represented by pendants and beads made of stone, shell, bone, and teeth of animals. Rare exemplars are made from material of non-local provenance, such as petrified wood or segments of fossil sea-lily (crinoids) and are indicators of a broad geographic activity-range and/or regional interactions among local groups of hunter-gatherers. Artisanal instruments associated with rock art, for example, lamps made from stone and clay as well as pieces of ochre, belong to a specific category. Aesthetic-looking minerals with appealing colours and textures, such as serpentine, rock crystal, chalcedony, and jasper, it may be assumed, were intended for religious or cultic purposes, but also may have been curated simply because of their natural rarity. These art-related items likely had symbolic value and spiritual meaning apart from purely decorative function. Understanding utilitarian art objects offers insights to every-day life of the Palaeolithic people of the Urals, and their behavioural and environmental adjustments, which culminated in multifarious, iconographic expressions at the end of the Last Glacial stage.  相似文献   
267.
268.
Tree-ring research in the Altai-Sayan Mountains so far only considered a limited number of well-replicated site chronologies. The dendroecological and palaeoclimatological potential and limitations of large parts of south-central Russia therefore remain rather unexplored. Here, we present a newly updated network of 13 larch (Larix sibirica Ldb.) tree-ring width (TRW) chronologies from mid to higher elevations along a nearly 1000 km west-to-east transect across the greater Altai-Sayan region. All data were sampled between 2009 and 2014. The corresponding site chronologies cover periods from 440 to 860 years. The highest TRW agreement is found between chronologies ≥2200 m asl, whereas the material from lower elevations reveals overall less synchronized interannual to longer-term growth variability. While fluctuations in average June–July temperature predominantly contribute to the growth at higher elevations, arid air masses from Mongolia mainly affect TRW formation at lower elevations. Our results are indicative for the dendroclimatological potential of the Altai-Sayan Mountains, where both, variation in summer temperature and hydroclimate can be robustly reconstructed back in time. These findings are valid for a huge region in central Asia where reliable meteorological observations are spatially scarce and temporally restricted to the second half of the 20th century. The development of new high-resolution climate reconstruction over several centuries to millennia will further appear beneficial for timely endeavors at the interface of archaeology, climatology and history.  相似文献   
269.
Ancient genomes can help us detect prehistoric migrations, population contractions, and admixture among populations. Knowing the dynamics of demography is invaluable for understanding culture change in prehistory, particularly the roles played by demic and cultural diffusion in transformations of material cultures. Prehistoric Europe is a region where ancient genome analyses can help illuminate the interplay between demography and culture change. In Europe, there is more archeological evidence, in terms of detailed studies, radiometric dates, and explanatory hypotheses that can be evaluated, than in any other region of the world. Here I show some important ways that ancient genomes have given us insights into population movements in European prehistory. I also propose that studies might be increasingly focused on specific questions of culture change, for example in evaluating the makers of “transitional” industries as well as the origins of the Gravettian and spread of the Magdalenian. I also discuss genomic evidence supporting the large role that demic expansion has played in the Neolithization of Europe and the formation of the European population during the Bronze Age.  相似文献   
270.
Fragmentary remains of ornithomimids (Ornithomimidae indet.) from the Lower Santonian (Upper Cretaceous) Kansai locality in northwestern Fergana (Tajikistan) are described, and the composition of its dinosaurian assemblage is updated.  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