全文获取类型
收费全文 | 1647篇 |
免费 | 66篇 |
出版年
2020年 | 19篇 |
2019年 | 21篇 |
2018年 | 40篇 |
2017年 | 37篇 |
2016年 | 51篇 |
2015年 | 45篇 |
2014年 | 31篇 |
2013年 | 597篇 |
2012年 | 56篇 |
2011年 | 54篇 |
2010年 | 72篇 |
2009年 | 60篇 |
2008年 | 37篇 |
2007年 | 75篇 |
2006年 | 69篇 |
2005年 | 20篇 |
2004年 | 31篇 |
2003年 | 22篇 |
2002年 | 18篇 |
2001年 | 17篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 15篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 18篇 |
1994年 | 11篇 |
1993年 | 9篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 14篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1972年 | 10篇 |
1971年 | 5篇 |
1970年 | 7篇 |
1969年 | 5篇 |
排序方式: 共有1713条查询结果,搜索用时 15 毫秒
181.
182.
183.
M.B. Mednikova M.V. Dobrovolskaya A.P. Buzhilova M.N. Kandinov 《Archaeology, Ethnology and Anthropology of Eurasia》2010,38(1):102-117
A fossil humerus from Khoroshevsky Island, Khvalynsk, Saratov Province, previously believed to have been lost eighty years ago, was studied by osteometric, X-ray, tomographic, histological, and paleopathological methods. The results suggest that the fossil represents an adult Neanderthal, apparently male, displaying a peculiar hormonal status which ? nds no direct parallels among known human physiological conditions, either normal or pathological. 相似文献
184.
185.
The results of the lead isotope analysis (LIA) of 15 copper‐base artefacts from the Bronze Age site of al‐Midamman, Yemen, are reported. The LIA data suggest the existence of an indigenous Bronze Age metal production and exchange system centred on the southern Red Sea region, distinct from those in neighbouring regions of Arabia and the Levant. These preliminary results are highly significant for the archaeology of the region, suggesting that local prehistoric copper extraction sites have thus far gone unrecorded, and highlighting the need for systematic archaeometallurgical fieldwork programmes in the countries surrounding the southern Red Sea. 相似文献
186.
187.
Douglas V. Armstrong Mark Hauser David W. Knight Stephan Lenik 《International Journal of Historical Archaeology》2009,13(1):94-111
An archaeological GIS is used to examine the late eighteenth-century cultural landscape of St. John, US Virgin Islands. Land
use patterns are reconstructed using a combination of historic maps, tax records, and survey reconnaissance. The study demonstrates
significant, heretofore undocumented, transitions taking place that reflect dynamic cultural and economic change within Danish
West Indian plantation society that includes a significant trend towards land ownership by free-colored St. Johnians more
than a half a century before emancipation. These venues of freedom are discussed in relation to broader patterns of estate
consolidation and economic shifts. 相似文献
188.
V. SÁNCHEZ E. VINDEL T. MARTÍN-CRESPO M. CORBELLA E. CARDELLACH D. BANKS 《Geofluids》2009,9(4):338-355
The fluorite deposits of Asturias (northern Iberian Peninsula) are hosted by rocks of Permo‐Triassic and Palaeozoic age. Fluid inclusions in ore and gangue minerals show homogenization temperatures from 80 to 170°C and the presence of two types of fluids: an H2O–NaCl low‐salinity fluid (<8 eq. wt% NaCl) and an H2O–NaCl–CaCl2 fluid (7–13 wt% NaCl and 11–14 wt% CaCl2). The low salinity and the Cl/Br and Na/Br ratios (Cl/Brmolar 100–700 and Na/Brmolar 20–700) are consistent with an evaporated sea water origin of this fluid. The other end‐member of the mixture was highly saline brine with high Cl/Br and Na/Br ratios (Cl/Brmolar 700–13 000 and Na/Brmolar 700–11 000) generated after dissolution of Triassic age evaporites. LA‐ICP‐MS analyses of fluid inclusions in fluorite reveal higher Zn, Pb and Ba contents in the high‐salinity fluids (160–500, 90–170, 320–480 p.p.m. respectively) than in the low‐salinity fluid (75–230, 25–150 and 100–300 p.p.m. respectively). The metal content of the fluids appears to decrease from E to W, from Berbes to La Collada and to Villabona. The source of F is probably related to leaching of volcanic rocks of Permian age. Brines circulated along faults into the Palaeozoic basement. Evaporated sea water was present in permeable rocks and faults along or above the unconformity between the Permo‐Triassic sediments and the Palaeozoic basement. Mineralization formed when the deep brines mixed with the surficial fluids in carbonates, breccias and fractures resulting in the formation of veins and stratabound bodies of fluorite, barite, calcite, dolomite and quartz and minor amounts of sulphides. Fluid movement and mineralization occurred between Late Triassic and Late Jurassic times, probably associated with rifting events related to the opening of the Atlantic Ocean. This model is also consistent with the geodynamic setting of other fluorite‐rich districts in Europe. 相似文献
189.
190.