全文获取类型
收费全文 | 8463篇 |
免费 | 317篇 |
专业分类
8780篇 |
出版年
2020年 | 109篇 |
2019年 | 156篇 |
2018年 | 188篇 |
2017年 | 211篇 |
2016年 | 267篇 |
2015年 | 191篇 |
2014年 | 173篇 |
2013年 | 2548篇 |
2012年 | 239篇 |
2011年 | 258篇 |
2010年 | 286篇 |
2009年 | 250篇 |
2008年 | 223篇 |
2007年 | 241篇 |
2006年 | 240篇 |
2005年 | 119篇 |
2004年 | 118篇 |
2003年 | 108篇 |
2002年 | 111篇 |
2001年 | 124篇 |
2000年 | 87篇 |
1999年 | 108篇 |
1998年 | 76篇 |
1997年 | 61篇 |
1996年 | 75篇 |
1995年 | 85篇 |
1994年 | 81篇 |
1993年 | 86篇 |
1992年 | 78篇 |
1991年 | 64篇 |
1990年 | 60篇 |
1989年 | 76篇 |
1988年 | 66篇 |
1987年 | 78篇 |
1986年 | 74篇 |
1985年 | 88篇 |
1984年 | 75篇 |
1983年 | 99篇 |
1982年 | 79篇 |
1981年 | 83篇 |
1980年 | 77篇 |
1979年 | 73篇 |
1978年 | 78篇 |
1977年 | 67篇 |
1976年 | 76篇 |
1975年 | 72篇 |
1974年 | 56篇 |
1973年 | 59篇 |
1972年 | 64篇 |
1970年 | 49篇 |
排序方式: 共有8780条查询结果,搜索用时 0 毫秒
1.
2.
Albert A. Dahlberg 《Journal of archaeological science》1983,10(6):552-553
3.
4.
5.
J.M.P. Cabral M.A. Gouveia A.M. Alarcão J. Alarcao 《Journal of archaeological science》1983,10(1):61-70
The concentrations of two major elements and thirteen trace elements in 73 selected sherds of fine grey ware from the Iron Age and Roman period, excavated at Conimbriga, Santa Olaia and Tavarede, Portugal, were determined by instrumental neutron activation analysis. These concentrations were used to calculate distance matrices which were then subjected to cluster analysis employing SAHN and k-means methods, as well as to principal components analysis, to group the sherds according to the overall similarity of their compositional characteristics. The results showed that equivalent groupings appeared regardless of the taxonomic method used. Two major clusters were recognized corresponding to two different sites, namely Conimbriga and Santa Olaia, suggesting that the ceramics from these sites were made locally. No significant differences in compositional patterns were observed between iron age and roman sherds from Conimbriga. 相似文献
6.
7.
Larry V. St. Louis 《Journal of regional science》1989,29(3):373-385
ABSTRACT. This paper examines the RAS, Mc Menamin and Haring, and Lagrange-multiplier update methods in the context of the dual accounting system of the rectangular input-output model. The motivation was to determine if the additional information contained in the dual system is exploitable, while maintaining the integrity of the rectangular structure with all its advantages. Tests were conducted on the performance of the various algorithms for a derivative Leontief model relative to their performance on the rectangular structure. The results obtained for rectangular tables were generally better than those obtained for the more conventional Leontief ones. 相似文献
8.
E. A. JUDGE 《The Journal of religious history》1989,15(4):394-412
9.
10.