全文获取类型
收费全文 | 10727篇 |
免费 | 415篇 |
出版年
2020年 | 147篇 |
2019年 | 199篇 |
2018年 | 237篇 |
2017年 | 271篇 |
2016年 | 342篇 |
2015年 | 227篇 |
2014年 | 224篇 |
2013年 | 3142篇 |
2012年 | 311篇 |
2011年 | 349篇 |
2010年 | 363篇 |
2009年 | 302篇 |
2008年 | 271篇 |
2007年 | 277篇 |
2006年 | 264篇 |
2005年 | 156篇 |
2004年 | 127篇 |
2003年 | 132篇 |
2002年 | 145篇 |
2001年 | 167篇 |
2000年 | 132篇 |
1999年 | 163篇 |
1998年 | 109篇 |
1997年 | 88篇 |
1996年 | 95篇 |
1995年 | 112篇 |
1994年 | 101篇 |
1993年 | 115篇 |
1992年 | 93篇 |
1991年 | 86篇 |
1990年 | 86篇 |
1989年 | 98篇 |
1988年 | 83篇 |
1987年 | 98篇 |
1986年 | 98篇 |
1985年 | 113篇 |
1984年 | 113篇 |
1983年 | 134篇 |
1982年 | 100篇 |
1981年 | 111篇 |
1980年 | 104篇 |
1979年 | 103篇 |
1978年 | 98篇 |
1977年 | 93篇 |
1976年 | 93篇 |
1975年 | 91篇 |
1974年 | 76篇 |
1973年 | 78篇 |
1972年 | 79篇 |
1970年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Spatial compactness has been proposed as a suitable criterion for assessing whether electoral boundaries reflect partisan interests. Although several different measures of spatial compactness have been developed, only limited efforts have been made to compare and evaluate them in the context of electoral redistricting. This paper assesses alternative spatial compactness measures and applies conceptually appealing measures to the provincial ridings proposed by British Columbia's Royal Commission on Electoral Boundaries (1988). 相似文献
62.
Michael A. Nelson 《Journal of regional science》1992,32(1):39-53
ABSTRACT. The proposition that a decentralized structure of local governments can effectively constrain public sector growth is empirically investigated. Data on Swedish municipal sector size for the 1942–87 period are analyzed within the context of a median voter model. The results indicate that decentralization, measured by the number of units of local government serving a given population, constrains the influence of institutional factors (e.g., rent seeking, bureaucracy) on local budgets as long as these units exceed some minimal threshold size. The findings support the view that communities should be given the flexibility to determine their own ideal pattern of local governments. 相似文献
63.
64.
Three rare Himyaritic coins found in the territory of the ancient Hadramawt kingdom are published for the first time. Two of the coins bear the name of the king,'Amdan Bayyin, while the third has the name of Tha'ran Ya'ub. 相似文献
65.
66.
67.
68.
69.
An attempt has been made to relate steatite artifacts to the source of rock from which they were manufactured, using the distribution patterns of rare earth elements. Radiochemical- and instrumental-neutron activation analyses of Shetland steatites suggest that the use of rare earth elements in artifact provenancing may be unreliable. Concentrations of rare earth elements in many Shetland steatites are too low to be measured reliably by a cost effective method. The relative importance of primary igneous and secondary metasomatic processes in controlling steatite rare earth element geochemistry is discussed and geological arguments against the existence of unique rare earth ‘fingerprints’ for steatite are presented. 相似文献
70.