全文获取类型
收费全文 | 3250篇 |
免费 | 124篇 |
出版年
2020年 | 32篇 |
2019年 | 46篇 |
2018年 | 80篇 |
2017年 | 74篇 |
2016年 | 105篇 |
2015年 | 76篇 |
2014年 | 59篇 |
2013年 | 1051篇 |
2012年 | 115篇 |
2011年 | 110篇 |
2010年 | 119篇 |
2009年 | 112篇 |
2008年 | 79篇 |
2007年 | 124篇 |
2006年 | 109篇 |
2005年 | 45篇 |
2004年 | 46篇 |
2003年 | 36篇 |
2002年 | 34篇 |
2001年 | 35篇 |
2000年 | 25篇 |
1999年 | 40篇 |
1998年 | 26篇 |
1997年 | 20篇 |
1996年 | 24篇 |
1995年 | 33篇 |
1994年 | 21篇 |
1993年 | 28篇 |
1992年 | 27篇 |
1991年 | 29篇 |
1989年 | 21篇 |
1988年 | 26篇 |
1987年 | 33篇 |
1986年 | 33篇 |
1985年 | 31篇 |
1984年 | 27篇 |
1983年 | 27篇 |
1982年 | 33篇 |
1981年 | 30篇 |
1980年 | 28篇 |
1979年 | 21篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 23篇 |
1975年 | 23篇 |
1973年 | 16篇 |
1972年 | 17篇 |
1970年 | 16篇 |
1969年 | 16篇 |
1967年 | 18篇 |
排序方式: 共有3374条查询结果,搜索用时 15 毫秒
31.
V. MEJDAHL 《Archaeometry》1972,14(2):245-256
This article outlines the thermoluminescent dating technique employed at Risö. The intensity of beta and gamma radiation is determined by means of the TL phosphors CaSO4:Mn and CaSO4:Dy, and the determination of accumulated exposure is based on quartz and feldspar inclusions with a size of 0.3–0.5 mm. Results are presented of a dating programme comprising sherds, bricks, burned stones and burned clay (from kilns) from seventeen excavation sites. The age of the sites ranged from a.d. 1600 to 4000 b.c. 相似文献
32.
34.
35.
V. MEJDAHL 《Archaeometry》1969,11(1):99-104
36.
37.
38.
ABSTRACT. Traditional models of regional diversification do not capture the trade-off between stability and living standards. In this paper, we characterize regions as open activity models subjected to both productivity and price shocks. We then partially rank small diversification policies by the direction in which they point away from the current industrial structure in mean-variance space. Some general patterns emerge. In particular, diversification for regional self-sufficiency and away from regional comparative advantage may be undesirable. 相似文献
39.
"Malthusians maintain that rapid population growth aggravates poverty, while Marxists contend that social formations determine its nature and extent. Each perspective is incomplete, however, since it ignores the insights of the other. Latin American states, characterized by dependent capitalism formations and dominated by ruling elites, are generally incapable of solving the problems of population and poverty. Since population growth under dependent capitalism weakens labor's bargaining position against capital, reduced population growth is emphasized as a labor empowerment strategy the poor can implement on their own to improve their socioeconomic conditions." 相似文献
40.
Ashok V. Desai 《Development and change》1990,21(4):723-749
This paper analyses the results of a survey of twenty-four recent cases of technology imports into India. Over the last thirty years, large firms in Indian industry have come under increasing competitive pressure from small firms which pay lower wages and which are also favoured by government policy. Most small firms obtain technology through informal channels within the country. But some import technology; and larger firms import it in their defence against competition from small firms. Larger firms, with a history and a reputation, have better access to technology from abroad; smaller firms often go through an extensive search before they find a willing technology supplier. Irrespective of size, firms that import technology within their own specialization are observed to put more effort into technology choice, absorption and adaptation. Indian policies of across-the-board import substitution, by promoting diversification into new products developed abroad, tend to discourage specialization and hence to encourage technology imports and to work against technology absorption and innovation. 相似文献