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   8641篇
  免费   384篇
  2020年   119篇
  2019年   174篇
  2018年   489篇
  2017年   393篇
  2016年   488篇
  2015年   193篇
  2014年   168篇
  2013年   2001篇
  2012年   252篇
  2011年   398篇
  2010年   399篇
  2009年   260篇
  2008年   263篇
  2007年   327篇
  2006年   172篇
  2005年   139篇
  2004年   107篇
  2003年   104篇
  2002年   116篇
  2001年   144篇
  2000年   104篇
  1999年   114篇
  1998年   91篇
  1997年   82篇
  1996年   84篇
  1995年   71篇
  1994年   61篇
  1993年   73篇
  1992年   71篇
  1991年   62篇
  1990年   60篇
  1989年   57篇
  1988年   53篇
  1987年   60篇
  1986年   62篇
  1985年   72篇
  1984年   79篇
  1983年   84篇
  1982年   68篇
  1981年   68篇
  1980年   66篇
  1979年   62篇
  1978年   69篇
  1977年   68篇
  1976年   62篇
  1975年   73篇
  1974年   43篇
  1973年   39篇
  1972年   42篇
  1971年   38篇
排序方式: 共有9025条查询结果,搜索用时 15 毫秒
131.
Fifty-three copper-based metal fragments, recovered from the Robitaille site in southcentral Ontario, were analysed by neutron activation to establish their chemical make-up and to sort them by their trace elemental chemistries. Three different European copper samples, one brassy copper and 48 brass samples with five different chemistries were found. As few as eight trading actions may account for all of the recovered European metal fragments.  相似文献   
132.
133.
The possibility of lead isotope fractionation in ancient lead production is examined. Kinetic theory relating to isotopic fractionation in non-equilibrium evaporation is considered and the feasibility of the alteration of lead isotope abundance ratios in ore roasting and smelting is assessed. Previous experimental work is shown to have been inconclusive and conclusions are drawn on the need for further research to quantify the possible extent of fractionation in practice.  相似文献   
134.
Accelerator mass spectrometry radiocarbon ages have been taken for a test suite of small samples of material removed from some of the ‘beeswax’art figures found in rock shelters in northern Australia. The results indicate that we can reliably date this unique form of rock art with no noticeable damage. We had not expected to find figures of any great antiquity, and so we were surprised to find that the ages obtained spanned the time period from the recent past to about 4000 BP.  相似文献   
135.
A Roman archaeological site in northern Spain (La Maja, province of La Rioja) includes pottery workshops, part of an important ceramic industry that developed from about the first century BC to the first century AD. A geophysical study was planned to determine the extent of the industrial complex in the vicinity of an excavated kiln. Magnetic observations were done on a grid of 30 × 36m, with a sampling interval of 1m. Two dipolar-shaped anomalies were found: one in the north-east and the other in the south-west of the area. Low-pass and band-pass filters were used in the Fourier domain to enhance the characteristics of the magnetic data and to remove noise and undesirable shallow features. Three-dimensional polygonal prisms were used to model the magnetic anomalies based on palaeomagnetic measurements performed over an uncovered kiln that helped to constrain the induced and remanent parameters of the magnetizing fields.  相似文献   
136.
In recent decades, many Appalachian households have experienced declining incomes due to the loss of traditional male jobs in the mining and manufacturing sectors. One response to this decline has been an increase in female employment in formal sector activities. Another response is homework, or the home-based production of goods and services for sale in the formal and informal sectors. In rural Appalachia, where formal jobs are often unavailable or inadequate to support a household, many women are engaging in homework as an economic strategy. Consequently, economic restructuring cannot be fully understood without analyzing household strategies and gender relations. This paper examines the intersection of gender, households, and economic restructuring as it relates to women's homework and employment shifts in rural Appalachia. Research for this paper entailed qualitative interviews with 50 West Virginia women who are engaged in the home-based production of goods and services. The study analyzes the variety of homework activities done by rural women, their contribution to household incomes, and the effect of these activities on gender relations and divisions of labor in the home. The research forwarded in this study advances a conceptual understanding of household economic strategies and has some practical applications for women and economic development in underdeveloped regions .  相似文献   
137.
"A hedonic migration model is developed where regional amenities are viewed as influencing household production within the framework of the new demand theory. The inputs to household production are goods, time and housing. It is shown that economic growth in the economy as a whole will increase the relative attractiveness of regions that are relatively time-saving, in the sense that they have a lower time elasticity of household production. Hence, migration will flow into time saving regions and housing costs in those regions will rise as real GDP grows." The implied geographical focus is on the United States.  相似文献   
138.
139.
The Pacific Coast of North America was occupied by many distinctive groups of coastal hunter-gatherers at the times of early contacts with Europeans. Despite significant cultural diversity, Pacific Coast peoples shared lifeways oriented toward generally similar marine, nearshore, littoral, and estuarine habitats. In this paper, we examine some major issues that guide much of the archaeology done along the Pacific Coast, then discuss some of the theoretical and methodological problems that limit the efficacy of archaeological reconstructions. Most archaeological research conducted on North America's Pacific Coast has been oriented toward the search for the origins and development of a variety of cultural patterns. A comparative review of California and Northwest Coast sequences provides interesting parallels and discrepancies in the approaches taken in studying some of the major issues in Pacific Coast prehistory.  相似文献   
140.
As concept, policy and practice, affirmative action in Australia has continued to be the subject of political dissension. Currently, Liberal Party policy promises to dismantle the Affirmative Action Agency, while the Labor Government has recently added contract compliance guidelines to the 1986 Act Effective analysis of this institution requires that the political contingencies of policy‐framing and implementation be related to the micropolitics of the workplace. This article begins such an analysis. I argue that the current shape of the legislation enforces its projection as a top‐down ‘policy of persuasion’, a move which reflects and enhances the rhetoric and practices that serve relative advantages to men. Nevertheless, my critique of a ‘best practice’ organisation suggests something more: a dissonance between their expectations and their hostile reception in the workplace can prompt women to mobilise against the imposition of that advantage.  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