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   724篇
  免费   10篇
  2023年   8篇
  2022年   15篇
  2021年   17篇
  2020年   44篇
  2019年   73篇
  2018年   60篇
  2017年   77篇
  2016年   62篇
  2015年   19篇
  2014年   30篇
  2013年   153篇
  2012年   67篇
  2011年   11篇
  2010年   14篇
  2009年   9篇
  2008年   15篇
  2007年   17篇
  2006年   13篇
  2005年   13篇
  2004年   2篇
  2003年   6篇
  2002年   2篇
  2001年   2篇
  2000年   1篇
  1998年   3篇
  1994年   1篇
排序方式: 共有734条查询结果,搜索用时 15 毫秒
1.
Biogeographers, ecologists, palaeontologists, and conservation managers often deal with checklists in which not all individuals have been identified to a species level, or the accuracy of species identification is questionable. Is it possible and credible to investigate species richness based on such checklists? Studies on macrofauna in the Far Eastern seas, eastern Arctic seas, and adjacent waters of the Pacific and Arctic Oceans suggest that in different habitats and for diverse taxa, species, and higher taxa richness strongly correlate with each other and increase with an expansion in the study area and sample size according to the species–area law. Such an increase is higher in the bottom zone than in the pelagic. Species and higher taxa richness also show a decrease from lower to higher latitudes, which is in line with the Humboldt–Wallace’s law. According to Willis’ law and self-similarity in the organisation of taxonomic levels, species richness can be assessed based on the genus, family, and order richness. In other words, supraspecies richness itself can tell us the same as species richness and therefore certain global patterns revealed at the species level may also be revealed at the supraspecies level. Such a concordance in general trends among richness parameters at different taxonomic levels in practice implies that species richness can be studied based on lists that lack species identifications or lists with doubtful species identification. We suggest bolder use of supraspecies richness in science and practice, discussing the disadvantages and advantages of this approach.  相似文献   
2.
Up until the end of 2018, extreme right-wing parties and their anti-immigration discourse, now a common occurrence in other European countries, had not appeared on the Spanish political scene. However, in December of that year, the Spanish extreme right-wing party VOX reversed this trend and made significant electoral gains in the Andalusian regional elections. This phenomenon has led us to analyse, in this study, the role played by contextual factors (i.e., out-group size, territorial concentration of the immigrant population, demographic change in settlement locations, aggregated educational level and unemployment rate among the receiving society) in the rise in the number of VOX voters. To achieve this, VOX's results from all the polling stations in Andalusia contained in its 5946 census tracts were analysed. At the same time, each census tract was associated with its demographic, economic and educational data, and their relationship was analysed using a multilevel analysis with Mplus. The results show that the presence of economic immigrants is indeed associated with a higher percentage of VOX voters in Andalusia. However, despite this general trend, those census tracts with a high territorial concentration of Maghrebi immigrants are associated with a lower percentage of support for this extreme right-wing party. The opposite is found for Romanian immigrants. Moreover, areas with larger percentages of people with a high level of education influenced greater support for VOX. Thus our findings suggest the traditional explanations for the increased support for extreme right-wing parties in northern Europe do not provide clear patterns that can be extrapolated to Andalusia.  相似文献   
3.
4.
Policies concerning undocumented immigrants are inevitably ambivalent, creating uncertainty and confusion in the implementation process. We identify a clear example of this ambivalence —U.S. law setting standards for determining the credibility of asylum seekers—that resulted in an increase in asylum grants despite policymakers' intention to make it harder for individuals to obtain the status. We argue that this law, The REAL ID Act of 2005, sent mixed messages to immigration judges (IJs), street-level bureaucrats who implement immigration policy. It increased IJ discretion, but set vague limits. We theorize that IJs, behaving in a bounded rationality framework, use their professional legal training as a short-cut and look primarily to the courts for guidance. Our evidence supports our argument. After the passage of the REAL ID Act, IJ decision-making is more closely aligned with the preferences of their political and legal principals, and, in the final score, the federal circuit courts are the winners.  相似文献   
5.
Scholarship concerning the lives of enslaved African Americans in southern New England has shifted rapidly from outdated models of acculturation to conflict-driven models of domination and resistance. With the assumption of conflict as the outcome of all power relations, both economic production and historical contextuality have been overlooked, with slavery systems in New England simply equated with other regions of the Atlantic world, rather than compared and contrasted. This essay reconsiders contests over power in seventeenth- and eighteenth-century New England. Drawing on the work of Greene (1966), Piersen (1988), and others, I argue that the system of slavery in the region may represent an anomalous case in terms of the means of control or the means of resistance. By examining demographic patterns, economic production, and agricultural landscapes in Rhode Island's East Bay, I argue that there may be more to be learned from William D. Piersen's (1988, p. 143) concept of resistant accommodation as a middle ground between the two extremes of the theoretical spectrum. The essay concludes with suggestions for further research on the archaeology of African-American lives in the region.  相似文献   
6.
The objective of this research is to examine in depth the brokerage roles that supporting institutions play in conducting local business and applying technical knowledge inside clusters. We identify three main roles: a coordination role, characterized by the efforts that organizations play in internally coordinating themselves and establishing a shared institutional framework; an interconnector role, where organizations foster communication along the value chain of the industry; and a gatekeeper role that allows organizations to connect cluster members with external networks. Results obtained in the Toy Valley cluster provide evidence that each kind of supporting organization tends to specialize in specific roles, since universities are best for a coordination role with regard to technical knowledge while private organizations are key for vertical communication and coordination. Similar results were obtained when analysing the extra-cluster contacts that these organizations develop as gatekeepers, as they tend to establish specific communication conduits with similar alters in external networks.  相似文献   
7.
This article challenges democratic theorists’ disregard for democratic impatience by showing that the Book of Job not only defends impatience but that it intimates the merits of democratic impatience. Job is impatient along four dimensions that should speak to democratic theorists: he refuses to suffer, identifies his suffering as unjust, seeks to hold arbitrary power accountable, and recognizes patience’s irrationality in the face of injustice. Critically, I demonstrate that Job remains impatient in his mind, and thus does not abandon impatience – not even in an epilogue designed to stifle his impatient voice. While Job’s impatience is justified, it is not yet democratic, for it reneges on broader democratic claims, is not shared, and is undermined by his social privilege. I thus turn to Job’s wife – who is “Everywoman” both in a feminist and more generally democratic sense – to more fully develop a concept of democratic impatience.  相似文献   
8.
In the early 1970s, the Conference on Security and Cooperation in Europe (CSCE) was the cornerstone of French foreign policy regarding East-West relations. It was considered by Paris as the best way to maintain dialogue with Moscow as well as an instrument to reach the Gaullist goal of overcoming the European status quo. This double objective explains why the French adopted an ambiguous attitude during the CSCE: even though their goal was to challenge the Brezhnev doctrine and initiate a process to meet the aspirations of peoples under Soviet domination, they knew that this would be a lengthy process. For them, it was necessary to avoid provoking the Soviets by putting forward expressively liberal proposals. The French leaders of the 1970s saw the CSCE as the multilateral prolongation of the Gaullist policy of ‘détente, entente, cooperation’.  相似文献   
9.
The child-friendly city advocates for children's ‘right to the city’. Much of this advocacy focuses on the independent child, with little attention paid to the accompanied experiences of younger children, such as those travelling in prams. This paper draws on a material feminist perspective to help address this gap. We offer the concept of mother–child–pram assemblage to bring to the fore the corporeal dimensions of everyday pram journeys. By analysing sensory ethnographic materials collected with mothers and young children living in Wollongong, Australia, this paper highlights how the ‘affective affordances’ and ‘affective atmospheres’ of pram mobilities shape urban experience by reference to how motherhood and childhood are achieved on-the-move. We conclude with policy-relevant insights for the child-friendly city.  相似文献   
10.
After the Second World War, anti-communists of different backgrounds from Central and Eastern European countries decided to settle in Franco’s Spain, where they sought safety and a place to live during the Cold War. This article will provide an overview of their political profiles and assess the reasons these exiles chose Spain, a country excluded from the United Nations until 1955 and led by Francisco Franco. The article also shows how they settled in the dictatorship linked to the Nazis and Italian Fascists, and the ways in which they continued their struggles against Communism with public and private resources.  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