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   1337篇
  免费   99篇
  2024年   5篇
  2023年   58篇
  2022年   8篇
  2021年   14篇
  2020年   79篇
  2019年   117篇
  2018年   94篇
  2017年   91篇
  2016年   87篇
  2015年   70篇
  2014年   78篇
  2013年   274篇
  2012年   94篇
  2011年   43篇
  2010年   51篇
  2009年   48篇
  2008年   61篇
  2007年   29篇
  2006年   26篇
  2005年   23篇
  2004年   5篇
  2003年   14篇
  2002年   21篇
  2001年   9篇
  2000年   5篇
  1999年   11篇
  1998年   6篇
  1997年   7篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1983年   1篇
排序方式: 共有1436条查询结果,搜索用时 15 毫秒
1.
A mature/elderly female skeleton from the Anglo-Saxon cemetery at Eccles, Kent, is described. A diagnosis of Paget's disease of the left tibia is made. The macroscopic radiological features of perforating and non-perforating osteolytic lesions in the cranium and femora are described. The differential diagnosis is discussed. The lesions are considered to be due to metastatic carcinoma, possibly from a primary carcinoma of the breast. There is a brief resumé of other recorded examples of metastatic carcinoma in early skeletons.  相似文献   
2.
The United Arab Emirates (UAE) has sought to establish a national identity among its nationals since its inception in 1971. Contrary to the pessimism in its first few years, the UAE was able to create a national identity among its nationals despite their initially differing loyalties. The UAE has now embarked on a phase of creating a new national identity that includes non-nationals, encompassing migrants and expats. This study argues that this new identity aims to include, at least discursively, non-nationals, presenting them as an integral part of society. It should be noted that this new identity does not seek to standardize or assimilate the whole population, in contrast to the first identity, which aimed to standardize the nationals. Its primary aim is rather to express its appreciation of the migrant population through the notions of tolerance, diversity, and multiculturalism, while also preventing complaints from the nationals. This study analyses the ways of including non-nationals in a new national identity through national gatherings (national days), institutional activities (heritage festivals, cultural gatherings, cultural center visits and activities), media analyses (state-sponsored media), and foreign policy initiatives that emerged (or presented) due to domestic diversity, such as Pope's visit.  相似文献   
3.
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   
4.
This article demonstrates how the promotion of Indigenous women's political-electoral rights in Mexico has furthered a conservative agenda of state securitization. To do so, it presents a discourse analysis of national media reports focused on the story of Eufrosina Cruz, a Zapotec woman who became the figurehead for state-led initiatives to promote Indigenous women's rights. It argues that a colonial rescue narrative constructed through Cruz's figure helped generate new hegemonic discourses of gendered indigeneity that portrayed Indigenous peoples' alternative political practices and spaces as anti-democratic and illegal. In an era where advancements in party democracy were linked to processes of state securitization, these categorizations helped justify new forms of state intervention into Indigenous peoples' lives. By exploring how rights initiatives were discursively constructed through racialized, spatialized and gendered constructions of indigeneity, this article contributes to a critical geography of indigeneity within political geography.  相似文献   
5.
A new generation of greenways has emerged in recent years, the most ambitious of which are nationwide, interconnected networks of multi-use, multi-purpose greenways and trails, clustered under a single national vision. However, because these initiatives have been the focus of so few research studies, opportunities to glean lessons from their planning and implementation have been limited. This paper contributes to addressing this knowledge gap by presenting a comparative account of two networks, the Trans Canada Trail in Canada and Sendero de Chile in Chile. Using document analysis and interviews with officials closely involved in their development, the evolution of both networks is documented over time, emphasizing similarities and differences related to their planning and implementation. Both initiatives have faced significant challenges in reaching their connection goals and have availed themselves of a diverse range of opportunities and strategies to advance their agendas. A simple model of a virtuous cycle is proposed to highlight the positive feedback—between political and public support, sustained funding, partnership development, accessibility for urban residents, and connectivity of the network—generated by sustained network expansion over time. It is hoped that the insights offered from this analysis may offer guidance to inform the development of similar scale projects elsewhere.  相似文献   
6.
This article examines the epistemic practices of interpretive field geomorphology—that is, the in-the-moment act of “seeing the landscape” geomorphologically. Drawing on the philosophical works of Wittgenstein and Merleau-Ponty, it aims to bring to light the complex, multi-dimensional, knowledge-producing process of field observation and interpretation. Methodologically the study is based on geomorphologists' accounts of their fieldwork, gathered through questionnaire and interviews. By paying attention to what geomorphologists say they are doing in the field, interpretive field geomorphology is articulated as a combined cognitive, social, embodied, and affective experience through which understanding is arrived at. The paper thus sheds light on one part of what Brierley et al. call “the dark art” of geomorphological interpretation, and draws out implications in terms of researcher positionality, researcher training, and offering an epistemic justification for field-based pedagogies.  相似文献   
7.
Cooling centres provide respite, safety, and social support during extreme heat events for populations that do not have the resources to own or operate in-home air conditioning. The objective of this study was to measure the spatial accessibility of cooling centres and analyze the associations between cooling centre access and marginalization in Montreal, Toronto, and Vancouver, Canada. The potential spatial accessibility of cooling centres within a 15-minute walk was measured at the dissemination area scale using the two-step floating catchment area method. A two-stage modelling approach was used to analyze the associations between cooling centre access and marginalization. Approximately 62%, 58%, and 54% of the populations in Montreal, Toronto, and Vancouver had access to at least one cooling centre. In Montreal and Vancouver, high marginalization areas were more likely to have cooling centre access than low marginalization areas. Of the areas with cooling centre access, smaller access scores were observed in areas with high residential instability. Approximately one-fifth of the areas in each city had no cooling centre access and high marginalization, and may be considered for future cooling centres or programs that improve accessibility to existing centres.  相似文献   
8.
Environmental stewardship—a concept that describes the relationships between humans and the environment—is gaining increased attention as an approach that can address planetary sustainability issues. In-depth empirical investigations of local environmental stewardship are needed to understand how social-ecological context influences stewardship, as well as the arrangement of conceptual elements in applied settings. This study addresses these needs by conducting an in-depth exploration of environmental stewardship in the Niagara Region of Canada. A single embedded case study design is employed, with environmental stewardship initiatives constituting the individual units of analysis with the case. Analysis of the spatial arrangement of a total of 89 initiatives indicated that initiatives tended to cluster closer to the Niagara River and in more populous municipalities. The significance of collaboration, tensions between the environment and economic development, and concerns about political impacts emerged as themes across contextual factors. The configuration of stewardship elements reveals interesting discrepancies between initiatives and previous stewardship research focused on larger scales, individuals, and organizations. Further analysis is encouraged to illuminate environmental stewardship in other settings as well as advance relational understanding of conceptual elements.  相似文献   
9.
This essay explores the post-World War Two anti-colonial Maasina Rule in north Malaita, Solomon Islands, to show how a church leader Shem Irofa'alu decided to establish a religious movement independent of the state and the traditional evangelical church. Irofa'alu's movement indexes an important moment of culture change towards increasing enthusiasm for the often-overlooked Christianity-based forms of sovereignty in the region. It highlights that Maasina Rule was not only a powerful rupture in social processes, but also sharpened the growing division between state and church. Irofa'alu's role in Maasina Rule shows that his influence peaked between 1948 and 1950 and then went into rapid decline. This change in fortune coincided with a critical turning point in the colonial government's attempts to end the movement through appeasement. No longer the head of the evangelical church in Malu'u sub-district and frustrated about the mother church's governance, Irofa'alu retreated to his home area and set about establishing a new church, Boboa (‘Foundation’), his first attempt at organizing a self-governing assembly before introducing Jehovah's Witnesses in north Malaita. In later years, Irofa'alu became a prophet-exemplar for new generations of religious leaders trying to establish Malaitan sovereignties based on their own power to move the truth of prophecies away from foreign state and church organizations.  相似文献   
10.
The Narrative Policy Framework (NPF) suggests that narratives can be employed to define and contest policy problems. Yet, few NPF studies have explicitly addressed the narrative portrayal of problem intractability. What role do narratives play in a situation of uncertainty about the causes and solutions of the problem, when strong divergences regarding the values and interests of the policy actors exist? The article anchors the NPF to the literatures on problem definition and implementation to advance two propositions about (a) how differences in the use of narrative elements can be suggestive of the degree of problem (in-)tractability; and (b) whether other elements of tractability, namely the presence of a valid causal theory, are associated with the usage of narrative strategies. I test the propositions by analyzing media commentaries surrounding the implementation of European decisions to tackle a tree-killing epidemic in Italy. The findings suggest that narratives can helpfully illustrate the intractability inherent in the policy debate. However, narratives can also develop independently of factors that the implementation literature understands as conducive to lowering intractability, namely knowledge accumulation. The NPF may represent a promising alternative to understand policy implementation processes.  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