全文获取类型
收费全文 | 2059篇 |
免费 | 75篇 |
出版年
2023年 | 8篇 |
2020年 | 26篇 |
2019年 | 50篇 |
2018年 | 58篇 |
2017年 | 77篇 |
2016年 | 76篇 |
2015年 | 41篇 |
2014年 | 52篇 |
2013年 | 591篇 |
2012年 | 52篇 |
2011年 | 66篇 |
2010年 | 57篇 |
2009年 | 58篇 |
2008年 | 59篇 |
2007年 | 27篇 |
2006年 | 42篇 |
2005年 | 44篇 |
2004年 | 42篇 |
2003年 | 40篇 |
2002年 | 35篇 |
2001年 | 40篇 |
2000年 | 33篇 |
1999年 | 19篇 |
1998年 | 32篇 |
1997年 | 28篇 |
1996年 | 20篇 |
1995年 | 20篇 |
1994年 | 25篇 |
1993年 | 24篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1988年 | 14篇 |
1987年 | 19篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 29篇 |
1983年 | 22篇 |
1982年 | 28篇 |
1981年 | 15篇 |
1980年 | 18篇 |
1979年 | 18篇 |
1978年 | 10篇 |
1977年 | 20篇 |
1976年 | 21篇 |
1975年 | 12篇 |
1974年 | 12篇 |
1973年 | 8篇 |
1972年 | 9篇 |
1968年 | 8篇 |
排序方式: 共有2134条查询结果,搜索用时 15 毫秒
31.
Peter Gould 《The Canadian geographer》1991,35(4):324-332
Compared to the geographic wasteland south of your border, geography appears to have fared well in Canada, both as a formal discipline extending our understanding by illuminating the human and physical worlds, and as a subject taught at all levels to create informed and aware citizens. I known you think much remains to be done, and perhaps things always look a bit greener on the other side of the hill, but I hope you will not mind my somewhat envious gaze. In fact, when I received the five volumes of the 'curriculum guideline' for geography, issued by the Ontario Ministry of Education for the intermediate and senior divisions of your high schools (ome 1988), my feelings were not so much envy as panic, a panic that rapidly induced something close to intellectual paralysis. Because in a moment I can only describe now as utterly weak and foolish, I started to read them, only to learn that your senior students 'analyze, interpret … explain … design and develop networks, systems and simulations that involve six or more variables' (ome 1988, A12).
In retrospect, I still think my panic was justified. After 30 years of hard post-doctoral work I have reached the point where I can think about the interactions of maybe three variables, but hardly the combinatorial possibilities of six. Such ineptness would mean that I might just squeeze into your tenth grade and from there slowly work my way over the next two years towards those Olympian heights of analytical thought where dwell Ontario's high school graduates. 相似文献
In retrospect, I still think my panic was justified. After 30 years of hard post-doctoral work I have reached the point where I can think about the interactions of maybe three variables, but hardly the combinatorial possibilities of six. Such ineptness would mean that I might just squeeze into your tenth grade and from there slowly work my way over the next two years towards those Olympian heights of analytical thought where dwell Ontario's high school graduates. 相似文献
32.
33.
34.
35.
Kate Williams 《政策研究杂志》2021,49(1):37-66
As science becomes an increasingly crucial resource for addressing complex challenges in society, extensive demands are placed upon the researchers who produce it. Creating valuable expert knowledge that intervenes in policy or practice requires knowledge brokers to facilitate interactions at the boundary between research and policy. Yet, existing research lacks a compelling account of the ways in which brokerage is performed to gain credibility. Drawing on mixed‐method analysis of 12 policy research settings, I outline a novel set of strategies for attaining symbolic power, whereby policy experts position themselves and others via conceptual distances drawn between the “world of ideas” and the “world of policy and practice.” Disciplinary distance works to situate research as either disciplinary or undisciplinary, epistemic distance creates a boundary between complex specialist research and direct digestible outputs, temporal distance represents the separation of slow rigorous research and agile responsive analysis, and economic distance situates research as either pure and intrinsic or marketable and fundable. I develop a theoretical account that unpacks the boundaries between research communities and shows how these boundaries permit policy research actors to achieve various strategic aims. 相似文献
36.
This article explores the articulation—in different forms, at different periods, and by different actors—of ‘national self‐determination’ in Somalia and across the Somali‐speaking regions of the Horn of Africa. It explores how this concept can be understood in the context of protracted political fragmentation in Somalia—considering unresolved debates over the ideological foundations of state reconstruction, disagreements about the suitability of federalism, aspirations for the recognition of an independent Republic of Somaliland, and the distinctive trajectory of the Somali Regional State in Ethiopia. Taking a comparative, cross‐border and wide‐angled historical approach, the article argues that ideas of an ethno‐linguistically, culturally and religiously defined Somali ‘nation’ continue to coexist (and be reproduced, updated and used) within an environment of extreme political fragmentation and across multiple ‘state’ boundaries. This argument is made through comparative analysis of contemporary examples of the performance of Somali state and nationalist identities within and beyond the region and the distinctive transnational Somali‐language media environment within which these ideas circulate and compete. 相似文献
37.
Peter S. Wells 《Journal of Archaeological Research》1994,2(2):135-163
Recent research in central Europe is changing our understanding of the role of centers in economic and social systems of late prehistoric times. Increased attention to smaller, more typical settlements shows that they engaged in economic activities similar to those at the large, fortified complexes. Abundant new evidence pertaining to ritual activity indicates that ritual was often integrated into daily life at settlements. The evidence from the exceptionally rich data on late prehistoric central Europe can be of substantial value for developing models applicable to contexts in other parts of the world. 相似文献
38.
"The spread of HIV-1 in the United Kingdom is simulated by a model which integrates behavioural and epidemiological processes within a multi-regional population projection framework and represents the spatial heterogeneities in the distribution of HIV which have significant effects on transmission patterns. Analyses determine the significance of different parameters in contributing to prediction uncertainty and highlight the importance of behavioural change and international population movements." 相似文献
39.
40.