全文获取类型
收费全文 | 197篇 |
免费 | 8篇 |
专业分类
205篇 |
出版年
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 37篇 |
2012年 | 13篇 |
2011年 | 12篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有205条查询结果,搜索用时 0 毫秒
51.
52.
53.
54.
55.
The interactions of nature and society are intimately reflected in the degradation of the vast, yet diverse, landscapes and ecosystems of arid western China. The development of agriculture, especially irrigation, has altered rivers, soils and ecosystems so much that major ecological rehabilitation and restoration efforts have been needed since 1950. The catchments of the Tarim River in southern Xinjiang (the Tarim Basin) and of the Black River (Hei He) in Gansu Province and western Inner Mongolia provide examples of the benefits, difficulties and conflicts involved in dryland water management. In the early stages of the human development of these catchments, agriculture depending on irrigation using water from these inland rivers was encouraged. The over‐exploitation of these water resources led to such ecological problems as desiccation of lakes, drying out of rivers, degradation of soils and vegetation and lowering of groundwater levels, with consequent environmental and economic impacts. Since 1990 several high‐cost, national projects to re‐establish ecosystems have been initiated. Water is now released from dams in the headwaters of the rivers in order to restore water flows to the dried out lake basins. Such schemes have inevitably led to social problems and difficulties for the people who depended on the water from the dams for local irrigation. The contrasts in adjustments and attitudes over the use of water for agriculture and other economic activities, as opposed to schemes of restoration of ecosystems and ecological engineering, stem largely from two issues; inconsistent provision of information from the scientific community, and differing ideologies, namely environmental protection versus economic development. 相似文献
56.
This article re‐examines the EU's character and potential as a strategic actor, setting that analysis in the context of the debate on strategic culture. The definition of strategic culture as the political and institutional confidence and processes to manage and deploy military force, coupled with external recognition of the EU as a legitimate actor in the military sphere, lends itself to a reappraisal around four core questions. First, military capabilities: establishing a European strategic culture is vital in order to rationalize the acquisition of capabilities necessary for the range of humanitarian and peacekeeping tasks envisaged. Equally, without military capabilities, all talk of a strategic culture would ring hollow. This article discusses how much closer the EU has come to acquiring those essential capabilities. Second, while the EU has gained significant experience of, albeit limited, military/policing experiences and established a growing reputation and some credibility for ad hoc action, to what extent and in what quarters have these experiences engendered a sense of reliability and legitimacy for autonomous EU action? Third, given that so far operations in the Democratic Republic of Congo and the Balkans have depended on an integrated civil–military effort, do the policy‐making processes of the EU now ensure the appropriate level and depth of civil–military integration? Finally, considering that EU operations have been limited in time and scope, and that much of the EU's work in the Balkans has depended upon cooperation with NATO, what can be said of the evolving relationship between the EU and NATO? 相似文献
57.
PAUL FOLEY H.D. WATTS 《Tijdschrift voor economische en sociale geografie = Journal of economic and social geography = Revue de géographie économique et humaine = Zeitschrift für ?konomische und soziale Geographie = Revista de geografía económica y social》1996,87(2):136-145
A mature industrial region is often characterised by a lack of free-standing R&D units. This article shows that the absence of free-standing R&D units is paralleled by limited R&D activities within production sites. Most plants outsource some R&D activities, and the most frequently cited suppliers of R&D are consultants together with local colleges and universities. Externally-owned plants are more likely to employ full-time research staff and to seek further R&D from external sources. Limited R&D activities do not appear to reflect a lack of qualified staff in the local labour market. It is suggested that attempts to stimulate R&D might focus on the needs of the externally-owned plants or on the development of new economic activities with high R&D requirements. 相似文献
58.
59.
PIET H. PELLENBARG PAUL J.M. VAN STEEN 《Tijdschrift voor economische en sociale geografie = Journal of economic and social geography = Revue de géographie économique et humaine = Zeitschrift für ?konomische und soziale Geographie = Revista de geografía económica y social》2011,102(5):622-629
Both scientists and politicians increasingly emphasise the importance of well‐being as an indicator for economic performance, next to purely financial indicators such as national income and product accounts. There is an ongoing discussion about the most appropriate indicators to measure well‐being. In this paper we use the set of eight ‘life situation indicators’ used by the Netherlands Institute for Social Research, and concentrate on the regional dimension of well‐being, by comparing the spatial variation in well‐being in the Netherlands with the spatial patterns of the separate life situation indicators, that have been shown in this years' series of The Netherlands in Maps, in the successive issues of TESG's 2011 volume. We conclude that the highest levels of life satisfaction are reported for regions where the levels of good health and home ownership are high. 相似文献
60.
Derek J. Penslar † 《Journal of Israeli History》2013,32(1):65-77
According to conventional Zionist historiography, Herzl thought little about Arabs, and what he did have to say about them reflected benign and progressive, albeit paternalistic, sentiment. Critics of Zionism, on the other hand, claim that underlying the paucity of Herzl's comments on Arabs was a conspiracy of silence, for already in 1895 he was allegedly planning the expulsion of the Palestinians, although he only confided this dark scheme to his diary. This essay throws new light upon Herzl's attitudes towards Palestine's Arabs. It explores a variety of historiographical questions raised by the gulf that separates the camps of scholars who have written on this subject, and it critiques the way that historians have read Herzl's diary and privileged it over his other writings. 相似文献