全文获取类型
| 收费全文 | 258篇 |
| 免费 | 5篇 |
专业分类
| 263篇 |
出版年
| 2021年 | 1篇 |
| 2020年 | 1篇 |
| 2019年 | 5篇 |
| 2016年 | 2篇 |
| 2015年 | 5篇 |
| 2014年 | 1篇 |
| 2013年 | 18篇 |
| 2012年 | 9篇 |
| 2011年 | 15篇 |
| 2010年 | 12篇 |
| 2009年 | 21篇 |
| 2008年 | 16篇 |
| 2007年 | 16篇 |
| 2006年 | 17篇 |
| 2005年 | 8篇 |
| 2004年 | 3篇 |
| 2003年 | 5篇 |
| 2002年 | 1篇 |
| 2001年 | 3篇 |
| 2000年 | 3篇 |
| 1998年 | 2篇 |
| 1997年 | 2篇 |
| 1996年 | 6篇 |
| 1995年 | 6篇 |
| 1994年 | 6篇 |
| 1993年 | 4篇 |
| 1992年 | 2篇 |
| 1991年 | 2篇 |
| 1990年 | 7篇 |
| 1989年 | 6篇 |
| 1988年 | 4篇 |
| 1987年 | 5篇 |
| 1986年 | 3篇 |
| 1985年 | 3篇 |
| 1984年 | 5篇 |
| 1983年 | 2篇 |
| 1982年 | 2篇 |
| 1981年 | 1篇 |
| 1980年 | 7篇 |
| 1979年 | 4篇 |
| 1978年 | 4篇 |
| 1976年 | 3篇 |
| 1975年 | 4篇 |
| 1972年 | 1篇 |
| 1971年 | 3篇 |
| 1970年 | 1篇 |
| 1969年 | 1篇 |
| 1968年 | 1篇 |
| 1967年 | 3篇 |
| 1965年 | 1篇 |
排序方式： 共有263条查询结果，搜索用时 15 毫秒
21.
European security depends on the effective collaboration of the five major powers; it will be undermined by the extension of NATO, a policy driven by US domestic politics. The main threats to security are: the breakdown of political and economic stability; unintended nuclear proliferation and/or failure of the START process; Russia's evolving political and territorial aspirations. All three will remain marginal as long as Russia is constructively engaged with the West. NATO expansion threatens that engagement. It is seen by all strands of Russian opinion as violating the bargain struck in 1990 and will likely lead to the withdrawal of cooperation. Invitations to Poland, Hungary and the Czech Republic cannot be rescinded, but the consequences can be mitigated by refraining from integrating them into NATO's military structure, by ceasing to insist that NATO membership is open to all, and by perpetuating the de facto nuclear‐weapons‐free zone that presently exists in Central and Eastern Europe. Britain's stance could be pivotal. 相似文献
22.
The 7 February 2009 bushfires in the peri‐urban region to the north of metropolitan Melbourne heralded what many have called an entirely new epoch in terms of weather‐related disasters in Australia. A total of 173 people and 2000 properties were destroyed and, as with the 1939 fires in Victoria, a Royal Commission was subsequently instituted to inquire into the causes and responses to the fire. The Royal Commission has heard much evidence about alleged failings of fire response, communication and administration. It also considered land use planning issues and the associated regulatory framework. Using the Shire of Murrindindi as a case study, this paper argues that the location of population growth, and associated regulatory failure, are contributory, yet under‐researched, factors associated with life and property losses. The adoption of more robust planning tools which incorporate climate change considerations, we argue, is essential to anticipate and minimise the impacts of disastrous natural events such as bushfires. In the latter part of the paper, attention is drawn to a recent Victorian Civil and Administrative Tribunal decision which is groundbreaking in its use of the precautionary principle to prevent dwelling construction in an ‘inappropriate’ location as well as to some major inconsistencies between planning for flood and bushfire threats. 相似文献
23.
M. ALTAF ARAIN ROSE BLAIR† NORM FINKELSTEIN‡ JEFF BROOK§ MICHAEL JERRETT¶ 《The Canadian geographer》2009,53(2):165-190
The spatial and temporal variability of nitrogen dioxide (NO2 ) concentrations and their relationships with meteorology was evaluated in the Toronto–Hamilton urban airshed. NO2 concentrations were highest in the early morning and late evening. Mean concentrations were highest in winter, although individual one-hour NO2 concentrations were found to be highest in summer. Wind direction was the strongest control on hourly NO2 concentration, and temperature and wind speed also had an effect. Our analysis of NO2 concentration variation by wind direction showed that areas downwind of major highways, urban centres and industry were exposed to higher pollutant concentrations. Seasonal patterns of NO2 concentration displayed significant spatial heterogeneity, in particular, in Toronto. Onshore winds sheltered coastal inhabitants from the full extent of NO2 exposure they would otherwise experience. Seasonal variations in meteorology and emissions mean that the degree of spatial variability in NO2 concentrations changes from season to season. This study will help to improve existing land-use regression-based NO2 prediction models by incorporating meteorological controls on NO2 distributions for health effect studies. 相似文献
24.
STEVE N. GILLANDERS NICHOLAS C. COOPS MICHAEL A. WULDER NICHOLAS R. GOODWIN 《The Canadian geographer》2008,52(4):466-485
A major advantage of satellite remote sensing is that the imagery acquired provides a synoptic view of the landscape. Thus, repeat coverage by the satellite on a regular basis permits the detection of changes in land‐cover over time. This study demonstrates the application of remote sensing technology to the monitoring of mining activities at the Athabasca Oil Sands region of Alberta, Canada. First, we describe the techniques used to match a time sequence of Landsat imagery, both spatially and spectrally, to ensure that the spectral changes through time are due to land‐cover variations. A series of spectral trajectories were then extracted to assess changes in land‐cover through time. Secondly, a land‐cover classification was produced from the baseline 1984 imagery and, using historic and future mine extents, the classification was analyzed to determine the proportion of each land‐cover type affected through development. Results of the analysis indicate that since 1984 there has been a larger reduction in mixedwood dense and broadleaf vegetation classes than mixedwood sparse or dense conifer stands in the area. Based on the delineations of mine‐site activity, the area of woodland and wetland habitat subject to development has increased from approximately 2,520 hectare (ha) in 1984 to 32,930 ha in 2005. 相似文献
25.
MICHAEL L. CARRAFIELLO 《The Seventeenth century》2013,28(2):115-134
Abstract This synoptic essay explores trends in historical research and literary criticism on the theme of toleration. It surveys the current state of this lively field of enquiry and demonstrates how far the subject remains coloured by assumptions and narratives of change forged in the early modern era itself. It explores how tolerance and intolerance have been approached by intellectual and social historians and the implications of the recent growth of interest in religious tolerance and intolerance in the post-Reformation period among scholars of early modern literature. It highlights the conceptual problems and interpretative challenges that surround the subject and points towards the need for heightened sensitivity to the role and agency of language and texts, rhetorics and representations, in our analysis of the cultures of coexistence that emerged in the sixteenth and seventeenth centuries. 相似文献
26.
27.
28.
29.
The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) raised public awareness of the need to consider climate change in coastal management and gained international recognition when it received a joint award of a Nobel Peace Prize in 2007. The raised awareness of climate change surrounding the work of the IPCC was in large part responsible for the focus of the recent Australian national inquiry into coastal management in the context of potential climate change impacts on the coast, conducted by the House of Representatives Standing Committee on Climate Change, Water, Environment and the Arts. In the same year the then Minister of Climate Change, Senator Penny Wong, and the Department of Climate Change released a major government report Climate Change Risks to Australia's Coast and set up a national Coasts and Climate Change Council to provide advice to the government. This paper provides a review and analysis of the extent to which climate change issues, within the context of the broader global change debate, have influenced Australian coastal management through its legislation, policies and practice. In particular, the paper focuses on the impact of recent national reports and state government legislative and policy changes and draws conclusions on future directions for Australian coastal management. 相似文献
30.