全文获取类型
收费全文 | 313篇 |
免费 | 18篇 |
国内免费 | 20篇 |
专业分类
测绘学 | 6篇 |
大气科学 | 30篇 |
地球物理 | 84篇 |
地质学 | 137篇 |
海洋学 | 20篇 |
天文学 | 33篇 |
自然地理 | 41篇 |
出版年
2024年 | 2篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 16篇 |
2019年 | 15篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 17篇 |
2014年 | 10篇 |
2013年 | 25篇 |
2012年 | 19篇 |
2011年 | 20篇 |
2010年 | 15篇 |
2009年 | 16篇 |
2008年 | 22篇 |
2007年 | 19篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有351条查询结果,搜索用时 46 毫秒
341.
Mathematical Geosciences - A correction to this paper has been published: https://doi.org/10.1007/s11004-021-09942-0 相似文献
342.
Nick Middleton 《Natural Hazards》2018,92(1):57-70
This paper examines the theory and supporting evidence for links between desertification, drought and dust storms with a particular focus on studies undertaken in and around the Gobi Desert. Overgrazing of rangeland by pastoralists has been the most commonly cited cause of desertification in global drylands for more than 30 years, but the evidence supporting this link is not always convincing. Nonetheless, overgrazing, desertification and dust storms are frequently connected, regardless. Drought is another well-known and important driver of vegetation cover change. Distinguishing between vegetation cover adversely affected by drought and that reduced by grazing is imperative for policy makers because identifying the incorrect driver of vegetation change risks the development of inappropriate policy. 相似文献
343.
Rachel M.L. Wignall John E. Gordon Vanessa Brazier Colin C.J. MacFadyen Nick S. Everett 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):120-134
Climate change is a significant concern for nature conservation in the 21?st century. One of the goals of the 2014 Scottish Climate Change Adaptation Programme is to identify the consequences of climate change for protected areas and to put in place adaptation or mitigation measures. As a contribution to the process, this paper develops a methodology to identify the relative level of risk to nationally and internationally important geological and geomorphological sites in Scotland from the impacts of climate change. The methodology is based on existing understanding of the likely responses of different types of geosite to specific aspects of climate change, such as changes in rainfall, rising sea levels or increased storminess, and is applied to assess the likelihood of damaging impacts on groups of similar geoheritage features in sites with similar characteristics. The results indicate that 80 (8.8%) of the ~900 nationally and internationally important geoheritage sites in Scotland are at ‘high’ risk from climate change. These include active soft-sediment coastal and fluvial features, finite Quaternary sediment exposures and landforms in coastal and river locations, active periglacial features, sites with palaeoenvironmental records, finite or restricted rock exposures and fossils. Using this risk-based assessment, development of indicative geoheritage climate-change actions have been prioritised for these sites. Depending on the characteristics of the sites, management options may range from ‘do nothing’ to rescue excavations and posterity recording. Monitoring is an essential part of the management process to trigger evidence-based interventions. 相似文献
344.
正The idea that plate tectonics may not have operated deep in Earth's Precambrian past has a long legacy.What predated plate tectonics is unknown,and advances in data-from geochemical,geological and tectonic,to paleomagnetic,as well as modelling ap- 相似文献
345.
346.
Nick Novakowski 《GeoJournal》2010,75(6):553-565
This research provides a comparative examination of Ottawa as an archetype of a knowledge city. Among Canada’s four largest
cities, Ottawa is unique in terms of the characteristics of its labor force, the nature of its employment mix, and its infrastructure.
Since the high-tech downturn of 2001, some of Ottawa’s options as a knowledge city seem to be contracting, despite some simultaneously
encouraging signs (like recovering employment levels in the high-tech sector). This raises a question about Ottawa’s potential
longevity as a knowledge center. The challenge is to understand the inventory of obstacles faced by the city, and address
the sort of alchemy required to maintain and improve its competitiveness as a knowledge city. 相似文献
347.
Stephen Serjeant Seb Oliver † Michael Rowan-Robinson Hans Crockett Vasilis Missoulis Tim Sumner Carlotta Gruppioni Robert G. Mann Nick Eaton David Elbaz David L. Clements Amanda Baker reas Efstathiou Catherine Cesarsky Luigi Danese Alberto Franceschini Reinhardt Genzel y Lawrence Dietrich Lemke Richard G. McMahon George Miley Jean-Loup Puget Brigitte Rocca-Volmerange 《Monthly notices of the Royal Astronomical Society》2000,316(4):768-778
348.
349.
High-resolution rockfall inventories captured at a regional scale are scarce. This is partly owing to difficulties in measuring the range of possible rockfall volumes with sufficient accuracy and completeness, and at a scale exceeding the influence of localized controls. This paucity of data restricts our ability to abstract patterns of erosion, identify long-term changes in behaviour and assess how rockfalls respond to changes in rock mass structural and environmental conditions. We have addressed this by developing a workflow that is tailored to monitoring rockfalls and the resulting cliff retreat continuously (in space), in three-dimensional (3D) and over large spatial scales (>104 m). We tested our approach by analysing rockfall activity along 20.5 km of coastal cliffs in North Yorkshire (UK), in what we understand to be the first multi-temporal detection of rockfalls at a regional scale. We show that rockfall magnitude–frequency relationships, which often underpin predictive models of erosion, are highly sensitive to the spatial extent of monitoring. Variations in rockfall shape with volume also imply a systemic shift in the underlying mechanisms of detachment with scale, leading us to question the validity of applying a single probabilistic model to the full range of rockfalls observed here. Finally, our data emphasize the importance of cliff retreat as an episodic process. Going forwards, there will a pressing need to understand and model the erosional response of such coastlines to rising global sea levels as well as projected changes to winds, tides, wave climates, precipitation and storm events. The methodologies and data presented here are fundamental to achieving this, marking a step-change in our ability to understand the competing effects of different processes in determining the magnitude and frequency of rockfall activity and ultimately meaning that we are better placed to investigate relationships between process and form/erosion at critical, regional scales. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd 相似文献
350.
Some 60% of the agricultural land in the UK is grassland. This is mostly located in the wetter uplands of the west and north, with the majority intensively managed as permanent pasture. Despite its extent, there is a lack of knowledge regarding how agricultural practices have altered the hydrological behaviour of the underlying soils relative to the adjacent moorland covered by semi-natural grassland. Near-surface soil moisture content is an expression of the changes that have taken place and is critical in the generation of flood-producing overland flows. This study aims to develop a pioneering paired-plot approach, producing 1,536 moisture measurements at each of the monitoring dates throughout the studied year, that were subsequently analysed by a comparison of frequency distributions, visual cum geostatistical investigation of spatial patterns and mixed-effects regression modelling. The analysis demonstrated that the practices taking place in the pasture (ploughing, re-seeding and drainage) reduced the natural diversity in moisture patterns. Compared to adjacent moorland, the topsoil dried much faster in spring with the effects requiring offset with moisture from slurry applications in summer. With the onset of autumn rains, these applications then made the topsoil wetter than the moorland, heightening the likelihood of flood-producing overland flow. During the sampling within one such storm event, the adjacent moorland was almost as wet as the pasture with both visibly generating overland flow. These contrasts in soil moisture were statistically significant throughout. Further, they highlight the need to scale-up the monitoring with numerous plot pairs to see if the observed highly dynamic, contrasting behaviour is present at the landscape scale. Such research is fundamental to designing appropriate agricultural interventions to deliver sustainable sward production for livestock or methods of mitigating overland-flow incidence that would otherwise heighten flood risk or threaten water quality in rivers. 相似文献