全文获取类型
收费全文 | 411篇 |
免费 | 8篇 |
国内免费 | 4篇 |
专业分类
测绘学 | 16篇 |
大气科学 | 27篇 |
地球物理 | 86篇 |
地质学 | 170篇 |
海洋学 | 12篇 |
天文学 | 92篇 |
自然地理 | 20篇 |
出版年
2023年 | 2篇 |
2020年 | 3篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 23篇 |
2013年 | 16篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 17篇 |
2009年 | 30篇 |
2008年 | 22篇 |
2007年 | 24篇 |
2006年 | 23篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 29篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1984年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1975年 | 2篇 |
1971年 | 5篇 |
1970年 | 3篇 |
1967年 | 3篇 |
1958年 | 2篇 |
1956年 | 2篇 |
1953年 | 1篇 |
1952年 | 2篇 |
1951年 | 1篇 |
1950年 | 2篇 |
1949年 | 1篇 |
1948年 | 1篇 |
1942年 | 1篇 |
1940年 | 1篇 |
1939年 | 1篇 |
排序方式: 共有423条查询结果,搜索用时 15 毫秒
101.
Flood risk analysis in the Kosi river basin, north Bihar using multi-parametric approach of Analytical Hierarchy Process (AHP) 总被引:3,自引:0,他引:3
R. Sinha G. V. Bapalu L. K. Singh B. Rath 《Journal of the Indian Society of Remote Sensing》2008,36(4):335-349
The Kosi river in north Bihar plains, eastern India presents a challenge in terms of long and recurring flood hazard. Despite a long history of flood control management in the basin for more than 5 decades, the river continues to bring a lot of misery through extensive flooding. This paper revisits the flooding problem in the Kosi river basin and presents an in-depth analysis of flood hydrology. We integrate the hydrological analysis with a GIS-based flood risk mapping in parts of the basin. Typical hydrological characteristics of the Kosi river include very high discharge variability, and high sediment flux from an uplifting hinterland. Annual peak discharges often exceed the mean annual flood and the low-lying tracts of the alluvial plains are extensively inundated year after year. Our flood risk analysis follows a multi-parametric approach using Analytical Hierarchy Process (AHP) and integrates geomorphological, land cover, topographic and social (population density) parameters to propose a Flood Risk Index (FRI). The flood risk map is validated with long-term inundation maps and offers a cost-effective solution for planning mitigation measures in flood-prone areas. 相似文献
102.
Volker Fritsch 《Pure and Applied Geophysics》1953,24(1):207-213
Summary The observations of ten Aprils (1941–50) at Blue Hill have been analyzed, and it has been found that frost (night minimum temperature 32° F) (T) can be predicted on the basis of the 19h wet-bulb temperature (ti) by the formula:T=ti–k, in whichk is found to be 1.8 F deg. in clear weather and 2.1 F deg. in cloudy. The results of a test on an independent set of Aprils (1936–40), are satisfactory especially with clear skies at 19h. 相似文献
103.
104.
A map depicting predicted classes of soil magnetic susceptibility in Angola was produced. The map is based on a classification
system for the susceptibility of tropical soils set up by the authors and a 1:2,000,000 scale FAO soil map. Statistical data
of two large groups of parent rock—ultrabasic, basic and intermediate igneous rocks on the one hand and acid igneous rocks
and some slightly metamorphosed rocks and clastic sediments on the other—had been linked to three associated degrees of weathering.
These determining factors were used to classify Angolan soils, and the overall method is semi-quantitative. The resulting
map shows that easily available pedological information as given by FAO soil maps is generally appropriate to predict soil
magnetic susceptibility. Potential metal detector performance failures may be predicted. The resulting information is a useful
tool for planning the use of appropriate techniques in landmine clearance operations. 相似文献
105.
David L. McCollum Volker Krey Keywan Riahi Peter Kolp Arnulf Grubler Marek Makowski Nebojsa Nakicenovic 《Climatic change》2013,119(2):479-494
This paper assesses three key energy sustainability objectives: energy security improvement, climate change mitigation, and the reduction of air pollution and its human health impacts. We explain how the common practice of narrowly focusing on singular issues ignores potentially enormous synergies, highlighting the need for a paradigm shift toward more holistic policy approaches. Our analysis of a large ensemble of alternate energy-climate futures, developed using MESSAGE, an integrated assessment model, shows that stringent climate change policy offers a strategic entry point along the path to energy sustainability in several dimensions. Concerted decarbonization efforts can lead to improved air quality, thereby reducing energy-related health impacts worldwide: upwards of 2–32 million fewer disability-adjusted life years in 2030, depending on the aggressiveness of the air pollution policies foreseen in the baseline. At the same time, low-carbon technologies and energy-efficiency improvements can help to further the energy security goals of individual countries and regions by promoting a more dependable, resilient, and diversified energy portfolio. The cost savings of these climate policy synergies are potentially enormous: $100–600 billion annually by 2030 in reduced pollution control and energy security expenditures (0.1–0.7 % of GDP). Novel aspects of this paper include an explicit quantification of the health-related co-benefits of present and future air pollution control policies; an analysis of how future constraints on regional trade could influence energy security; a detailed assessment of energy expenditures showing where financing needs to flow in order to achieve the multiple energy sustainability objectives; and a quantification of the relationships between different fulfillment levels for energy security and air pollution goals and the probability of reaching the 2 °C climate target. 相似文献
106.
The role of technology for achieving climate policy objectives: overview of the EMF 27 study on global technology and climate policy strategies 总被引:2,自引:1,他引:2
Elmar Kriegler John P. Weyant Geoffrey J. Blanford Volker Krey Leon Clarke Jae Edmonds Allen Fawcett Gunnar Luderer Keywan Riahi Richard Richels Steven K. Rose Massimo Tavoni Detlef P. van Vuuren 《Climatic change》2014,123(3-4):353-367
This article presents the synthesis of results from the Stanford Energy Modeling Forum Study 27, an inter-comparison of 18 energy-economy and integrated assessment models. The study investigated the importance of individual mitigation options such as energy intensity improvements, carbon capture and storage (CCS), nuclear power, solar and wind power and bioenergy for climate mitigation. Limiting the atmospheric greenhouse gas concentration to 450 or 550 ppm CO2 equivalent by 2100 would require a decarbonization of the global energy system in the 21st century. Robust characteristics of the energy transformation are increased energy intensity improvements and the electrification of energy end use coupled with a fast decarbonization of the electricity sector. Non-electric energy end use is hardest to decarbonize, particularly in the transport sector. Technology is a key element of climate mitigation. Versatile technologies such as CCS and bioenergy are found to be most important, due in part to their combined ability to produce negative emissions. The importance of individual low-carbon electricity technologies is more limited due to the many alternatives in the sector. The scale of the energy transformation is larger for the 450 ppm than for the 550 ppm CO2e target. As a result, the achievability and the costs of the 450 ppm target are more sensitive to variations in technology availability. 相似文献
107.
Parth S. Mahapatra Sipra Panda Namrata Das Satyajit Rath Trupti Das 《Theoretical and Applied Climatology》2014,117(1-2):133-147
Black carbon (BC) mass concentration variation has been studied, over a period of 2 years (June 2010–May 2012) at Bhubaneswar. Daily, monthly and seasonal measurements revealed a clear winter maxima (5.6 μg/m3) of BC followed by post-monsoon (4.05 μg/m3), monsoon (3.02 μg/m3) and pre-monsoon (2.46 μg/m3). Nighttime BC mass concentrations have been found to be distinctly higher during winter followed by post-monsoon and monsoon. Investigations reveal that the winter maxima are due to a stable atmospheric condition and long-range transport over the Indo-Gangetic Plain and Western Asia. Local boundary layer dynamics and anthropogenic activities have been assumed to have a pronounced effect on the diurnal cycle seasonally. Statistical analysis suggests significant variation of BC during the months and non-significant during the days. The study also gives an insight into importance of BC study from health angle and suggests an assessment and management framework. Source apportionment study suggests that BC mass concentration observed at Bhubaneswar is generally dominated by fossil fuel combustion. 相似文献
108.
Climatic conditions such as relatively cold temperatures and dryness are able to limit malaria transmission. Climate change is therefore expected to alter malaria spread. A previous assessment of the potential impacts of climate change on the seasonality of malaria in Africa is revisited. Bias-corrected regional climate projections with a horizontal resolution of 0.5° are used from the Regional Model (REMO), which include land use and land cover changes. The malaria model employed is the climate-driven seasonality model (MSM) from the Mapping Malaria Risk in Africa project for which a comparison with data from the Malaria Atlas Project (MAP) and the Liverpool Malaria Model (LMM), and a novel validation procedure lends more credence to results. For climate scenarios A1B and B1 and for 2001–2050, REMO projects an overall drying and warming trend in the African malaria belt, that is largely imposed by the man-made degradation of vegetation. As a result, the malaria projections of the MSM show a decreased length of the malaria season in West Africa. The northern Sahel is no more longer suitable for malaria in the projections and shorter malaria seasons are expected for various areas farther south. In East Africa, higher temperatures and nearly unchanged precipitation patterns lead to longer transmission seasons and an increase in highland malaria. Assuming constant population numbers, an overall increase in person-months of exposure of up to 6 % is found. The results of this simple seasonality model are similar to previous projections from the more complex LMM. However, a different response to the warming of highlands is found for the two models. It is concluded that the MSM is an efficient tool to assess the climate-driven malaria seasonality and that an uncertainty analysis of future malaria spread would benefit from a multi-model approach. 相似文献
109.
Ocean Dynamics - Mesoscale eddies in the open ocean are mostly formed by baroclinic instability, in which the available potential energy from the large-scale slope of the isopycnals is converted... 相似文献
110.
Ezer Tal Carniel Sandro Amin Chabchoub de Camargo Ricardo Estrada-Allis Sheila N. Gao Guoping Greatbatch Richard J. Lermusiaux Pierre F. J. Liu Zhiyu Miyazawa Yasumasa Forster Alejandro Orfila Panickal Swapna Phillips Helen Pinones Andrea Stanev Emil Volker Christoph Xu Fanghua Young Emma 《Ocean Dynamics》2023,73(1):35-38