全文获取类型
收费全文 | 653篇 |
免费 | 31篇 |
国内免费 | 11篇 |
专业分类
测绘学 | 38篇 |
大气科学 | 86篇 |
地球物理 | 153篇 |
地质学 | 287篇 |
海洋学 | 62篇 |
天文学 | 34篇 |
综合类 | 5篇 |
自然地理 | 30篇 |
出版年
2022年 | 6篇 |
2021年 | 26篇 |
2020年 | 9篇 |
2019年 | 15篇 |
2018年 | 32篇 |
2017年 | 24篇 |
2016年 | 34篇 |
2015年 | 30篇 |
2014年 | 38篇 |
2013年 | 44篇 |
2012年 | 36篇 |
2011年 | 54篇 |
2010年 | 45篇 |
2009年 | 34篇 |
2008年 | 40篇 |
2007年 | 35篇 |
2006年 | 40篇 |
2005年 | 18篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1955年 | 1篇 |
1953年 | 1篇 |
1940年 | 1篇 |
1939年 | 3篇 |
排序方式: 共有695条查询结果,搜索用时 109 毫秒
291.
Grachev Andrey A. Krishnamurthy Raghavendra Fernando Harindra J. S. Fairall Christopher W. Bardoel Stef L. Wang Sen 《Boundary-Layer Meteorology》2021,181(2-3):395-422
Boundary-Layer Meteorology - Measurements of atmospheric turbulence at a site in Ferryland (Newfoundland) during the C-FOG (Coastal-Fog) field campaign in September–October 2018 are used to... 相似文献
292.
293.
Lozovatsky Iossif Wainwright Charlotte Creegan Edward Fernando Harindra J. S. 《Boundary-Layer Meteorology》2021,181(2-3):425-441
Boundary-Layer Meteorology - Formation of coastal fog was observed near the southern tip of Nova Scotia when warm, humid air was advected towards the shore over an area of colder water. The... 相似文献
294.
Theoretical and Applied Climatology - Colombia’s lightning climatology was studied using 16 years of high-resolution data from the Tropical Rainfall Measuring Mission Lightning Imaging Sensor... 相似文献
295.
Fernando O. Marques Fernando M. S. F. Marques António Mateus Jorge Figueiras Fernando M. Santos Rogério Mota Helena Amaral 《Environmental Geology》2005,47(8):1128-1137
A sodium bentonite is being used in the basal-isolation of landfills installed on strongly fractured granitic rocks of N Portugal (NW Iberia). To evaluate the performance of this clay as the ultimate impermeable basal barrier, a detailed study was carried out of the granite fracture network; the Na-bentonite was tested to characterize its mechanical and geotechnical behavior; geophysical surveys were made to search for landfill leakage and the waters found around the landfill were geochemically characterized. Fractures in the granite are usually open and devoid of mineral infillings or clay materials and, thus, permeability of the granite is very high. Dispersal of contaminants can be further enhanced by the position of the landfill on a high steep-sided ridge. Geophysical and geochemical data show evidence for seepage and dispersion of pollutants, which means that the clay failed as an ultimate isolation barrier against seepage. This investigation shows that this can be due to fracturing of the clay under load and/or to its non-homogeneous saturation and extreme shrinking character upon drying, which are accompanied by the formation of extensive cracking. Observations and experimental results suggest that the use of synthetic clays in the safe building of landfill bottom liners needs further research, and extreme care should be taken in preventing that clay water content suffers large variations after saturation, as this process considerably degrades the mechanical behavior and sealing properties of the studied Na-bentonite. 相似文献
296.
Ion trap mass spectrometry (ITMS) was used to obtain further qualitative information about the chemical composition of humic-like
substances (HULIS) in atmospheric particulate matter. Particles ≤10 μm (PM10) were collected on quartz fiber filters for 24 h in the region of Basel (Switzerland) and extracted with water. HULIS were
separated from inorganic salts by size exclusion chromatography (SEC) and detected by electrospray ionization in the negative
ion mode (ESI(−)). Series of consecutive fragment ion spectra (MSn) were recorded by ITMS. Full scan mass spectra of the extracts showed a mass distribution pattern characteristic for HULIS.
Different molecular ions were selected from this pattern for further fragmentations. Among them the molecular ion m/z 299 was considered as representative and intensively studied. Many MS2 and MS3 fragment spectra contained a fragment m/z 97 and a neutral loss of 80 u. Time-of-flight (TOF) MS and deuterium exchange experiments identified m/z 97 as hydrogen sulfate. MS2 and MS3 fragment spectra supported the existence of sulfate covalently bound to HULIS. The fragmentation behavior of sulfated HULIS
could be confirmed by model compounds. 相似文献
297.
298.
299.
Fernando Dalmasso 《Pure and Applied Geophysics》1939,1(1):80-98
Riassunto Richiamate, dopo qualche cenno storico sui principali terremoti eolici, le concezioni e le ipotesi di alcuni sismologi e geologi sull'instabilità geosismica dell'arcipelago e sulle sue cause, si espongono i dati micro e macrosismici del terremoto in oggetto. Dopo l'analisi dei medesimi, seguono alcuni cenni sulla natura quasi certamente tettonica del sisma e se ne prospettano le probabili cause. Chiudono la Nota alcune considerazioni sugli effetti meccanici della scossa in rapporto con l'edilizia delle Isole Eolie e sulle norme adatte nelle particolari condizioni locali a meglio garantire la stabilità dei fabbricati. 相似文献
300.
Fernando Gonzlez-Laxe 《Marine Policy》2005,29(6):495-505
The precautionary principle has become a reference rule for public actions and policies. Two conceptions coexist under this principle. The first one, based on the strengthening of the concept of environmental protection, aims to promote a prevention proportional to the potential risks. The second one looks for the eradication of risks and it may even require the “proof demand” of innocuousness. The application of the precautionary principle in the fishing sector became established as a reaction in view of the state of resources and the lack of efficacy to guarantee the sustainability of the exploitations. This document tries to stress the application of the precautionary principle in the framework of fisheries. First, it examines the concept of precaution, then it evaluates the concepts applied in the community policy, and thirdly, it concludes by pointing out the problems derived from its implementation. 相似文献