全文获取类型
收费全文 | 398篇 |
免费 | 29篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 19篇 |
大气科学 | 40篇 |
地球物理 | 119篇 |
地质学 | 147篇 |
海洋学 | 50篇 |
天文学 | 26篇 |
综合类 | 2篇 |
自然地理 | 29篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 24篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 21篇 |
2014年 | 11篇 |
2013年 | 27篇 |
2012年 | 31篇 |
2011年 | 25篇 |
2010年 | 26篇 |
2009年 | 16篇 |
2008年 | 25篇 |
2007年 | 15篇 |
2006年 | 18篇 |
2005年 | 8篇 |
2004年 | 15篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有432条查询结果,搜索用时 31 毫秒
401.
Patty Jo Watson 《Geoarchaeology》2008,23(1):173-175
The Neolithic revolution in the Near East: Transforming the human landscape. Alan H. Simmons, 2007, The University of Arizona Press, Tucson, Arizona, xvii +339 pp., $55.00 (cloth). 相似文献
402.
Large geographic and temporal extensions of the Río de la Plata Craton,South America,and its metacratonic eastern margin 总被引:1,自引:0,他引:1
João O.S. Santos Carlos J. Chernicoff Eduardo O. Zappettini Neal J. McNaughton Léo A. Hartmann 《International Geology Review》2019,61(1):56-85
Integration of existing isotopic and geological data allows a reconsideration of the distribution and age of the Río de la Plata Craton within South America. The reinterpretation increases the area of the craton to about 2,400,000 km2 with implications for the tectonic map of South America and for global reconstruction of palaeocontinents. Four areas previously considered as separate cratons (Luís Alves, Curitiba, Tebicuary, and Paranapanema) are interpreted as part of the same Río de la Plata Craton. The craton is organized into six provinces and domains: Buenos Aires–Piedra Alta, Taquarembó, Tebicuary, Luís Alves, Encantadas, and Nico Pérez. The term ‘Transplatense’ is proposed to replace ‘Trans-Amazonian’ for Rhyacian events that occurred within the Río de la Plata Craton. The craton is formed not only by dominant Rhyacian rocks and local Archaean rocks, but also by Statherian and Mesoproterozoic rocks. The domains are all partially to totally covered by Phanerozoic basins (Paraná, Chacoparanense, Claromecó, Salado, Balcarce, and Colorado) which makes their investigation difficult. The Ediacaran–Cambrian collisions of the Brasilian orogen generated tectonic mixtures of orogenic and cratonic zones. This is more evident in the eastern margin of the craton, which behaved as a metacraton. 相似文献
403.
Catherine M. CORRIGAN Michael E. ZOLENSKY Jason DAHL Michael LONG Joseph WEIR Clyde SAPP Patti Jo BURKETT 《Meteoritics & planetary science》1997,32(4):509-515
Abstract— We have investigated the porosity of a large number of chondritic interplanetary dust particles (IDPs) and meteorites by three techniques: standard liquid/gas flow techniques, a new, noninvasive ultrasonic technique, and image processing of backscattered images. The latter technique is obviously best-suited to sub-kilogram sized samples. We have also measured the gas and liquid permeabilities of some chondrites by two techniques: standard liquid/gas flow techniques, and a new, nondestructive pressure release technique. We find that chondritic IDPs have a somewhat bimodal porosity distribution. Peaks are present at 0 and 4% porosity; a tail then extends to 53%. Type 1–3 chondrite matrix porosities range up to 30%, with a peak at 2%. The bulk porosities for type 1–3 chondrites have the same approximate range as exhibited by the matrix, which indicates that other components of the bulk meteorites (including chondrules and aggregates) have the same average porosity as the matrix. These results reveal that the porosities of primitive materials at scales ranging from nanogram to kilogram are similar, which implies that similar accretion dynamics operated through 12 orders of size magnitude. Permeabilities of the investigated chondrites vary by several orders of magnitude, and there appears to be no simple dependence of permeability with degree of aqueous alteration, chondrite type or porosity. 相似文献
404.
405.
Diagnostic analysis of offensive odorants in a large municipal waste treatment plant in an urban area 总被引:1,自引:1,他引:0
K.-H. Kim S.-H. Jo H.-C. Song S. K. Pandey H.-N. Song J.-M. Oh Y. Sunwoo K. C. Choi 《International Journal of Environmental Science and Technology》2013,10(2):261-274
A diagnostic study was conducted to examine the effectiveness of malodor removal from a large-scale municipal waste treatment plant in an urban area. To this end, the odor pollution status was investigated from a total of 16 spots in the treatment facility to cover the dual treatment lines consisting of regenerative thermal oxidation (first stage) and a wet chemical scrubber (second stage). As a simple means to learn more about the odorant removal efficiency of different treatment units, samples collected from ambient spots as well as before and after each treatment unit were analyzed for 22 key offensive odorants (i.e., reduced sulfur compounds, carbonyl compounds, nitrogenous compounds, volatile organic compounds, and fatty acids) along with dilution-to-threshold ratios based on the air dilution sensory test. The removal patterns differed greatly between different odorant groups across different processing units. The effectiveness of this dual treatment system was optimized for such odorants as hydrogen sulfide and ammonia, while it was not the case for others (e.g., some aldehydes and organic acids). The results thus suggest the need for the validation of the efficiency in many types of odor processing units and for establishing new control techniques to cover a list of odorants un-subordinate to preexisting methods. 相似文献
406.
407.
Hexagonal segmentations of space have long been known for their advantages vis à vis squared partitions in discretizing spatial variables, be it natural phenomena or human‐related features. However, readily available and easy‐to‐use tools to manipulate and interact with hexagonal rasters remain widely unavailable today. This article presents a first step to enable the use of hexagonal rasters in the GIS field. A format to encode cartographical hexagonal meshes as simple ASCII files is specified through a context‐free grammar. Named HexASCII, this file format provides a simple means of storing and sharing such rasters. A set of simple tools based on the HexASCII format is presented, allowing their creation and basic interaction with traditional GIS software. 相似文献
408.
409.
Climate change may affect ocean and ice conditions in coastal oceans and thus have significant impacts on coastal infrastructure, marine navigation, and marine ecosystems. In this study a three-dimensional ice–ocean model is developed to examine likely changes of ocean and ice conditions over the Newfoundland and Labrador Shelves in response to climate change. The model is configured with a horizontal grid of approximately 7?km and a vertical grid of 46 levels and is run from 1979 to 2069. The projection period is 2011 to 2069 under a median emission scenario A1B used by the Intergovernmental Panel on Climate Change. For the projection period, the surface atmospheric forcing fields used are from the Canadian Regional Climate Model over the North Atlantic. The open boundary conditions come from the Canadian Global Climate Model, Version 3 (CGCM3), adjusted for the 1981–2010 mean of the Simple Ocean Data Assimilation model output. The simulated fields over the 1981–2010 period have patterns consistent with observations. Over the Newfoundland and Labrador Shelves during the projection period, the model shows general trends of warming, freshening, and decreasing ice. From 2011 to 2069, the model projects that under A1B sea surface temperature will increase by 1.4°C; bottom temperature will increase by 1.6°C; sea surface salinity will decrease by 0.7; bottom salinity will decrease by 0.3; and sea-ice extent will decrease by 70%. The sea level will rise by 0.11?m at the St. John's tide-gauge station because of oceanographic change, and the freshwater transport of the Labrador Current will double as a result of freshening. The regional ice–ocean model reproduces more realistic present climate conditions and projects considerably different future climate conditions than CGCM3. 相似文献
410.
Souza João Paulo da Ponte Avansi Michelle Chaves Kuroda Belila Aline Maria Poças Vidal Alexandre Campane 《Computational Geosciences》2021,25(5):1457-1471
Computational Geosciences - The identification of micropore systems in carbonate rocks is an important task of image processing because of the high impact these systems cause on fluid flow.... 相似文献