全文获取类型
收费全文 | 211篇 |
免费 | 12篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 15篇 |
地球物理 | 69篇 |
地质学 | 86篇 |
海洋学 | 11篇 |
天文学 | 35篇 |
自然地理 | 3篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 2篇 |
2013年 | 12篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1954年 | 1篇 |
1952年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有223条查询结果,搜索用时 15 毫秒
21.
Y. Thomas He Arthur G. Fitzmaurice Azra Bilgin Sunkyung Choi Peggy O’Day John Horst James Harrington H. James Reisinger David R. Burris Janet G. Hering 《Applied Geochemistry》2010
The behavior of As in the subsurface environment was examined along a transect of groundwater monitoring wells at a Superfund site, where enhanced reductive dechlorination (ERD) is being used for the remediation of groundwater contaminated with chlorinated solvents. The transect was installed parallel to the groundwater flow direction through the treatment area. The ERD technology involves the injection of organic C (OC) to stimulate in situ microbial dechlorination processes. A secondary effect of the ERD treatment at this site, however, is the mobilization of As, as well as Fe and Mn. The concentrations of these elements are low in groundwater collected upgradient of the ERD treatment area, indicating that, in the absence of the injected OC, the As that occurs naturally in the sediment is relatively immobile. Batch experiments conducted using sediments from the site inoculated with an Fe(III)- and As(V)-reducing bacterium and amended with lactate resulted in mobilization of As, Fe and Mn, suggesting that As mobilization in the field is due to microbial processes. 相似文献
22.
Roberto Cossu Monique Petitdidier Julian Linford Vincent Badoux Luigi Fusco Benoit Gotab Ladislav Hluchy Giuditta Lecca Fabrizio Murgia Camiel Plevier Philippe Renard Horst Schwichtenberg Wim Som de Cerff Viet Tran Gerald Vetois 《Earth Science Informatics》2010,3(3):135-148
Due to its intensive data processing and highly distributed organization, the multidisciplinary Earth Science applications community is uniquely positioned for the uptake and exploitation of Grid technologies. Currently Enabling Grids for E-sciencE, and other large Grid infrastructures are already deployed and capable of operational services. So far however, the adoption and exploitation of Grid technology throughout the Earth Science community has been slower than expected. The Dissemination and Exploitation of GRids in Earth sciencE project, proposed by the European Commission to assist and accelerate this process in a number of different ways, had between its main goals the creation of a roadmap towards Earth Science Grid platform. This paper presents the resulting roadmap. 相似文献
23.
The Chihuahua City region, located in the semiarid-arid northern highlands of Mexico, has experienced intensive groundwater abstraction during the last 40 years to meet water demands in the region. A geochemical survey was carried out to investigate the evolution from baseline to modern conditions of a 130-km flow path including the El Sauz–Chihuahua–Aldama–San Diego de Alcalá regions. The research approach included the use of major chemical elements, chlorofluorocarbons and environmental isotope (18O, 2H, 13C and 14C) tracers. Stable isotopes indicate that groundwater evolves from the evaporation of local rainfall and surface water. Groundwater located at the lower end of the flow section is up to 6000 years old and older groundwater in the order of 9000 years BP was found in a deep well located in the upper part of the flow system, implying contribution from a neighbour basin. The background groundwater chemistry upstream of Chihuahua City results from feldspar weathering. Beyond Chihuahua City the chemical conditions are strongly modified owing to disposal of sewage from public and industrial water supplies into the Rio Chuviscar, subsequent allocation of this water to agricultural irrigation areas and direct infiltration under the river bed. As a consequence, anions like chloride and sulphate are mainly related to surface sources. Nitrate is controlled in part by sewage from public supply and industry and in part by agricultural practices. Arsenic and fluoride are related to weathering of rock formations of local mineralized ranges and subsequent enrichment of the basin-fill by magmatic processes. The results of this study have implications for groundwater management in an arid region that depends entirely on groundwater for domestic, industrial and agricultural water consumption. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
24.
25.
26.
Prof. Dr. Horst Falke 《International Journal of Earth Sciences》1974,63(3):819-849
After a comment on the stratigraphical classification and the subdivision of Permian strata, a review on their occurrences in Central and Western Europe including the Alps is given. Within this area, the strata can be summarized to a northern, a central, and a “Verrucano” province. The Autunian (Lower Rotliegend) has been typically developed in the central province where it is best preserved. It is characterized by many different sedimentation processes the most important of which are described. They lead to the conclusion that the sediment deposition mainly took place in fresh water lakes and through fluviatile transport. On the other hand, the deposition of the Saxonian (Upper Rotliegend) took place in a much drier climate. Finally, the differences between the two types of climate are described. 相似文献
27.
28.
César A. Zen Vasconcellos Dimiter Hadjimichef Magno Machado Benno Bodmann Marcelo Netz-Marzola Geovane Naysinger Mariana Vargas Magaña Peter O. Hess Horst Stöcker Steven Gullberg Remo Ruffini 《Astronomische Nachrichten》2024,345(2-3):e240029
We outline our experience in organizing the first edition of the Workshop on Matter, Astrophysics, Gravitation, Ions and Cosmology, held in virtual and in-person format, denominated MAGIC23, held from 6 to 10 March, 2023, in Praia do Rosa, Santa Catarina, Brazil. The event aimed to bring together leading academic scientists, professors, students, and research scholars for exchanging experiences and discuss the most recent innovations, trends, practical challenges, and experimental and theoretical solutions adopted in the investigation fields within the scope of the meeting. The workshop offered to the participants a platform for scientific and academic projects, partnerships, and presentation of high-quality research contributions describing original and unpublished results on topics related to matter, astrophysics, gravitation, ions, and cosmology. 相似文献
29.
P. A. Curran A. J. van der Horst R. A. M. J. Wijers 《Monthly notices of the Royal Astronomical Society》2008,386(2):859-863
Gamma-ray burst (GRB) afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared to the BeppoSAX or pre- Swift era. Specifically, relatively few breaks, consistent with jet breaks, are observed in the X-ray light curves of these bursts. If these breaks are truly missing, it has serious consequences on the interpretation of GRB jet collimation and energy requirements, and the use of GRBs as cosmological tools. Here, we address the issue of X-ray breaks that are possibly 'hidden' and hence the light curves are misinterpreted as being single power laws. We do so by synthesizing X-ray telescope (XRT) light curves and fitting both single and broken power laws, and comparing the relative goodness of each fit via Monte Carlo analysis. Even with the well-sampled light curves of the Swift era, these breaks may be left misidentified, hence caution is required when making definite statements on the absence of achromatic breaks. 相似文献
30.
Dr. Horst Piller 《Contributions to Mineralogy and Petrology》1952,3(4):307-334
Zusammenfassung Es wird mit Hilfe von Zeigerdiagrammen eine anschauliche Darstellung vom Zustandekommen der Phasenkontrasterscheinungen gegeben. An Hand theoretischer Überlegungen und experimenteller Versuche wird die besondere Eignung der Phasenkontrastmikroskopie für die Bestimmung der Brechzahl transparenter dünner Teilchen nach der Immersionsmethode nachgewiesen. Daraus ergeben sich Vorteile für die mikroskopische Beurteilung der Minerale in Tonfraktionen. Das wird an zwei praktischen Beispielen gezeigt. Der Vergleich der Ergebnisse der mit dem Phasenkontrastverfahren durchgeführten Tonuntersuchungen mit den auf röntgenographischem Wege erzielten läßt eine gute Übereinstimmung erkennen. 相似文献