全文获取类型
收费全文 | 557篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 10篇 |
大气科学 | 8篇 |
地球物理 | 152篇 |
地质学 | 241篇 |
海洋学 | 39篇 |
天文学 | 61篇 |
综合类 | 1篇 |
自然地理 | 55篇 |
出版年
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 18篇 |
2013年 | 27篇 |
2012年 | 13篇 |
2011年 | 23篇 |
2010年 | 25篇 |
2009年 | 22篇 |
2008年 | 22篇 |
2007年 | 17篇 |
2006年 | 25篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 16篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1984年 | 5篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1968年 | 4篇 |
1965年 | 6篇 |
1964年 | 4篇 |
1962年 | 4篇 |
1953年 | 5篇 |
1952年 | 4篇 |
1951年 | 5篇 |
1950年 | 4篇 |
1949年 | 8篇 |
排序方式: 共有567条查询结果,搜索用时 171 毫秒
251.
V. V. Sokolov A. I. Kopylov S. V. Zharykov V. G. Kurt A. V. Berezin 《Astrophysics and Space Science》1995,231(1-2):343-346
A central part of the GRB 790613 field is investigated, which contains about 1/3 of the area of 99% confidence of the GRB localization. Up to V 25 no blue optical counterparts were found. This can be interpreted as the absence in the field of single compact objects of the neutron star type as a possible potential source of -burst, up to a distance of 30 pc. 相似文献
252.
Melih Ertan Çinar Tuncer Katagan Bilal Öztürk Özdemir Egemen Zeki Ergen Ahmet Kocatas Mesut Önen Fevzi Kirkim Kerem Bakir Güley Kurt Ertan Dagli Asli Kaymakçi Sermin Açik Alper Dogan & Tahir Özcan 《Marine Ecology》2006,27(3):229-246
Temporal and spatial variation in soft‐bottom benthic communities following recovery from a pollution episode were studied between January and September 2004 in and around Alsancak Harbor, located in the polluted part of Izmir Bay (Aegean Sea, eastern Mediterranean). Samples were collected at seven stations by van Veen grab. Three additional stations were sampled by means of a beam trawl to take into account large mobile animals and for a better estimate of the local biodiversity. A total of 231 species belonging to 10 zoobenthic groups were found. Polychaetes contributed 90% of the total faunal populations and mollusks 87% of the total biomass in the area. Community parameters varied significantly among stations and sampling periods; number of species ranged from 2 to 79 per 0.1 m2 grab sample; density from 20 to 81,720 ind·m?2; biomass from 0.1 to 4190 g·m?2; Shannon–Wiener diversity index (log2 base) from 0.4 to 4.4; and Pielou's evenness index from 0.11 to 1.0. Collections indicate that a number of species, including those sensitive to pollution, have colonized the area where azoic conditions had been previously reported. A total of six exotic species, Streblospio gynobranchiata, Polydora cornuta, Hydroides dianthus, Hydroides elegans, Anadara demiri and Fulvia fragilis, probably transferred to the area via ballast water or hull fouling, dominated soft or hard substrata in and near Alsancak Harbor. The first two species accounted for more than 70% of the total population in the area, while A. demiri contributed the most to the biomass (93%, at station 7). 相似文献
253.
Depth Distribution and Abundance of Northern Adriatic Littoral Rocky Reef Blennioid Fishes (Blenniidae and Tripterygion) 总被引:3,自引:0,他引:3
Abstract. Species' depth distributions and abundances were visually assessed along 24 transects in a northern Adriatic assemblage of blennioid fishes (14 species of Blenniidae , 1 species of Triptery-giidue). Total abundance of blennioids was highest in 0.5-1 m depth, decreasing upwards and downwards. Species diversity (S hannon -W iener ) is highest at the shallowest depth (0-0.5 in). The curybathic species Parablennius incognitus, Lipophrys dalmatinus, Tripterygion tripteronotus , and Parablennius tentacularis were most abundant at all depths (relative to the species investigated). All stenobathic species were most abundant at 0-0.5 m. Depth distribution patterns and abundance ranks of species were similar at western, eastern, southern, and northern transects. 相似文献
254.
Prof. Dr. Kurt Wegener 《Pure and Applied Geophysics》1949,14(1-2):50-52
Sans résumé 相似文献
255.
256.
Prof. Dr. Kurt Wegener 《Pure and Applied Geophysics》1951,19(3-4):124-128
Zusammenfassung Einige einfache Beziehungen zwischen den Schwere-Werten und der Formung der Gebirge werden gezeigt.
Summary Some simple relations between the formation of the mountains and the gravity are discussed.相似文献
257.
Kurt Kalle 《Ocean Dynamics》1953,6(1):32-33
Zusammenfassung Auf der Grundlage der Hansen-Schumacherschen Kippthermometertabellen werden vier Fluchtentafeln entworfen, deren Vorzüge in ihrer besonders schnellen Herstellungsweise, ihrer einfachen und zeitersparenden Anwendungsweise und ihrem verhältnismäßig geringen Raumbedarf bestehen.
Nomograms for correcting the readings of reversible thermometers
Summary Basing on correction tables for reversible thermometers after Hansen-Schumacher four nomograms are designed which are characterized by their particularly quick way of establishment, their simple and time-saving way of employment and the comparatively small space required.
Nomogrammes pour corriger les indications de thermomètres à renversement
Résumé Quatre nomogrammes sont présentés qui s'appuient sur les tables de correction pour les thermomètres à renversement d'après Hansen-Schumacher. Ces nomogrammes sont signalés par leur mode particulièrement rapide d'établissement et par leur simplicité et vitesse d'emploi; de plus, ils sont peu encombrants.相似文献
258.
Prof. Dr. Kurt Wegener 《Pure and Applied Geophysics》1952,23(1):145-146
Summary Two determination of the sun's temperatur by application of the law ofWien on 2 published bolometer-curves of the Astrophysical Observatory, Washington. 相似文献
259.
260.
Frank Gaardsted Meng Zhou Vladimir Pavlov Alexey Morozov Kurt S. Tande 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(11):1465-1473
Data collected on a cruise in January 2008, using a laser optical plankton counter, conductivity–temperature–depth sensors, and a lowered acoustic Doppler current profiler, was used to study the mesoscale distribution and advection of overwintering Calanus finmarchicus in its deep water winter habitat off the shelf of northern Norway. The overwintering animals were generally located immediately below the Atlantic Water (AW) in Arctic Intermediate Water (AIW), in the 600–1200 m depth range. The depth of the interface between AW and AIW varied considerably in the area and this was clearly reflected in the C. finmarchicus distribution. Maximum abundance varied from about 80 ind m?3 to more than 200 ind m?3 at the different stations. Current measurements showed the richness of mesoscazle eddies, with speeds exceeding 70 cm s?1 at the surface and rapidly decreasing with depth. In the main overwintering layer the eddy features were also clearly seen, but with speeds generally below 20 cm s?1. C. finmarchicus were found in the whole survey area, but they were not homogeneously distributed. Advection of the copepods resulted in relatively high local rates of change in overwintering C. finmarchicus abundance with mean value of 8% per day in the area. It is clear that mesoscale physical processes greatly contribute to the variability in the abundance of overwintering C. finmarchicus off the shelf of northern Norway. The collected data are also a valuable addition to the generally sparse datasets on the C. finmarchicus winter distribution and the role of the Lofoten basin in the large scale system is also discussed. 相似文献