首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   231篇
  免费   0篇
测绘学   1篇
大气科学   8篇
地球物理   36篇
地质学   69篇
海洋学   41篇
天文学   75篇
自然地理   1篇
  2022年   5篇
  2021年   7篇
  2020年   6篇
  2019年   9篇
  2018年   14篇
  2017年   8篇
  2016年   16篇
  2015年   6篇
  2014年   10篇
  2013年   18篇
  2012年   15篇
  2011年   13篇
  2010年   10篇
  2009年   6篇
  2008年   12篇
  2007年   15篇
  2006年   9篇
  2005年   7篇
  2004年   4篇
  2003年   5篇
  2002年   5篇
  2001年   4篇
  2000年   1篇
  1999年   3篇
  1998年   1篇
  1997年   2篇
  1995年   1篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1988年   2篇
  1987年   2篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1979年   3篇
  1978年   1篇
排序方式: 共有231条查询结果,搜索用时 15 毫秒
51.
We investigate the photometric system consisting of the AZT-8 telescope BVRI filters, and IMG 1024S CCD-camera. The coefficients of the transformation from the instrumental values of magnitudes and color indexes to the standard Johnson-Cousins system for the BVRI bands are derived.  相似文献   
52.
A major field of research since the 1920s has been methods and theories of economic regionalization. The territorial-production complex is now recognized as a key developmental tool within the framework of economic-planning regions. Recently, there has been a more marked growth of study into problems of natural-resource development, social progress and change in the U.S.S.R. as well as into the spatial structure of other nations, particularly other socialist countries and non-socialist developing countries.  相似文献   
53.
54.
Shevchenko  G. V.  Kantakov  G. A. 《Water Resources》2004,31(2):226-234
Analysis of sea current velocities showed that the principal flow has a southeastern horizontal direction and downward vertical direction. This flow pattern persisted throughout the observational period. Abrupt temperature drops and water salinity rises are indicative of the near-shore upwelling that was recorded twice during this period. A steady tendency toward a decrease in oxygen concentration and an increase in pH was observed during the observations.  相似文献   
55.
This paper describes a method for calculating the station corrections to earthquake energy class and the acoustic impedance based on records of earthquake codas in the 0.8–1.8 Hz frequency band. The calculation is based on measurements of the relative coda level at two stations, with one of the two being used as the reference. The data were recorded by digital seismometers: CMG-3TB (GURALP), CMG-5TD (GURALP), CMG-6TD (GURALP), and GMS-AC-73i HHV (GeoSIG). We present estimates of class corrections for the Kamchatka network of seismic stations.  相似文献   
56.
Izvestiya, Physics of the Solid Earth - The style of the seismotectonic deformation of the Earth’s crust in the Caucasus and its immediate surroundings corresponds to the thrust setting with...  相似文献   
57.
The paper presents a comparative analysis of the intrinsic noises of seismometers operating at Kamchatka seismic stations: CMG-3TB (GURALP), CMG-5TD (GURALP), CMG-6TD (GURALP), GMS-AC-73i HHV (GeoSIG), SM3os (GEOTECH+), S5Sos (KF GS), and SM3kv. It is shown that the dynamic range of the seismometers is narrower at low frequencies in the area of weak signals.  相似文献   
58.
The paper presents new information on the chemical composition of the insoluble aerosol fraction in the atmospheric surface boundary layer of different climatic zones of the North Atlantic (temperate humid, arid and semiarid, equatorial humid). The material for this study was collected during 12 expeditions. Nylon meshes were used to catch aerosols along the course of vessels. Aerosols above the North Atlantic consist of lithogenic, biogenic, and anthropogenic particles transported from different regions, which governs the differences in their concentrations and mineral and chemical compositions. Significant (by more than an order of magnitude) enrichment of aerosols in Cu, Cd, Zn, Pb, Sb, and Se is related to anthropogenic atmospheric pollution.  相似文献   
59.
Izvestiya, Atmospheric and Oceanic Physics - Based on the available geological and geodetic data, it has been established that the structures of the Alpine–Himalayan–Indonesian mobile...  相似文献   
60.
In this study, the grain-size and clay-mineral compositions of 73 surface sediment samples collected in a variety of environmental settings in the White Sea are presented to characterize recent sedimentation processes, reconstruct transport pathways, and identify potential source areas of the terrigenous components. Areas >100 m deep are invariably characterized by silty clay, whereas areas <100 m deep exhibit more heterogeneous grain-size compositions plausibly explained by coastal erosion and (re-)distribution mechanisms, particularly tidal currents. The dominance of sand in the estuarine areas of the Onega and Dvina rivers as well as toward the Gorlo Strait connecting the White Sea with the Barents Sea is attributed to increased current speeds. Illite and smectite are the dominant clay minerals in recent sediments of the southwestern and eastern White Sea sectors, respectively. Their distribution patterns largely depend on the geology of the source areas, and mirror surface circulation patterns, especially in Dvina Bay. Smectite is a key clay mineral in White Sea surface sediments, as it reveals the dominating influence of the Northern Dvina’s runoff on sedimentation and water circulation throughout the basin. In comparison to other Eurasian shelf seas, the White Sea is characterized by a greater diversity of clay-mineral assemblages, which range from illite- to smectite-dominated sectors containing variable amounts of chlorite and kaolinite.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号