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   13006篇
  免费   177篇
  国内免费   93篇
测绘学   264篇
大气科学   853篇
地球物理   2451篇
地质学   5067篇
海洋学   1298篇
天文学   2661篇
综合类   62篇
自然地理   620篇
  2022年   148篇
  2021年   218篇
  2020年   208篇
  2019年   245篇
  2018年   560篇
  2017年   451篇
  2016年   499篇
  2015年   227篇
  2014年   453篇
  2013年   687篇
  2012年   509篇
  2011年   643篇
  2010年   609篇
  2009年   711篇
  2008年   633篇
  2007年   649篇
  2006年   551篇
  2005年   373篇
  2004年   348篇
  2003年   308篇
  2002年   309篇
  2001年   264篇
  2000年   272篇
  1999年   187篇
  1998年   193篇
  1997年   186篇
  1996年   129篇
  1995年   143篇
  1994年   133篇
  1993年   111篇
  1992年   83篇
  1991年   113篇
  1990年   104篇
  1989年   86篇
  1988年   94篇
  1987年   119篇
  1986年   95篇
  1985年   123篇
  1984年   118篇
  1983年   120篇
  1982年   101篇
  1981年   96篇
  1980年   116篇
  1979年   102篇
  1978年   96篇
  1977年   86篇
  1976年   70篇
  1975年   76篇
  1974年   78篇
  1973年   75篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
1.
Solar System Research - The possibility of determining the thermophysical characteristics of the lunar soil by a penetrating probe when using solar heat as a heater is considered. The effectiveness...  相似文献   
2.
Izvestiya, Atmospheric and Oceanic Physics - Our survey of various space image consumers identified that the geographic coverage, regularity, and frequency of observations are the most important...  相似文献   
3.
Doklady Earth Sciences - A first set of K–Ar isotopic ages obtained, which allowed to estimate the age of the largest volcanoes of the Anaunsky Dol (3.2, 2.2 and 1.9 Ma) and eruptive centers...  相似文献   
4.
Astronomy Reports - The initial form of present-day space optical observations contain considerable geometrical and brightness distortions. This problem can be solved based on geometrical...  相似文献   
5.
Geomagnetism and Aeronomy - The paper considers a special class of artifacts that appears in the useful signal when the source moves along a discrete matrix of the receiver. A parasitic component...  相似文献   
6.
Taseiko  O. V.  Moskvichev  V. V.  Chernykh  D. A. 《Water Resources》2019,46(6):983-991
Water Resources - The basic indicators of regional water use have been identified and assessed as a component of a single social–natural–technogenic system. These indicators have been...  相似文献   
7.
Izvestiya, Atmospheric and Oceanic Physics - The problem of atmospheric correction for shortwave channels of a multispectral low-resolution scanning radiometer onboard the Meteor-M No. 2 satellite...  相似文献   
8.
Geomagnetism and Aeronomy - Winter thunderstorms in Kamchatka are a rare meteorological phenomenon. Temporal variations of the quasi-static electric field and meteorological values at the Paratunka...  相似文献   
9.
Lower Palaeogene extrusive igneous rocks of the Faroe Islands Basalt Group (FIBG) dominate the Faroese continental margin, with flood basalts created at the time of breakup and separation from East Greenland extending eastwards into the Faroe‐Shetland Basin. This volcanic succession was emplaced in connection with the opening of the NE Atlantic; however, consensus on the age and duration of volcanism remains lacking. On the Faroe Islands, the FIBG comprises four main basaltic formations (the pre‐breakup Lopra and Beinisvørð formations, and the syn‐breakup Malinstindur and Enni formations) locally separated by thin intrabasaltic sedimentary and/or volcaniclastic units. Offshore, the distribution of these formations remains ambiguous. We examine the stratigraphic framework of these rocks on the Faroese continental margin combining onshore (published) outcrop information with offshore seismic‐reflection and well data. Our results indicate that on seismic‐reflection profiles, the FIBG can be informally divided into lower and upper seismic‐stratigraphic packages separated by the strongly reflective A‐horizon. The Lower FIBG comprises the Lopra and Beinisvørð formations; the upper FIBG includes the Malinstindur and Enni formations. The strongly reflecting A‐horizon is a consequence of the contrast in properties of the overlying Malinstindur and underlying Beinisvørð formations. Onshore, the A‐horizon is an erosional surface, locally cutting down into the Beinisvørð Formation; offshore, we have correlated the A‐horizon with the Flett unconformity, a highly incised, subaerial unconformity, within the juxtaposed and interbedded sedimentary fill of the Faroe‐Shetland Basin. We refer to this key regional boundary as the A‐horizon/Flett unconformity. The formation of this unconformity represents the transition from the pre‐breakup to the syn‐breakup phase of ocean margin development in the Faroe–Shetland region. We examine the wider implications of this correlation considering existing stratigraphic models for the FIBG, discussing potential sources of uncertainty in the correlation of the lower Palaeogene succession across the Faroe–Shetland region, and implications for the age and duration of the volcanism.  相似文献   
10.
Water Resources - The space–time variations in the Oka basin water chemistry have been considered. The specific features in the river water and groundwater pollution along the Oka channel and...  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