全文获取类型
收费全文 | 9104篇 |
免费 | 2161篇 |
国内免费 | 656篇 |
专业分类
测绘学 | 38篇 |
大气科学 | 3篇 |
地球物理 | 7221篇 |
地质学 | 2781篇 |
海洋学 | 410篇 |
天文学 | 148篇 |
综合类 | 408篇 |
自然地理 | 912篇 |
出版年
2024年 | 13篇 |
2023年 | 64篇 |
2022年 | 209篇 |
2021年 | 268篇 |
2020年 | 329篇 |
2019年 | 395篇 |
2018年 | 313篇 |
2017年 | 286篇 |
2016年 | 258篇 |
2015年 | 328篇 |
2014年 | 419篇 |
2013年 | 450篇 |
2012年 | 507篇 |
2011年 | 534篇 |
2010年 | 437篇 |
2009年 | 512篇 |
2008年 | 531篇 |
2007年 | 656篇 |
2006年 | 685篇 |
2005年 | 559篇 |
2004年 | 574篇 |
2003年 | 496篇 |
2002年 | 415篇 |
2001年 | 307篇 |
2000年 | 343篇 |
1999年 | 284篇 |
1998年 | 280篇 |
1997年 | 225篇 |
1996年 | 264篇 |
1995年 | 205篇 |
1994年 | 194篇 |
1993年 | 172篇 |
1992年 | 109篇 |
1991年 | 68篇 |
1990年 | 49篇 |
1989年 | 51篇 |
1988年 | 41篇 |
1987年 | 30篇 |
1986年 | 23篇 |
1985年 | 7篇 |
1984年 | 1篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 16篇 |
1954年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
??????M8.0????????????????????С???????????????????о???????????λ????????????????????ν???ие???????????????????1??M8.0??????????????????????????????????????С????????????????????????????????????????????????42°????????????????????????????20 km??2?????????????????????????????????????10 km?????????????????С??????????????????????????????????????????????????????λ?????????7 km??3??2??14??
ML3.7?????????????????93°?????????????????????С??????????????????????????????????2???????£????????????????????????????????????????????????????????????????4??2??28??ML3.8?????????λ?????????????????????????????????????????????????????????£???????????? 相似文献
992.
河西地区重力动态变化的二维离散小波多尺度分解 总被引:7,自引:5,他引:2
采用二维离散小波的多尺度分解技术,对1994~1995年和2002~2003年的河西地区重力动态变化进行分解,提取该地区不同层次的重力动态变化异常,结果反映了不同深度在一定尺度意义上的介质密度的动态变化分布。 相似文献
993.
M. Vaccari C. Lari L. Angeretti D. Fadda C. Gruppioni F. Pozzi O. Prouton H. Aussel T. Babbedge P. Ciliegi A. Franceschini E. Gonzalez-Solares F. La Franca S. Oliver I. Perez-Fournon M. Rowan-Robinson S. Serjeant P. Väisänen 《Monthly notices of the Royal Astronomical Society》2005,358(2):397-418
We present the final analysis of the European Large Area Infrared Space Observatory ( ISO ) Survey (ELAIS) 15-μm observations, carried out with the ISO Camera (ISOCAM) instrument on board the ISO .
The data-reduction method, known as the Lari Method, is based on a mathematical model of the behaviour of the detector and was specifically designed for the detection of faint sources in ISOCAM/ISO Photopolarimeter (ISOPHOT) data. The method is fully interactive and leads to very reliable and complete source lists.
The resulting catalogue includes 1923 sources detected with signal-to-noise ratio of > 5 in the 0.5–100 mJy flux range and over an area of 10.85 deg2 split into four fields, making it the largest non-serendipitous extragalactic source catalogue obtained to date from the ISO data.
This paper presents the concepts underlying the data-reduction method together with its latest enhancements. The data-reduction process, the production and basic properties of the resulting catalogue are discussed. The catalogue quality is assessed by means of detailed simulations, optical identifications and comparison with previous analyses. 相似文献
The data-reduction method, known as the Lari Method, is based on a mathematical model of the behaviour of the detector and was specifically designed for the detection of faint sources in ISOCAM/ISO Photopolarimeter (ISOPHOT) data. The method is fully interactive and leads to very reliable and complete source lists.
The resulting catalogue includes 1923 sources detected with signal-to-noise ratio of > 5 in the 0.5–100 mJy flux range and over an area of 10.85 deg
This paper presents the concepts underlying the data-reduction method together with its latest enhancements. The data-reduction process, the production and basic properties of the resulting catalogue are discussed. The catalogue quality is assessed by means of detailed simulations, optical identifications and comparison with previous analyses. 相似文献
994.
995.
996.
The 2dF Galaxy Redshift Survey: the bJ -band galaxy luminosity function and survey selection function
Peder Norberg Shaun Cole Carlton M. Baugh Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Nicholas J. G. Cross Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,336(3):907-931
997.
根据对常德1631年地震事件的史料鉴别,尤其是江陵为典型七度震害这一事实,运用震声传播方向和地光物理场以及地震烈度衰减关系,拟合推断此地震事件的序列主要由安乡北6 3/4级地震、常德北太阳山7级地震、澧县6级地震、大庸6级地震和澧县—安乡6 1/2级地震组成,相应的地震地质背景是江汉—洞庭地区晚更新世以来的剩余形变呈四象限分布。若考虑地震-构造相关分布为“Z”字型,则该地震事件的主控构造——太阳山断裂带东断裂具左旋走滑的力学机制。根据区域地震—构造相关发展过程,常德大震事件可视为1668年郯城8 1/2级地震的前震序列组成部分。 相似文献
998.
The Las Campanas/AAT rich cluster survey – I. Precision and reliability of the photometric catalogue
Kevin A. Pimbblet Ian Smail Alastair C. Edge Warrick J. Couch Eileen O'Hely Ann I. Zabludoff 《Monthly notices of the Royal Astronomical Society》2001,327(2):588-600
The Las Campanas Observatory and Anglo-Australian Telescope Rich Cluster Survey (LARCS) is a panoramic imaging and spectroscopic survey of an X-ray luminosity-selected sample of 21 clusters of galaxies at . Charge-coupled device (CCD) imaging was obtained in B and R of typically 2° wide regions centred on the 21 clusters, and the galaxy sample selected from the imaging is being used for an on-going spectroscopic survey of the clusters with the 2dF spectrograph on the Anglo-Australian Telescope. This paper presents the reduction of the imaging data and the photometric analysis used in the survey. Based on an overlapping area of 12.3 deg2 we compare the CCD-based LARCS catalogue with the photographic-based galaxy catalogue used for the input to the 2dF Galaxy Redshift Survey (2dFGRS) from the APM, to the completeness of the GRS/APM catalogue, . This comparison confirms the reliability of the photometry across our mosaics and between the clusters in our survey. This comparison also provides useful information concerning the properties of the GRS/APM. The stellar contamination in the GRS/APM galaxy catalogue is confirmed as around per cent, as originally estimated. However, using the superior sensitivity and spatial resolution in the LARCS survey evidence is found for four distinct populations of galaxies that are systematically omitted from the GRS/APM catalogue. The characteristics of the 'missing' galaxy populations are described, reasons for their absence examined and the impact they will have on the conclusions drawn from the 2dF Galaxy Redshift Survey are discussed. 相似文献
999.
1000.