全文获取类型
收费全文 | 4496篇 |
免费 | 822篇 |
国内免费 | 656篇 |
专业分类
测绘学 | 851篇 |
大气科学 | 385篇 |
地球物理 | 353篇 |
地质学 | 1305篇 |
海洋学 | 182篇 |
天文学 | 110篇 |
综合类 | 1130篇 |
自然地理 | 1658篇 |
出版年
2024年 | 7篇 |
2023年 | 54篇 |
2022年 | 147篇 |
2021年 | 185篇 |
2020年 | 173篇 |
2019年 | 182篇 |
2018年 | 156篇 |
2017年 | 236篇 |
2016年 | 227篇 |
2015年 | 248篇 |
2014年 | 331篇 |
2013年 | 310篇 |
2012年 | 367篇 |
2011年 | 407篇 |
2010年 | 354篇 |
2009年 | 231篇 |
2008年 | 254篇 |
2007年 | 278篇 |
2006年 | 288篇 |
2005年 | 261篇 |
2004年 | 227篇 |
2003年 | 183篇 |
2002年 | 139篇 |
2001年 | 119篇 |
2000年 | 95篇 |
1999年 | 96篇 |
1998年 | 58篇 |
1997年 | 68篇 |
1996年 | 37篇 |
1995年 | 44篇 |
1994年 | 39篇 |
1993年 | 33篇 |
1992年 | 28篇 |
1991年 | 22篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 7篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
排序方式: 共有5974条查询结果,搜索用时 15 毫秒
1.
C.S. Botzler J. Snigula R. Bender N. Drory G. Feulner G.J. Hill U. Hopp C. Maraston C. Mendes de Oliveira 《Astrophysics and Space Science》2003,284(2):393-396
The Munich Near-IR Cluster Survey (MUNICS) is a wide-area, medium-deep, photometric survey selected in the K' band. The project's
main scientific aims are the identification of galaxy clusters up to redshifts of unity and the selection of a large sample
of field early-type galaxies up to z < 1.5 for evolutionary studies. We created a Large Scale Structure catalog, using a new structure finding technique specialized
for photometric datasets, that we developed on the basis of a friends-of-friends algorithm. We tested the plausibility of
the resulting galaxy group and cluster catalog with the help of Color-Magnitude Diagrams (CMD), as well as a likelihood- and
Voronoi-approach.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
本文提出了一个普适的衡量成团天体系统成员概率计算结果的有效性指数:E=1-NΣ{P(i)[1-P(i)]}/ΣP(i)Σ[1-P(i)]},并以此对以Sanders方法为基础的各种成员确定模型的有效性进行了分析.从总体上说,运动学资料(自行、视向速度等)是一类有效的观测判据. 相似文献
3.
M. A. P. Torres J. Casares I. G. Martínez-Pais P. A. Charles 《Monthly notices of the Royal Astronomical Society》2002,334(1):233-240
We present a library of 47 open-cluster integrated spectra, mostly obtained at CASLEO (San Juan, Argentina) in the range 3600 < λ < 7400 Å , which are made available at CDS. The data are combined with previous spectra to obtain 10 high signal-to-noise ratio basic templates in the young and intermediate-age domains, which are also provided in the library. These Galactic disc templates represent the increased time resolution spectral evolution of a stellar population unit around the Solar metallicity level. The improved signal-to-noise ratio of the present templates with respect to previous template lists, together with their increased time resolution, allowed us to improve the fundamental parameters of some open clusters. The present spectral library will be useful for several astrophysical applications, particularly for population syntheses of star-forming giant galaxies. 相似文献
4.
5.
STUDY ON BEIJING''''S EMERGING MOBILE COMMUNICATION INDUSTRIAL CLUSTER AND ITS POLICY IMPLICATIONS 总被引:1,自引:0,他引:1
1INTRODUCTIONClusters,definedasgeographicallyproximategroupsofinterconnectedcompaniesandassociatedinstitutionsinparticularfields,linkedbycommonalitiesandcomple-mentarities(PORTER,2000),havearousedanintenseinterestofurbanandregionalplanningresearchersandpolicymakersoverthepastdecades.Itiswidelyrecog-nizedthatclusterscanpromoteproductivityandinno-vation,developlocalcompetitiveadvantages.Popular-izedbyMichaelPORTERinhisbook“TheCompetitiveAdvantageofNationsin1990,theclusterisnotanewcon… 相似文献
6.
倪万魁 《地球科学与环境学报》1996,(3)
本文根据大量的调查资料,采用多指标评判打分法对铜川市区滑坡逐一进行了危险性综合评价,旨在为该区滑坡的预测与防治提供可靠的依据。 相似文献
7.
利用上海天文台的照相底片资料,确定了疏散星团NGC6530天区364颗恒星的自行和成员概率,并对有关自行测定的方法、结果和精度等问题作了较为详细的介绍和讨论。使用的底片历元差为87年,全部恒星自行中误差的均方根值为1.09mas/a。 相似文献
8.
9.
Gary Bridge 《Geoforum》2008,39(4):1570-1584
This paper explores the radical possibilities of pragmatism for geography using the illustration of arguments concerning a renewed (urban) public realm through the exchange of validity claims in communication. Pressing further the pragmatist possibilities of Habermas’s idea of communicative action it draws on John Dewey’s work, and a range of contemporary pragmatist philosophers, to consider human communicability in its widest sense. This is then explored using an example of the spatiality and performativity of body-minds in a range of communicative spaces of the city. Then the paper moves on to consider the radical implications of pragmatism for geography in general in terms of body-mind/environment relations; a transactional view of space; experience, rationality and radical democracy. 相似文献
10.
Identifying China’s leading world city: a network approach 总被引:3,自引:0,他引:3
This paper reports our research on China’s world cities. Formal network analysis of air passenger linkages for recent years
among China’s most populous cities and among many of the world’s largest cities allows us to identify the country’s leading
world city from among the leading Mainland candidates, Beijing, Shanghai and Guangzhou. We theorize our findings about China’s
world cities in relation to both global forces (and China’s increasing entanglement with them) and the policies and actions
of the national state. We examine the national and global urban network through a longitudinal, two-level analysis of airline
passenger travel for four time points between about 1990 and 2005. We show that Beijing was China’s leading world city at
the beginning of the time period, a status it lost nationally in as early as 1995, and then globally 10 years later. On the
other hand Shanghai became China’s leading world city, and it acquired this status first nationally in 2000, and then globally
in 2005. The changing status of the Chinese capital corresponds to the country’s increasing involvement with the capitalist
world economy. Shanghai’s ascendance as the leading world city in China may indicate that global forces have come to play
an increasingly important role relative to that of the developmental state.
相似文献
Michael F. TimberlakeEmail: |