全文获取类型
收费全文 | 1696篇 |
免费 | 64篇 |
国内免费 | 8篇 |
专业分类
测绘学 | 19篇 |
大气科学 | 132篇 |
地球物理 | 413篇 |
地质学 | 541篇 |
海洋学 | 170篇 |
天文学 | 341篇 |
综合类 | 12篇 |
自然地理 | 140篇 |
出版年
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 32篇 |
2020年 | 32篇 |
2019年 | 38篇 |
2018年 | 44篇 |
2017年 | 37篇 |
2016年 | 72篇 |
2015年 | 59篇 |
2014年 | 63篇 |
2013年 | 103篇 |
2012年 | 65篇 |
2011年 | 85篇 |
2010年 | 77篇 |
2009年 | 118篇 |
2008年 | 73篇 |
2007年 | 81篇 |
2006年 | 74篇 |
2005年 | 45篇 |
2004年 | 70篇 |
2003年 | 51篇 |
2002年 | 46篇 |
2001年 | 41篇 |
2000年 | 33篇 |
1999年 | 27篇 |
1998年 | 29篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1990年 | 9篇 |
1989年 | 16篇 |
1988年 | 5篇 |
1987年 | 17篇 |
1986年 | 8篇 |
1985年 | 22篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 7篇 |
1977年 | 15篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 10篇 |
1972年 | 12篇 |
1969年 | 5篇 |
排序方式: 共有1768条查询结果,搜索用时 708 毫秒
821.
822.
A novel method is presented which will enhance the sensitivity of neutrino telescopes to identify transient sources such as Gamma-Ray Bursts (GRBs) and core-collapse Supernovae (SNe). Triggered by the detection of high energy neutrino events from IceCube or other large scale neutrino telescopes, an optical follow-up program will allow the identification of the transient neutrino source. We show that once the follow-up program is implemented, the achievable sensitivity of IceCube to neutrinos from SNe and GRBs would increase by a factor of 2–3. The program can be realized with a small network of automated 1–2 m telescopes and has rather modest observing time requirements. 相似文献
823.
824.
J. I. Davies S. Roberts S. Sabatini 《Monthly notices of the Royal Astronomical Society》2005,356(2):794-800
Galaxy harassment has been proposed as a physical process that morphologically transforms low surface density disc galaxies into dwarf elliptical galaxies in clusters. It has been used to link the observed very different morphology of distant cluster galaxies (relatively more blue galaxies with 'disturbed' morphologies) with the relatively large numbers of dwarf elliptical galaxies found in nearby clusters. One prediction of the harassment model is that the remnant galaxies should lie on low surface brightness tidal streams or arcs. We demonstrate in this paper that we have an analysis method that is sensitive to the detection of arcs down to a surface brightness of 29 B μ and we then use this method to search for arcs around 46 Virgo cluster dwarf elliptical galaxies. We find no evidence for tidal streams or arcs and consequently no evidence for galaxy harassment as a viable explanation for the relatively large numbers of dwarf galaxies found in the Virgo cluster. 相似文献
825.
826.
827.
828.
Mikko Kaasalainen Petr Pravec Lenka Šarounová Jenni Virtanen Anders Erikson Josef ?urech Johan S.V. Lagerros Claes-Ingvar Lagerkvist John Davies Peter Kušnirák Vasilij G. Shevchenko Irina N. Belskaya 《Icarus》2004,167(1):178-196
We present new observations and models of the shapes and rotational states of the eight near-Earth Asteroids (1580) Betulia, (1627) Ivar, (1980) Tezcatlipoca, (2100) Ra-Shalom, (3199) Nefertiti, (3908) Nyx, (4957) Brucemurray, and (5587) 1990 SB. We also outline some of their solar phase curves, corrected to common reference geometry with the models. Some of the targets may feature sizable global nonconvexities, but the observable solar phase angles were not sufficiently high for confirming these. None is likely to have a very densely cratered surface. We discuss the role of the intermediate topographic scale range in photometry, and surmise that this scale range is less important than large or small scale lengths. 相似文献
829.
Alison Sills † Tim Adams Melvyn B. Davies Matthew R. Bate 《Monthly notices of the Royal Astronomical Society》2002,332(1):49-54
We performed high-resolution simulations of two stellar collisions relevant for stars in globular clusters. We considered one head-on collision and one off-axis collision between two 0.6-M⊙ main-sequence stars. We show that a resolution of about 100 000 particles is sufficient for most studies of the structure and evolution of blue stragglers. We demonstrate conclusively that collision products between main-sequence stars in globular clusters do not have surface convection zones larger than 0.004 M⊙ after the collision, nor do they develop convection zones during the 'pre-main-sequence' thermal relaxation phase of their post-collision evolution. Therefore, any mechanism which requires a surface convection zone (i.e. chemical mixing or angular momentum loss via a magnetic wind) cannot operate in these stars. We show that no disc of material surrounding the collision product is produced in off-axis collisions. The lack of both a convection zone and a disc proves a continuing problem for the angular momentum evolution of blue stragglers in globular clusters. 相似文献
830.