全文获取类型
收费全文 | 186篇 |
免费 | 10篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 15篇 |
大气科学 | 8篇 |
地球物理 | 57篇 |
地质学 | 50篇 |
海洋学 | 8篇 |
天文学 | 38篇 |
综合类 | 3篇 |
自然地理 | 20篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2018年 | 10篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 11篇 |
2009年 | 18篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 8篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1980年 | 1篇 |
排序方式: 共有199条查询结果,搜索用时 15 毫秒
61.
We aim to numerically study evolution of Alfv′en waves that accompany short-lasting swirl events in a solar magnetic flux-tube that can be a simple model of a magnetic pore or a sunspot. With the use of the FLASH code we numerically solve three-dimensional ideal magnetohydrodynamic equations to simulate twists which are implemented at the top of the photosphere in magnetic field lines of the flux-tube. Our numerical results exhibit swirl events and Alfv′en waves with associated clockwise and counterclockwise rotation of magnetic lines, with the largest values of vorticity at the bottom of the chromosphere, and a certain amount of energy flux. 相似文献
62.
Piotr Flin 《Astrophysics and Space Science》1982,83(1-2):437-439
The mean density of matter, as estimated from deep optical samples of galaxies, is too low to close the Universe. However, some additional considerations do not exclude such a possibility. 相似文献
63.
Piotr Gronkowski 《Astrophysics and Space Science》2004,294(3-4):135-150
Interaction between the strong solar wind and the dark side of a cometary nucleus was considered. It was calculated that the
potential of the dark side of the cometary nucleus could be numerically large and negative. Assuming that the nucleus of the
comet has surface mantle which consists of loose, fine dust-ice particles, it was shown that cometary particles could electrostatically
levitate over the nucleus. It was examined how this phenomenon affected the changes in the cometary brightness. Calculations
were carried out for realistically assumed values of a large range of cometary parameters. It was shown that the considered
mechanism could lead to the variations of cometary brightness, sometimes even to the outbursts of brightness. 相似文献
64.
65.
Piotr A. Dybczyński 《Earth, Moon, and Planets》2002,90(1-4):483-488
We simulated the passage of a star through the Oort cometary cloud andanalyzed the resulting sample of observable long period
comets, noting strong asymmetries in the directional distribution of the perihelion points of thosecomets. We discuss the
results previously published byWeissman (1996) for the same case. An explanation is suggestedwhy the isotropic output can
be obtained only for a very peculiar case. The``cometary shower' density variation with time is also presented and thetime-dependence
of the directional distribution is discussed. 相似文献
66.
Summary. A hardware configuration and program are described for interfacing a DIGICO spinner rock magnetometer to an APPLE microcomputer. This configuration provides full control of measurements and permits storage of the results on floppy or hard discs. A similar configuration can be used to operate the anisotropy unit. 相似文献
67.
On the basis of the published times of minima and our own observations, we analysed the period change of the Algol-type eclipsing binary CU Pegasi. Over almost seventy years of observations, the parabolic period change has been clearly seen as dP/dt = 1.38 × 10−6 d/year. The estimated mass transfer in the system is about 1 × 10−7 MM⊙/year. 相似文献
68.
69.
Szymon Gburek Janusz Sylwester Miroslaw Kowalinski Jaroslaw Bakala Zbigniew Kordylewski Piotr Podgorski Stefan Plocieniak Marek Siarkowski Barbara Sylwester Witold Trzebinski Sergey V. Kuzin Andrey A. Pertsov Yurij D. Kotov Frantisek Farnik Fabio Reale Kenneth J. H. Phillips 《Solar physics》2013,283(2):631-649
Solar Photometer in X-rays (SphinX) was a spectrophotometer developed to observe the Sun in soft X-rays. The instrument observed in the energy range ≈?1?–?15 keV with resolution ≈?0.4 keV. SphinX was flown on the Russian CORONAS–PHOTON satellite placed inside the TESIS EUV and X telescope assembly. The spacecraft launch took place on 30 January 2009 at 13:30 UT at the Plesetsk Cosmodrome in Russia. The SphinX experiment mission began a couple of weeks later on 20 February 2009 when the first telemetry dumps were received. The mission ended nine months later on 29 November 2009 when data transmission was terminated. SphinX provided an excellent set of observations during very low solar activity. This was indeed the period in which solar activity dropped to the lowest level observed in X-rays ever. The SphinX instrument design, construction, and operation principle are described. Information on SphinX data repositories, dissemination methods, format, and calibration is given together with general recommendations for data users. Scientific research areas in which SphinX data find application are reviewed. 相似文献
70.
ABSTRACTGeomasking techniques displace point data to new locations in order to protect privacy while maintaining overall spatial distributions. If the end users of geomasked data are unaware that the data are masked, there is a risk that they will incorrectly associate individuals at the new locations with the masked data attributes. The probability of correct and false household identification depends on human understanding of whether maps contain masked coordinates and the spatial relationships of the points to contextual geographic data. Using a map-based experiment, this study finds that confidence in performing a household identification is substantially lowered when masked points are situated equidistantly between residential parcels. Despite initial notifications that data are masked, map users often report confidence in assigning masked points to specific households. Only map users who receive frequent notifications that the points are masked have reduced confidence in associating them with particular households, thereby lowering identification risk. 相似文献