全文获取类型
收费全文 | 212篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 6篇 |
地球物理 | 22篇 |
地质学 | 136篇 |
海洋学 | 19篇 |
天文学 | 28篇 |
自然地理 | 2篇 |
出版年
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 16篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 13篇 |
2007年 | 24篇 |
2006年 | 12篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有214条查询结果,搜索用时 818 毫秒
131.
132.
Long-term data on the evolution of the parameters of motion of 15 artificial satellites of the Earth in orbits with minimal heights of 400–1100 km were used to study the density variations in the upper atmosphere at minimums of four cycles of solar activity. It was found that the density at these heights considered increased by about 7% at the minimum of solar cycle 20 as compared to solar cycle 19. Later, the density fell rather linearly at the minimums of cycles 21 and 22. The statistical processing of the data for solar cycles 20–22 demonstrated that the density decreased by 4.6% over ten years and by 9.9% over 20 years. Analyzing the density variations during the four cycles of solar activity, we found that the long-term decrease in density observed at the minimums of cycles 20–22 is caused mainly by specific variations of the solar activity parameters (namely, the solar radio flux and the level of geomagnetic disturbance).__________Translated from Astronomicheskii Vestnik, Vol. 39, No. 2, 2005, pp. 177–183.Original Russian Text Copyright © 2005 by Volkov, Suevalov. 相似文献
133.
134.
135.
Observations of the pair of galaxies VV 330 with the SCORPIO multimode instrument on the 6-m Special Astrophysical Observatory telescope are presented. Large-scale velocity fields of the ionized gas in Hα and brightness distributions in continuum and Hα have been constructed for both galaxies with the help of a scanning Fabry-Perot interferometer. Long-slit spectroscopy is used to study the stellar kinematics. Analysis of the data obtained has revealed a complex structure in each of the pair components. Three kinematic subsystems have been identified in UGC 5600: a stellar disk, an “inner gas ring” turned with respect to the disk through ~80°, and an outer gas disk. The stellar and outer gas disks are noncoplanar. Possible scenarios for the formation of the observed multicomponent kinematic galactic structure are considered, including the case where the large-scale velocity field of the gas is represented by the kinematic model of a disk with a warp. The velocity field in the second galaxy of the pair, UGC 5609, is more regular. A joint analysis of the data on the photometric structure and the velocity field has shown that this is probably a late-type spiral galaxy whose shape is distorted by the gravitational interaction, possibly, with UGC 5600. 相似文献
136.
A. V. Volkov A. A. Sidorov N. E. Savva E. E. Kolova K. Yu. Murashov 《Doklady Earth Sciences》2017,472(2):178-183
The geochemical features and conditions of formation of the Paleozoic epithermal Au–Ag mineralization in the pre-accretion Kedon (D2–3) volcanoplutonic belt located within the Omolon craton terrain are described. The new data on the composition and contents of trace and rare-earth elements (REEs) in igneous ores of epithermal deposits is provided. The elevated grades of a wide range of trace elements as compared to the average values of the upper crust have been identified. 相似文献
137.
A. V. Volkov V. Yu. Prokofiev E. E. Tyukova V. A. Sidorov K. Yu. Murashov N. V. Sidorova M. A. Zemskova 《Geology of Ore Deposits》2017,59(2):112-130
This paper is focused on the new data for geology, mineralogy, and geochemistry of stockworks consisting of steep and gentle quartz veins and veinlets forming a complex multilevel structure at the Rodion deposit. These stockworks range from 25 to 150 m in thickness. Average gold grade is 1.8 g/t. Ore minerals pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, and native gold are predominantly concentrated on the vein and veinlet walls. Thermal metamorphism caused by the intrusion of the Ulakhan granodiorite pluton is the important singularity of the deposit. The deposit ore is enriched in chalcophile microelements Au, Ag, As, Sb, Cu, Pb, Zn, and Bi as compared to the average composition of the upper crust and hosting Permian sequences. The enrichment factors range from a few to hundreds of times. Bi, W, Pb, Ag, and Na2O are positively correlated between each other and with Au. The highest correlation coefficient 0.59 is between Au and Bi. Au is negatively correlated with Ba, Li, Co, Ni, Mn, Ti, and Be. The stockwork ores were formed involving homogeneous low-saline (9.4–4.3 wt % NaCl equiv) substantially aqueous bicarbonate-chloride fluid at 275–330°C and 300–1840 bar fluid pressure. Fluid has a high concentration of CO2 (up to 349 g/kg of water) and is reductive (СО2/СН4 = 17–37.3). Na and Ca are the major cations in the fluid, whereas K and Mg are minor. In addition, many microelements were detected in the fluid: As, Li, Rb, Cs, Mo, Ag, Sb, Cu, Zn, Cd, Pb, U, Ga, Ge, Ti, Mn, Fe, Co, Ni, V, Cr, Y, Zr, Sn, Ba, W, Au, Hg, and REE. The results obtained are consistent with the metamorphic–magmatic formation model of orogenic gold–quartz deposits within the Yana–Kolyma belt. 相似文献
138.
139.
We have obtained the first UBV(RI)
C
photoelectric light curves of the recently discovered eclipsing binary BD +66 1663 = GSC 4479 412 (P = 7.04d, V = 10.14). We have derived relative and absolute parameters of the binary, and analyzed the interstellar extinction towards
the object. Though the star is located in the field of the young open cluster Be 59, we demonstrate that it is not a member. 相似文献
140.
A. A. Sin’kevich N. E. Veremey N. N. Volkov Yu. A. Dovgalyuk V. D. Stepanenko G. G. Shchukin 《Russian Meteorology and Hydrology》2010,35(10):665-672
Results are presented of complex study of the clouds during the modification works aiming to prevent precipitation. To estimate
the modification effect, a new technique is presented based upon comparison of the IR-radiometer measurements data, from the
Meteosat satellite, on radiation temperature of the clouds after modification and those in natural development cycle. It is
shown that for the case under study, radiation temperature increase is observed in the pixel corresponding to the city in
which precipitation should be prevented. 相似文献