全文获取类型
收费全文 | 31715篇 |
免费 | 5714篇 |
国内免费 | 9786篇 |
专业分类
测绘学 | 1806篇 |
大气科学 | 11617篇 |
地球物理 | 4808篇 |
地质学 | 12012篇 |
海洋学 | 5346篇 |
天文学 | 5621篇 |
综合类 | 1981篇 |
自然地理 | 4024篇 |
出版年
2024年 | 163篇 |
2023年 | 455篇 |
2022年 | 999篇 |
2021年 | 1279篇 |
2020年 | 1290篇 |
2019年 | 1618篇 |
2018年 | 1256篇 |
2017年 | 1322篇 |
2016年 | 1362篇 |
2015年 | 1551篇 |
2014年 | 2138篇 |
2013年 | 2313篇 |
2012年 | 2307篇 |
2011年 | 2330篇 |
2010年 | 2133篇 |
2009年 | 2608篇 |
2008年 | 2433篇 |
2007年 | 2609篇 |
2006年 | 2343篇 |
2005年 | 2118篇 |
2004年 | 1785篇 |
2003年 | 1539篇 |
2002年 | 1264篇 |
2001年 | 1183篇 |
2000年 | 1118篇 |
1999年 | 964篇 |
1998年 | 860篇 |
1997年 | 656篇 |
1996年 | 554篇 |
1995年 | 476篇 |
1994年 | 460篇 |
1993年 | 372篇 |
1992年 | 287篇 |
1991年 | 236篇 |
1990年 | 157篇 |
1989年 | 128篇 |
1988年 | 112篇 |
1987年 | 54篇 |
1986年 | 65篇 |
1985年 | 70篇 |
1984年 | 52篇 |
1983年 | 47篇 |
1982年 | 38篇 |
1981年 | 32篇 |
1980年 | 24篇 |
1979年 | 3篇 |
1978年 | 18篇 |
1977年 | 21篇 |
1972年 | 2篇 |
1954年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Simulation of double cold cores of the 35°N section in the Yellow Sea with a wave-tide-circulation coupled model 总被引:1,自引:0,他引:1
Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea
was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section
is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located
near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores
are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the
west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content
is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter. This temperature
pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is
heated and strong thermocline is formed. Large zonal span of the 35°N section (about 600 km) makes the cold cores have more
opportunity to survive. The double cold cores phenomena disappears in early autumn when the west cold core vanishes first
with the dropping of the thermocline position.
Supported by the National Basic Research Program of China (No. G1999043809) and the National Science Foundation of China (No.
49736190). 相似文献
122.
对武汉区域气象中心并行计算机系统进行了详细地介绍,分析了并行计算机体系结构、网络和存储系统特点;给出了在并行计算机SP上实现数值预报业务并行化的部分结果;对数值预报模式在串、并行编程环境下的结果进行了分析比较。 相似文献
123.
张晓晖 《成都信息工程学院学报》2002,17(3):166-169
通过对影响能见度的因素的分析,提出了一种能见度预报方法-综合分析法,极大地提高了能见度的预报准确率。 相似文献
124.
125.
126.
127.
128.
129.
M. R. Bate S. H. Lubow G. I. Ogilvie K. A. Miller 《Monthly notices of the Royal Astronomical Society》2003,341(1):213-229
We analyse the non-linear, three-dimensional response of a gaseous, viscous protoplanetary disc to the presence of a planet of mass ranging from 1 Earth mass (1 M⊕ ) to 1 Jupiter mass (1 MJ ) by using the zeus hydrodynamics code. We determine the gas flow pattern, and the accretion and migration rates of the planet. The planet is assumed to be in a fixed circular orbit about the central star. It is also assumed to be able to accrete gas without expansion on the scale of its Roche radius. Only planets with masses M p ≳ 0.1 MJ produce significant perturbations in the surface density of the disc. The flow within the Roche lobe of the planet is fully three-dimensional. Gas streams generally enter the Roche lobe close to the disc mid-plane, but produce much weaker shocks than the streams in two-dimensional models. The streams supply material to a circumplanetary disc that rotates in the same sense as the orbit of the planet. Much of the mass supply to the circumplanetary disc comes from non-coplanar flow. The accretion rate peaks with a planet mass of approximately 0.1 MJ and is highly efficient, occurring at the local viscous rate. The migration time-scales for planets of mass less than 0.1 MJ , based on torques from disc material outside the Roche lobes of the planets, are in excellent agreement with the linear theory of type I (non-gap) migration for three-dimensional discs. The transition from type I to type II (gap) migration is smooth, with changes in migration times of about a factor of 2. Starting with a core which can undergo runaway growth, a planet can gain up to a few MJ with little migration. Planets with final masses of the order of 10 MJ would undergo large migration, which makes formation and survival difficult. 相似文献
130.