全文获取类型
收费全文 | 4840篇 |
免费 | 995篇 |
国内免费 | 1501篇 |
专业分类
测绘学 | 541篇 |
大气科学 | 780篇 |
地球物理 | 1033篇 |
地质学 | 2872篇 |
海洋学 | 833篇 |
天文学 | 215篇 |
综合类 | 452篇 |
自然地理 | 610篇 |
出版年
2024年 | 36篇 |
2023年 | 141篇 |
2022年 | 319篇 |
2021年 | 330篇 |
2020年 | 316篇 |
2019年 | 365篇 |
2018年 | 318篇 |
2017年 | 299篇 |
2016年 | 299篇 |
2015年 | 298篇 |
2014年 | 302篇 |
2013年 | 313篇 |
2012年 | 377篇 |
2011年 | 346篇 |
2010年 | 373篇 |
2009年 | 296篇 |
2008年 | 326篇 |
2007年 | 251篇 |
2006年 | 248篇 |
2005年 | 195篇 |
2004年 | 166篇 |
2003年 | 109篇 |
2002年 | 138篇 |
2001年 | 117篇 |
2000年 | 120篇 |
1999年 | 137篇 |
1998年 | 124篇 |
1997年 | 98篇 |
1996年 | 115篇 |
1995年 | 73篇 |
1994年 | 62篇 |
1993年 | 71篇 |
1992年 | 60篇 |
1991年 | 51篇 |
1990年 | 37篇 |
1989年 | 16篇 |
1988年 | 24篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1979年 | 4篇 |
1976年 | 2篇 |
1958年 | 3篇 |
1957年 | 2篇 |
1954年 | 4篇 |
1933年 | 2篇 |
排序方式: 共有7336条查询结果,搜索用时 649 毫秒
121.
本文通过联剖、电测深、磁法和测温法等综合工作成果,分析、推断出汤上屯热水构造的产状、性质和热水出露条件,圈定出了热水分布范围. 相似文献
122.
Geometric form of Haiyuan fault zone in the crustal interior and dynamics implications 总被引:1,自引:0,他引:1
The deep seismic reflection data on profile HY2 are reprocessed by the method of simultaneous inversion of velocity distribution
and interface position. By the travel-time inversion with the data of the diving wave Pg and fault plane reflection wave,
we determine the geometric form and velocity of Haiyuan fault zone interior and surrounding rock down to 10 km depth. The
measured data show that the amplitudes have strong attenuation in the range of stake number 37–39 km, suggesting the fault
zone has considerable width in the crustal interior. The results of this paper indicate that to the north of the fault zone
the crystalline basement interface upheaves gradually from southwest to northeast and becomes shallow gradually towards northeast,
and that to the south of the fault zone, within the basin between Xihua and Nanhua mountains, the folded basement becomes
shallow gradually towards southwest. The obliquity of the fault zone is about 70° above the 3 km depth, about 60° in the range
of the 3–10 km depths. From the results of this paper and other various citations, we believe that Haiyuan fault zone is in
steep state from the Earth’s surface to the depth of 10 km.
Foundation item: Joint Seismological Science Foundation of China (201001) and State Key Basic Research Development and Programming Project
(95-13-02-02).
Contribution No. RCEG200308, Exploration Geophysical Center, China Earthquake Administration. 相似文献
123.
Distribution characteristics and petroleum geological significance of the Silurian asphaltic sandstones in Tarim Basin 总被引:1,自引:0,他引:1
The Tarim Basin is a typical superimposed basin in which there have occurred multiphase adjustment and destruction of the reservoirs. The widely distributed asphaltic sandstones of the Silurian are the very product after destruction of the reservoirs. Studies show that the Silurian asphaltic sandstones distributed in both the middle and western parts on the basin are controlled chiefly by the Caledonian oil source area and by the Tazhong, Tabei and Bachu uplifts, whereas the distribution of the asphaltic sandstones on local structural belts is controlled by the reservoir's sedimentary system. Vertically, most of the asphaltic sandstones are under the regional caprock of red mudstones and the upper sandstone section of compact lithology. Due to the difference of hydrocarbon destruction in the early stage and the influence of hydrocarbon recharge in the late stage, the asphaltic sandstones and oil-bearing sandstones in the Tazhong area can be vertically divided into the upper and lower sections and they have an interactive distribution relationship as well. Asphaltic sandstones exist not only in intergranular pores but also inside the grains of sand and between the crevices, proving the destruction of early reservoirs due to uplifting. The existence of asphaltic sandstones over a large area reveals that the large-scale migration and accumulation and the subsequent destruction of hydrocarbons in the Craton area. The destruction caused a loss of the reserve resources of the Palaeozoic amounting to nearly 13.3 billion tons. Asphaltic sandstones formed after the destruction of oil and gas may serve as an effective caprock which is beneficial to accumulation of hydrocarbons and formation of the pool sealed by asphaltic sandstones in the later stage. The destruction of the early Silurian hydrocarbons depends on the stratigraphic burial depth. The deep part under the northern slope of Tazhong is an area favorable to search of undestroyed Silurian oil reservoirs. 相似文献
124.
125.
126.
127.
128.
Methane-rich fluid inclusions in skarn near the giant REE–Nb–Fe deposit at Bayan Obo, Northern China
We report fluid inclusion data for skarn, formed at the contact between Hercynian granitoids and dolomite of the Proterozoic Bayan Obo Group, in the vicinity of Bayan Obo REE–Nb–Fe deposit, Inner Mongolia, China. Three types of fluid inclusions are identified: two-phase CH4-rich, three-phase liquid–vapour–solid and two-phase aqueous inclusions. Using microthermometry and laser Raman microprobe analysis to calculate isochores for CH4-bearing inclusions, we estimate fluid trapping conditions at T=280 to 344 °C and P<1 to 2.3 kbar. Such conditions are compatible with formation of CH4 inclusions as a result of reaction between graphite in the country rocks (black slate sequence) and fluids derived from magma. The lack of carbonaceous material in the inclusions supports the hypothesis that CH4 was generated during fluid migration rather than by in situ reaction. In contrast to the skarn, and despite the fact that similar graphite-bearing slates are found in the host rocks, no CH4-bearing inclusions have been so far reported from Bayan Obo REE ores. We therefore conclude that the skarn-forming fluids in the contact aureole of the Hercynian granitoids were not involved at any stage in the formation of the Bayan Obo deposit. 相似文献
129.
130.
在信息传播媒体的竞争日益严酷的时代,面对天气预报节目只依靠简单的画面加解说,拉洋片式传统方法这样一种一成不变的局面,策划创意制作出《天气资讯》节目,打破天气预报节目以往的节目形式和播出形式,以极少的投入获得最大的社会效益和经济效益。 相似文献