首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   132篇
  免费   7篇
  国内免费   8篇
测绘学   2篇
大气科学   5篇
地球物理   29篇
地质学   55篇
海洋学   20篇
天文学   20篇
综合类   8篇
自然地理   8篇
  2024年   1篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   5篇
  2019年   6篇
  2018年   10篇
  2017年   5篇
  2016年   4篇
  2015年   7篇
  2014年   4篇
  2013年   13篇
  2012年   10篇
  2011年   16篇
  2010年   9篇
  2009年   12篇
  2008年   4篇
  2007年   6篇
  2006年   7篇
  2005年   5篇
  2004年   5篇
  2003年   3篇
  2001年   3篇
  2000年   3篇
  1999年   1篇
  1998年   2篇
  1996年   1篇
  1994年   1篇
  1985年   1篇
排序方式: 共有147条查询结果,搜索用时 31 毫秒
71.
The work presents a review of natural-science representations on the rotary motion of matter and its piecewise structure. Development of dense GPS-networks allowed to experimentally confirm the concept of block structures of the geophysical environment and to prove rotary character of block movement. An analysis of both the migration of earthquake sources and the movement of sections of tectonic plates’ borders has allowed to reveal general properties of such movements and to prove their wave nature. It is shown that within the limits of rotational model, blocks and plates are interconnected among themselves by the elastic long-range fields forming a uniform planetary geodynamic field. It is offered to use the geodynamic solutions of rotational model in the one class of phenomena as a basis at the construction of a new geological paradigm — wave moment geodynamics.  相似文献   
72.
Ocean Science Journal - Contamination by persistent organic pollutants including polycyclic aromatic hydrocarbons (PAHs) constitutes a major concern in relation to aquatic ecosystems. To study the...  相似文献   
73.
It is shown that a suitable interaction between dark energy and dark matter in locally rotationally symmetric (LRS) Bianchi-I space-time can solve the coincidence problem and not contradict the accelerated expansion of present Universe. The interaction parameters are estimated from observational data.  相似文献   
74.
The hydrological and morphological processes in the mouth area of the Upper Angara (which ranks second in terms of water abundance among Baikal Lake tributaries) are considered. The major external factors that determine those processes have been revealed. The main features of the delta??s water regime, including the effect of anthropogenic level rise in the lake, are described. Specific attention is paid to morphological processes in the delta and on the barrier bar, separating a large mouth lagoon from the lake.  相似文献   
75.
76.
We present a new, reliably dated Mesoproterozoic paleopole for Siberia, based on a combined geochronological and paleomagnetic study of mafic rocks within the Mesoproterozoic Sololi Group of the Olenek Uplift in northern Siberia. Ion microprobe (SHRIMP) U–Pb analysis yields crystallisation ages of 2036 ± 11 Ma for zircon from a basement granite and 1473 ± 24 Ma for baddeleyite from a large dolerite sill within the Kyutingde Formation. The baddeleyite result indicates that the lower Sololi Group is significantly older than was suggested by previous K–Ar results. Paleomagnetic analysis of the dolerite sill and related mafic intrusive rocks yields a paleopole at 33.6°N, 253.1°E, A95 = 10.4°. A positive baked-contact test between the Kyutingde sill and sedimentary country rocks shows that the magnetisation is primary. Comparison of this paleopole with coeval results for Laurentia provides a revised reconstruction between Siberia and Laurentia, and implies that these two continents were parts of a single Mesoproterozoic supercontinent since at least 1473 Ma. We argue that Siberia, Laurentia, and Baltica belonged to the same supercontinent between 1473 Ma and mid-Neoproterozoic time.  相似文献   
77.
It has been shown that the main uranium ore mineral, pitchblende (uranium dioxide), is a natural analog of synthetic uraninite (also uranium dioxide), which constitutes 96% of spent nuclear fuel (SNF). Geochronological studies of the U‐Pb isotope systems in unaltered pitchblende from the orebodies reveal that these systems remained completely closed over the entire period (approximately 135 Ma) since the formation of the deposits. The bulk of the primary uranium ores within the Streltsovskoye ore field was influenced to various degrees by post‐ore hydrothermal solutions that led to pitchblende spherulites being replaced by pseudomorphs of an amorphous phase with a U‐Si composition; this phase also re‐precipitated in veinlets proximal to the pitchblende pseudomorphs. A technique specially developed by the authors was used to carry out quantitative counts of the abundance of uranium minerals by calculating the uranium mass balance in one of the orebodies subjected to hydrothermal alteration. The calculations reveal minimal uranium loss from the orebody. Uranium liberated in the process of the pseudomorphic replacement of pitchblende was immediately fixed, in situ, in the newly formed coffinite‐like amorphous U‐Si phase as a result of the development of an efficient geochemical barrier that prevented the long‐distance migration of uranium. In assessing the long‐term safety of underground SNF repositories, the results of the present study give us confidence that SNF uraninite, in terms of the preservation of its integrity as a mineral phase, provides for the reliable long‐term isolation of uranium, transuranium elements, and fission products that are “sealed” in the uraninite matrix. In the case of the mineral transformation of the uraninite matrix by hydrothermal solutions, the liberated uranium would be efficiently immobilized by the newly formed amorphous U‐Si phase.  相似文献   
78.
The taxonomic composition of the palynological assemblage of the Dongning Formation is supplemented. The palynological assemblage corresponds to those from the Lipovtsy Formation (Aptian) in the Razdolnaya Basin of Primorye (Russia) and the Muling Formation (Aptian) in the Jixi Basin of eastern Heilongjiang (China). It is found that the age of the Dongning Formation is Aptian. The palynological assemblage is characterized by dominance of spores of Gleicheniaceae; they are accompanied by spores of Cyatheaceae. The most important feature of the palynological assemblage of the Dongning Formation is the presence of angiosperm pollen (Tricolpites sp., T. micromunus, T. vulgaris, Retitricolpites georgiensis, R. vulgaris, Clavatipollenites hughesii, Quercites sparsus, Fraxiniopollenites variabilis).  相似文献   
79.
80.
Polycyclic aromatic hydrocarbons (PAHs) content and distribution was studied in the northern part of modern rift zone. All samples analysed represent slightly altered clastic deposits and hot water discharging in springs and from wells. To study PAH in present-day gas emission traps with diatomite absorbent were installed in the Skógalón geothermal field. All samples were analysed by the method of Shpol'sky spectroscopy. Hydrothermally altered deposits show the highest amount of PAH. Data obtained allow to believe that the distribution of PAH is closely associated with the dynamics of the hydrothermal environment. The fissure formation and temperature fluctuation in hydrothermal systems can govern both the processes of PAH synthesis and sorption. The evidences of PAH migration up through the Skjálfandi and Öxarfjörður sedimentary basins show that hydrocarbons associate mainly with hydrothermal minerals and deep ground waters. Studying PAH associations can be used as an indicator of hydrocarbons distribution, ways of migration and possible zones of accumulation in the land and marine sedimentary basins in active and ancient rift zones of Iceland.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号