全文获取类型
收费全文 | 29410篇 |
免费 | 454篇 |
国内免费 | 319篇 |
专业分类
测绘学 | 619篇 |
大气科学 | 1822篇 |
地球物理 | 5290篇 |
地质学 | 11308篇 |
海洋学 | 2989篇 |
天文学 | 6880篇 |
综合类 | 68篇 |
自然地理 | 1207篇 |
出版年
2022年 | 300篇 |
2021年 | 459篇 |
2020年 | 514篇 |
2019年 | 560篇 |
2018年 | 1096篇 |
2017年 | 1048篇 |
2016年 | 1155篇 |
2015年 | 548篇 |
2014年 | 1047篇 |
2013年 | 1689篇 |
2012年 | 1158篇 |
2011年 | 1444篇 |
2010年 | 1285篇 |
2009年 | 1568篇 |
2008年 | 1340篇 |
2007年 | 1401篇 |
2006年 | 1310篇 |
2005年 | 759篇 |
2004年 | 708篇 |
2003年 | 665篇 |
2002年 | 690篇 |
2001年 | 622篇 |
2000年 | 573篇 |
1999年 | 463篇 |
1998年 | 481篇 |
1997年 | 459篇 |
1996年 | 392篇 |
1995年 | 350篇 |
1994年 | 380篇 |
1993年 | 294篇 |
1992年 | 298篇 |
1991年 | 288篇 |
1990年 | 322篇 |
1989年 | 220篇 |
1988年 | 226篇 |
1987年 | 268篇 |
1986年 | 209篇 |
1985年 | 316篇 |
1984年 | 276篇 |
1983年 | 258篇 |
1982年 | 275篇 |
1981年 | 203篇 |
1980年 | 243篇 |
1979年 | 195篇 |
1978年 | 211篇 |
1977年 | 165篇 |
1976年 | 163篇 |
1975年 | 172篇 |
1974年 | 167篇 |
1973年 | 166篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
841.
N. J. Pawar 《Journal of the Geological Society of India》2016,87(4):499-499
842.
N. M. Sushchevskaya O. V. Levchenko E. P. Dubinin B. V. Belyatsky 《Geochemistry International》2016,54(3):237-256
The study of magmatism and tectonic structure of the East Indian or Ninetyeast Ridge (NER) reveals the geochemical similarity of mantle sources for the NER and Kerguelen Plateau melts. Magmas related to the Kerguelen plume were derived from an enriched mantle source, whereas the NER tholeiitic basalts originated from a source contaminated by a depleted material. While, depleted basalt varieties were not found within the NER basalts. It was shown that magmatic rocks forming the NER were generated by high degrees (30%) of partial melting within the ancient Wharton spreading ridge due to the activity of the Kerguelen plume, which was located at this time in the vicinity of the ridge. The most significant impact of the plume on the NER structures was recorded at 70–50 Ma ago. 相似文献
843.
A. G. Kalmykov E. A. Manuilova G. A. Kalmykov V. S. Belokhin N. I. Korobova O. M. Makarova E. V. Kozlova R. A. Khamidullin V. A. Shishkov A. G. Ivanova 《Moscow University Geology Bulletin》2016,71(6):429-435
The possible reservoir type of the Bazhenov Formation relative to the intervals enriched in phosphates (apatite varieties) is described in this work. The phosphate rocks are characterized by a highly developed pore space; their porosity can reach up to 14%. Along with this, these rocks have explicit geochemical characteristics of oil-reservoir rocks in comparison with other rock samples in the well. As an example, the productivity index and oil-saturation index for phosphates are twice as high as the background values. The composition of such rocks can slightly vary: fluorine can be observed in phosphate minerals, while the rock is always enriched in organic matter (>8 wt %). 相似文献
844.
N. P. Fadeeva E. V. Kozlova E. N. Poludetkina T. A. Shardanova N. V. Pronina A. V. Stupakova G. A. Kalmykov A. N. Khomyak 《Moscow University Geology Bulletin》2016,71(1):41-49
The factors that are responsible for the formation of the hydrocarbon-generation potential and its occurrence in the Devonian carbonate sequences (Domanik Formation) of the Volga–Ural petroliferous basin are considered. The rocks of this formation are characterized by a high generation potential that is sufficient for the formation of large oil and gas accumulations. The highly carbonaceous deposits lack reservoirs. 相似文献
845.
This work describes a young extrusive massif in the uppermost reaches of the Chegem River (Bashilauzu-su River), which had been considered as a feeder of the great sequence of Upper Pliocene rhyolite ignimbrites of the Verkhnechegemskaya caldera. The Upper Pleistocene age of the stratum, extrusive origin of automagmatic breccias and fluidolites, as well as its difference from rhyolites of the caldera are proven. The Bashilsky swell, located in the Late Pleistocene glacial trough, is evidence of young volcanism in this area, which has not been previously proposed. 相似文献
846.
R. S. Sautkin R. A. Khamidullin N. I. Korobova 《Moscow University Geology Bulletin》2016,71(2):205-211
The problem of studying the Domanik deposits and their reservoir potential is among the most important ones. The discovery of hydrocarbon deposits in similar rocks at various depths, the considerable variability of reservoir properties, and ambiguity in establishing the values of the effective thickness set the task for researchers to estimate them more reliably. The high-carbon kerogenic-carbonate-siliceous stratum that is characterized by the development of differently-oriented systems of fractures is of outstanding interest. 相似文献
847.
J. I. Rostovceva A. N. Stafeev T. V. Sukhanova I. V. Latysheva V. L. Kosorukov 《Moscow University Geology Bulletin》2016,71(4):281-289
Based on the spore-pollen data, the mineral composition of clay rocks, analyzed structures and facies, and a general paleogeographic analysis, the sedimentation conditions and landscapes of islands located during the Late Bajocian in the region of the present-day the Crimean Mountains have been reconstructed. It is shown that the sublatitudinally elongated insular land zone had a width of 30 km, the heights of the islands were no more than 1 km, with steep mudflow-affected northern slopes and with an extensive river system on the southern slopes. 相似文献
848.
849.
850.