全文获取类型
收费全文 | 32230篇 |
免费 | 492篇 |
国内免费 | 395篇 |
专业分类
测绘学 | 694篇 |
大气科学 | 2071篇 |
地球物理 | 5923篇 |
地质学 | 12227篇 |
海洋学 | 3226篇 |
天文学 | 7501篇 |
综合类 | 95篇 |
自然地理 | 1380篇 |
出版年
2022年 | 314篇 |
2021年 | 491篇 |
2020年 | 558篇 |
2019年 | 595篇 |
2018年 | 1165篇 |
2017年 | 1113篇 |
2016年 | 1241篇 |
2015年 | 618篇 |
2014年 | 1109篇 |
2013年 | 1828篇 |
2012年 | 1246篇 |
2011年 | 1550篇 |
2010年 | 1406篇 |
2009年 | 1691篇 |
2008年 | 1467篇 |
2007年 | 1508篇 |
2006年 | 1399篇 |
2005年 | 865篇 |
2004年 | 823篇 |
2003年 | 779篇 |
2002年 | 843篇 |
2001年 | 763篇 |
2000年 | 665篇 |
1999年 | 528篇 |
1998年 | 531篇 |
1997年 | 501篇 |
1996年 | 433篇 |
1995年 | 396篇 |
1994年 | 423篇 |
1993年 | 320篇 |
1992年 | 317篇 |
1991年 | 319篇 |
1990年 | 351篇 |
1989年 | 239篇 |
1988年 | 239篇 |
1987年 | 284篇 |
1986年 | 231篇 |
1985年 | 343篇 |
1984年 | 311篇 |
1983年 | 279篇 |
1982年 | 293篇 |
1981年 | 230篇 |
1980年 | 258篇 |
1979年 | 205篇 |
1978年 | 233篇 |
1977年 | 178篇 |
1976年 | 182篇 |
1975年 | 190篇 |
1974年 | 195篇 |
1973年 | 177篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
91.
92.
G. S. Ripp A. G. Doroshkevich M. V. Badmatsyrenov N. S. Karmanov 《Geochemistry International》2007,45(6):538-545
The composition and nature of high-Cr minerals in lithic clasts from the carbonatites of the Veseloe occurrence, northern Transbaikalia, were considered. In order to determine their source, the Cr-bearing phases were compared with chromite, magnetite, and rutile from ultrabasic rocks, mantle xenoliths, and eclogites. It was suggested that the xenoclasts studied were formed at great depths, whereas the carbonatites were directly derived from the mantle rather than formed by the crustal differentiation of a silicate-carbonate melt. 相似文献
93.
94.
This paper presents an integrated measurement technique based on DC methods (vertical electrical sounding, electrical resistivity tomography) which was used to identify faults and determine their geoelectric parameters in the western part of the Chuya basin. New information on the structure of the Chagan River valley located in the zone of the disastrous 27 September 2003 Chuya earthquake has been obtained from the results of these methods. Geoelectric cross-sections of the sedimentary sequence and the upper part of the basement were obtained from VES data, showing the block structure of the study area. Electrical resistivity tomography sections confirm the presence of a major fault between basement blocks of different heights and indicate the presence of faults bounding the valley on its right side and in the southwestern part. 相似文献
95.
A. V. Mityukov A. M. Nikishin O. A. Almendinger S. N. Bolotov V. A. Lavrishchev N. K. Myasoedov E. V. Rubtsova 《Moscow University Geology Bulletin》2012,67(2):81-92
This work is based on the results of 2-D and 3-D surveys in the Tuapse Basin and field works in the Crimea-Caucasus region. Seven zones were outlined in the model of sedimentation starting from the eroded mountain structure of the Greater Caucasus down to deep water sediments of the Tuapse Basin. The slope and deep-water sediments of channels and fan complexes are characterized. Volume models of the sedimentation system in the Black Sea are shown for the first time. 相似文献
96.
97.
Current and future wide field surveys in infrared passbands present opportunities for ultra low‐mass stellar sample selection via proper motions, as well as or instead of purely photometric techniques. Furthermore, proper motion measurements yield additional clues as to candidate membership of cluster or field (kinematic) populations. In this paper we review some recent results and speculate as to the possibilities afforded by the next generation of wide‐field infrared surveys. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
98.
Results of numerical simulations using the WRF-ARW nonhydrostatic model are presented for eight episodes of intense convection over European Russia in the summer of 2007. The calculations were performed on four nested grids with horizontal grid meshes of 27, 9, 3, and 1 km. Convection was parametrized on the first two grids and explicitly resolved on the other two. It has been found that simulations on finer grids with explicit calculation of convective flows make it possible to reproduce heavy rainfalls and strong-wind zones in the areas of intense convection. A preliminary verification of the short-range predictions of convective systems shows that the maximum 12-h precipitation totals and the maximum winds at 10 m are close, in the order of magnitude, to the observed values. Prediction of convection centers is the weakest point. Difficulties in the model verification associated with the absence of data with high space-time resolution are discussed. 相似文献
99.
E. K. Semenov N. N. Sokolikhina E. V. Sokolikhina 《Russian Meteorology and Hydrology》2013,38(10):661-668
The genetic and synoptic classifications of the Novorossiysk Bora are created using the data of daily observations at the Novorossiysk meteorological station and other available synoptic information. Obtained are the quantitative criteria of these classifications, and on this base worked out are the basic scenarios of the generation and evolution of this dangerous phenomenon on the Black Sea coast of Russia. According to the genetic classification, the Bora was divided into four types: frontal, air-mass, monsoon, and gravity. Quantitative criteria worked out for each type can be used for the more accurate forecast of this destructive phenomenon near Novorossiysk. According to the synoptic classification, four classes were distinguished: Azores, North Atlantic, Siberian, and Arctic. 相似文献
100.