全文获取类型
收费全文 | 97662篇 |
免费 | 1910篇 |
国内免费 | 763篇 |
专业分类
测绘学 | 2171篇 |
大气科学 | 6667篇 |
地球物理 | 19840篇 |
地质学 | 35435篇 |
海洋学 | 8756篇 |
天文学 | 21235篇 |
综合类 | 426篇 |
自然地理 | 5805篇 |
出版年
2022年 | 661篇 |
2021年 | 1135篇 |
2020年 | 1215篇 |
2019年 | 1356篇 |
2018年 | 3188篇 |
2017年 | 2918篇 |
2016年 | 3158篇 |
2015年 | 1665篇 |
2014年 | 2891篇 |
2013年 | 4992篇 |
2012年 | 3635篇 |
2011年 | 4318篇 |
2010年 | 3718篇 |
2009年 | 4667篇 |
2008年 | 4087篇 |
2007年 | 4160篇 |
2006年 | 3943篇 |
2005年 | 3590篇 |
2004年 | 3688篇 |
2003年 | 3226篇 |
2002年 | 2652篇 |
2001年 | 2170篇 |
2000年 | 2120篇 |
1999年 | 1658篇 |
1998年 | 1709篇 |
1997年 | 1557篇 |
1996年 | 1348篇 |
1995年 | 1342篇 |
1994年 | 1148篇 |
1993年 | 1103篇 |
1992年 | 1030篇 |
1991年 | 1064篇 |
1990年 | 1030篇 |
1989年 | 892篇 |
1988年 | 828篇 |
1987年 | 986篇 |
1986年 | 850篇 |
1985年 | 1084篇 |
1984年 | 1231篇 |
1983年 | 1156篇 |
1982年 | 1062篇 |
1981年 | 1006篇 |
1980年 | 877篇 |
1979年 | 848篇 |
1978年 | 823篇 |
1977年 | 704篇 |
1976年 | 708篇 |
1975年 | 685篇 |
1974年 | 640篇 |
1973年 | 722篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
991.
P. M. Kartashov T. A. Gornostaeva A. V. Mokhov O. A. Bogatikov 《Doklady Earth Sciences》2016,467(2):412-414
A CdSe high-pressure polymorph of the NaCl structural type of a0 = 0.549 nm and Fm–3m space group was discovered in nature for the first time. Its composition is within range of CdSe–CdSe1–х where x = 0.2 apfu. The phase was discovered as abundant nanosize inclusions in irgizite-type condensate glass separated from the sample of impact rock of the Zhamanshin crater (Central Kazakhstan). The treated mineral was presumably formed within a gas–plasma cloud at the moment of impact. 相似文献
992.
M. D. Kravchishina A. P. Lisitzin A. Yu. Lein V. N. Lukashin A. N. Novigatsky A. A. Klyuvitkin 《Doklady Earth Sciences》2016,467(1):284-288
The first data were obtained on the vertical chlorin flux in the water column and its accumulation in the upper layer of sediments of the Caspian Sea. Seasonal variability of the chlorine concentration in sedimentary matter was evaluated. The tendency of decrease in the phytoplankton-synthesized (allochtonous) organic matter content was revealed over approximately the past 60 years. 相似文献
993.
I. S. Sharygin A. V. Golovin A. V. Korsakov N. P. Pokhilenko 《Doklady Earth Sciences》2016,467(1):270-274
Tychite Na6Mg2(CO3)4(SO3) is a rare natural Na and Mg sulfatocarbonate. It is found only as minor mineral in deposits of saline lakes in the United States, Canada, Uganda, and China. In these continental evaporites tychite has sedimentary genesis. In this study, we report the first occurrence of tychite as a crystal phase in the melt inclusions in olivine from mantle xenoliths of the Udachnaya-East kimberlite pipe. This find provides an evidence for the probability of tychite crystallization from melts; i.e., this rare sulfatocarbonate may have a magmatic origin as well. 相似文献
994.
Fathy Shaaban Turki M. Habeebullah Essam A. Morsy Safwat Gabr 《Arabian Journal of Geosciences》2016,9(20):754
This work presents the application of the ground-penetrating radar (GPR) method and electric resistivity tomography (ERT) technique in outlining a zone of contamination due to the light non-aqueous phase liquid (LNAPL) plume underground in the area of an impacted fuel station, close to Abha City. The GPR has been performed using SIR3000 unit with the 100 and 400 MHz antennas. The main objective of the GPR survey was to evaluate the lateral extension of contamination. The complex GPR signature of the plume was well characterized. Low reflectivity zone corresponds to hydrocarbon vapor phase in the vadose zone. Enhanced reflections are associated with free and residual products in the fractured saturated zone directly above the water table. An electric resistivity tomography (ERT) survey was performed on four profiles within the site to investigate the vertical and horizontal extent of the contamination plume and to define the bottom of the landfill. The 2D electric profiles show the presence of low-resistivity (4O to 37 Ω m) anomalies that refers to the presence of accumulated hydrocarbons. From the interpretation of the GPR and ERT profile, it was possible to locate the top and bottom of the contamination plume of the waste disposal site. The radar signal penetrated deep enough and enabled the identification of a second reflector at approximately 10-m deep, interpreted as the hard basement surface which causes the strong amplitude reflection in the GPR profile. The results of GPR and ERT showed good agreement. 相似文献
995.
V. I. Kaevitser N. A. Rimskii-Korsakov I. V. Smolyaninov V. M. Razmanov A. P. Krivtsov 《Oceanology》2016,56(5):714-720
This paper presents the results of three-dimensional acoustic seabed mapping in the region of the Taman Peninsula in the Black Sea using an interferometric side-scan sonar and an acoustic profiler. Mapping has revealed underwater objects identified as manifestations of underwater mud volcanism. Detailed analysis of sonar images of the relief and seabed profiles in the region of the objects has confirmed the original hypothesis. 相似文献
996.
997.
Izvestiya, Atmospheric and Oceanic Physics - International investigations into the correlation between tropical cyclones (TCs) and the ionosphere are associated with great difficulties in proving... 相似文献
998.
The first data on the chemical composition of dispersed matter from sedimentary traps are reported. The suspended components of sedimentary matter (amorphous silica, organic matter, carbonates, and lithogenic material, as well as Fe, Mn, and minor elements) are considered. As a result, it is shown that the intraannual variability in vertical fluxes of sedimentary matter is characterized by a seasonal increase in spring and autumn. The high fluxes of the components of sedimentary matter on the northern and southern slopes of the Derbent Basin in winter are explained by precipitation of material from the nepheloid layer that forms over the contour current. 相似文献
999.
A. N. Ovsuchenko M. Yu. Menshikov E. A. Rogozhin A. M. Korzhenkov 《Izvestiya Atmospheric and Oceanic Physics》2016,52(8):816-840
The results of comprehensive research into the area of the upper reach of the Mzymta River (Western Caucasus) are presented. The evidence of strong earthquakes that struck the study area throughout history is studied. The periods when mud flows and rockslides associated with the earthquakes are identified to fall between 3100–4000 and 700–1200 years ago. Paleoseismological results are correlated to the results of archeological excavations. As a result, it is revealed that the periods of tectonic disasters coincided with the onsets of the period when the area was uninhabited (abandoned) by people. The results of the present comprehensive research provide additional information to specify the seismic hazard and the chronology of human habitation in the region. 相似文献
1000.
A. A. Kucheiko A. Yu. Ivanov A. A. Davydov A. Yu. Antonyuk 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):1031-1040
This paper is devoted to the detection and identification of icebergs in the Russian Arctic Seas from the use of high- and medium-resolution radar and optical images from EROS-B, Radarsat-1, Radarsat-2, SPOT-4 and SPOT-5 Earth observation satellites. In July–September of 2011–2013, the SCANEX Research and Development Center, the Federal State Unitary Enterprise Atomflot, and other partner organizations provided operational satellite monitoring of icebergs in the Kara Sea and the Laptev Sea. More than 130 highly detailed optical and radar images were received and processed. The Vilkitsky Strait—one of the narrowest and most dangerous places within the Northern Sea Route—was chosen as an experimental polygon. As a result, iceberg location in the strait during the 2011–2013 navigation periods was analyzed, as were the iceberg size, area, drift direction, and height. 相似文献