全文获取类型
收费全文 | 41851篇 |
免费 | 623篇 |
国内免费 | 334篇 |
专业分类
测绘学 | 1287篇 |
大气科学 | 3061篇 |
地球物理 | 8499篇 |
地质学 | 13806篇 |
海洋学 | 3611篇 |
天文学 | 10259篇 |
综合类 | 123篇 |
自然地理 | 2162篇 |
出版年
2021年 | 334篇 |
2020年 | 382篇 |
2019年 | 448篇 |
2018年 | 972篇 |
2017年 | 898篇 |
2016年 | 1173篇 |
2015年 | 663篇 |
2014年 | 1112篇 |
2013年 | 2010篇 |
2012年 | 1218篇 |
2011年 | 1610篇 |
2010年 | 1468篇 |
2009年 | 2024篇 |
2008年 | 1780篇 |
2007年 | 1803篇 |
2006年 | 1690篇 |
2005年 | 1271篇 |
2004年 | 1297篇 |
2003年 | 1185篇 |
2002年 | 1225篇 |
2001年 | 1086篇 |
2000年 | 1016篇 |
1999年 | 893篇 |
1998年 | 884篇 |
1997年 | 888篇 |
1996年 | 711篇 |
1995年 | 666篇 |
1994年 | 625篇 |
1993年 | 543篇 |
1992年 | 475篇 |
1991年 | 486篇 |
1990年 | 466篇 |
1989年 | 485篇 |
1988年 | 434篇 |
1987年 | 503篇 |
1986年 | 456篇 |
1985年 | 537篇 |
1984年 | 658篇 |
1983年 | 568篇 |
1982年 | 558篇 |
1981年 | 505篇 |
1980年 | 441篇 |
1979年 | 432篇 |
1978年 | 445篇 |
1977年 | 381篇 |
1976年 | 341篇 |
1975年 | 349篇 |
1974年 | 324篇 |
1973年 | 362篇 |
1972年 | 260篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
Di Baofeng Katsenis Loukas Stamatopoulos Constantine A. Panoskaltsis Vassilis P. 《Landslides》2021,18(6):2297-2307
Landslides - Earthquake-induced landslides involve excessive movement of slopes, usually along slip surfaces. This seismic movement of slopes may depend crucially on (a) the soil response along the... 相似文献
163.
Hartmut H. Hellmer Monika Rhein Günther Heinemann Janna Abalichin Wafa Abouchami Oliver Baars Ulrich Cubasch Klaus Dethloff Lars Ebner Eberhard Fahrbach Martin Frank Gereon Gollan Richard J. Greatbatch Jens Grieger Vladimir M. Gryanik Micha Gryschka Judith Hauck Mario Hoppema Oliver Huhn Torsten Kanzow Boris P. Koch Gert König-Langlo Ulrike Langematz Gregor C. Leckebusch Christof Lüpkes Stephan Paul Annette Rinke Bjoern Rost Michiel Rutgers van der Loeff Michael Schröder Gunther Seckmeyer Torben Stichel Volker Strass Ralph Timmermann Scarlett Trimborn Uwe Ulbrich Celia Venchiarutti Ulrike Wacker Sascha Willmes Dieter Wolf-Gladrow 《Ocean Dynamics》2016,66(11):1379-1413
164.
The zonal structure of the distribution of filaments is considered. The mean latitudes of two filament bands are calculated in each solar hemisphere at the minima of the sunspot cycle in the period 1924–1986: middle latitude
2, m
and low latitude
1, m
. It is shown that the mean latitude of the filament band
2, m
at the minimum -m of the cycle correlates, with = 0.94, with the maximum - M sunspot area S(M) and maximum Wolf number W(M) in the succeeding solar cycle M. It is shown that the mean latitude of the low-latitude filament band
1, m
is linearly dependent on the mean latitude filament band
2, m + 1 at the succeeding minimum. We found a correlation of the latitude of the low-latitude filament band
1, m
with the maximum sunspot area in the M + 1 cycle. This enables us to predict the power of two succeeding 11-year solar cycles on the basis of the latitude of filament bands at the minimum of activity, 1985–1986: W(22) - 205 ± 10, W(23) - 210 ± 10. The importance of the relationships found for theory and applied aspects is emphasized. An attempt is made to interpret the relationships physically. 相似文献
165.
The quantitative distribution and grain-size composition of the suspended particulate matter (SPM) in the marginal filter
of the Severnaya Dvina River during the summer low-water periods of 2001–2005 were first analyzed in seawater on board of
the vessel immediately after its sampling (without preliminary treatment) using a Coulter counter. This analysis revealed
the main regularities in the transformation of the grain-size spectra at successive salinity steps of the marginal filter
as well as the boundaries between these steps based on the data obtained by direct complex studies of the SPM dispersion.
It is established that the water salinity is the main factor that controls the changes in the grain-size distribution and
the composition of the particulate matter in the marginal filter. The concentrations of the pelitic fraction and the salinity
demonstrate negative correlations between each other. It is shown that the areas characterized by the mass development of
phytoplankton are located along the outer boundary of the marginal filter (at the biological step), where the salinity amounts
to 23–24 psu. The content of the suspended forms of some chemical (lithogenic) elements and the Corg indicating the SPM’s genetic composition and their relations with the grain-size composition of the latter and the environments
are studied. 相似文献
166.
The reproduction of dynamic processes in the stratosphere at extratropical latitudes is considered in calculations of the atmospheric module of the global climate model of the Institute of Numerical Mathematics, Russian Academy of Sciences, with an upper boundary of 0.2 hPa (~60 km) for the period from 1979 to 2008 in comparison with the data observational. Changes in temperature, zonal wind, activity of planetary waves, heat fluxes in the lower stratosphere, and sudden stratospheric warmings with the displacement and splitting of the polar vortex, as well as the distribution of associated circulation anomalies in the troposphere, are analyzed. 相似文献
167.
168.
A. P. Dykes 《Landslides》2007,4(3):279-290
The West Mouth of the Great Cave at Niah in Sarawak, northwest Borneo and the North Passage that leads to the West Mouth contain
large deposits of guano. The main deposit, several metres thick in places, forms the sloping floor of the entire North Passage.
A mass movement deposit identified in the West Mouth, having a volume of 600 m3, originated as a guano mudflow up the North Passage in the order of 40,000 years ago. This failure of the guano slope was
investigated to determine whether particular conditions or events could be identified as the most likely causes. The physical,
hydrological and geotechnical properties of samples of the material were determined so that the stability of the slope could
be assessed. Stability analyses showed that shearing failure of the slope would require inputs of water to the slope in quantities
for which no feasible explanation can be suggested. However, the properties of the guano are similar to those of loess, indicating
a high susceptibility to ‘hydrocollapse’. Very shallow failure of the slope, possibly as several smaller mudflows, could therefore
have occurred due to additional water in quantities that could realistically be supplied as rainwater spray, possibly with
a seismic trigger. The climate must therefore have been wetter than it is at present. These findings have implications for
the interpretation of sediment deposits in other relict caves. 相似文献
169.
Kyra Chester Paul Joshua Silverstein Mark P. S. Krekeler 《Environmental Earth Sciences》2017,76(10):369
Cigarette smoking is a well-recognized cause of lung cancer and other diseases and is a major contributor to indoor air pollution in numerous settings worldwide. Most cigarette lighters use rare earth element (REE) mischmetal in their flints in order to aid ignition, and these lighters thus have pyrophoric properties. REE particulate emitted from these lighters presents a complexity in the role of health of smokers that has yet to be explored fully. Furthermore, these particles are likely present in numerous urban settings and contribute to the complexities of urban geochemistry. Details of the material properties of rare earth element (REE) particulate derived from smoking lighters are determined first the first time. Particulate was investigated using back-scatter detection scanning electron microscopy techniques and transmission electron microscopy techniques. Several particle types were observed and demonstrate a diverse range of size and textures, many of which are previously not documented and are much smaller than previous basic scanning electron microscopy investigations. These include irregularly shaped fragments of mischmetal, micrometer-scale spherules, aggregates of nanospherules, and platy sponge-like nanoparticles. All of these particles have significant REE content, and most are of a particle size that can be deposited deep in the lung. The available literature regarding toxicity of REEs and the material science data presented here argues very strongly for cause for concern. 相似文献