全文获取类型
收费全文 | 38844篇 |
免费 | 627篇 |
国内免费 | 240篇 |
专业分类
测绘学 | 754篇 |
大气科学 | 2580篇 |
地球物理 | 7630篇 |
地质学 | 14062篇 |
海洋学 | 3545篇 |
天文学 | 8720篇 |
综合类 | 87篇 |
自然地理 | 2333篇 |
出版年
2022年 | 257篇 |
2021年 | 440篇 |
2020年 | 499篇 |
2019年 | 576篇 |
2018年 | 1011篇 |
2017年 | 1013篇 |
2016年 | 1078篇 |
2015年 | 582篇 |
2014年 | 1034篇 |
2013年 | 1850篇 |
2012年 | 1191篇 |
2011年 | 1629篇 |
2010年 | 1441篇 |
2009年 | 1796篇 |
2008年 | 1629篇 |
2007年 | 1688篇 |
2006年 | 1556篇 |
2005年 | 1058篇 |
2004年 | 1074篇 |
2003年 | 1112篇 |
2002年 | 996篇 |
2001年 | 868篇 |
2000年 | 797篇 |
1999年 | 723篇 |
1998年 | 715篇 |
1997年 | 723篇 |
1996年 | 588篇 |
1995年 | 572篇 |
1994年 | 501篇 |
1993年 | 453篇 |
1992年 | 409篇 |
1991年 | 424篇 |
1990年 | 437篇 |
1989年 | 391篇 |
1988年 | 369篇 |
1987年 | 400篇 |
1986年 | 415篇 |
1985年 | 508篇 |
1984年 | 545篇 |
1983年 | 542篇 |
1982年 | 496篇 |
1981年 | 454篇 |
1980年 | 429篇 |
1979年 | 408篇 |
1978年 | 375篇 |
1977年 | 384篇 |
1976年 | 344篇 |
1975年 | 353篇 |
1974年 | 340篇 |
1973年 | 370篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: 3. Secondary Inhabitants
Abstract. Vacated microborings in periostracum of live mussels of the Florida Escarpment redox community (depth of 3266 m) become a habitat for a prolific secondary microbiota consisting of a variety of prokaryotic and a few eukaryotic organisms. Periostracum surface is also colonized by diverse microorganisms, dominated by presumed chemolithotrophic bacteria with stacks of intracellular lamellae. Unlike sheltered microflora within borings, the surface community is heavily grazed upon by numerous archaeogastropods and ciliates. 相似文献
962.
Oceanology - Abstract—The paper contains original data on the rock-forming and rare element compositions in the Pliocene–Holocene alkaline basaltoids of the Tsushima Basin Sea of Japan,... 相似文献
963.
Oceanology - Abstract—The paper studies carbon transformation and transfer processes in the crust and mantle. Sediments dragged into subduction zones are dewatered, broken down, and altered... 相似文献
964.
Oceanology - Measurements of currents and Antarctic Bottom Water properties overflowing the sill from the Weddell to the Scotia Sea are described. The bottom water overflows the sill of one of the... 相似文献
965.
Morozov E. G. Frey D. I. Polukhin A. A. Krechik V. A. Artemiev V. A. Gavrikov A. V. Kasian V. V. Sapozhnikov F. V. Gordeeva N. V. Kobylyansky S. G. 《Oceanology》2020,60(5):573-588
Oceanology - Results of a mesoscale survey in the Powell Basin in the northern part of the Weddell Sea are analyzed. The survey included 24 CTD casts (6 × 4) with an interval of six nautical... 相似文献
966.
Oceanology - This paper reports the results of investigations on the radioecological state of bottom sediments of the Ob–Yenisei shoal area and Ob and Yenisei estuaries. Materials were... 相似文献
967.
Gorbunov M. E. Koval O. A. Mamontov A. E. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(1):52-60
Izvestiya, Atmospheric and Oceanic Physics - The phase-screen (split-step) method is widely used for modeling wave propagation in inhomogeneous media. The method of plane phase screens is best... 相似文献
968.
Korzhenkov A. M. Gadzhiev M. S. Ovsyuchenko A. N. Lar’kov A. S. Rogozhin E. A. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(7):633-656
Izvestiya, Atmospheric and Oceanic Physics - As a result of studies conducted in the city of Derbent, it is established that its monumental fortification structures erected at the end of the 560s... 相似文献
969.
Despite threats emanating from the influence of climate and non-climate forcing on the barrier island coastal region of southwestern Nigeria, the extent of the coastal erosion is poorly understood. We report evidence of coastal erosion and sediment accumulation in the region over a 34-year period (1973–2017), using Landsat imagery at intervals of approximately six years. Landsat image corrections and various water-extraction algorithms were used to systematically delineate coastal erosion and accumulation in the area. The region was subdivided into western and eastern subregions separated by Lagos Harbour. In the west, erosion took place during the periods 1973–1979, 1979–1984, 1990–1999 and 2005–2011, whereas in the east, erosion occurred during 1973–1979, 1990–1999 and 1999–2005. Coastal sediment accumulation occurred in the east during 1979–1984, 1984–1990, 2005–2011 and 2011–2017, whereas gains in the west occurred during 1984–1990, 1999–2005 and 2011–2017. The study revealed substantial net erosion of 1 228.1 ha in the region as a whole, over the full period. Sediment accumulation accompanying the coastal erosion appears to be linked to longshore drift. Erosion between 1973 and 2011 was probably attributable to climate change (storms and tidal conditions), longshore drift, the inflow and outflow of water at Lagos Harbour, coastal morphology and, possibly, human impacts. However, the coastal changes between 2011 and 2017 were more obviously associated with human activities, such as development of the Eko Atlantic construction project. Coastal surveillance, together with the use of environmentally sensitive protective measures, could possibly help to reduce coastal erosion in the region. Careful coastal management practices, including artificial nourishing and the installation of resilient structures (e.g. seawalls), should be undertaken to protect human settlements that are already at risk from sea-level rise. 相似文献
970.
The paper analyses results of the numerical simulation of upwelling events in the north-western part of the Black Sea, mostly
near the South Crimea. The calculations were performed using a numerical model based on primitive hydrodynamics equations.
Emphasis is laid on the case when a salinity front simulating the Black Sea rim current is prescribed in the initial conditions.
The interaction of the Black Sea rim current's stream with the coastline and bottom topography leads to the development of
an upwelling near the Crimea's coast, even in the absence of wind forcing. The paper discusses the structure of the three-dimensional
circulation of waters in the shelf area of the NW Black Sea. Numerical modelling results are matched up with the satellite
data obtained by the HRPT receiving station.
Translated by Vladimir A. Puchkin. 相似文献