全文获取类型
收费全文 | 389篇 |
免费 | 7篇 |
国内免费 | 4篇 |
专业分类
测绘学 | 19篇 |
大气科学 | 25篇 |
地球物理 | 76篇 |
地质学 | 160篇 |
海洋学 | 12篇 |
天文学 | 91篇 |
自然地理 | 17篇 |
出版年
2023年 | 2篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 12篇 |
2014年 | 21篇 |
2013年 | 14篇 |
2012年 | 13篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 29篇 |
2008年 | 22篇 |
2007年 | 24篇 |
2006年 | 21篇 |
2005年 | 18篇 |
2004年 | 11篇 |
2003年 | 28篇 |
2002年 | 18篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1986年 | 4篇 |
1984年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1975年 | 2篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1967年 | 3篇 |
1958年 | 2篇 |
1956年 | 2篇 |
1953年 | 1篇 |
1952年 | 1篇 |
1951年 | 1篇 |
1950年 | 2篇 |
1949年 | 1篇 |
1948年 | 1篇 |
1942年 | 1篇 |
1940年 | 1篇 |
1939年 | 1篇 |
排序方式: 共有400条查询结果,搜索用时 15 毫秒
111.
112.
113.
114.
115.
116.
Ocean Dynamics - Mesoscale eddies in the open ocean are mostly formed by baroclinic instability, in which the available potential energy from the large-scale slope of the isopycnals is converted... 相似文献
117.
Monika Nausch Günther Nausch Hans Ulrich Lass Volker Mohrholz Klaus Nagel Herbert Siegel Norbert Wasmund 《Estuarine, Coastal and Shelf Science》2009,83(4):434-442
In July 2007, phosphorus input by an upwelling event along the east coast of Gotland Island and the response of filamentous cyanobacteria were studied to determine whether introduced phosphorus can intensify cyanobacterial bloom formation in the eastern Gotland Basin. Surface temperature, nutrient concentrations, phytoplankton biomass and its stoichiometry, as well as phosphate uptake rates were determined in two transects between the coasts of Gotland and Latvia and in a short grid offshore of Gotland. In the upwelling area, surface temperatures of 11–12 °C and average dissolved inorganic phosphorus (DIP) concentrations of 0.26 μM were measured. Outside the upwelling, surface temperatures were higher (15.5–16.6 °C) and DIP supplies in the upper 10 m layer were exhausted. Nitrite and nitrate concentrations (0.01–0.22 μM) were very low within and outside the upwelling region. Abundances of filamentous cyanobacteria were highly reduced in the upwelling area, accounting for only 1.4–6.0% of the total phytoplankton biomass, in contrast to 18–20% outside the upwelling. The C:P ratio of filamentous cyanobacteria varied between 32.8 and 310 in the upwelling region, most likely due to the introduction of phosphorus-depleted organisms into the upwelling water. These organisms accumulate DIP in upwelling water and have lower C:P ratios as long as they remain in DIP-rich water. Thus, diazotrophic cyanobacteria benefit from phosphorus input directly in the upwelling region. Outside the upwelling region, the C:P ratios of filamentous cyanobacteria varied widely, between 240 and 463, whereas those of particulate material in the water ranged only between 96 and 224. To reduce their C:P ratio from 300 to 35, cyanobacteria in the upwelling region had to take up 0.05 mmol m−3 DIP, which is about 20% of the available DIP. Thus, a larger biomass of filamentous cyanobacteria may be able to benefit from a given DIP input. As determined from the DIP uptake rates measured in upwelling cells, the time needed to reduce the C:P ratio from 300 to 35 was too long to explain the huge bloom formations that typically occur in summer. However, phosphorus uptake rates increased significantly with increasing C:P ratios, allowing phosphorus accumulation within 4–5 days, a span of time suitable for bloom formation in July and August. 相似文献
118.
John M. Livingston Vladimir N. Kapustin Beat Schmid Philip B. Russell Patricia K. Quinn Timothy S. Bates Philip A. Durkee Peter J. Smith Volker Freudenthaler Matthias Wiegner Dave S. Covert Santiago Gassó Dean Hegg Donald R. Collins Richard C. Flagan John H. Seinfeld Vito Vitale Claudio Tomasi 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):594-619
119.
Thermal conduction in cosmological SPH simulations 总被引:1,自引:0,他引:1
120.
R. Heinkelmann J. Boehm H. Schuh S. Bolotin G. Engelhardt D. S. MacMillan M. Negusini E. Skurikhina V. Tesmer O. Titov 《Journal of Geodesy》2007,81(6-8):483-501
Within the International Very Long Baseline Interferometry (VLBI) Service for Geodesy and Astrometry (IVS), long time-series
of zenith wet and total troposphere delays have been combined at the level of parameter estimates. The data sets were submitted
by eight IVS Analysis Centers (ACs) and cover January 1984 to December 2004. In this paper, the combination method is presented
and the time-series submitted by the eight IVS ACs are compared with each other. The combined zenith delays are compared with
time-series provided by the International Global Navigation Satellite System (GNSS) Service (IGS), and with zenith delays
derived from the European Centre for Medium-Range Weather Forecasts (ECMWF). Before the combination, outliers are eliminated
from the individual time-series using the robust BIBER (bounded influence by standardized residuals) estimator. For each station
and AC, relative weight factors are obtained by variance component estimation. The mean bias of the IVS ACs’ time-series with
respect to the IVS combined time-series is 0.89 mm and the mean root mean square is 7.67 mm. Small differences between stations
and ACs can be found, which are due to the inhomogeneous analysis options, different parameterizations, and different treatment
of missing in-situ pressure records. Compared to the IGS zenith total delays, the combined IVS series show small positive
mean biases and different long-term trends. Zenith wet delays from the ECMWF are used to validate the IVS combined series.
Inconsistencies, e.g., long-term inhomogeneity of the in-situ pressure data used for the determination of VLBI zenith delays,
are identified. 相似文献