全文获取类型
收费全文 | 38393篇 |
免费 | 286篇 |
国内免费 | 225篇 |
专业分类
测绘学 | 781篇 |
大气科学 | 1799篇 |
地球物理 | 7301篇 |
地质学 | 15029篇 |
海洋学 | 3618篇 |
天文学 | 9036篇 |
综合类 | 103篇 |
自然地理 | 1237篇 |
出版年
2022年 | 491篇 |
2021年 | 717篇 |
2020年 | 761篇 |
2019年 | 837篇 |
2018年 | 1724篇 |
2017年 | 1572篇 |
2016年 | 1664篇 |
2015年 | 633篇 |
2014年 | 1436篇 |
2013年 | 2105篇 |
2012年 | 1661篇 |
2011年 | 1944篇 |
2010年 | 1836篇 |
2009年 | 2042篇 |
2008年 | 1822篇 |
2007年 | 2027篇 |
2006年 | 1775篇 |
2005年 | 940篇 |
2004年 | 849篇 |
2003年 | 845篇 |
2002年 | 777篇 |
2001年 | 786篇 |
2000年 | 671篇 |
1999年 | 439篇 |
1998年 | 458篇 |
1997年 | 493篇 |
1996年 | 357篇 |
1995年 | 379篇 |
1994年 | 348篇 |
1993年 | 303篇 |
1992年 | 304篇 |
1991年 | 304篇 |
1990年 | 360篇 |
1989年 | 288篇 |
1988年 | 275篇 |
1987年 | 277篇 |
1986年 | 204篇 |
1985年 | 315篇 |
1984年 | 324篇 |
1983年 | 320篇 |
1982年 | 291篇 |
1981年 | 263篇 |
1980年 | 280篇 |
1979年 | 210篇 |
1978年 | 249篇 |
1977年 | 214篇 |
1976年 | 187篇 |
1975年 | 195篇 |
1974年 | 181篇 |
1973年 | 215篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
921.
Tkachenko E. V. Debolskiy A. V. Mortikov E. V. Glazunov A. V. 《Izvestiya Atmospheric and Oceanic Physics》2022,58(3):219-236
Izvestiya, Atmospheric and Oceanic Physics - This study presents the results of large-eddy simulation (LES) of the evening transition in the atmospheric boundary layer in the case of free... 相似文献
922.
Izvestiya, Atmospheric and Oceanic Physics - This paper considers the problem of generating internal gravity waves that arise when a stratified flow with a shear flow runs into a single underwater... 相似文献
923.
Gorchakov G. I. Kopeikin V. M. Karpov A. V. Gushchin R. A. Datsenko O. I. Buntov D. V. 《Izvestiya Atmospheric and Oceanic Physics》2022,58(5):466-475
Izvestiya, Atmospheric and Oceanic Physics - Measurements of electric currents of saltation in the wind-sand flux and currents caused by the wind transport of dust aerosol particles have been... 相似文献
924.
V. M. Kushnir 《Physical Oceanography》1995,6(3):229-236
Data on the fine vertical structure of currents and hydrological elements in the Black Sea, obtained through the use of a hydrophysical OLT profiler, are examined. Vertical exchange coefficients are evaluated, whose distribution is characterized by the occurrence of minima in the seasonal pycnocline and main halocline, a maximum in the core of the cold intermediate layer (CIL), and relatively steady values within the 300–500 m layer. The vertical exchange coefficient values, are consistent with the data acquired through other techniques, and the profiles of this parameter vertically are more detailed.Translated by Vladimir A. Puchkin. 相似文献
925.
926.
I. F. Gablina L. L. Demina O. B. Dmitrenko N. S. Os’kina E. A. Popova T. A. Khusid V. V. Shilov 《Oceanology》2011,51(3):476-490
The first thorough analysis of microfossils from ore-bearing sediments of the Ashadze-1 hydrothermal field in the Mid-Atlantic
Ridge sampled during cruise 26 of the R/V Professor Logachev in 2005 revealed the substantial influence of hydrothermal processes on the preservation of planktonic calcareous organisms,
as well as on the preservation and composition of the benthic foraminifers. From the lateral and vertical distribution patterns
and the secondary alterations of the microfossils, it is inferred that the main phase of the hydrothermal mineralization occurred
in the Holocene. Heavy metals (Cu, Co, Cr, and Ag) were accumulated by foraminiferal tests and in their enveloping Fe-Mn crusts.
The distribution of authigenic minerals replacing foraminiferal tests demonstrates local zoning related to the hydrothermal
activity. There are three mineral-geochemical zones defined: the sulfide zone, the zone with an elevated Mg content, and zone
of Fe-Mn crusts. 相似文献
927.
Amy R. Kirkham Ludwig E. Jardillier Ross HollandMikhail V. Zubkov Dave J. Scanlan 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(7):733-744
Photosynthetic picoeukaryotes (PPEs) of a size <3 ??m can contribute significantly to primary production. Here, PPE community structure was analysed along an extended Ellett Line transect, an area in the North Atlantic well studied by physical oceanographers but largely neglected in the field of microalgal ecology. Distribution patterns of specific PPE classes were determined using dot-blot hybridization analysis, while the taxonomic composition of specific PPE classes was revealed by phylogenetic analysis of plastid 16S rRNA gene sequences. In addition, we performed fluorescent in situ hybridization (FISH) analysis of seawater samples collected along the transect to provide a PCR-independent survey of class level PPE distribution patterns. We found the PPE community was dominated by members of the Prymnesiophyceae, Prasinophyceae and Mamiellophyceae. Interestingly, phylogenetic analysis revealed several novel Prymnesiophyceae and Prasinophyceae phylotypes (with only 85-96% identity to neighbouring sequences) within lineages for which cultured counterparts are unknown. 相似文献
928.
In the Boussinesq approximation, we study the nonlinear effects observed in the process of propagation of internal waves in
the presence of turbulence. The space damping factor of the waves is evaluated. The Stokes drift velocity and the Euler velocity
of the mean current induced by waves due to the presence of nonlinearity are determined. It is shown that the principal contribution
to the wave transfer is made by the horizontal velocity of the induced current. The Stokes drift is significant only near
the bottom. The vertical component of the Stokes drift velocity obtained with regard for the turbulent viscosity is nonzero. 相似文献
929.
Lina Fernandes G.N. Nayak D. Ilangovan D.V. Borole 《Estuarine, Coastal and Shelf Science》2011,91(3):388-399
Two core sediment samples; one from inner part (ManI) and the other closer to the mouth (ManII); were collected from the intertidal regions of Manori, a tidally influenced creek near Mumbai, India. Both the cores were subjected to various geochemical analyses to determine parameters such as pH, sediment components, total organic carbon, total nitrogen, total phosphorus and selected metals viz., Fe, Mn, Cu, Pb, Co, Ni, Zn, Cr, Al, Ca and V. Analysis of 210Pb activity was employed to assess the sediment deposition trend of the area. The data was further processed using factor and cluster analyses. The results indicate that the sediments from site ManI, had finer sediment composition, higher porosity, organic matter and metal contents but exhibited an erratic decline in 210Pb activity downcore. Also ManI showed higher C:N ratio and enrichment factor values as compared to site ManII. The inner area (ManI) probably received a greater input of organic matter from the erosion of terrestrial matter as well as domestic and industrial discharge. Sediments from site ManII had typical marine organic matter composition (lower C:N ratio). The concentration of metals at this site was also low indicating the contents were getting diluted by freshwater and seawater mixing. 相似文献
930.
Stephen W.B. Cole Ricardo A. Scrosati Jamie C. Tam Andrea V. Sussmann 《Journal of Sea Research》2011,65(1):33-37
We investigated the regional variation in barnacle (Semibalanus balanoides) recruit and adult abundance on the NW Atlantic coast. At the end of the recruitment season (June–July), we sampled wave-exposed rocky intertidal sites in two regions on the open Atlantic coast (Maine, AM, and Nova Scotia, AN) and in two regions on the Gulf of St. Lawrence coast (Northumberland Strait, GN, and Cape Breton Island, GC). Recruit density was highest in the southernmost region (AM), followed by GN and, then, by AN and GC. Regional values of nearshore primary productivity (satellite data of chlorophyll-a concentration, a surrogate for phytoplankton abundance) were highest for AM and GN, suggesting that food supply (barnacles are filter feeders) is an important factor determining regional recruitment patterns. Adult barnacle density was regionally decoupled from recruit density. Adults occurred in very low abundances on the Gulf of St. Lawrence coast (GN and GC) and were relatively abundant on the Atlantic coast (AM and AN), although always in much lower abundances than recruits. The low adult densities on the Gulf of St. Lawrence coast seem to result mainly from intense ice scour, as this coast freezes extensively every winter, as opposed to the ice-free Atlantic coast. Ice scour thus appears to override regional recruitment differences in determining adult density. Therefore, our data suggest that both pelagic food supply and benthic disturbance contribute to setting regional patterns in barnacle population structure on the NW Atlantic coast. 相似文献