全文获取类型
收费全文 | 22899篇 |
免费 | 232篇 |
国内免费 | 130篇 |
专业分类
测绘学 | 354篇 |
大气科学 | 1203篇 |
地球物理 | 4354篇 |
地质学 | 8987篇 |
海洋学 | 2230篇 |
天文学 | 5266篇 |
综合类 | 42篇 |
自然地理 | 825篇 |
出版年
2022年 | 263篇 |
2021年 | 431篇 |
2020年 | 394篇 |
2019年 | 461篇 |
2018年 | 939篇 |
2017年 | 864篇 |
2016年 | 879篇 |
2015年 | 365篇 |
2014年 | 765篇 |
2013年 | 1287篇 |
2012年 | 897篇 |
2011年 | 1089篇 |
2010年 | 1054篇 |
2009年 | 1212篇 |
2008年 | 1038篇 |
2007年 | 1217篇 |
2006年 | 1060篇 |
2005年 | 565篇 |
2004年 | 533篇 |
2003年 | 539篇 |
2002年 | 559篇 |
2001年 | 508篇 |
2000年 | 409篇 |
1999年 | 333篇 |
1998年 | 322篇 |
1997年 | 328篇 |
1996年 | 254篇 |
1995年 | 261篇 |
1994年 | 236篇 |
1993年 | 182篇 |
1992年 | 208篇 |
1991年 | 181篇 |
1990年 | 195篇 |
1989年 | 187篇 |
1988年 | 156篇 |
1987年 | 182篇 |
1986年 | 170篇 |
1985年 | 205篇 |
1984年 | 198篇 |
1983年 | 197篇 |
1982年 | 188篇 |
1981年 | 172篇 |
1980年 | 162篇 |
1979年 | 182篇 |
1978年 | 158篇 |
1977年 | 142篇 |
1976年 | 133篇 |
1975年 | 136篇 |
1974年 | 125篇 |
1973年 | 165篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
We have examined wind-induced circulation in the Sea of Okhotsk using a barotropic model that contains realistic topography
with a resolution of 9.25 km. The monthly wind stress field calculated from daily European Centre for Medium-Range Weather
Forecasting (ECMWF) Re-Analysis data is used as the forcing, and the integration is carried out for 20 days until the circulation
attains an almost steady state. In the case of November (a representative for the winter season from October to March), southward
currents of velocity 0.1–0.3 m s−1 occur along the bottom contours off the east of Sakhalin Island. The currents are mostly confined to the shelf (shallower
than 200 m) and extend as far south as the Hokkaido coast. In the July case (a representative for the summer season from April
to September), significant currents do not occur, even in the shallow shelves. The simulated southward current over the east
Sakhalin shelf appears to correspond to the near-shore branch of the East Sakhalin Current (ESC), which was observed with
the surface drifters. These seasonal variations simulated in our experiments are consistent with the observations of the ESC.
Dynamically, the simulated ESC is interpreted as the arrested topographic wave (ATW), which is the coastally trapped flow
driven by steady alongshore wind stress. The volume transport of the simulated ESC over the shelf reaches about 1.0 Sv (1
Sv = 106 m3s−1) in the winter season, which is determined by the integrated onshore Ekman transport in the direction from which shelf waves
propagate.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
112.
113.
V. I. Valsenko 《Physical Oceanography》1992,3(6):417-424
A numerical model is developed for the generation of internal waves induced by a barotropic tidal wave travelling over large bottom features. Motion equations consider the non-linear terms, as well as the terms responsible for horizontal turbulent exchange. The fluid is assumed to be continuously stratified. In the framework of the developed model, a packet of short non-linear internal waves is shown to occur together with a long baroclinic tide. In the absence of non-linear terms in the equations of motion, the model data are qualitatively and quantitatively consistent with the data provided by known linear models.Translated by V. Puchkin. 相似文献
114.
115.
The expansion of the temperature anomaly field in the North Atlantic is considered using natural orthogonal functions of depth. It is shown that the first few components of this expansion describe the field both at the surface and in the upper 1000 m layer accurately enough. The relation between the water temperature anomaly at some levels and the above components is estimated for various regions of the ocean.Translated by Mikhail M. Trufanov. 相似文献
116.
117.
Some aspects of the upper ocean layer dynamics are considered, including the Ekman transport, the relation of the thickness of the quasi-homogeneous layer to the thickness of the layer of rotation of the drift current vector, and the correlation between the level of the turbulent energy dissipation and the thickness of the quasi-homogeneous layer. 相似文献
118.
119.
120.
An extensive experimental and computational investigation of the combined and separate effects of free surface and body on the lift characteristics of a pair of fins attached to a strut and fin alone is conducted. The results reveal that the free-surface effect becomes significant when the depth of submergence to chord ratio (H/c) is less than three. The effect of the strut is also realized for shallower depth of submergence of the fins through free-surface deformation leading to a significant change in the incidence angle of the flow to the fins. The numerical results based on the Higher Order Boundary Element Method with the linearized free-surface condition show good agreement with the experimental results for fin (foil) alone even at shallow submergence, but some discrepancies appear for the fin attached to the strut at higher speeds mostly due to the neglect of the nonlinear free-surface effect. 相似文献