全文获取类型
收费全文 | 5826篇 |
免费 | 1305篇 |
国内免费 | 1603篇 |
专业分类
测绘学 | 1479篇 |
大气科学 | 2107篇 |
地球物理 | 897篇 |
地质学 | 2762篇 |
海洋学 | 733篇 |
天文学 | 116篇 |
综合类 | 367篇 |
自然地理 | 273篇 |
出版年
2024年 | 48篇 |
2023年 | 184篇 |
2022年 | 355篇 |
2021年 | 421篇 |
2020年 | 381篇 |
2019年 | 372篇 |
2018年 | 212篇 |
2017年 | 316篇 |
2016年 | 267篇 |
2015年 | 339篇 |
2014年 | 506篇 |
2013年 | 389篇 |
2012年 | 459篇 |
2011年 | 406篇 |
2010年 | 345篇 |
2009年 | 381篇 |
2008年 | 366篇 |
2007年 | 453篇 |
2006年 | 408篇 |
2005年 | 313篇 |
2004年 | 302篇 |
2003年 | 250篇 |
2002年 | 183篇 |
2001年 | 159篇 |
2000年 | 137篇 |
1999年 | 139篇 |
1998年 | 105篇 |
1997年 | 107篇 |
1996年 | 105篇 |
1995年 | 76篇 |
1994年 | 54篇 |
1993年 | 50篇 |
1992年 | 35篇 |
1991年 | 29篇 |
1990年 | 20篇 |
1989年 | 19篇 |
1988年 | 7篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有8734条查询结果,搜索用时 0 毫秒
151.
ICES baseline survey of trace metals in European shelf waters 总被引:1,自引:0,他引:1
Balls P.; Cofino W.; Schmidt D.; Topping G.; Wilson S.; Yeats P. 《ICES Journal of Marine Science》1993,50(4):435-444
152.
塘沽海区海底地形的SAR影像仿真与反演研究 总被引:1,自引:0,他引:1
利用袁业立、金梅兵(1997)提出的海底地形SAR影像仿真与反演模型,对渤海塘沽海区的一张Radarsat SAR影像进行了仿真和水深反演研究。研究结果表明:仿真影像与真实SAR影像基本吻合,反演水深与实际水深也有较好的一致性;进一步证实了袁业立(1997)SAR成像机理的正确性和在中国近海利用SAR影像进行浅海水深探测的可行性。 相似文献
153.
154.
Shinya Magome Tomohiro Yamashita Takeshi Kohama Atsushi Kaneda Yuichi Hayami Satoru Takahashi Hidetaka Takeoka 《Journal of Oceanography》2007,63(5):761-773
Jellyfish patch formation is investigated by conducting a drifter experiment combined with aerial photography of a sustained
patch of the moon jellyfish in Hokezu Bay, Japan. Jellyfish patches are aggregations of individuals that are caused by a combination
of swimming (active influence) and advection by currents (passive influence). The drifter experiment involved the injection
of 49 drifters around a distinct surface patch of jellyfish within an area of approximately 300 m × 300 m. The drifters’ motion,
caused only by the passive influence, was recorded in a series of 38 aerial photographs taken over approximately 1 h. The
ambient uniform current field larger than the patch scale was estimated from the movement of the centroid position of drifters,
while the distribution of horizontal divergence and relative vorticity around the patch was estimated from the time-derivative
in areas of triangles formed by the drifters. The centroid positions of both drifters and patches moved stably toward the
bay head at different speeds. The difference vector between the patch and drifter centroids was directed to the sun, and was
opposite to the ambient current. The distributions of vorticity and divergence around patches exhibited inhomogeneity within
the patch scale, and the drifters in this nonuniform current field aggregated near the convergence area within 1 h. The results
suggest that horizontal patch formation is predominantly influenced by passive factors at the surface of Hokezu Bay. Furthermore,
the upward swimming against downwelling may make sustained patch in surface layer. 相似文献
155.
156.
157.
158.
159.
The seismic expression of a salt-filled channel which cuts across the Mid North Sea High in Quadrant 37 is described, with features interpreted as being produced by salt-edge dissolution forming both eastern and western margins of the channel. The apparent half-graben nature of the channel is shown to be only superficial, and due to complex faulting associated with, but not defining, its western margin. The shallower faulting here is a Mesozoic to early Tertiary growth fault related to local dissolution of Zechstein salt. The dissolution effect appears in turn to have been localized by the presence of a deeper fault that was already downthrown to the east in Zechstein times, when it seems to have limited the eastward progradation of Zechstein shelf carbonates and anhydrites, and had probably ceased to move significantly before the onset of the Late Cimmerian erosional phase. The origin of this arcuate fault is tentatively ascribed to subsidence around a granite batholith. Zechstein salt originally spread some distance to the east and west of the channel; it was dissolved from the edges inwards, mainly before the Late Cretaceous, giving rise to a thicker Mesozoic sequence on parts of the flanks of the channel than in the middle. Besides providing an interesting structural case history, the features described have implications regarding Zechstein sedimentation, reservoir potential, the tectonic history of the North Sea, and the nature of the Mid North Sea High itself. 相似文献
160.
本文以1981~1984年4~9月累计18个月在闵中、闵东渔场开展中上层鱼类资源开发性探捕调查的材料,报道了扁舵鲣的生态分布、群体结构和生活史主要特征。鱼群先后于4~7月由南而北进入本渔场,数量分布以5月为多;栖息的最适温、盐度分别为23.5~25.5℃和33~34;渔获群体由0~V龄组成;性成熟的最小年龄为Ⅰ龄,最小叉长271~280mm;生长参数L_∞=484.44mm,W_∞=2050.76g,K=0.5109,t_0=0.3598;瞬时自然死亡率为0.8937,开发比率为0.2138,属于轻度利用的鱼类资源,尚有较大的开发潜力。 相似文献