全文获取类型
| 收费全文 | 243篇 |
| 免费 | 9篇 |
| 国内免费 | 16篇 |
专业分类
| 测绘学 | 2篇 |
| 大气科学 | 12篇 |
| 地球物理 | 22篇 |
| 地质学 | 12篇 |
| 海洋学 | 206篇 |
| 综合类 | 4篇 |
| 自然地理 | 10篇 |
出版年
| 2023年 | 2篇 |
| 2022年 | 2篇 |
| 2021年 | 3篇 |
| 2020年 | 11篇 |
| 2019年 | 3篇 |
| 2018年 | 6篇 |
| 2017年 | 6篇 |
| 2016年 | 2篇 |
| 2015年 | 11篇 |
| 2014年 | 4篇 |
| 2013年 | 25篇 |
| 2012年 | 3篇 |
| 2011年 | 4篇 |
| 2010年 | 3篇 |
| 2009年 | 22篇 |
| 2008年 | 14篇 |
| 2007年 | 19篇 |
| 2006年 | 7篇 |
| 2005年 | 14篇 |
| 2004年 | 8篇 |
| 2003年 | 10篇 |
| 2002年 | 10篇 |
| 2001年 | 16篇 |
| 2000年 | 21篇 |
| 1999年 | 5篇 |
| 1998年 | 6篇 |
| 1997年 | 3篇 |
| 1996年 | 5篇 |
| 1995年 | 5篇 |
| 1994年 | 1篇 |
| 1993年 | 4篇 |
| 1992年 | 3篇 |
| 1991年 | 1篇 |
| 1989年 | 1篇 |
| 1986年 | 1篇 |
| 1985年 | 2篇 |
| 1984年 | 3篇 |
| 1983年 | 2篇 |
排序方式： 共有268条查询结果，搜索用时 171 毫秒
61.
62.
63.
64.
65.
66.
67.
The lifting motor pump is the core equipment of the deep-sea hydraulic pipeline lifting system, and its research results are one of the important technical reserves for the research and development of marine mineral resources. It is an essential capacity for lifting motor pump to allow coarse particles pass through the flow passages, to realize this requirement, an increased flowrate method is employed to design a wide flow passage for an innovative six-stage lifting motor pump. Based on Computational Fluid Dynamics (CFD), the anti-blocking performance of the lifting motor pump designed by the conventional method and the increased flowrate method are compared, which show that the latter is better than the former. Numerical simulations of the internal two-phase flow inside the innovative pump are presented, and the flow parameters such as pressure, velocity and particle trajectory are obtained. According to the design method of the six-stage lifting motor pump, a two-stage lifting motor pump is manufactured, and the relevant performance experiments are performed. The results obtained by numerical simulation is in a good agreement with the experimental ones, thus the validity and accuracy of the numerical model and method is verified. The innovative two-stage lifting motor pump can operate smoothly with low noise and no blockage occurs, and its performance meets the design goals and requirements. 相似文献
68.
69.
Elucidation of important nursery habitats for young fish can aid in the management and assessment of fish stocks. Herring (Clupea harengus) in the Baltic Sea primarily spawn in coastal areas, but larvae are also present in off-shore, open sea areas. To investigate if sheltered coastal habitats provide a better growth environment for larval herring, we compared short-term growth (as indexed by whole body RNA:DNA ratios) of larval herring from three habitat types of the northwest Baltic proper (sheltered inner bay, exposed outer bay, and open sea). In addition, we compared individual RNA content of adult female Eurytemora affinis (a common Baltic copepod) among these different habitats. High RNA levels in these copepods indicate high production of nauplii, which are important food for larval herring. Both RNA:DNA ratios of larval herring and RNA content of E. affinis were significantly greater in embayment habitats, suggesting that the sheltered coastal areas are high quality nursery habitats for young Baltic herring. 相似文献
70.
J.R. Wilson B.R. Broitman J.E. Caselle D.E. Wendt 《Estuarine, Coastal and Shelf Science》2008,79(3):483-490
Recruitment of pelagic larval fishes to the nearshore environment is dependent on a suite of biological and physical processes operating at many spatial and temporal scales. Nearshore circulation processes associated with coastal upwelling are widely upheld as major determinants of year class strength for many rockfishes (Sebastes spp.), but the mechanism by which these processes drive recruitment is largely unknown. We used Standard Monitoring Units for the Recruitment of Fishes (SMURFs) to monitor recruitment of two rockfish complexes (Sebastes spp.) and cabezon (Scorpaenichthys marmoratus) from March to September of 2004 and 2005 at 3 sites along the central California coast. We examined the relationship between recruitment of these fishes and measurements of oceanographic variability associated with upwelling dynamics, including in situ water temperature, AVHRR sea surface temperature, the Bakun upwelling index, and an index of alongshore surface water transport. We found that rockfish comprising the KCGB complex (Sebastes atrovirens, Sebastes caurinus, Sebastes carnatus, Sebastes chrysomelas) recruit during early summer, while fishes of the BYO complex (Sebastes melanops, Sebastes flavidus, Sebastes serranoides), as well as cabezon recruit during late summer. Our results provide limited support for an association between the arrival of juvenile pelagic rockfish and cabezon to the nearshore environment and physical processes related to upwelling and relaxation. Beyond the limitations of our bimonthly sampling scheme, the lack of a clear pattern may be related to the near absence of upwelling–relaxation cycles along this stretch of coast during these two study periods. Moreover, the settlement and recruitment of nearshore fishes may be closely tied to processes occurring earlier in the larval stage. 相似文献