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近岸海域底质重金属生态风险评价初步研究   总被引:32,自引:0,他引:32       下载免费PDF全文
甘居利 《水产学报》2000,24(6):533-538
根据金属元素在地壳、海水、近海沉积物和海洋生物体内的丰度,吸收金属毒性实验研究成果,也考虑了沉积物内金属赋存形态对生物体吸收金属的影响,以及海洋生态系统对金属毒性的敏感程度,初步建立了近岸渔业海域沉积物重金属的生态风险评价指标体系。应用该体系对南海东北部红海湾沉积物重金属的生态风险性作试评价,所得结论同其它研究结果互为补充和借鉴,并能为南海区半封闭型海湾规模化养殖的环境容量研究提供有益的参考。  相似文献
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We examined quantitative catches of large medusae from summer bottom trawl surveys that sampled virtually the same grid station on the eastern Bering Sea shelf using the same methodology every year from 1979 to 1997. This series shows a gradual increase in biomass of medusae from 1979 to 1989, followed by a dramatic increase in the 1990s. The median biomass increased tenfold between the 1982–1989 and 1990–1997 periods. Most of this biomass was found within the Middle Shelf Domain (50 <  z  < 100 m). The greatest rate of increase occurred in the north-west portion of this domain. Whether this dramatic increase in biomass of gelatinous zooplankton has resulted from some anthropogenic perturbation of the Bering Sea environment or is a manifestation of natural ecosystem variability is unclear. However, several large-scale winter/spring atmospheric and oceanographic variables in the Bering Sea exhibited concomitant changes beginning around 1990, indicating that a possible regime change occurred at this time.  相似文献
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关于容纳量及其研究   总被引:16,自引:0,他引:16  
容纳量概念来源于种群增长逻辑斯谛方程。80年代以来,作为海洋可持续发展的科学依据,对容纳量的研究明显加强,并在研究规模、应用范围和研究方法等方面取得新的进展。“九五”计划中,我国进一步加强了容纳量研究,如养殖容量评估、总允许渔获量评估和生态系统持续产量评估等。在进一步研究中,应该注重对容纳量动态特性的研究。  相似文献
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In 1997, the Bering Sea ecosystem, a productive, high-latitude marginal sea, demonstrated that it responds on very short time scales to atmospheric anomalies. That year, a combination of atmospheric mechanisms produced notable summer weather anomalies over the eastern Bering Sea. Calm winds, clear skies, and warm air temperatures resulted in a larger-than-normal transfer of heat to surface waters and the establishment of a shallow mixed layer. In spring, significant new production occurred below the shallow pycnocline over the Middle Shelf, depleting the subpycnocline nutrient reservoir that normally exists during summer. Following the depletion of nitrate and silicate from the system, a sustained (≥ 4 months) bloom of coccolithophores ( Emiliania huxleyi ) was observed – a phenomenon not previously documented in this region. Summer Middle Shelf Domain copepod concentrations were higher for some species in 1997 than in the early 1980s. Warmer surface water and lack of wind mixing also changed the basic distribution of hydrographic regimes on the south-eastern shelf and altered the strength and position of fronts or transition zones where apex predators seek elevated food concentrations. The Inner Front was well inshore of its normal position, and adult euphausiids (the primary prey of short-tailed shearwaters, Puffinus tenuirostris ) were unavailable at, and shoreward of, the front in autumn. High shearwater mortality rates followed the period of low euphausiid availability. Some, but not all, of these anomalous conditions re-occurred in 1998. These observations are another demonstration that the structure and function of marine ecosystems are intimately tied to forcing from the atmosphere. Alteration of climatological forcing functions, expressed as weather, can be expected to have large impacts on this ecosystem and its natural resources.  相似文献
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Towards ecosystem-based fisheries management   总被引:11,自引:0,他引:11  
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Indicators to support an ecosystem approach to fisheries   总被引:9,自引:0,他引:9  
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Ecopath—一种生态系统能量平衡评估模式   总被引:8,自引:0,他引:8  
仝龄 《渔业科学进展》1999,20(2):102-107
Eopath模式是一种研究生态系统的工具。它根据能量平衡原理,用线性齐次方程组描述生 态系统的生物组成和能量流动过程,定量某些生态学参数,用于深入研究生态系统的特征和变化。本文介绍了Eopath模式的理论方法以及如何建立生态系统Ecopath模型和调试模型和调试模型,试图扩大其应用。最后简要地给出两个Ecopath模型应用实例,一个是美国阿拉斯加威廉姆王子湾生态系统Eco-path模型,它用50个生物组成较为全面地描述该生态  相似文献
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