全文获取类型
收费全文 | 121篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
大气科学 | 5篇 |
地球物理 | 12篇 |
海洋学 | 115篇 |
综合类 | 7篇 |
自然地理 | 6篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 7篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 1篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
排序方式: 共有145条查询结果,搜索用时 0 毫秒
81.
《African Journal of Marine Science》2013,35(4):593-596
The first detailed elasmobranch fisheries data for the Kingdom of Bahrain are presented, based on surveys of fish markets in April 2012. At least 25 species were recorded, including undescribed taxa. The milk shark Rhizoprionodon acutus was the most frequently recorded species; together with the Arabian smoothhound Mustelus mosis and banded eagle ray Aetomylaeus nichofii, these species comprised 53% of individual abundance. Sharks were almost entirely small individuals <1 m total length (TL). Males of small shark species were largely mature, whereas nearly all individuals of larger sharks were immature. For several elasmobranch species, landings were significantly biased towards males, which were largely mature. The species assemblage showed some notable differences in composition to that of adjacent Qatar, sampled at the same time of year, highlighting the importance of local data collection. 相似文献
82.
《Marine Policy》2015
Extensive criticisms of the management of marine fisheries periodically arise for a variety of reasons. While the complexity of the US fisheries management process is partially to blame, these reasons manifest themselves in statements that include a perceived decline in living marine resource abundance levels, a proposed change in the regulatory infrastructure, or improvements in stock abundance that some feel should allow for new entrants. Following these criticisms are calls to end the federal management process or at the very least the replacement of the fishery management agency leadership. These demands driven by rent seeking behavior use short-term declines in abundance as justification when the long-run abundance measures would have indicated improvements in stock abundance and achievement of management objectives. Empirical, long-run, stock abundance indices are estimated using synthetic demand methodology, based on bioeconomic fishery theory, applied in a general and partial equilibrium theory framework to determine if maximum sustainable yield (MSY) management targets have been achieved and maintained for four fisheries considered to be successfully managed and one characterized as a socio-economic disaster. The abundance of a fish stock is more influence by extra-market and extra-fishery forces than by fisheries managers who base allocation decisions solely on single species stock assessments. 相似文献
83.
《Marine Policy》2015
This article explores the role of market information and learning in multiple unit combinatorial markets for fishing quota. Combinatorial auctions allow trading of packages of different types of quotas (for example for different regions or industry) in the same auction market. Bidders can submit package bids which would allow them to enjoy synergy benefits. However, to realize the full benefit bidders require comprehensive understanding of the market. This article focuses on the impact of varying levels of information feedback on performance in multiple unit forward combinatorial auctions using laboratory experiments. In a general context of trade in fishery quota, it was asked whether (a) providing additional market information and (b) learning through time helps in more efficient outcomes. It is found that much of the benefits of information are derived from structural effects, like repeated rounds and package valuations. Providing additional market information does not improve auction performances to a large extent. These results will be useful in designing more efficient combinatorial markets for fisheries quota. 相似文献
84.
《Marine Policy》2015
Management strategies are challenging to implement in Zanzibar's fisheries because the local people depend upon these resources for basic subsistence. This difficulty epitomizes the vital need for sustainable management: the more people need a fishery, the harder it is to limit fishing to allow regeneration. Comparing fisheries management strategies in two coastal villages in Unguja, the largest island of Zanzibar, Tanzania, this paper confirms the results of existing scholarship that communitybased strategies provide the most promising solutions to this challenge. Interviews with officials from the Department of Fisheries and Marine Resources, Village Fishermen Committees, and 51 fishermen in the villages of Kizimkazi Dimbani and Jambiani reveal the efficacy of strategies where local fishermen are centrally involved. The fishermen interviews reveal ignorance of existing fishing regulations and a lack of enforcement while fishermen at both sites noted that many illegal methods of fishing are still in use and expressed concern that such methods damage fish stocks. The Village Fishermen Committees, a recently implemented community-based initiative, are well attended by fishermen, and constitute a management strength that this paper concludes should be the foundation of future policy. To be successful, these committees need additional educational and financial resources. 相似文献
85.
86.
Biodiversity and environmental characteristics of the bycatch assemblages from the tropical tuna purse seine fisheries in the eastern Atlantic Ocean 下载免费PDF全文
Nerea Lezama‐Ochoa Hilario Murua Jon Ruiz Pierre Chavance Alicia Delgado de Molina Ainhoa Caballero Igor Sancristobal 《Marine Ecology》2018,39(3)
The impact of human activities such as fishing has been identified as a main factor in diversity loss in the open ocean. This paper studies the diversity patterns and environmental characteristics of the bycatch assemblages in Fish Aggregating Devices (FADs) and Free School sets (sets made on schools of tuna) from the tropical tuna purse seine fishery in the eastern Atlantic Ocean (35°W–15°E and 20°N–15°S). Data were collected from scientific observer programmes carried out between 2003 and 2011 on board Spanish and French fleets. The results showed different structure and diversity patterns of the bycatch assemblages depending on the fishing mode, with higher number of species and diversity found in FAD sets than in Free School sets. Bycatch assemblages showed preferences for specific oceanographic characteristics of the Atlantic Ocean, such as the equatorial and seasonal coastal upwelling systems, the Cape Lopez front system and the Guinea dome. The type of set and sea surface temperature play an important role to describe the diversity patterns of these species. These results confirm the importance of integrating different methods to study the marine ecosystem towards the correct implementation of the Ecosystem Approach to Fishery Management (EAFM). 相似文献
87.
以现代渔港经济区理念看广东惠来县神泉港的发展 总被引:1,自引:0,他引:1
分析了现代渔港经济区的内涵、构建思路与关键问题,指出神泉渔港发展所面临的问题、发展的优势与发展的契机,并结合现代渔港经济区理念,具体探讨了神泉现代渔港经济区的发展设想、发展策略与对策措施。 相似文献
88.
南中国海及泰国湾渔业资源过度利用现状及保护对策 总被引:1,自引:0,他引:1
南中国海及泰国湾具有丰富的浅海和热带的生物多样性,支持着一个世界重要的渔场,同时南中国海及泰国湾周边的国家还是目前亚洲太平洋地区工业化和经济快速增长的中心,关系着东南亚及相邻地区的政治和经济的稳定.过去对渔业资源的过度开发利用,造成了该海区渔业资源减少,海岸环境退化严重.虽然南中国海及泰国湾周边国家过去都实施了相应的海洋环境保护行动计划,然而缺乏区域协调措施大大降低了这些行动的有效性.文中对南中国海及泰国湾渔业资源过度利用现状进行了诊断分析,识别了渔业资源过度利用造成的环境问题以及这些环境问题的跨境影响, 相似文献
89.
The closure of the Hawaiian longline swordfish fishery over the period 2001–2004, which was motivated by the protection of endangered sea turtles, created the elements of a natural experiment that allows identification of the market transfer of catch (and sea turtle bycatch) to other regions. This paper exploits the fact that the vessels in the Hawaiian longline fishery sell their catch in the US fresh swordfish market to analyze the pattern of changes in US fresh and frozen swordfish consumption both before and after the closure regulation was imposed. The mechanisms by which any unintended consequences on endangered sea turtles in other fishery locations in the world are shown to take place through the US swordfish market. At the estimated annual market transfer, a bootstrap analysis of the probability distribution of bycatch rates indicates that the regulation led to an additional 2882 sea turtle interactions at the sample means. 相似文献
90.
Learning about ecosystem processes and patterns is an essential component of Ecosystem Based Fishery Management and the sustainable use of natural resources. 相似文献