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41.
吉林省西部沙地与甸子地土壤动物的比较研究   总被引:5,自引:3,他引:5  
殷秀琴  张宝田 《中国沙漠》1996,16(2):149-156
吉林省西部沙地和甸子地典型区土壤动物比较研究表明,沙地大型土壤动物的优势类群数明显多于甸子地,而中小型土壤动物优势类群数则相反。两个生境的稀有类群有明显差异,反映了它们对环境的适应性及指示作用。甸子地的多样性、均匀度指数均高于沙地。  相似文献   
42.
赵琦  沈前彬  唐将  朱可 《物探与化探》2003,27(5):399-402
通过对四川5处大熊猫保护区的与动、植物发育有关元素的1:20万化探资料的研究,认为蜂桶沟、卧龙生态环境最好;唐家河、小寨子次之;王朗则是有益和有毒元素并存.总体看保护区的生态地球化学环境是好的,大自然给大熊猫的生长发育提供了较为良好的环境.  相似文献   
43.
Julie Urbanik   《Geoforum》2007,38(6):1205-1218
The first major wave in the conflict over modern biotechnologies took place in the United States at the federal level. Biotechnology proponents were able to capture the federal regulatory structure, so today, a second wave of anti-biotech activism focused at the local and state levels is emerging. This article examines what enables or constrains place-based anti-biotech activism through a case study of the conflict over genetically engineered (GE) animals in Massachusetts. I demonstrate how, in spite of a highly visible animal advocacy and anti-GE presence, GE animal proponents have mobilized effective politics of place strategies to suppress local debate by exercising territorial control in relation to two places – the state of Massachusetts as a whole and the animal research laboratory specifically.  相似文献   
44.
Shipping noise is a threat to marine wildlife. Grey seals are benthic foragers, and thus experience acoustic noise throughout the water column, which makes them a good model species for a case study of the potential impacts of shipping noise. We used ship track data from the Celtic Sea, seal track data and a coupled ocean-acoustic modelling system to assess the noise exposure of grey seals along their tracks. It was found that the animals experience step changes in sound levels up to ~ 20 dB at a frequency of 125 Hz, and ~ 10 dB on average over 10–1000 Hz when they dive through the thermocline, particularly during summer. Our results showed large seasonal differences in the noise level experienced by the seals. These results reveal the actual noise exposure by the animals and could help in marine spatial planning.  相似文献   
45.
刘小卓  张晓明  董波 《海洋科学》2018,42(3):157-168
MicroRNAs(miRNAs)是一类小分子非编码RNA,通过特异性结合靶基因,对靶基因转录后表达进行调控。miRNAs参与众多生物学过程并发挥关键调控角色。作者介绍了miRNAs生物合成和作用机制,回顾了近年来海洋动物miRNA研究取得的进展,并阐述了目前已知的miRNA对海洋动物重要生理过程的调控过程和机制,旨在为今后更深入地研究海洋动物miRNA功能提供参考。  相似文献   
46.
水生动物行为生态学是动物行为生态学的重要分支,对理解水生动物的生存行为机制、指导渔业生产和保护濒危水生动物具有重要意义。近年来,随着新型研究技术和手段的出现,水生动物行为生态学在短时间内得到了迅速发展。水生动物行为多种多样,本文主要综述了水生动物行为生态学的研究方法与手段,探讨了水生动物运动行为、摄食行为、繁殖行为和集群行为等方面的研究进展,并展望了水生动物行为生态学的研究与应用前景,以期为水生动物行为生态学研究与应用提供借鉴和参考。  相似文献   
47.
ArA,EPA和DHA在水生动物中应用的研究进展   总被引:5,自引:0,他引:5  
ArA,EPA和DHA是水生动物卵巢中卵磷脂、精子中的磷脂酰乙醇胺以及卵母细胞等的主要组成成分,能够影响产卵率、受精率、卵径大小、卵黄囊的体积、孵化率及存活率等,这三种必需脂肪酸在细胞结构、物质代谢和能量调节等方面具有重要作用,能够维持细胞通透性,增强消化酶活性,从而促进水生动物的生长;还能够影响细胞吞噬能力及呼吸爆发强度,并可以通过控制与免疫相关的酶活性以及类二十烷的产生而增强水生动物机体的免疫能力;其中的ArA可以通过调节皮质醇以及其他未知途径调节水生动物抵抗各种应激的能力。对这三种高度不饱和脂肪酸对水生动物生长、繁殖、免疫功能的影响和抗应激能力以及三者之间的关系作了综述并提出了问题和展望,以期对水产养殖提供理论参考。  相似文献   
48.
INTRODUCTIONThedevelopmentofshrimpcultureshasbeenaffectedseverelybyviraldiseases(CatandSu,1993).Atpresent,however,thepathwayofvirustransmissiontopenaeidshrimpisnotunderstoodanditisthereforedifficulttopreventtheoccurrenceandspreadofshrimpviraldiseases.Toreducethelossescausedbyviralinfection,thedevelopmentofearlyandaccuratediagnostictechniquesisessential(Bruceetal.,1994;Changetal.,1993;Huangetal.,1995;Vickersetal.,1993).Anenzymeimmunoassaytechniquefordetectingbaculoviralmidgutglandnecrosi…  相似文献   
49.
Seagrass beds are susceptible to various natural and human-induced disturbances. Disturbances affect not only seagrasses, but also the abundance and diversity of associated macrofaunal communities. The Andaman Sea coast of Thailand was heavily affected by the tsunami of December 26, 2004. To examine its impact on seagrass macrofaunal communities, we compared the abundance, diversity and taxa composition by quantitative samplings in 2001 (before the tsunami) and in 2005 and 2006 (after the tsunami). Macrobenthic animals and sediments were collected from vegetated and nonvegetated areas of two sites that had received different levels of tsunami disturbances. A large decline in abundance and diversity was observed in the nonvegetated areas after the tsunami, whereas an increase was observed in the vegetated areas. The magnitude of decline and subsequent recovery of abundance and diversity of macrobenthic animals in nonvegetated areas were similar between the two sites, suggesting that their temporal changes were not solely related to the magnitude of the tsunami disturbance. Similarity of the benthic animals differed greatly between 2001 and 2005–2006 at the nonvegetated areas, whereas it varied less among the 3 years at the seagrass-vegetated areas. This study demonstrated that the presence of seagrass vegetation alters the patterns of temporal variation in macrofaunal assemblages and subsequent recovery processes following a tsunami.  相似文献   
50.
The vertical migration on mangrove trunks of the gastropod Cerithidea decollata was followed for 5 weeks, in a Kenyan mangrove. Most of the times, snails forage on the mud surface, during low tide, and climb back on trees well before the incoming tide. As soon as the sea retreats, the downward migration takes place and the snails spread again on the ground. The migratory behaviour of snails can vary widely, depending on the relative tide intensity, and different strategies can be exhibited. Individuals can spend several days on trees without migrating to the ground, around Spring Tides, or else, they might remain on the ground without bothering to migrate upwards, during Neap Tides, when the study area is not reached by the water. These irregular animal behaviours, relating to the complicated tide succession, can hardly be explained by the sole presence of an internal clock, and direct cues seem necessary to switch between different strategies, tuning the snails migratory behaviour to the actual local sea conditions.  相似文献   
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