全文获取类型
收费全文 | 152篇 |
免费 | 13篇 |
国内免费 | 22篇 |
专业分类
地球物理 | 34篇 |
地质学 | 20篇 |
海洋学 | 114篇 |
综合类 | 12篇 |
自然地理 | 7篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 15 毫秒
51.
Andres H. Arias Carla V. Spetter Rubén H. Freije Jorge E. Marcovecchio 《Estuarine, Coastal and Shelf Science》2009
Polycyclic aromatic hydrocarbons (PAHs), one of the major groups of anthropogenic environmental pollutants, were firstly identified and measured in coastal waters, native mussels and fish of an industrialized South American estuary. 相似文献
52.
53.
54.
农田生态系统的生物多样性受到限制,害虫失去了天敌的控制易形成爆发性危害;杀虫剂的使用在消灭害虫的同时也消灭了害虫的天敌,遗传变异和有毒环境的自然选择使害虫产生高抗性,导致杀虫剂的防治效果下降,于是不得不增加农药的使用量而陷入恶性循环.适当增加环境中有益生物的数量可实现害虫的有效控制;有益生物人工饲养技术的发展为防治农业害虫奠定了较好的基础.但是,投资与收益者不能统一的矛盾以及滥用农药使生物防治技术的应用受到限制.加大政府的支持力度,建立有益生物利用保护区和适宜的投入运行机制,加强多种生物配合利用方面的研究可促进有益生物利用技术的研发与推广. 相似文献
55.
Offshore oil platforms and fouling communities in the southern Arabian Gulf (Abu Dhabi) 总被引:1,自引:0,他引:1
Stachowitsch M Kikinger R Herler J Zolda P Geutebrück E 《Marine pollution bulletin》2002,44(9):853-860
This study examined the fouling organisms on the legs of offshore oil platforms at two sites in the southern Arabian Gulf (offshore Abu Dhabi, United Arab Emirates). 100% of the metal structures was colonized by encrusting organisms. Both the number of individuals and the total biomass tended to decrease with depth. The total weight of dead shells always exceeded that of living organisms. Sessile filter feeders dominated the biomass, whereas small mobile forms had the largest number of individuals. The biomass at the deeper platform (22 m) was dominated by bivalves, barnacles and bryozoans, while polychaetes and amphipods had the greatest number of individuals. Biomass values here ranged from 1 g/0.1 m2 at 20 m to 147 g/0.1 m2 at 5 m; the corresponding individual numbers were 266 (20 m) and 11,814 indiv./0.1 m2 (5 m). The results at the shallower platform (11 m) differed in several respects: barnacles clearly dominated over bivalves, and sponges exceeded byrozoans, while total individual numbers fell due to a decline in polychaete dominance. Biomass values here ranged from 84 g/0.1 m2 at 10 m to 153 g/0.1 m2 at 0 m; the corresponding individual numbers were 695 (10 m) and 3,125 indiv./0.1 m2 (0 m). The potential role of such fouling communities on artificial structures in the Gulf is discussed. 相似文献
56.
57.
本文研究了改性粘土悬浮液中硫酸根对其去除藻华生物效率的影响,通过Zeta电位、沉降速率和粒径分布等分析了改性粘土对藻华生物的去除效率,探讨了硫酸根与改性粘土的作用机制。结果显示:改性粘土对抑食金球藻(Aureococcus anophagefferens)的去除效率随悬浮液中硫酸根浓度的增加呈现先降低后升高的趋势,改性湖北土和改性江苏土对抑食金球藻去除率较低时(40%)的硫酸根浓度分别为6.46×10–3—2.42×10–1mol/L和6.46×10–3—2.42×10–2mol/L;改性粘土颗粒的Zeta电位随着硫酸根浓度的增加而降低,然后保持相对稳定;悬浮液中改性粘土颗粒的沉降速率和中值粒径D50呈现先增加后降低的趋势,对于改性江苏土,在硫酸根浓度为2.42×10–2mol/L时颗粒的沉降速率最大。综上所述,悬浮液中硫酸根主要通过降低粘土颗粒表面电荷密度、桥联改性粘土组分和影响粘土颗粒分散性等作用影响改性粘土对藻华生物的去除效率。 相似文献
58.
Ramos-Gómez J Martins M Raimundo J Vale C Martín-Díaz ML DelValls TA 《Marine pollution bulletin》2011,62(7):1538-1549
Sediment toxicity assessments using caged organisms present advantages over using laboratory and native community studies. The use of caged Arenicola marina in sediment toxicity assessments was evaluated. Lugworms were exposed in situ to sediments from coastal and port areas in Spain for seven days, and the activities of the biotransformation enzymes ethoxyresorufin O-deethylase, dibenzylfluorescein dealkylase and glutathione S-transferase, the activities of the antioxidant enzymes glutathione reductase and glutathione peroxidase and lipid peroxidation were then analyzed as biomarkers. Biomarker results and sediment physicochemical data were integrated. Cádiz Bay (SW Spain) sediments presented metal contamination that was not linked to a biochemical response. In LPGC Port (SW Spain), Pb contamination exhibited a moderate toxic potential, while PAHs, and presumably pharmaceuticals, provoked biochemical responses that efficiently prevented lipid peroxidation. In Santander Bay (N Spain), exposure to PAHs and, presumably, pharmaceuticals induced biomarker responses, but lipid peroxidation occurred nevertheless. These results indicated that caged A. marina were effective for the assessment of sediment quality and that the selected biomarkers were sufficiently sensitive to identify chemical exposure and toxicity. 相似文献
59.
60.