全文获取类型
收费全文 | 1170篇 |
免费 | 80篇 |
专业分类
林业 | 82篇 |
农学 | 29篇 |
基础科学 | 1篇 |
157篇 | |
综合类 | 105篇 |
农作物 | 70篇 |
水产渔业 | 152篇 |
畜牧兽医 | 523篇 |
园艺 | 27篇 |
植物保护 | 104篇 |
出版年
2023年 | 22篇 |
2022年 | 45篇 |
2021年 | 71篇 |
2020年 | 67篇 |
2019年 | 68篇 |
2018年 | 54篇 |
2017年 | 52篇 |
2016年 | 52篇 |
2015年 | 32篇 |
2014年 | 54篇 |
2013年 | 57篇 |
2012年 | 71篇 |
2011年 | 72篇 |
2010年 | 42篇 |
2009年 | 31篇 |
2008年 | 54篇 |
2007年 | 59篇 |
2006年 | 32篇 |
2005年 | 33篇 |
2004年 | 32篇 |
2003年 | 25篇 |
2002年 | 20篇 |
2001年 | 8篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1995年 | 4篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1967年 | 5篇 |
1902年 | 3篇 |
1900年 | 5篇 |
1898年 | 2篇 |
1897年 | 2篇 |
1896年 | 3篇 |
1887年 | 2篇 |
排序方式: 共有1250条查询结果,搜索用时 859 毫秒
991.
Aquatic food security: insights into challenges and solutions from an analysis of interactions between fisheries,aquaculture, food safety,human health,fish and human welfare,economy and environment
下载免费PDF全文
![点击此处可从《Fish and Fisheries》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Simon Jennings Grant D Stentiford Ana M Leocadio Keith R Jeffery Julian D Metcalfe Ioanna Katsiadaki Neil A Auchterlonie Stephen C Mangi John K Pinnegar Tim Ellis Edmund J Peeler Tiziana Luisetti Craig Baker‐Austin Mary Brown Thomas L Catchpole Fiona J Clyne Stephen R Dye Nathan J Edmonds Kieran Hyder Janette Lee David N Lees Owen C Morgan Carl M O'Brien Birgit Oidtmann Paulette E Posen Ana Ribeiro Santos Nick G H Taylor Andrew D Turner Bryony L Townhill David W Verner‐Jeffreys 《Fish and Fisheries》2016,17(4):893-938
Fisheries and aquaculture production, imports, exports and equitability of distribution determine the supply of aquatic food to people. Aquatic food security is achieved when a food supply is sufficient, safe, sustainable, shockproof and sound: sufficient, to meet needs and preferences of people; safe, to provide nutritional benefit while posing minimal health risks; sustainable, to provide food now and for future generations; shock‐proof, to provide resilience to shocks in production systems and supply chains; and sound, to meet legal and ethical standards for welfare of animals, people and environment. Here, we present an integrated assessment of these elements of the aquatic food system in the United Kingdom, a system linked to dynamic global networks of producers, processors and markets. Our assessment addresses sufficiency of supply from aquaculture, fisheries and trade; safety of supply given biological, chemical and radiation hazards; social, economic and environmental sustainability of production systems and supply chains; system resilience to social, economic and environmental shocks; welfare of fish, people and environment; and the authenticity of food. Conventionally, these aspects of the food system are not assessed collectively, so information supporting our assessment is widely dispersed. Our assessment reveals trade‐offs and challenges in the food system that are easily overlooked in sectoral analyses of fisheries, aquaculture, health, medicine, human and fish welfare, safety and environment. We highlight potential benefits of an integrated, systematic and ongoing process to assess security of the aquatic food system and to predict impacts of social, economic and environmental change on food supply and demand. 相似文献
992.
Taylor Alan H. Airey-Lauvaux Catherine Estes Becky Harris Lucas Skinner Carl N. 《Landscape Ecology》2020,35(12):2777-2790
Landscape Ecology - Spatial patterns of fire severity are influenced by fire-vegetation patch dynamics and topography. Since the late nineteenth century, fire exclusion has increased fuels and... 相似文献
993.
Thiago M. Costa Alice K. Inoue-Nagata Andreza H. Vidal Simone da G. Ribeiro Tatsuya Nagata 《Plant pathology》2020,69(6):1042-1050
The severe yellowing disease (amarelão) on melon plants is a serious problem in Brazil, although the causative agent remained unknown for a long time. Recently, recombinant isolates of cucurbit aphid-borne yellows virus (CABYV) were reported as the possible causative agents of this disease on melon plants. Although aphids are known to be the vectors of the common type of CABYV isolates, almost no aphid colony was observed in the major melon fields in Brazil with high incidence of the severe yellowing disease. In contrast, whiteflies are often abundant. Based on this observation, the hypothesis of the transmission of recombinant CABYV by whiteflies was evaluated. After thorough transmission experiments, we found that this recombinant CABYV isolate was transmitted by the whitefly Bemisia tabaci MEAM1, but not by Aphis gossipii. Furthermore, the host response by whitefly-based inoculation in cucurbits and other indicator plants showed differences in host range when compared to the common type of CABYV. Due to its transmissibility by the whitefly and the distant relationship of the P3/P5 protein to CABYV, the name “cucurbit whitefly-borne yellows virus” is proposed for this recombinant CABYV. This is the second report of polerovirus transmission by the whitefly B. tabaci, following the report of pepper whitefly-borne vein yellows virus. 相似文献
994.
995.
996.
997.
Tatiana Salerno Márcio Garcia Ribeiro Amanda Keller Siqueira Priscilla Anne Melville Aline Artioli Machado Yamamura Aristeu Vieira da Silva 《Research in veterinary science》2010,88(2):211-287
Prototheca zopfii has been considered one of the most important causes of environmental mastitis in Brazil. These algae are refractory to conventional therapy and cause great damage to the mammary gland. The present study evaluated the in vitro algaecide effect of sodium hypochlorite and iodine based antiseptics on 27 P. zopfii strains isolated from the milk of cattle. Low concentrations of sodium hypochlorite (0.0390625-0.15625%) and iodine (0.15625-0.625%) were effective against the isolates. These antiseptics may be recommended for hygiene routines, pre and postdipping and cauterization of bovine mammary glands infected by P. zopfii. 相似文献
998.
Gosmann G Barlette AG Dhamer T Arçari DP Santos JC de Camargo ER Acedo S Gambero A Gnoatto SC Ribeiro ML 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(2):156-161
Leaves of Ilex paraguariensis are used to prepare a tea known as maté which is a common beverage in several South American countries. The ethanol extract was fractionated to identify the compounds responsible for the anti-adipogenic activity in 3T3-L1 cells. Extracts of both fresh and dried maté leaves were subjected to column chromatography using molecular permeation to obtain the saponin (20?% yields) and the polyphenol extracts (40?% yields) from the fresh and dried leaves. The phenolic content was determined using high-performance liquid chromatography analysis and the Folin-Ciocalteau method. Also, maté extracts (50?μg/ml to 1,000?μg/ml) did not display citotoxicity using MTT. The polyphenol extract from the dried leaves was the most effective (50?μg/ml) in the inhibition of triglyceride accumulation in 3T3-L1 adipocytes, and rutin (100?μg/ml) likely accounted for a large portion of this activity. Additionally, maté extracts had a modulatory effect on the expression of genes related to the adipogenesis as PPARγ2, leptin, TNF-α and C/EBPα. 相似文献
999.
Amanda J. Souza Patrícia O. Santos Marcio S.T. Pinto Tierry T. WermelingerElane S. Ribeiro Simone C. SouzaMariana F. Deus Maria C. SouzaJosé Xavier-Filho Kátia V.S. FernandesAntonia Elenir A. Oliveira 《Crop Protection》2011,30(6):651-657
The seed coat is the first host or non-host tissue contacted by bruchids, suggesting its participation in the evolutionary adaptation of bruchids to favor legume seeds. In the present work, we studied the influence of seed coat on the ability of Callosobruchus maculatus (Coleoptera: Bruchidae F.) larvae to penetrate, develop in and survive on seeds. Our results showed that the oviposition, larval eclosion and adult emergence of C. maculatus were drastically reduced in some seeds and that the time necessary for the surviving larvae to perforate the seed coat increased by up to 100% in these seeds. The surviving larvae that crossed the Phaseolus vulgaris (Leguminosae B.) seed coat reached only 55.6% of the mass of a normal larva. The seed coat of some seeds was very toxic to insect larval development. Despite individual variations, seed coats were generally highly restrictive to the development and survival of the bruchid. The study of the seed coat efficiency as a protection tissue against penetration of insects can provide an important tool for new strategies for crop protection. The strengthening of the seed coat defense mechanisms may represent an efficient strategy because the seed chemical defense barrier would be moved to the outer structures and damage to the embryo would be minimized or avoided. 相似文献
1000.