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71.
长江口及邻近水域渔业环境质量的现状及变化趋势研究 总被引:10,自引:8,他引:10
本文根据2000~2002年6个航次的调查资料,对长江口及邻近水域的渔业环境质量进行全面研究及变动趋势分析。研究结果表明,长江口及邻近水域营养盐含量十分丰富,约90%无机氮是以硝酸盐形态存在。该水域主要受营养盐、重金属及有机物的污染。其中杭州湾水域受污染程度最为严重。长江口及邻近水域浮游植物初级生产主要受磷营养盐的限制。总的来说,长江口及邻近水域渔业环境质量正呈逐步下降趋势。 相似文献
72.
Adam-Berret M Boulard M Riaublanc A Mariette F 《Journal of agricultural and food chemistry》2011,59(5):1767-1773
Model systems composed of tristearin in solid state and tricaprin in liquid state with different solid-fat content (SFC) and storage time have been investigated by relaxation NMR and NMR diffusometry. The T(2) relaxation of the tricaprin in the melt exhibited a bimodal distribution as previously observed. The SFC had a major effect on the T(2) relaxation. This effect was explained according to the fast diffusive exchange model in porous media. According to this model the changes in T(2) relaxation as a function of the SFC and storage time were explained by the decrease of the surface-to-volume ratio of the crystal induced by Ostwald ripening. The diffusion coefficient D of the tricaprin in the melt decreased for higher SFC. Since no significant variation of D was observed for different diffusion time, D reflected the long-range connectivity and the tortuosity was calculated. During storage the diffusion coefficient remained constant. 相似文献
73.
How does forest certification contribute to boreal biodiversity conservation? Standards and outcomes in Sweden and NW Russia 总被引:2,自引:0,他引:2
Marine Elbakidze Per AngelstamKjell Andersson Mats NordbergYurij Pautov 《Forest Ecology and Management》2011,262(11):1983-1995
Forest Stewardship Council (FSC) is one of the leading forest certification schemes. While many studies concern political aspects and social outcomes of FSC, little is known about the contribution of certification to biodiversity conservation. In Europe, the Russian Federation and Sweden have the largest areas of FSC-certified forest. We assessed the potential of FSC certification for boreal biodiversity conservation in terms of standard content, and outcomes as habitat area set aside and habitat network functionality. First, we compared the biodiversity conservation indicators at different spatial scales in Swedish and Russian FSC standards. Second, focusing on one large state forest management unit in each country, we compared the areas of formally and voluntarily set aside forests for biodiversity conservation. Third, we evaluated the structural habitat connectivity by applying morphological spatial pattern analysis, and potential functional connectivity by using habitat suitability index modelling for virtual species. The Russian standard included indicators for all spatial scales of biodiversity conservation, from tree and stand to landscape and ecoregions. The Swedish standard focused mainly on stand and tree scales. The area of voluntary set-asides for FSC was similar in Sweden and Russia, while formal protection in the Russian case study was three times higher than in the Swedish one. Swedish set-aside core areas were two orders of magnitude smaller, had much lower structural and potential functional connectivity and were located in a fragmented forestland holding. We conclude that to understand the potential of FSC certification for biodiversity conservation both the standard content, and its implementation on the ground, need to be assessed. We discuss the potential of FSC certification for biodiversity conservation with different levels of ambition. We stress the need for developing rapid assessment tools to evaluate outcomes of FSC for biodiversity conservation on the ground, which could be used by forest managers and FSC-auditors toward adaptive governance and management. 相似文献
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Angelstam Per Manton Michael Elbakidze Marine Sijtsma Frans Adamescu Mihai Cristian Avni Noa Beja Pedro Bezak Peter Zyablikova Iryna Cruz Fatima Bretagnolle Vincent Díaz-Delgado Ricardo Ens Bruno Fedoriak Mariia Flaim Giovanna Gingrich Simone Lavi-Neeman Miri Medinets Sergey Melecis Viesturs Muñoz-Rojas Jose Schäckermann Jessica Stocker-Kiss Andrea Setälä Heikki Stryamets Natalie Taka Maija Tallec Gaelle Tappeiner Ulrike Törnblom Johan Yamelynets Taras 《Landscape Ecology》2019,34(7):1461-1484
Landscape Ecology - Place-based transdisciplinary research involves multiple academic disciplines and non-academic actors. Long-Term Socio-Ecological Research (LTSER) platform is one concept with ~... 相似文献
76.
桁拖网渔具刚性栅栏对虾类的分隔性能 总被引:1,自引:0,他引:1
刚性栅栏是实现拖网渔具种类选择性捕捞的主要装置。通过海上生产试验,结合SELECT模型分析不同栅条间距(15mm、20mm和25mm)的刚性栅栏对哈氏仿对虾( Parapenaeopsis hardwickii )和葛氏长臂虾( Palaemon graxieri )的分隔性能:试验结果显示,随着栅条间距的增大,栅栏对虾类的重量分隔率逐渐增大;个体接触分隔栅栏的慨率呵使用常数来表示,即接触慨率与个体尺寸无关;比较不同虾类对分隔栅栏的接触慨率后发现,接触慨率不存在种类间、栅栏间的显著性差异(P〉0.05);个体接触分隔栅栏的概率均大于0.9,说明大多数个体都接触到分隔栅栏,但拒绝全部接触栅栏的假设,这主要与桁拖网结构和分隔栅栏的安装有关;随着栅条间距的增大,栅栏对虾类的50%选择体长(L50)逐渐增大,但选择范围(SR)没有显著差异。 相似文献
77.
大菱鲆hepcidin抗菌肽基因的克隆及在大肠杆菌中的高效表达 总被引:1,自引:0,他引:1
通过同源克隆结合RACE的方法从大菱鲆(Scophthal mus maximus)肝脏中克隆了大菱鲆hepcidin抗菌肽基因全长cDNA(GenBank accession number AY994074)。大菱鲆hepcidin基因cDNA全长778bp,包含有1个273bp的开放阅读框,编码1个长90氨基酸的前体肽。将大菱鲆hepcidin抗菌肽基因的成熟肽序列重组至原核表达载体pGEX-4T-1中,用IPTG诱导后,SDS-PAGE电泳显示在29ku处有特异性蛋白条带出现,表达的融合蛋白主要以包涵体形式存在,融合蛋白约占总蛋白的26%。Western-blotting分析发现表达的融合蛋白可以特异性地与GST抗体相识别。这些结果表明大菱鲆hepcidin抗菌肽基因成功实现了原核表达。 相似文献
78.
智利外海茎柔鱼繁殖生物学初步研究 总被引:1,自引:0,他引:1
对2007年-2009年我国鱿钓船在东南太平洋智利外海生产期间所采集的1 374个茎柔鱼样品性成熟度进行观察,初步研究了其繁殖生物学特性。结果表明:智利外海茎柔鱼为大型群体,常年产卵,无明显的产卵高峰期。渔获物雌雄比例约为2.65∶1。雌、雄个体性腺成熟度差异不明显,其中成熟个体所占比例小,分别占总量的3.9%和6.7%。缠卵腺长和缠卵腺重随着性腺成熟度增加逐步增大,成熟个体性腺指数明显大于未成熟个体。雌、雄个体性腺指数存在差异,雌性个体Ⅳ期性腺指数与胴长成正比,而雄性则成反比。雌性和雄性茎柔鱼的初次性成熟胴长(ML50%)分别为638.3 mm和565.3 mm。 相似文献
79.
浒苔和条浒苔生长及其氨氮吸收动力学特征研究 总被引:4,自引:1,他引:4
研究了浒苔(Enteromorpha prolifera)和条浒苔(Enteromorpha clathrata)在室内条件下的生长及其氨氮吸收动力学特征。结果表明:浒苔和条浒苔藻体体重日生长率分别为17.30%和16.82%;浒苔和条浒苔藻体幼苗在温度25℃和光照140μmol/(m2.s)的条件下达到最大体长日生长率,分别为78.9%和82.1%。在1~10 g/L密度范围内,浒苔和条浒苔对NH4+-N的吸收速率随密度和时间的增加而增加,当藻体密度为10 g/L时,NH4+-N浓度分别下降了86.43%和84.13%。两种浒苔对NH4+-N吸收速率与介质中NH4+-N浓度呈显著的线性关系,在NH4+-N浓度为400μmol/L时,30 min后浒苔和条浒苔的吸收速率分别为421和409μmol/(gDW.h),说明两种浒苔吸收氨氮的方式以被动扩散为主。在400μmol/L的起始浓度下,浒苔和条浒苔对NH4+-N的吸收速率随时间变化呈现3个不同阶段:在75 min内呈快速吸收阶段,75~185 min为内部NH4+-N控制的吸收阶段,250 min后为外界NH4+-N浓度控制的吸收阶段;在700 min后,... 相似文献
80.