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961.
962.
Biodiversity in managed forests depends on management practices that determine the forest structure. The influence of stand structure on centipede diversity was investigated by comparing centipede communities from different forest development phases. Using the quadrat counts method, soil samples were taken thrice during 2000 (in spring, summer and autumn) from a deforested area and three evenly aged beech stands (juvenile, pole and timber phases) in managed beech forests in Slovenia. The characteristics of centipede communities and the similarities among them were estimated. The collection comprised 1150 centipedes representing 32 species. At a single site, 10–24 species were found. The average density was between 22 and 808 individuals per m2. Differences among communities from different sites were found. The highest species number and abundance were found in the juvenile phase and the lowest in the deforested area. The occurrence of species differed among phases, but none of the species found with a high incidence in one development phase was restricted to that phase. The composition of the centipede community was more sensitive to the successional status of the forest than to the season. A comparison with differently structured forest was made, which suggests that homogenisation leads to reduced centipede diversity. To preserve biodiversity and healthy forest functioning, the maintenance of heterogeneity within a forest stand should be an important focus of management operations.  相似文献   
963.
Historical Museology Meets Tropical Biodiversity Conservation   总被引:1,自引:0,他引:1  
The great scientific importance of historical collections is a well-established fact. On the contrary, their value as vehicles to promote public awareness and effective conservation projects in some of the most valuable biodiversity hotspots in the tropics appear to have been greatly overlooked by Natural History Museums and similar institutions. Utilising the vertebrate collections of Italian institutions as a case study, the great potential of these medium-sized museums to popularising and promoting biodiversity in some of the most valuable regions of the world, utilising the history of their collections and of the men which collected and studied them, is emphasised.  相似文献   
964.
This study explores the association of 24 polychaete species with sandy and muddy habitats located in a sub-arctic fjord, and across Atlantic Canada including Labrador, Newfoundland, and the Gulf of St. Lawrence. Key characters used to facilitate species identification are also summarized. Within Bonne Bay, distinctive polychaete assemblages were associated with specific sediment types and polychaete species richness and density were significant both predictors of corresponding total (infaunal) density and species richness. Polychaetes were denser and more diverse in sandy sediments, partly because sandy locales were associated with the outer portion of the bay, and therefore were closer to the more productive and diverse Gulf of St. Lawrence. In general, species that occupied both sediment types were more widely distributed within Bonne Bay and across the region. The biogeography of most species also suggests that the Bonne Bay fauna is transitional between Labrador and Acadian biogeographic provinces.  相似文献   
965.
千岛湖岛屿化对植物多样性的影响初探   总被引:16,自引:3,他引:13  
选取千岛湖典型破碎化区域,研究了水库形成后引起的岛屿化对植物物种多样性的影响.在18个大中小型岛屿和一处陆地对照中设立了26个样方,调查乔木和灌木的种类和数量.乔木物种丰富度的单因素方差分析显示:F=13.0,P=0.000,说明各类岛屿间乔木物种差异极显著.多重比较发现大岛上乔木物种丰富度显著高于小岛和中岛,与对照陆地差别不大;灌木的分析显示:F=1.31,P=0.29,说明小、中、大岛和对照陆地灌木物种丰富度差异不显著.Spearman相关性分析显示乔木物种与岛屿面积显著相关,随岛屿面积增大而增加,而灌木物种相关性不显著.Shannon多样性指数分析表明,无论乔木还是灌木其多样性都是大岛最大,陆地次之,而小岛上灌木多样性指数大于中岛.Simpson优势度和Pielou均匀度分析显示,乔木样地中大岛的物种分布均匀性最好,优势种的优势度最低,而灌木样地中小岛的均匀度最高,优势种的优势度最不明显.  相似文献   
966.
基于空间分析的保护生物学研究   总被引:16,自引:1,他引:16       下载免费PDF全文
 保护生物学家和生态学家早就认识到只有准确地辨识保护对象的空间位置、 范围、 及其相邻的关系(例如边缘)和连接度, 以及依存的地形和气候等生境条件, 才能发现生物种群和生境在空间的扩散与收缩、 增长与灭绝的动态, 揭示分布的格局, 从而系统、 全面地了解保护对象和生境的存在状态、 破碎程度和变化趋势, 进行有效的自然保护。 得益于新兴的空间分析技术, 保护生物学自20世纪90年代以来取得了很大的进步。基于空间分析的保护生物学研究是最近10年左右大力发展的新保护生物学的重要基础。 该文结合作者的研究工作,综述了基于空间分析的保护生物学项目, 探讨了保护生物学发展历史、 主要研究方法与应用、 以及今后的可能发展趋势。 在生物多样性的丰度和分布的空间解绎部分,通过综述世界保护监测中心的图解全球生物多样性的工作, 如国家尺度的生物多样性水平、 植物多样性的分布中心和维管束植物科的多样性等的空间分布 ,介绍了 Dobson等图示美国主要濒危植物、 鸟类、 鱼类和软体动物等4个主要类群在县(County) 为基本空间单位上分布的空间格局, 讨论了生物多样性空间解绎的意义。在第二部分用世界资源研究所的全球森林监测(Global forest watch)项目, 美国的国家保护缺失区分析(GAP analysis)项目, 美国林务局的无路自然区域(Roadless area)保护项目和加拿大自然审计(Nature audit)项目, 以及北美和东亚生物多样性空间分布的比较分析和生物入侵的空间分析等具体实例来说明生物多样性空间分布变化比较分析方法的应用。 过去20年来, 面向空间格局的生态学和保护生物学研究得到了快速的发展, 特别是空间格局的描述、 由地统计演变而成的空间统计、 地理信息系统、 基于个体(或栅格)的空间解绎模拟模型、 基于斑块(Patch)的种群理论及其发展(如复合种群理论, 源 汇模型等)等。在第三部分, 以美国森林破碎度空间格局分析和美国太平洋西北演替后期森林的空间格局分析为例, 介绍了空间格局分析在保护生物学中的应用。 同时介绍了澳大利亚保护生态学家Lindenmayer 和美国著名景观生态学家Franklin 2002年提出的模板(Matrix)保护理论,把保护的眼光不局限在面积不多而且分散的保护区中,应注意景观模板和保护区相邻的原生区域的综合保护, 这样将大大扩展保护的范围, 并且平衡保护与发展的关系。最后, 介绍了在保护生物学中已有一定应用的空间模型和模拟, 包括了空间解绎模型(Spatial explicit model)、 基于过程(Process-based)的空间模拟模型、 面向代理(Agent-based)的空间适应模拟模型(SWAM)以及与此有关的动态全球植被模型(DGVM)。 通过上面的讨论和综述, 预测一个新的保护生物学的分支: 空间保护生物学, 已经逐渐成熟问世, 这门基于现代信息技术和空间技术的新学科已经而且还将为全球生物多样性的研究和保育作出重大的贡献。  相似文献   
967.
Brian Moss 《Hydrobiologia》2007,584(1):381-394
The European Water Framework Directive offers an unprecedented opportunity for improvement of ecological quality of both freshwater and marine systems. It has implications for every aspect of how catchments are used by human societies and could potentially mean a step change in how waters and catchments are managed. It must be implemented, however, by official bodies, which seem likely to apply ecologically outdated approaches, used in the past simply to manage water quality, to tackle the very different problem of improving ecological quality. Ecological quality can be characterised by parsimony of available nutrients, characteristic physical and biological structure, strong connectivity among systems and mechanisms of resilience to cope with normal, natural change. The implications of these are that high quality systems in a given location do not have unique lists of species and single formulae for how the biodiversity is constituted. They have considerable inherent variability whilst preserving their fundamental functional characteristics. This appears not to have been recognised by official bodies that seek simple taxonomic indices as measures of quality. To some extent this is a function of the way the Directive has been written, but a slavish adherence to this approach may undermine the spirit of the Directive and result in a failure to bring about the fundamental reform that is needed.  相似文献   
968.
A single adult Coccinella novemnotata (the nine-spotted lady beetle) was recently discovered by a Cornell University student amongst a series of specimens collected in early October 2006 in Arlington, Virginia. The specimen is the first individual collected in eastern North America in over fourteen years and is only the sixth of its species known to be collected anywhere in North America in the last ten years. This discovery reopens questions regarding the current status of this once common species. Interactions with exotic species, global climate change, and shifting land use patterns have all been postulated as possible factors in this species decline. This discovery is the first in a new program in the USA designed to educate the public regarding biodiversity and conservation and to engage them in a survey of native and exotic lady beetle species.  相似文献   
969.
970.
The epifauna associated with two of the most common species of kelp in the Arctic, Laminaria digitata (Hudson) Lamouroux, 1813 and Saccharina latissima (Linnaeus) Lane, , Mayes, Druehl and Saunders 2006 [synonym: L. saccharina (Linnaeus) Lamouroux, 1813] were examined in Kongsfjorden, Svalbard. The aim of this study was to test whether species richness of epifauna was influenced by seasonality of recruitment supply (spring and summer) or by age of the substrate (lamina). From 20 algae specimens (ten—L. digitata, ten—S. latissima), a total of 27 epifaunal taxa were identified with bryozoans as the most species-rich group. Total species richness ranged from one to nine species per lamina. No significant difference in species richness was observed between the two kelp species. In both macroalgae, more epifauna taxa were registered on lamina in May (mean 6) than in August (mean 3). This indicates that the time chosen for sampling had a significant impact on the species richness pattern. The number of epifaunal species was significantly negatively correlated with increasing age of the lamina. There are indications that diversity of the epifauna on lamina is influenced to a large extent by substrate (lamina) surface area, environmental stress and the presence of meroplankton in the water column.  相似文献   
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