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1.
Disturbance plays an integral part in generating heterogeneity required for ecosystem persistence, but the increased amplitude and duration of disturbances linked to drivers of global change could result in ecosystem shifts or collapse. Biomonitoring over time provides insights into trajectories of ecosystem change. The responses of two instream animal taxa to two contrasting disturbance events, a major flood event and the long-term cumulative effects of land-use changes, were assessed in 1999–2012 by quantifying variation and change in abundance of functional groups based on flow rate sensitivity, water quality and metrics of ecological condition. All metrics recovered to pre-flood conditions within seven months after the flood event. Similarly, cumulative impacts of land use effected significant decreases in some but not all metrics. Indices that did not change, including SASS total score and ASPT, were the result of insufficient consideration of the decrease in the abundance of sensitive taxa specifically, and the abundance of all taxa in general. The decrease in abundance of sensitive taxa could signal imminent collapse in certain metrics. Evidence is also provided for a shift in the structure of fish assemblages linked to the decrease and loss of taxa sensitive to ecosystem degradation caused by the longer-term impacts of land-use change. 相似文献
2.
目的探索山西省健康人群的肠道菌群组成特征及性别和年龄对肠道菌群组成的影响。方法应用16S rRNA基因测序技术,对山西省99名健康个体的粪便细菌DNA进行测序分析。结果山西省健康人群的肠道菌群在属水平分为两个集群,相对丰度最高的分别是拟杆菌属和普氏菌属;在区分这两个集群中,拟杆菌属与普氏菌属的曲线下面积(AUC)分别是0.97、1.00。男性组与女性组的物种丰富度(richness)和多样性(diversity)差异都无统计学意义(均P>0.05),基于Bray-Curtis距离的主坐标分析(PCoA)图显示两组人群的样本分布没有明显分离(相似性分析:r=-0.0296,P>0.05),LEfSe分析显示与性别分组有关的细菌很少。30-39岁、40-49岁和50-59岁三组人群的物种丰富度和多样性差异都无统计学意义(均P>0.05),基于Bray-Curtis距离的PCoA图显示三组人群的样本分布没有明显分离(相似性分析:r=0.0109,P>0.05),LEfSe分析显示几乎没有与年龄分组有关的细菌。结论山西省健康人群的肠道菌群更倾向分为两种肠型(拟杆菌型和普氏菌型)。性别对肠道菌群组成可能没有显著影响,30-59岁人群的肠道菌群组成比较稳定 相似文献
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近年来,随着观鸟活动和鸟类科研工作在辽宁的持续开展(Baietal.2015,汤姆·滨客2016),辽宁各地不断发现鸟种分布新记录种(白清泉等2019)。2012至2020年间,在丹东、大连、抚顺等市先后发现小鸦鹃(Centropus bengalensis)、雪鹀(Plectrophenax nivalis)、红翅凤头鹃(Clamator coromandus)、宝兴歌鸫(Turdus mupinensis)和黄眉姬鹟(Ficedula narcissina)5种,经查阅相关资料(邱英杰等2006,郑光美2017),确定为辽宁省鸟类分布新记录种。 相似文献
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报道了在辽宁省丹东市白石砬子国家自然保护区采集到的2个辽宁省新记录种,即虫草科(Cordycip-itaceae)的下垂虫草(Cordyceps nutans Pat.)和日本棒束孢(1sariajaponica Yusuda),并描述了其形态特征和生境分布. 相似文献
7.
José María Fernández‐Palacios Lea de Nascimento Rüdiger Otto Juan D. Delgado Eduardo García‐del‐Rey José Ramón Arévalo Robert J. Whittaker 《Journal of Biogeography》2011,38(2):226-246
Macaronesia is a biogeographical region comprising five Atlantic Oceanic archipelagos: the Azores, Madeira, Selvagen (Savage Islands), Canaries and Cape Verde. It has strong affinities with the Atlantic coast of the Iberian Peninsula and the north‐western fringes of Africa. This paper re‐evaluates the biogeographical history and relationships of Macaronesia in the light of geological evidence, which suggests that large and high islands may have been continuously available in the region for very much longer than is indicated by the maximum surface area of the oldest current island (27 Ma) – possibly for as long as 60 million years. We review this literature, attempting a sequential reconstruction of Palaeo‐Macaronesia from 60 Ma to the present. We consider the implications of these geological dynamics for our understanding of the history of colonization of the present islands of Macaronesia. We also evaluate the role of these archipelagos as stepping stones and as both repositories of palaeo‐endemic forms and crucibles of neo‐endemic radiations of plant and animal groups. Our principal focus is on the laurel forest communities, long considered impoverished relicts of the Palaeotropical Tethyan flora. This account is therefore contextualized by reference to the long‐term climatic and biogeographical history of Southern Europe and North Africa and by consideration of the implications of changes in land–sea configuration, climate and ocean circulation for Macaronesian biogeography. We go on to provide a synthesis of the more recent history of Macaronesian forests, which has involved a process of impoverishment of the native elements of the biota that has accelerated since human conquest of the islands. We comment briefly on these processes and on the contemporary status and varied conservation opportunities and threats facing these forests across the Macaronesian biogeographical region. 相似文献
8.
基于组合评价法的湖南省农业可持续发展区域分异 总被引:1,自引:0,他引:1
从农业资源与环境、农业生产与经济、农业人口与社会3个评价维度构建了区域农业可持续发展指标体系, 运用主成分分析法、熵值法、模糊Borda法、因子分析法及聚类分析法和GIS技术, 通过组合评价方法定量研究湖南省农业可持续发展区域分异现状。结果表明: 湖南省农业可持续发展在区域上总体呈现出不平衡的发展状态, 农业可持续发展综合水平以长株潭城市群为核心, 由东至西递减; 农业人口与社会可持续发展水平南北低中部高, 东部强西部弱; 农业生产与经济可持续发展水平围绕湘北洞庭湖农业区和湘南农业综合区向外围递减; 农业资源与环境可持续发展水平表现为一横两纵优势带和南北两个落后圈。 相似文献
9.
灰水足迹是稀释水污染物至达标需要的淡水体积,是评价水污染程度与水环境质量的重要方法,对灰水足迹进行核算与分析,可以促进福建省提高水环境质量,构建可持续的水生态环境。借鉴Hoekstra等提出的灰水足迹核算方法,对福建省及各地市2001-2017年的灰水足迹进行核算,对其时空变化特征进行评价并使用对数平均迪式指数分解法(Logarithmic Mean Divisia Index Method,LMDI)模型对灰水足迹变动的驱动因素进行分解。结果表明:a)总氮是决定灰水足迹总量的主要污染物,非点源污染是灰水足迹的最主要来源但占比由68.25%降至63.35%;b)福建省灰水足迹总量降低了9.58%,且各项指标都呈下降趋势,在空间上,灰水足迹总量及剩余灰水足迹东南多西北少,人均灰水足迹及灰水足迹强度东少西多;c)福建省灰水足迹变动的驱动因素中,经济因素是最大正向驱动因素,产生2932.96亿m3的贡献量,技术因素是最大负向驱动因素,产生-2630.31亿m3的贡献量。最后,针对福建省水污染问题提出建议:a)开展非点源污染防治专项;b)加快速度提高城镇生活污水处理水平;c)优化产业结构,提高灰水足迹效率;d)切实落实生态补偿制度,调动各市水环境保护积极性;e)加强环境监管力度,加大技术投入。 相似文献
10.
Ricardo Villalba 《Biotropica》2011,43(1):41-49
In this study, we use tree‐ring records to determine the climate factors controlling the growth of Centrolobium microchaete, a high‐value timber species from the tropical dry Chiquitano forest in Bolivia. We present the first tree‐ring chronologies from C. microchaete for Concepción and Santa Mónica, Bolivia. Statistical analyses show that the chronologies are of good quality and have a significant common signal between trees. The growth of C. microchaete is strongly influenced by climatic conditions during late spring–early summer. Abundant precipitations concurrent with below‐average temperatures during this period of the year favor tree growth. Climate variations in late spring–early summer explain >40 percent of the total variance in C. microchaete tree growth during the interval 1943–2005. Minor differences in tree responses to climate recorded between the two stands may reflect differences in the extent of the dry season and in soil water capacity between sites. Although the chronologies cover the past 180 yr, adding samples from older individuals would permit the extension of these records further back in time. The strong climate dependency of tree growth suggests that predicted future climate changes in the region could have a significant influence on C. microchaete tree growth during the 21st century. 相似文献