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51.
While natural resource exploration and extraction activity is expanding in the Neotropics, our understanding of wildlife response to such activity is almost non‐existent. Primates, which fulfill important ecological roles and face numerous anthropogenic threats, are of particular concern. We studied primate group distribution before, during, and after natural gas pipeline construction in the Peruvian Amazon to investigate whether primates spatially avoid areas of disturbance. We monitored primates on eight transects 20 times per annual sampling period in three consecutive years and analyzed changes in group observations relative to the pipeline right‐of‐way in a multi‐season occupancy modeling framework. Overall primate group encounter rates were low (<half) compared to a nearby protected area. Contrary to expectations, we did not see clear evidence of spatial avoidance of the pipeline area. Although higher overall encounter rates before construction suggested lower primate use of the area during and following construction, this pattern could not be confirmed statistically, and probability of colonization and extinction of transect sections in the occupancy analysis could not be differentiated from zero. These results are probably attributable to a combination of low numbers of primate encounters and high spatial variability in primate use of different transects. This study provides valuable preliminary data and a methodological framework for understanding the response of an ecologically important group of mammals to anthropogenic activity. We encourage other researchers to continue exploring the impacts of natural resource exploration‐ and extraction‐related activities in the tropics, as such activities are likely to have a growing effect on ecosystems.  相似文献   
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尽管国内外对养殖污水处理已提出了一系列的工艺技术,但因经济原因养殖污水直接灌溉农田在我国农村地区仍较为常见.为了解长期畜禽养殖污水直灌对稻田土壤质量的影响,在浙江省绍兴市柯桥区选择了养殖污水直灌不同年限(0、4、7、13年)的稻田,比较研究了养殖污水直接灌溉对稻田土壤不同深度土层中各形态氮和磷含量的影响,探讨了长期养殖污水灌溉对氮、磷在土壤剖面中垂直迁移的影响.结果表明: 长期养殖污水直接灌溉可显著提高稻田土壤中氮和磷的积累,积累量随灌溉年限的增长而增加,其中磷素的增幅高于氮素.养殖污水灌溉4、7和13年后,土壤表层中全P和全N分别比对照增加了43.6%、95.2%、1484%和7.7%、17.0%、28.4%.土壤氮素的变化为NH4+-N、NO3--N>酸解有机氮>非酸解有机氮;土壤有效磷的变化明显大于全磷.长期养殖污水灌溉可促进氮、磷在土壤剖面中的垂直迁移,增加对地下水的污染风险.
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基于生态经济分区的土壤质量及其变化与农户行为分析   总被引:17,自引:1,他引:16  
通过1980年土壤普查数据和1999~2000年土壤质量调查和地下水调查数据进行对比和空间计算,看出土壤质量变化在空间上存在较大的空间变异性;在综合自然、社会经济信息,对曲周县进行的生态经济综合分区基础上进行农户调查,对各分区土壤质量状况及其变化以及不同分区之间农户行为差异的分析表明:农户主要通过种植行为选择和经营投人和资源利用等行为对土壤质量和环境产生影响。不同类型农户在种植行为选择和经营投入上有较大差别.  相似文献   
56.
三种回归分析方法在Hyperion影像LAI反演中的比较   总被引:2,自引:0,他引:2  
孙华  鞠洪波  张怀清  林辉  凌成星 《生态学报》2012,32(24):7781-7790
借助GPS进行地面精确定位,利用LAI-2000冠层分析仅在攸县黄丰桥林场开展130个样地(60m×60m)的叶面积指数(Leaf Area Index,LAI)测量.采用FLAASH模块对Hyperion数据进行大气校正并与地面同步冠层观测数据进行拟合,通过研究地面实测LAI与Hyperion影像波段及其衍生的系列植被指数(NDVI、RVI等)的相关性,筛选出估算叶面积指数的植被指数因子.应用曲线估计、逐步回归及偏最小二乘三种回归分析技术分别建立叶面积指数的最优估算模型.结果表明:参与建模的因子中,比值植被指数(RVI)与LAI的相关性最大,敏感性最高,其次是SARVI0.1,NDVI705,NDVI,SARVI0.1,SARVI0.25;曲线估计、逐步回归分析和偏最小二乘回归三种分析方法所建的6个回归模型中,偏最小二乘回归的拟合效果最好,预测值与实测值的决定系数R2为0.84、曲线估计的拟合效果最低,预测值与实测值的决定系数R2为0.64;建模精度分析表明,选用5-6个自变量因子进行LAI建模是可靠的,以6个植被因子建立的偏最小二乘回归模型预测精度最高.  相似文献   
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Although it is clear that the farmlands neighbouring fragmented forests are utilized by some forest birds, it is not clear how birds in general respond to farmland habitat mosaic. An effort was made to determine how bird density and foraging assemblages were influenced by farm structural characteristics and distance from forest edge. Thirty farms up to a distance of 12 km around Kakamega forest in western Kenya were studied. Farm structure entailed size, hedge volume, habitat heterogeneity, woody plant density, plant diversity and crop cover. Birds were surveyed using line transects and DISTANCE analyses and classified into six feeding guilds and three habitat associations. Size of farms increased away from the forest, as woody plant density, plant diversity, indigenous trees and subsistence crop cover declined. The most important farm structure variable was hedge volume, which enhanced bird species richness, richness of shrub‐land bird species and insectivorous bird density (R = 0.58, P < 0.01). Bird density increased with tree density while indigenous trees were suitable for insectivores and nectarivores. There were very few forest bird encounters. Agricultural practices incorporating maintenance of hedges and sound selection of agroforestry trees can enhance conservation of birds on farmland, though, not significantly for forest species.  相似文献   
58.
Summary In the fragmented agricultural landscapes of temperate southern Australia, broad‐scale revegetation is underway to address multiple natural resource management issues. In particular, commercially‐driven fodder shrub plantings are increasingly being established on non‐saline land to fill the summer‐autumn feed gap in grazing systems. Little is known of the contribution that these and other planted woody perennial systems make to biodiversity conservation in multifunctional landscapes. In order to address this knowledge gap, a study was conducted in the southern Murray Mallee region of South Australia. Selected ecological indicators, including plant and bird communities, were sampled in spring 2008 and autumn 2009 in five planted saltbush sites and nearby areas of remnant vegetation and improved pasture. In general, remnant vegetation sites had higher biodiversity values than saltbush and pasture sites. Saltbush sites contained a diverse range of plants and birds, including a number of threatened bird species not found in adjacent pasture sites. Plant and bird communities showed significant variation across saltbush, pasture and remnant treatments and significant differences between seasons. This study demonstrates that saltbush plantings can provide at least partial habitat for some native biota within a highly modified agricultural landscape. Further research is being conducted on the way in which biota, such as birds, use available resources in these dynamic ecosystems. An examination of the effects of grazing on biodiversity in saltbush would improve the ability of landholders and regional natural resource management agencies in making informed land management decisions.  相似文献   
59.
Liquid and gaseous fuels from biotechnology: challenge and opportunities   总被引:3,自引:0,他引:3  
Abstract: This paper presents challenging opportunities for production of liquid and gaseous fuels by biotechnology. From the liquid fuels, ethyl alcohol production has been widely researched and implemented. The major obstacle for large scale production of ethanol for fuel is the cost, whereby the substrate represents one of the major cost components. Various scenarios will be presented for a critical assessment of cost distribution for production of ethanol from various substrates by conventional and high rate processes. The paper also focuses on recent advances in the research and application of biotechnological processes and methods for the production of liquid transportation fuels other than ethanol (other oxygenates; diesel fuel extenders and substitutes), as well as gaseous fuels (biogas, methane, reformed syngas). Potential uses of these biofuels are described, along with environmental concerns which accompany them. Emphasis is also put on microalgal lipids as diesel substitute and biogas/methane as a renewable alternative to natural gas. The capturing and use of landfill gases is also mentioned, as well as microbial coal liquefaction. Described is also the construction and performance of microbial fuel cells for the direct high-efficiency conversion of chemical fuel energy to electricity. Bacterial carbon dioxide recovery is briefly dealt with as an environmental issue associated with the use of fossil energy.  相似文献   
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[目的] 农用地膜主要成分为聚乙烯(polyethylene,PE),因其难以被降解,其废弃物常造成“白色污染”,本研究从常年覆盖农用地膜的土壤中筛选PE降解菌,并探究其对PE制品的降解效能。[方法] 采集的土壤样品用PE为唯一碳源的无机盐培养基进行富集,筛选、纯化PE降解菌,分离菌通过形态染色、生理生化特征、16S rRNA基因序列分析进行鉴定,检测其在不同PE浓度(0%、0.05%、0.10%、0.25%、0.50%、1.00%、2.00%、3.00%)的无机盐培养基中的生长曲线,最后通过扫描电镜、光镜观察,检测分离菌对农用地膜的降解效能。[结果] 从土壤中筛选获得一株能够降解PE的分离菌株(命名为SW1),初步鉴定其为放线菌的诺卡氏菌属Nocardia sp.。SW1的生长对PE具有明显浓度依赖,在含2% PE的无机盐培养基中生长最快,在培养的第48 h菌液浓度开始明显增加,第60 h达到最大,而在不含PE的无机盐培养基中未见生长。形态生理学观察表明,35℃培养15 d后,扫描电镜观察可见有大量菌嵌入膜内或附于膜表面生长,膜表面粗糙,并开始出现破损;培养60 d后,光镜观察可见膜大面积破损,并出现空洞。[结论] 从土壤中筛选获得了一株能够有效降解PE制品的放线菌菌株Nocardia sp. SW1。该研究丰富了PE制品降解微生物的菌种资源,为PE塑料废弃物的生物降解提供了科学数据与参考。  相似文献   
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