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安徽省及其邻区航磁异常特征与地震活动性 总被引:2,自引:0,他引:2
本文首先对应用区域磁测资料进行地震蕴震层研究的可能性作了分析。以安徽省及其邻区为例,讨论了深部磁结构与地震活动性的关系。不同层次的磁异常特征,反映出本地区存在着东西向的隆坳块体和近南北向的窄长深坳陷带。前者为长期地质发展过程中形成的物性条带或边缘构造带;后者则为中新生代构造运动活跃的构造带,两者对本区的地震活动性有明显影响。 相似文献
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水平梯度法提取重磁源边界位置 总被引:11,自引:0,他引:11
本文介绍了一种用水平梯度极大值确定密度和磁性体边界的方法,并由计算机自动搜索成图。可广泛用于区域重磁异常的构造解释之中。 相似文献
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对中国大陆科学钻探孔区——江苏省东海县毛北地区的55块榴辉岩样品进行了古地磁研究,并从中抽样测试了等温剩磁、磁滞迴线、磁组构、热磁化率以及电子探针和镜下分析,结果表明,毛北榴辉岩有两组稳定的剩磁,即反向磁化和正向磁化,稳定剩磁方向分别为:D=94.3°,I=-29.1°和D=273.7°,I=15.4°,携带正向磁化与携带反向磁化样品的磁化强度和密度变化很大;毛北榴辉岩的磁各向异性度非常弱,最小轴方向很难确定;等温剩磁和磁滞迴线显示磁铁矿可能是毛北榴辉岩的主要载磁矿物,且在以Mr/Ms和Hcr/Hc的对数为纵、横坐标的图上落在视单畴(PSD)区域.根据磁性特征,对毛北榴辉岩的磁性载体成因、剩磁获得机制及构造意义进行了讨论. 相似文献
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Biomarkers are generally applied to detect pollution in environmental monitoring. Such biological responses should accurately reflect the stress over time in a quantitative manner. As such, the initial and maximum responses induced by stress, as well as adaptation and recovery of these biomarkers, need to be fully understood or else erroneous false-negative or false-positive may be arrived. However, most of the biomarker studies only provided information on initially induced responses under different concentrations of toxicants, while biological adaptation and recovery were poorly known. In this study, the time required for induction, adaptation and recovery of lysosomal integrity in green-lipped mussel Perna viridis upon exposure to benzo[a]pyrene was investigated over a period of 62 days. Maximum induction occurred on day 6 when lysosomal integrity was significantly reduced by 51%, and no further change or adaptation was detected thereafter. When mussels were depurated in clean seawater after 18 days of exposure to benzo[a]pyrene, a gradual recovery was observed, with lysosomal integrity returning to its background level and showing a complete recovery after 20 days of depuration. Lysosomal integrity was significantly correlated with the body burden concentrations of benzo[a]pyrene and condition index of the mussels. The relatively fast induction (6 days) and recovery (20 days) without apparent adaptation suggested that lysosomal integrity in P. viridis can serve as a good biomarker in biomonitoring, as its response is not likely to generate both false-negative and false-positive results. 相似文献
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Lysosomal integrity in mussels has been applied as a biomarker to detect the pollution of trace organics and metals in the natural environments. However, few studies have examined the effects of water quality on the response of lysosomal integrity, in particular total ammonia-nitrogen (TAN) and dissolved oxygen (DO). This study demonstrated that high level of TAN (2.0 mg/l) and low DO (2.5 mg O2/l) could significantly reduce the lysosomal integrity in green-lipped mussel Perna viridis, respectively by 33% and 38%, whereas the mussel lysosomal integrity decreased by 70% in the combined treatment of TAN and low DO under laboratory conditions after one week. The mussel lysosomal integrity of all treatment groups could return to the control level after a three week recovery period. In the field validation in Victoria Harbour, Hong Kong during an one-year study period, lysosomal integrity in P. viridis identified the cleanest site east to the harbour, where the lowest TAN and highest DO concentrations were found. While lysosomal integrity in mussels seemed not affected by seasonal changes, approximately 40% of the variation of this biomarker could be attributable to the changes in TAN and DO in seawater. In conclusion, the response of the mussel lysosomal integrity can be confounded by both TAN and DO prevailing in the natural environments and thus caution must be exercised in relating the observed changes in lysosomal integrity to any specific pollutant in coastal water quality monitoring studies. 相似文献
89.
Tjeerdema RS 《Marine pollution bulletin》2008,57(6-12):275-279
Nuclear magnetic resonance spectroscopy (NMR) has been employed over many years for the elucidation of chemical structures. However, in more recent years it has been used to characterize sublethal actions of pollutants in aquatic organisms. For instance, in vivo NMR involves live, intact organisms or cell cultures and the application of chemical stressors to reveal toxic mechanisms in real time. Alternatively, NMR-based metabolomics involves rapid cessation of metabolic activity following chemical exposure (via liquid N(2)) to provide an assessment of metabolic actions via more traditional NMR analysis. Two examples are briefly presented to exemplify the power of NMR for assessing toxic actions in marine and freshwater organisms. 相似文献
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