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A new method is described to extract significant phrases in the title and the abstract of scientific or technical documents. The method is based upon a text structure analysis and uses a relatively small dictionary. The dictionary has been constructed based on the knowledge about concepts in the field of science or technology and some lexical knowledge, for significant phrases and their component items may be used in different meanings among the fields. A text analysis approach has been applied to select significant phrases as substantial and semantic information carriers of the contents of the abstract.The results of the experiment for five sets of documents have shown that the significant phrases are effectively extracted in all cases, and the number of them for every document and the processing time is fairly satisfactory. The information representation of the document, partly using the method, is discussed with relation to the construction of the document information retrieval system.  相似文献   
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This meta-analysis was conducted to estimate the magnitude of gender difference in three-dimensional (3-D) mental rotation ability and to investigate how factors related to test administration conditions play a role in varying gender difference effect sizes and threatening validity. Individuals’ 3-D mental rotation ability was measured by the Purdue Spatial Visualization Tests: Visualization of Rotations (PSVT:R). We integrated 70 effect sizes of gender differences in mental rotation ability measured by the PSVT:R which were obtained from 40 primary studies. The results indicated that male participants outperformed females on the test (Hedges’ g?=?0.57). The I 2 statistic indicated 41.7 % of variation in effect sizes reflects real heterogeneity. The moderator analysis indicated that male superiority on spatial ability tasks measured by the PSVT:R is related to the implementation of time limits. The gender difference became larger when stringent time limits (equal or less than 30 s per item) were implemented.  相似文献   
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When a response pattern does not fit a selected measurement model, one may resort to robust ability estimation. Two popular robust methods are biweight and Huber weight. So far, research on these methods has been quite limited. This article proposes the maximum a posteriori biweight (BMAP) and Huber weight (HMAP) estimation methods. These methods use the Bayesian prior distribution to compensate for information lost due to aberrant responses. They may also be more resistant to the detrimental effects of downweighting the nonaberrant responses. The effectiveness of BMAP and HMAP was evaluated through a Monte Carlo simulation. Results show that both methods, especially BMAP, are more effective than the original biweight and Huber weight in correcting mild forms of aberrant behavior.  相似文献   
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Brachial-ankle pulse wave velocity (baPWV) has become a popular modality of arterial stiffness measurement. However, its projected arterial segment does not include the proximal aorta which plays important roles for attenuating cardiac pulsation and reducing afterload. We hypothesised that aerobic capacity would be more strongly associated with PWV including the proximal aorta than that omitting the proximal aorta. To test our hypothesis, we compared the association between aerobic capacity and arterial stiffness parameters omitting vs. including the proximal aorta (i.e. baPWV vs. heart-ankle PWV [haPWV]) in 82 apparently healthy men (18–64 years). Estimated VO2max significantly correlated with baPWV (r?=??0.394, P?<?.001), and more strongly with haPWV (r?=??0.546, P?<?.001). The forward stepwise multi-regression analysis revealed that haPWV (β?=??0.335), as well as age, heart rate, and body mass index (β?=??0.280 to ?0.297), was a significant independent determinant explaining variance of estimated VO2max. These results suggest that aerobic capacity is influenced more strongly by the proximal aortic stiffness than distal aortic stiffness.  相似文献   
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Measures of socioeconomic status (SES) are routinely used in analyses of achievement data to increase statistical power, statistically control for the effects of SES, and enhance causality arguments under the premise that the SES-achievement relationship is moderate to strong. Empirical evidence characterizing the strength of the SES-achievement relationship and its moderators suggests that this relationship is surprisingly modest, with an average SES-achievement correlation of .22, although it appears to have strengthened in the past 3 decades. The modest SES-achievement relationship has important implications for using SES measures in educational data analyses. We provide evidence of this relationship and of the need to use theoretical models to guide the construction and selection of SES measures in analyses of achievement data.  相似文献   
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