全文获取类型
| 收费全文 | 102篇 |
| 免费 | 1篇 |
专业分类
| 教育 | 43篇 |
| 科学研究 | 37篇 |
| 体育 | 9篇 |
| 综合类 | 1篇 |
| 信息传播 | 13篇 |
出版年
| 2023年 | 1篇 |
| 2020年 | 3篇 |
| 2019年 | 2篇 |
| 2018年 | 1篇 |
| 2017年 | 1篇 |
| 2015年 | 1篇 |
| 2014年 | 2篇 |
| 2013年 | 1篇 |
| 2012年 | 7篇 |
| 2011年 | 16篇 |
| 2010年 | 9篇 |
| 2009年 | 11篇 |
| 2008年 | 6篇 |
| 2007年 | 2篇 |
| 2006年 | 4篇 |
| 2005年 | 8篇 |
| 2004年 | 5篇 |
| 2003年 | 2篇 |
| 2001年 | 2篇 |
| 2000年 | 3篇 |
| 1999年 | 3篇 |
| 1997年 | 1篇 |
| 1994年 | 1篇 |
| 1993年 | 4篇 |
| 1992年 | 1篇 |
| 1990年 | 1篇 |
| 1989年 | 3篇 |
| 1984年 | 1篇 |
| 1978年 | 1篇 |
排序方式： 共有103条查询结果，搜索用时 31 毫秒
91.
We present an image retrieval framework based on automatic query expansion in a concept feature space by generalizing the vector space model of information retrieval. In this framework, images are represented by vectors of weighted concepts similar to the keyword-based representation used in text retrieval. To generate the concept vocabularies, a statistical model is built by utilizing Support Vector Machine (SVM)-based classification techniques. The images are represented as "bag of concepts" that comprise perceptually and/or semantically distinguishable color and texture patches from local image regions in a multi-dimensional feature space. To explore the correlation between the concepts and overcome the assumption of feature independence in this model, we propose query expansion techniques in the image domain from a new perspective based on both local and global analysis. For the local analysis, the correlations between the concepts based on the co-occurrence pattern, and the metrical constraints based on the neighborhood proximity between the concepts in encoded images, are analyzed by considering local feedback information. We also analyze the concept similarities in the collection as a whole in the form of a similarity thesaurus and propose an efficient query expansion based on the global analysis. The experimental results on a photographic collection of natural scenes and a biomedical database of different imaging modalities demonstrate the effectiveness of the proposed framework in terms of precision and recall. 相似文献
92.
93.
Phytate： impact on environment and human nutrition. A challenge for molecular breeding 总被引：6，自引：0，他引：6
Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus
and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic
cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates
in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo
(maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol
and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair,
signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral
composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases
isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes
of phytases are compared, and the application of phytase in food and feed is discussed.
Project supported by the Danish Agency for Science, Technology and Innovation, Copenhagen, Denmark and HarvestPlus 相似文献
94.
长期以来学术界传统观点认为文学思维和科学思维属于两个截然不同的范畴,科学就是理性逻辑,而文学则等同于感性形象,两者谈不上有任何本质联系。从文学思维与科学思维在某种程度上整合统一的可能性出发,在阐明文学思维和科学思维本质特征的同时揭示它们在思维结构上的共通性——两者都是线性思维与非线性思维的迭加。 相似文献
95.
Brahmi FA London SK Emmett TW Barclay AR Kaneshiro KN 《Medical reference services quarterly》1999,18(2):1-11
For more than twenty years, the Ruth Lilly Medical Library has been a traditional part of the Indiana University School of Medicine curriculum. Recently, following changes to the curriculum, the Library's role has evolved to include responsibility for developing and teaching a Medical Informatics rotation as part of the senior year clerkships. Heavy emphasis is placed on acquiring life-long learning skills, especially on locating and critically appraising the best clinical evidence in the medical literature. In its first four months, the rotation has been quite favorably received by both students and faculty, but will continue changing to keep pace with future curriculum alterations and new technology. 相似文献
96.
97.
去游乐场玩过碰碰车吗?我想大多数同学有过这样愉快又刺激的经历,但是,碰碰船可不是轻易就能玩到了吧!不要着急,今天,咱们就来制作一个小型碰碰船,只用一支蜡烛就能让你体验到蒸汽机的伟大力量! 相似文献
100.