首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   34469篇
  免费   398篇
  国内免费   30篇
教育   25404篇
科学研究   3214篇
各国文化   207篇
体育   2096篇
综合类   34篇
文化理论   576篇
信息传播   3366篇
  2022年   135篇
  2021年   231篇
  2020年   373篇
  2019年   510篇
  2018年   2796篇
  2017年   2792篇
  2016年   2255篇
  2015年   552篇
  2014年   697篇
  2013年   4446篇
  2012年   794篇
  2011年   1376篇
  2010年   1331篇
  2009年   892篇
  2008年   1169篇
  2007年   1658篇
  2006年   519篇
  2005年   779篇
  2004年   834篇
  2003年   695篇
  2002年   520篇
  2001年   436篇
  2000年   431篇
  1999年   416篇
  1998年   222篇
  1997年   261篇
  1996年   263篇
  1995年   227篇
  1994年   223篇
  1993年   205篇
  1992年   312篇
  1991年   317篇
  1990年   341篇
  1989年   327篇
  1988年   302篇
  1987年   253篇
  1986年   263篇
  1985年   336篇
  1984年   278篇
  1983年   263篇
  1982年   206篇
  1981年   214篇
  1980年   188篇
  1979年   247篇
  1978年   222篇
  1977年   199篇
  1976年   166篇
  1975年   136篇
  1974年   122篇
  1973年   156篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
961.
The present study examined the role of verbal working memory (memory span and tongue-twister), two-character Chinese pseudoword reading (two tasks), rapid automatized naming (RAN) (letters and numbers), and phonological segmentation (deletion of rimes and onsets) in inferential text comprehension in Chinese in 31 less competent comprehenders compared with 37 reading comprehension control students and 23 chronological age controls. It was hypothesized that the target students would perform poorly on these cognitive and linguistic tasks as compared with their controls. Furthermore, verbal working memory and pseudoword reading would explain a considerable amount of individual variation in Chinese text comprehension. RAN would have a nonsignificant role in text comprehension. Structural equation analyses and hierarchical multiple regression analyses generally upheld these hypotheses. Our findings support current literature of the role of verbal working memory in reading comprehension found in English. The results, however, suggest differential role of the constructs and the tasks in reading comprehension and provide some answers for comprehension impairment in Chinese students.  相似文献   
962.
Phonological awareness, phonological memory, and phonological access to lexical storage play important roles in acquiring literacy. We examined the convergent, discriminant, and predictive validity of these phonological processing abilities (PPA) in 389 3-, 4-, and 5-year-old children. Confirmatory factor analysis supported the validity of each PPA as separate from general cognitive ability and separate from each other. Multigroup structural equation modeling (SEM) with mean structure demonstrated that older preschoolers have better developed latent PPA than younger preschoolers but that the structure of PPA is equivalent. RAN was found uniquely associated with letter knowledge and text discrimination in younger preschoolers, and PA was found uniquely associated with word reading skills in older preschoolers. Finally, general cognitive ability was only indirectly associated with emergent literacy via PPA. These results highlight the importance of PPA in the early literacy development of English-speaking preschool children.  相似文献   
963.
We summarize a conference on scientific inquiry bringing together science educators, cognitive scientists and philosophers of science with three goals:
1.  to establish how much consensus exists about scientific inquiry,
2.  to discuss implications of that consensus for teaching science,
3.  to identify areas where consensus is lacking to establish where further research and discussion would be most valuable.
This research was supported by NSF grant ESIE #0343196 awarded to the authors. The opinions expressed in this article are those of the authors and do not necessarily reflect the views of the National Science Foundation. Paper presented at the International History and Philosophy of Science and Science Teaching Group meeting in Leeds, England July 15–18, 2005.  相似文献   
964.
Gödel’s proof     
In 1931, the great Austrian mathematician Kurt Gödel proved “all consistent axiomatic formulations of number theory include undecidable propositions”. This discovery of Gödel and its proof had enormous repercussions in mathematics and computer science. The proof hinged upon the writing of a self-referential mathematical statement, in the same way as the liar’s paradox — I am lying — is a self-referential statement. In this three-part article, we describe Gödel’s discovery and his famous proof.  相似文献   
965.
OBJECTIVE: Children's Advocacy Centers (CACs) aim to improve child forensic interviewing following allegations of child abuse by coordinating multiple investigations, providing child-friendly interviewing locations, and limiting redundant interviewing. This analysis presents one of the first rigorous evaluations of CACs' implementation of these methods. METHODS: This analysis is part of a quasi-experimental study, the Multi-Site Evaluation of Children's Advocacy Centers, which evaluated four CACs relative to within-state non-CAC comparison communities. Case abstractors collected data on investigation methods in 1,069 child sexual abuse cases with forensic interviews by reviewing case records from multiple agencies. RESULTS: CAC cases were more likely than comparison cases to feature police involvement in CPS cases (41% vs. 15%), multidisciplinary team (MDT) interviews (28% vs. 6%), case reviews (56% vs. 7%), joint police/child protective services (CPS) investigations (81% vs. 52%) and video/audiotaping of interviews (52% vs. 17%, all these comparisons p<.001). CACs varied in which coordination methods they used, and some comparison communities also used certain coordination methods more than the CAC with which they were paired. Eighty-five percent of CAC interviews took place in child-friendly CAC facilities, while notable proportions of comparison interviews took place at CPS offices (22%), police facilities (18%), home (16%), or school (19%). Ninety-five percent of children had no more than two forensic interviews, and CAC and comparison differences on number of interviews were mostly non-significant. CONCLUSIONS: Relative to the comparison communities, these CACs appear to have increased coordination on investigations and child forensic interviewing. The CAC setting was the location for the vast majority of CAC child interviews, while comparison communities often used settings that many consider undesirable. CACs showed no advantage on reducing the number of forensic interviews, which was consistently small across the sample.  相似文献   
966.
A.  J.  Dalton 《英语沙龙》2011,(2):18-19
  相似文献   
967.
A.  J.  Dalton 《英语沙龙》2011,(3):46-47
  相似文献   
968.
969.
In this paper, a novel reconstruction technique based on level set method and algebraic reconstruction technique is proposed for multiphase flow computed tomography (CT) system. The curvature-driven noise reduction method is inserted into the conventional iteration procedure of algebraic reconstruction technique to improve the image quality and convergence speed with limited projection data. By evolving the image as a set of iso-intensity contours after each updation, the sufficient number of iterations for acceptable results is reduced by 80%-90%, while the image quality is enhanced obviously. Quantitative evaluation of image quality is given by using both relative image error and correlation coefficient. The resultant images can be utilized to detect flow regimes for monitoring industrial multiphase flow. Laboratory results demonstrate the feasibility of the proposed method. Phantoms of four typical flow regimes can be reconstructed from few-view projection data efficiently, and the corresponding image errors and correlation coefficients are acceptable for the cases tested in this paper.  相似文献   
970.
Considering the uncertainty of material performance, geometric characteristic and analysis method, the analysis of statistical parameters of the resistance of cast ball-and-socket support joints and the reliability analysis are carried out by JC method (improved first-order second-moment method) based on the relevant experimental data. Results show that the resistance partial factor of the joint increases with the increase of the reliability index. The resistance partial factors are suggested corresponding to the reliability index under different load combinations. Moreover, the suggested resistance partial factor is adopted in reliability design, and it is found that the reliability index of the joint is larger than the target reliability index. The optimal load combination is the one in which live load plays an important control role. Finally, based on the suggested resistance partial factors, the reliability analysis of cast ball-and-socket support joints of a project is conducted.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号