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   3175篇
  免费   46篇
  国内免费   9篇
教育   2221篇
科学研究   292篇
各国文化   54篇
体育   234篇
综合类   2篇
文化理论   23篇
信息传播   404篇
  2023年   14篇
  2022年   33篇
  2021年   55篇
  2020年   113篇
  2019年   132篇
  2018年   157篇
  2017年   165篇
  2016年   140篇
  2015年   103篇
  2014年   133篇
  2013年   803篇
  2012年   112篇
  2011年   103篇
  2010年   108篇
  2009年   91篇
  2008年   89篇
  2007年   82篇
  2006年   77篇
  2005年   46篇
  2004年   43篇
  2003年   50篇
  2002年   37篇
  2001年   36篇
  2000年   35篇
  1999年   23篇
  1998年   18篇
  1997年   24篇
  1996年   23篇
  1995年   20篇
  1994年   19篇
  1993年   20篇
  1992年   18篇
  1991年   32篇
  1990年   11篇
  1989年   22篇
  1988年   11篇
  1987年   20篇
  1986年   13篇
  1985年   22篇
  1984年   16篇
  1983年   13篇
  1982年   18篇
  1981年   11篇
  1980年   13篇
  1979年   16篇
  1978年   14篇
  1977年   8篇
  1975年   8篇
  1973年   7篇
  1971年   6篇
排序方式: 共有3230条查询结果,搜索用时 15 毫秒
31.
This cross-cultural study examined continuity in parent-child relationships from infancy to middle childhood in a sample of German families. Connections were traced between individual differences in a composite of markers of the parent-child attachment relationship system (including classification of the infant via the Strange Situation and parent via the Adult Attachment Interview and for mothers' ratings of sensitivity) and later parent-child communications. Fundings within the mother-child relationship revealed modest links between the composite and communications and were taken to suggest that the divergent fields of attachment and family communication research are addressing similar underlying relationship processes involving the interplay between relatedness and autonomy. Further findings revealed that the composite modestly predicted variability in children's competence in forming friendships and that differences in concurrent child-mother communications significantly added to and possibly mediated these effects. Results were interpreted as supporting a process model of development, whereby adaptation is influenced by both current and past relationship status.  相似文献   
32.
Word sense disambiguation (WSD) is meant to assign the most appropriate sense to a polysemous word according to its context. We present a method for automatic WSD using only two resources: a raw text corpus and a machine-readable dictionary (MRD). The system learns the similarity matrix between word pairs from the unlabeled corpus, and it uses the vector representations of sense definitions from MRD, which are derived based on the similarity matrix. In order to disambiguate all occurrences of polysemous words in a sentence, the system separately constructs the acyclic weighted digraph (AWD) for every occurrence of polysemous words in a sentence. The AWD is structured based on consideration of the senses of context words which occur with a target word in a sentence. After building the AWD per each polysemous word, we can search the optimal path of the AWD using the Viterbi algorithm. We assign the most appropriate sense to the target word in sentences with the sense on the optimal path in the AWD. By experiments, our system shows 76.4% accuracy for the semantically ambiguous Korean words.  相似文献   
33.
This paper examines the factors affecting the performance of global query expansion based on term co-occurrence data and suggests a way to maximize the retrieval effectiveness. Major parameters to be optimized through experiments are term similarity measure and the weighting scheme of additional terms. The evaluation of four similarity measures tested in query expansion reveal that mutual information and Yule's Y, which emphasize low frequency terms, achieve better performance than cosine and Jaccard coefficients that have the reverse tendency. In the evaluation of three weighting schemes, similarity weight performs well only with short queries, whereas fixed weights of approximately 0.5 and similarity rank weights were effective with queries of any length. Furthermore, the optimal similarity rank weight achieving the best overall performance seems to be the least affected by test collections and the number of additional terms. For the efficiency of retrieval, the number of additional terms needs not exceed 70 in our test collections, but the optimal number may vary according to the characteristics of the similarity measure employed.  相似文献   
34.
Several methods of detecting the presence of various chemical species are considered. A specific example of atomic hydrogen in lead selenide is examined and used to illustrate some important principles.  相似文献   
35.
Although religiosity promotes resilient outcomes in African American (AA) adolescents, there is a lack of research that examines the protective role of religious development in the context of stressful life events (SLEs). In 1,595 AA adolescents, a cohort-sequential design was used from ages 12 to 18 to examine subtypes of religiosity, as well as distinct developmental patterns within subtypes. The protective role of religious development was also examined in the context of SLEs. The study findings indicated two subtypes of religiosity—extrinsic and intrinsic religiosity—as well as low and high developmental patterns in the identified subtypes. Furthermore, the protective influence of extrinsic and intrinsic religiosity gradually diminished from age 12 to 18 in the context of SLEs.  相似文献   
36.
Many American and European art museums are now featuring small, highly-focused shows in their exhibition programs. In 1990, the Indianapolis Museum of Art organized an exhibition that reunited, for the first time in a century, the four landscape paintings created by neo-impressionist Georges Seurat during the last summer of his life. Using Seurat at Gravelines: The Last Landscapes as an example, this article addresses the advantages — for museums and their visitors — of the small temporary exhibition.  相似文献   
37.
38.
39.
This qualitative, exploratory study examines issues of age and aging surrounding mega-serial (daily soap opera) production in Tamil Nadu, India. This study is timely for demographic reasons (a rapidly aging Indian population) and for the centrality of mega-serials to India’s entertainment landscape, coupled with the genre’s long history of engaging global audiences with real-world social issues. Two data sources are utilized: focus groups with 16 mega-serial viewers and interviews with 25 members of the Tamil mega-serial industry. Situated in scholarship on gerontology/age studies and media/culture industry studies, analysis yields two broad themes related to (a) representations of age/aging and elder-oriented storylines in contemporary Tamil mega-serials and (b) recent industry changes that may forestall mega-serials’ potential to center age and aging as core narrative elements. Overall, evidence points to an industry and audience(s) in considerable transition.  相似文献   
40.
Cartilage injuries are often devastating and most cannot be cured because of the intrinsically low regenerative capacity of cartilage tissues. Although stem-cell therapy has shown enormous potential for cartilage repair, the therapeutic outcome has been restricted by low survival rates and poor chondrocyte differentiation in vivo. Here, we report an injectable hybrid inorganic (IHI) nanoscaffold that facilitates fast assembly, enhances survival and regulates chondrogenic differentiation of stem cells. IHI nanoscaffolds that strongly bind to extracellular matrix (ECM) proteins assemble stem cells through synergistic 3D cell–cell and cell–matrix interactions, creating a favorable physical microenvironment for stem-cell survival and differentiation in vitro and in vivo. Additionally, chondrogenic factors can be loaded into nanoscaffolds with a high capacity, which allows deep, homogenous drug delivery into assembled 3D stem-cell-derived tissues for effective control over the soluble microenvironment of stem cells. The developed IHI nanoscaffolds that assemble with stem cells are injectable. They also scavenge reactive oxygen species and timely biodegrade for proper integration into injured cartilage tissues. Implantation of stem-cell-assembled IHI nanoscaffolds into injured cartilage results in accelerated tissue regeneration and functional recovery. By establishing our IHI nanoscaffold-templated 3D stem-cell assembly method, we provide a promising approach to better overcoming the inhibitory microenvironment associated with cartilage injuries and to advance current stem-cell-based tissue engineering.  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