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   20062篇
  免费   276篇
  国内免费   54篇
教育   14705篇
科学研究   1461篇
各国文化   225篇
体育   1498篇
综合类   46篇
文化理论   133篇
信息传播   2324篇
  2021年   210篇
  2020年   297篇
  2019年   450篇
  2018年   608篇
  2017年   638篇
  2016年   577篇
  2015年   382篇
  2014年   559篇
  2013年   4111篇
  2012年   523篇
  2011年   543篇
  2010年   476篇
  2009年   470篇
  2008年   487篇
  2007年   453篇
  2006年   496篇
  2005年   433篇
  2004年   319篇
  2003年   308篇
  2002年   272篇
  2001年   408篇
  2000年   332篇
  1999年   288篇
  1998年   206篇
  1997年   195篇
  1996年   201篇
  1995年   171篇
  1994年   177篇
  1993年   173篇
  1992年   241篇
  1991年   243篇
  1990年   273篇
  1989年   252篇
  1988年   213篇
  1987年   222篇
  1986年   224篇
  1985年   205篇
  1984年   212篇
  1983年   205篇
  1982年   164篇
  1981年   156篇
  1980年   157篇
  1979年   226篇
  1978年   193篇
  1977年   140篇
  1976年   147篇
  1975年   127篇
  1974年   122篇
  1973年   131篇
  1971年   130篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
Rapid advances in technology have provided the potential to connect citizens to their surroundings in unprecedented ways. While many scholars examine different types of efficacy as a predictor of behavior (e.g., internal, external, and political), it is essential to examine how confident citizens feel in their ability to use the technology before understanding how they will use it politically. Research shows that perceived competence increases motivation, which is correlated with behavior. This study examined how traditional measures of efficacy and a new measure affect online political behaviors, concluding that technological efficacy is a reliable construct predicting online news use and expression.  相似文献   
143.
This paper examines the effect of modifiers on the stability of a vinyl acetate/ethylene copolymer dispersion adhesive upon aging. Eighteen common modifiers were added to a well-characterized vinyl acetate/ethylene copolymer dispersion (Dur-O-Set® E-150) in known concentrations and dry-film samples were subjected to 16–17 years of dark aging and seven to eight years of light aging. Yellowing, pH, gloss, swelling, cohesive strength, and flexibility were monitored for changes upon aging. Generally, the neat Dur-O-Set® E-150 (no additives) was found to become acidic on aging, but was fairly resistant to yellowing. It also swelled substantially in toluene, was of high gloss, medium strength, and flexible, and remained so on aging. No modifier was found to improve these properties. Various solvents, wetting agents, and thickeners did not alter the properties by much, while plasticizers, freeze-thaw stabilizer, glycerin, and certain fillers had a more negative effect.  相似文献   
144.
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is quickly becoming a critical tool in the field of art conservation. This technique provides high-resolution spatial maps of both inorganic and organic components located within cross-sectional samples collected from works of art. With recent advances in surface analysis, ToF-SIMS can now be used to identify specific amino acids present in protein-containing materials as well as fatty acids in drying oils. For example, the detection of the ion fragment associated with the amino acid hydroxyproline can be used to confirm the use of animal glue in a paint sample. As an analytical technique, ToF-SIMS avoids the need for derivatization/silylation reagents, with no interference by the presence of pigments. Furthermore, the layered systems that are often encountered in historical paint samples remain intact throughout the analytical procedure. This allows for the co-localization of organic and inorganic species in specific layers (e.g. egg yolk paint atop a glue ground). Because of this ability to localize the analytical signal to approximately 6?µm or less, the mass spectral information can be used to produce mass-resolved and spatially-resolve images which can be correlated to previous studies of the same samples. In this study, ToF-SIMS was used to analyze a paint cross section obtained from a painting attributed to Raphael, and another from a painting by the Sienese artist Matteo di Giovanni.  相似文献   
145.
Public libraries across the country design and deliver programs for military veterans and their families, often collaborating with other organizations and agencies. The examples were assembled from both general and specialized interviews with librarians, and literature and Internet searches, with summaries of programs assembled and written by multiple researchers. The specific limitations on the listing in this article are clearly outlined in the first section. Overall, however, the article provides a good introductory overview of what’s going on in veteran’s programs and services in America’s public libraries in over seventy libraries in forty states. We hope this list of what public libraries have organized or are doing will supply other public librarians with ideas on how to provide new services or enhance their existing ones.  相似文献   
146.
147.
148.
The history of sports literature has enjoyed renewed interest over the last few years, with a noticeable increase in the number of Anglo-Saxon works and the revival of French research. Through fiction, it is possible to understand the processes whereby ideas spread and collective imaginaries are constructed. In this regard, this article revisits the history of rugby union through the prism of a cine-novel, Le P'tit Parigot (1926), which was presented in serialised form via the newspaper L'Intransigeant and as a six-episode film in cinemas. It depicts the misfortunes of Georges Grigny-Latour, also known as the ‘P'tit Parigot’, son of an academic and captain of the French rugby union football team. This sport serial is a historical source of precious and useful information enabling us to address the representations of rugby at the time. The article aims to characterise the ambiguous identity of the sport during the Roaring Twenties, an identity that was torn between a Parisian spirit cultivating the idea of rugby as the inheritance of Anglo-Saxon values, and a provincial vision using it as a means of territorial expression.  相似文献   
149.
150.
The aim of this study was to examine spatiotemporal characteristics and joint angles during forward and backward walking in water at low and high stride frequency. Eight healthy adults (22.1 ± 1.1 years) walked forward and backward underwater at low (50 pulses) and high frequency (80 pulses) at the xiphoid process level with arms crossed at the chest. The main differences observed were that the participants presented a greater speed (0.58 vs. 0.85 m/s) and more asymmetry of the step length (1.24 vs. 1.48) at high frequency whilst the stride and step length (0.84 vs. 0.7 m and 0.43 vs. 0.35 m, respectively) were lower compared to low frequency (P < 0.05). Support phase duration was higher at forward walking than backward walking (61.2 vs. 59.0%). At initial contact, we showed that during forward walking, the ankle and hip presented more flexion than during backward walking (ankle: 84.0 vs. 91.8º and hip: 22.8 vs. 8.0º; P < 0.001). At final stance, the knee and hip were more flexed at low frequency than at high frequency (knee: 150.0 vs. 157.0º and hip: ?12.2 vs. –14.5º; P < 0.001). The knee angle showed more flexion at forward walking (134.0º) than backward walking (173.1º) (P < 0.001). In conclusion, these results show how forward and backward walking in water at different frequencies differ and contribute to a better understanding of this activity in training and rehabilitation.  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