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   24422篇
  免费   431篇
  国内免费   16篇
教育   17424篇
科学研究   2136篇
各国文化   237篇
体育   2137篇
综合类   13篇
文化理论   229篇
信息传播   2693篇
  2022年   188篇
  2021年   318篇
  2020年   471篇
  2019年   765篇
  2018年   1000篇
  2017年   967篇
  2016年   845篇
  2015年   518篇
  2014年   740篇
  2013年   4893篇
  2012年   696篇
  2011年   702篇
  2010年   515篇
  2009年   510篇
  2008年   563篇
  2007年   511篇
  2006年   451篇
  2005年   429篇
  2004年   380篇
  2003年   375篇
  2002年   353篇
  2001年   488篇
  2000年   403篇
  1999年   372篇
  1998年   212篇
  1997年   217篇
  1996年   250篇
  1995年   243篇
  1994年   191篇
  1993年   209篇
  1992年   328篇
  1991年   288篇
  1990年   297篇
  1989年   282篇
  1988年   241篇
  1987年   292篇
  1986年   260篇
  1985年   294篇
  1984年   238篇
  1983年   199篇
  1982年   175篇
  1981年   158篇
  1980年   137篇
  1979年   245篇
  1978年   178篇
  1977年   157篇
  1976年   141篇
  1975年   131篇
  1974年   135篇
  1971年   119篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
11.
This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three-dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R2 values of >0.85 for all variables excluding deadlift mean velocity (R2 = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance.  相似文献   
12.
A significant number of archaeological finds of the 13th–16th century from the Tuscan sites of Germagnana and Gambassi in Valdelsa—FI, was studied by different physico-chemical investigations (SEM–EDS, ICP, Mössbauer spectroscopy, XRD, XRF, TG-DTA) in order to contribute to clarify the production methodology and the pre-industrial glass manufacture technology. The studied samples are mainly non-vitreous finds as production waste, refractory materials, crucibles and raw materials; also vitreous finds as frits, skims, glasses (glass masses, glass working waste and finished products) have been taken into consideration. The obtained petrographic and physico-chemical data strongly suggest that both Gambassi and Germagnana glass manufactures were strictly connected with the sources of vitrifiable materials, situated in Tuscan sand quarries. In particular a comparison between sands from the neighbouring quarries and appropriate finds of the two archaeological sites evidences that the employed vitrifiable materials possibly belong to La Casina La Cava resort. The archaeological classification, based on macroscopic observation and stratigraphic position, was compared and verified with the scientific classification of the examined finds of Germagnana and Gambassi sites based on their composition, morphology and physico-chemical properties.  相似文献   
13.
Continuous observation of the physical activity of 56 preadolescent children was conducted in four regions of England from October 1988 to July 1989. Observations were undertaken during school break times, lunch times, and physical education lessons, as well as during the children's free time. Of total time observed, the children spent 32.4% of it engaged in moderate to vigorous physical activity (MVPA). Children were shown to be most active during school breaks and least active during free time at home. However, it is thought that cardiorespiratory benefits are best achieved by participation in sustained periods of MVPA. Only 8 (14%) of the 56 children were observed to participate in MVPA for sustained periods of 20 min or longer. A random sample of 55 physical education lessons was observed. Only 6 children engaged in MVPA for sustained periods of 5 min or more, and no children participated in MVPA for 10 min or longer. The implications of these results are that, although the children engaged in a reasonable amount of MVPA, it may not have been sustained for periods of sufficient length to produce a cardiovascular training response. Consideration is given to ways of promoting lifelong involvement in physical activity.  相似文献   
14.
15.
16.
17.
18.
19.
Despite increased enrollment, outcomes such as grade point average (GPA), persistence, and graduation rates for college students with learning disabilities (LD) continue to lag behind those of their nondisabled peers. Reasons for the differences vary but may include academic and social integration, factors identified as important to the success of college students in general. This research investigated the relative influence of background characteristics, precollege achievement, and college integration variables on the academic success and intent to persist of college freshmen and sophomores with LD. While academic and social integration were not unique predictors of college GPA, both integration variables were unique predictors of intent to persist. The findings suggest that beyond high school achievement and background characteristics, college experiences as captured by academic and social integration are promising constructs to help explain the persistence of college students with LD. Implications for future research and practices for high school and college personnel are discussed.  相似文献   
20.
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