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   8492篇
  免费   78篇
  国内免费   20篇
教育   5929篇
科学研究   1104篇
各国文化   31篇
体育   466篇
综合类   6篇
文化理论   137篇
信息传播   917篇
  2022年   34篇
  2021年   45篇
  2020年   85篇
  2019年   126篇
  2018年   840篇
  2017年   873篇
  2016年   613篇
  2015年   160篇
  2014年   168篇
  2013年   789篇
  2012年   202篇
  2011年   424篇
  2010年   403篇
  2009年   254篇
  2008年   315篇
  2007年   439篇
  2006年   105篇
  2005年   154篇
  2004年   226篇
  2003年   159篇
  2002年   89篇
  2001年   106篇
  2000年   145篇
  1999年   89篇
  1998年   72篇
  1997年   75篇
  1996年   62篇
  1995年   42篇
  1994年   45篇
  1993年   33篇
  1992年   75篇
  1991年   69篇
  1990年   60篇
  1989年   62篇
  1988年   74篇
  1987年   58篇
  1986年   78篇
  1985年   70篇
  1984年   55篇
  1983年   69篇
  1982年   53篇
  1981年   40篇
  1980年   29篇
  1979年   52篇
  1978年   49篇
  1977年   37篇
  1976年   42篇
  1975年   31篇
  1974年   33篇
  1973年   33篇
排序方式: 共有8590条查询结果,搜索用时 78 毫秒
61.
62.
In the article we solve path planning task for an agent being multirotor unmanned aerial vehicle (multicopter). We propose an approach of estimating path geometry constraints based on UAV flight dynamics model and control constraints. Than we introduce a new path finding method which takes into consideration those geometry constraints and study this method both theoretically and empirically.  相似文献   
63.
64.
ABSTRACT

The aims of the present study were to provide an in-depth comparison of inter-limb asymmetry and determine how consistently asymmetry favours the same limb during different vertical jump tests. Eighteen elite female under-17 soccer players conducted unilateral squat jumps (SJ), countermovement jumps (CMJ) and drop jumps (DJ) on a portable force platform, with jump height, peak force, concentric impulse and peak power as common metrics across tests. For the magnitude of asymmetry, concentric impulse was significantly greater during the SJ test compared to CMJ (p = 0.019) and DJ (p = 0.003). No other significant differences in magnitude were present. For the direction of asymmetry, Kappa coefficients revealed fair to substantial levels of agreement between the SJ and CMJ (Kappa = 0.35 to 0.61) tests, but only slight to fair levels of agreement between the SJ and DJ (Kappa = ?0.26 to 0.18) and CMJ and DJ (Kappa = ?0.13 to 0.26) tests. These results highlight that the mean asymmetry value may be a poor indicator of true variability of between-limb differences in healthy athletes. The direction of asymmetry may provide a useful monitoring tool for practitioners in healthy athletes, when no obvious between-limb deficit exists.  相似文献   
65.
There is no denying the impact that the coronravirus disease (COVID-19) outbreak has had on many aspects of our lives. This article looks at the potential impact of COVID-19 on student learning as schools abruptly morphed into virtual learning environments using data from several instructional, practice, and assessment solutions offered by Renaissance. First, three hypothetical learning scenarios are considered using normative data from Star assessments to explore the potential impact on reading and math test performace. Next, data on Focus Skills are used to highlight which grades may have missed the most foundational math and reading content if instruction was stopped or reduced. Last, data from two of Renaissance's practice tools are used to evaluate whether students were practicing key skills following school closures. The article concludes that academic decline will likely occur but may be tempered by the increased use of practice tools; effects may look different for math and reading; and may impact grades and schools differently. As such, schools may need to leverage decision-making frameworks, such as the Multi-tiered Systems of Support/Response-to-Intervention (MTSS/RTI) framework, more than ever to identify needs and target instruction where it matters most when school begins in fall 2020.  相似文献   
66.
Data from surveys of parents of students in Russian schools of various types in the years 2006 to 2011 show a high level of desire to invest in their children's education. There has been a high degree of stability in aspirations and investment in spite of the economic problems caused by global recession.  相似文献   
67.
N. Mukunda 《Resonance》2011,16(9):796-797
  相似文献   
68.
69.
70.
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