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   10797篇
  免费   85篇
  国内免费   21篇
教育   7458篇
科学研究   1443篇
各国文化   54篇
体育   667篇
综合类   6篇
文化理论   164篇
信息传播   1111篇
  2022年   49篇
  2021年   73篇
  2020年   122篇
  2019年   207篇
  2018年   969篇
  2017年   955篇
  2016年   698篇
  2015年   207篇
  2014年   238篇
  2013年   1231篇
  2012年   239篇
  2011年   465篇
  2010年   448篇
  2009年   293篇
  2008年   361篇
  2007年   476篇
  2006年   138篇
  2005年   185篇
  2004年   252篇
  2003年   180篇
  2002年   110篇
  2001年   123篇
  2000年   164篇
  1999年   114篇
  1998年   97篇
  1997年   88篇
  1996年   82篇
  1995年   57篇
  1994年   64篇
  1993年   52篇
  1992年   102篇
  1991年   95篇
  1990年   86篇
  1989年   92篇
  1988年   99篇
  1987年   76篇
  1986年   104篇
  1985年   97篇
  1984年   83篇
  1983年   88篇
  1982年   78篇
  1981年   54篇
  1980年   47篇
  1979年   68篇
  1978年   63篇
  1977年   54篇
  1976年   61篇
  1974年   45篇
  1973年   42篇
  1937年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
Trans-Pacific transport of enhanced ozone plumes has been mainly attributed to fossil fuel combustion in Asia in spring, but less attention has been paid to vegetation fires in Asia. Here we show that the El Niño-Southern Oscillation (ENSO)-modulated fires in Southeast Asia, rather than Asian fossil fuel plumes, dominate the interannual variability of springtime trans-Pacific transport of ozone across the entire North Pacific Ocean. During El Niño springs, the intensified fires from both the Indochinese Peninsula and Indonesia, together with large-scale circulation anomalies, result in enhanced ozone plumes that stretch over 15 000 km in both the lower-middle and upper troposphere. This enhancement is also observed in the in situ measurements of ozone concentration, with an almost 10% increase at Mauna Loa Observatory, Hawaii, a unique site to monitor the long-distance transport over the North Pacific. This study reports an unexpectedly strong influence of vegetation fires, linked with climate variability, on global tropospheric chemistry and proves once more how complex the interactions in the climate system are.  相似文献   
74.
75.
Families immigrating to Australia face many challenges integrating into the educational system, including language barriers and interrupted schooling. We have qualitatively evaluated the educational concerns of Arabic migrants from Sudan and Iraq to Melbourne, Victoria, Australia, a city that receives a high percentage of Australia's immigrants. Using an interactive paradigm incorporating focus group discussions for thematic analysis, we concluded that the parents’ frame of reference for education was a more didactic style of learning. Parents viewed education as an essential part of the way forward for their children in Australia. However, it was stressful for them to try to cope with a new host nation's expectation of their involvement in their children's education while at the same time dealing with a language barrier. Professionals should look to empower parents with structural information about the key elements of the educational curriculum with minimal reliance on written technical language and match their expectations of parental involvement to the situation of the parents.  相似文献   
76.
77.
78.
79.
80.
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   
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