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   37693篇
  免费   557篇
  国内免费   37篇
教育   27481篇
科学研究   3390篇
各国文化   290篇
体育   2704篇
综合类   42篇
文化理论   349篇
信息传播   4031篇
  2021年   327篇
  2020年   498篇
  2019年   718篇
  2018年   1522篇
  2017年   1624篇
  2016年   1349篇
  2015年   638篇
  2014年   837篇
  2013年   6645篇
  2012年   878篇
  2011年   1192篇
  2010年   926篇
  2009年   775篇
  2008年   963篇
  2007年   956篇
  2006年   725篇
  2005年   618篇
  2004年   650篇
  2003年   549篇
  2002年   601篇
  2001年   691篇
  2000年   651篇
  1999年   619篇
  1998年   329篇
  1997年   386篇
  1996年   407篇
  1995年   369篇
  1994年   337篇
  1993年   354篇
  1992年   511篇
  1991年   478篇
  1990年   506篇
  1989年   513篇
  1988年   499篇
  1987年   420篇
  1986年   430篇
  1985年   497篇
  1984年   426篇
  1983年   455篇
  1982年   359篇
  1981年   350篇
  1980年   323篇
  1979年   450篇
  1978年   371篇
  1977年   338篇
  1976年   296篇
  1975年   245篇
  1974年   234篇
  1973年   259篇
  1971年   195篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
Using data on the ‘career’ paths of one thousand ‘leading scientists’ from 1450 to 1900, what is conventionally called the ‘rise of modern science’ is mapped as a changing geography of scientific practice in urban networks. Four distinctive networks of scientific practice are identified. A primate network centred on Padua and central and northern Italy in the sixteenth century expands across the Alps to become a polycentric network in the seventeenth century, which in turn dissipates into a weak polycentric network in the eighteenth century. The nineteenth century marks a huge change of scale as a primate network centred on Berlin and dominated by German-speaking universities. These geographies are interpreted as core-producing processes in Wallerstein’s modern world-system; the rise of modern scientific practice is central to the development of structures of knowledge that relate to, but do not mirror, material changes in the system.
David M. EvansEmail:
  相似文献   
996.
阿成  茼子 《文化交流》2008,(2):34-38
洋太太跨国拯救"干女儿"   "妈妈,您醒醒啊!"2006年3月19日,8岁的小女孩黄金美跪在母亲的病床前,抓住妈妈的手,呜呜哭泣.黄金美知道,36岁的妈妈是因为女儿的"心"而昏倒的.……  相似文献   
997.
In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.  相似文献   
998.
The primary roles for nutrition in sprints are for recovery from training and competition and influencing training adaptations. Sprint success is determined largely by the power-to-mass ratio, so sprinters aim to increase muscle mass and power. However, extra mass that does not increase power may be detrimental. Energy and protein intake are important for increasing muscle mass. If energy balance is maintained, increased mass and strength are possible on a wide range of protein intakes, so energy intake is crucial. Most sprinters likely consume ample protein. The quantity of energy and protein intake necessary for optimal training adaptations depends on the individual athlete and training demands; specific recommendations for all sprinters are, at best, useless, and are potentially harmful. However, if carbohydrate and fat intake are sufficient to maintain energy levels, then increased protein intake is unlikely to be detrimental. The type and timing of protein intake and nutrients ingested concurrently must be considered when designing optimal nutritional strategies for increasing muscle mass and power. On race day, athletes should avoid foods that result in gastrointestinal discomfort, dehydration or sluggishness. Several supplements potentially influence sprint training or performance. Beta-alanine and bicarbonate may be useful as buffering agents in longer sprints. Creatine may be efficacious for increasing muscle mass and strength and perhaps increasing intensity of repeat sprint performance during training.  相似文献   
999.
A sport-specific measure of moral disengagement was developed in 2 studies. In Study 1, a 59-item questionnaire was developed and tested with 308 athletes from 5 team sports. A series of confirmatory factor analyses (CFA) testing different models suggested the model that best fitted the data had 6 first-order factors that could be represented by 1 second-order factor. Study 2 involved 305 athletes from the same 5 sports. CFA confirmed the 6-factor, second-order structure for the final 32-item measure. Results from Study 2 supported the construct validity of the scale, providing evidence for the factorial, concurrent, convergent, and discriminant validity. The Moral Disengagement in Sport Scale (MDSS) is proposed as a valid and reliable measure of moral disengagement for use in the sport context.  相似文献   
1000.
Visual and postural control of an arbitrary posture: the handstand   总被引:1,自引:0,他引:1  
The aim of this study was to increase our understanding of postural regulation by analysing an arbitrary posture - the handstand. We assessed the relative influence of peripheral vision and central visual anchoring on the postural balance of gymnasts in the inverted-stand posture. Displacements of the centre of pressure, the angles between the body segments, and the gymnast's height in the handstand were analysed. Postural regulation in the handstand appeared to be organized according to a system similar to that in erect posture, with three articular levels suggesting the existence of a typical organization of human posture. Moreover, both intra-modal (central and peripheral vision) and inter-modal sensory systems (vision and other balance systems) contributed to the postural regulation. The results are interpreted in terms of an ecological approach to posture in which postural regulation can be considered as an emergent phenomenon.  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