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   579篇
  免费   21篇
教育   362篇
科学研究   62篇
各国文化   7篇
体育   103篇
综合类   1篇
文化理论   11篇
信息传播   54篇
  2023年   3篇
  2022年   10篇
  2021年   16篇
  2020年   25篇
  2019年   34篇
  2018年   54篇
  2017年   49篇
  2016年   46篇
  2015年   22篇
  2014年   21篇
  2013年   106篇
  2012年   28篇
  2011年   21篇
  2010年   19篇
  2009年   15篇
  2008年   28篇
  2007年   16篇
  2006年   8篇
  2005年   16篇
  2004年   11篇
  2003年   6篇
  2002年   5篇
  2001年   3篇
  2000年   5篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   4篇
  1985年   2篇
  1984年   1篇
  1981年   1篇
  1979年   2篇
  1978年   2篇
  1974年   1篇
  1973年   2篇
  1972年   1篇
  1903年   1篇
排序方式: 共有600条查询结果,搜索用时 265 毫秒
1.
Zusammenfassung.   Die intelligente Ressourcenadaption ist eine der gro?en Herausforderungen für die n?chste Generation mobiler Navigationssysteme. Da man typischerweise mehrere Fortbewegungsarten oder Verkehrsmittel kombinieren muss, um an einen Zielort zu gelangen, muss sichergestellt werden, dass mobile, allgegenw?rtige Navigationshilfen dies über eine jeweils situationsangepasste Benutzerschnittstelle unterstützen. Der notwendige Wechsel zwischen verschiedenen Positionierungstechnologien soll für den Endbenutzer m?glichst unbemerkt bleiben. Im folgenden wird ein hybrides Personennavigationssystem vorgestellt, das die in bestimmten Fortbewegungssituationen verfügbaren Positionierungstechnologien und deren Genauigkeit optimal nutzt, um die Pr?sentation der Wegbeschreibung auf verschiedene Endger?te und Ausgabemodalit?ten sowie die kognitive Ressourcenlage des Benutzers zu adaptieren. Eingegangen am 28. Februar 2001 / Angenommen am 8. August 2001  相似文献   
2.
Zusammenfassung  Diese Arbeit stellt ein Modell und ein System zur Steuerung von Exoskeletten mit Hilfe von elektrischen Signalen vor, die an den Muskeln des Benutzers gemessen werden. Anhand dieser Signale wird der eigene Drehmomentbeitrag des Benutzer zur gewünschten Bewegung abgesch?tzt, und ein einstellbarer Faktor bestimmt das vom Exoskelett hinzugefügte Drehmoment in Bezug auf den Beitrag des Benutzers. Die Signale werden durch ein komplexes biomechanisches Modell ausgewertet. CR subject classification  J.3 ; J.7 ; I.6.5  相似文献   
3.
Reports about political scandals have increased lately. Yet the general impact of news visuals and the specific role of lightness and darkness cues in images of scandalized politicians remain unclear. With the help of an experiment, the present pilot study examined the influence of candidate images and the effects of particular image backgrounds (light versus dark). While the foreground of the image depicting a politician involved in a scandal remained unchanged, the background was systematically altered. The results revealed that a light background had a positive effect on recipients’ attitudes toward the politician. In contrast, participants exposed to a dark image background demanded a more severe punishment for the politician.  相似文献   
4.
5.
6.
In this article, we build on Stigler and Becker’s (1977) “consumption capital theory” and propose a novel conceptualization of film quality for the analysis of motion picture franchises. Generally, this theory predicts that the utility consumers derive from a particular good or service increases with prior consumption. We test our theoretical conjectures by drawing on the population of sequels that were running in the US between 1992 and 2011. The empirical results point to the explanatory power of the proposed framework. Film executives may use our findings to improve the profitability of their sequel productions. From a theoretical point of view, consumption capital theory allows for a more refined analysis of sequel performance along different dimensions. Moreover, it may provide a fruitful basis for the analysis of other serial media content, including books, TV, music, and games.  相似文献   
7.
Resin-dentin bond degradation is a major cause of restoration failures. The major aim of the current study was to evaluate the impact of a remineralization medium on collagen matrices of hybrid layers of three different adhesive resins using nanotechnology methods. Coronal dentin surfaces were prepared from freshly extracted premolars and bonded to composite resin using three adhesive resins (FluoroBond II, Xeno-III-Bond, and iBond). From each tooth, two central slabs were selected for the study. The slabs used as controls were immersed in a simulated body fluid (SBF). The experimental slabs were immersed in a Portland cement-based remineralization medium that contained two biomimetic analogs (biomineralization medium (BRM)). Eight slabs per group were retrieved after 1, 2, 3, and 4 months, respectively and immersed in Rhodamine B for 24 h. Confocal laser scanning microscopy was used to evaluate the permeability of hybrid layers to Rhodamine B. Data were analyzed by analysis of variance (ANOVA) and Tukey’s honest significant difference (HSD) tests. After four months, all BRM specimens exhibited a significantly smaller fluorescent area than SBF specimens, indicating a remineralization of the hybrid layer (P≤0.05). A clinically applicable biomimetic remineralization delivery system could potentially slow down bond degradation.  相似文献   
8.
The FIFA World Cup for men (hereafter referred to as the FIFA World Cup) is possibly the biggest global media event. Winning or losing often gives rise to expressions of collective degrees of national pride or disappointment. But, it is not only the performance of the teams that is of significance in this respect; the devotion of fans to the game and their loyalty to their own national team are also an important vehicle of identity and self-affirmation as a nation. Thus, no country can afford to dispense with the travelling model of the enthusiastic fan as a representative of national identity. Through an ethnographic study of Ghana’s state-financed fan trip to the FIFA World Cup 2010 in South Africa, we will show how the actors involved (government, opposition, fans and media) negotiate national identity and representation.  相似文献   
9.
This paper reviews the FIFA World Cups 1998–2010 with data available from the FIFA website and assesses the performance of each region in relation to the number of World Cup qualifications spots that the region is awarded. We raise the issue of whether FIFA should be more concerned with the participation of more members from its federations in the World Cup than the financial gain from doing so. Our non-econometric analysis illustrates that the current allocation may be resulting in the awarding of qualification spots to teams that if not unfair, certainly warrants discussion. We seek to demonstrate that the current system of qualification is based neither on ensuring the qualification of the best 32 teams in the world, nor does it fairly allocate qualification spots on the number of teams per federation or any other metric. We conclude with a plea for more transparent allocation processes.  相似文献   
10.
The aim of this study was to evaluate the predictive potential provided by two ventilatory inflection points (VIP1 and VIP2) examined in field without using gas analysis systems and uncomfortable facemasks. A calibrated respiratory inductance plethysmograph (RIP) and a computerised routine were utilised, respectively, to derive ventilation and to detect VIP1 and VIP2 during a standardised field ramp test on a 400 m running track on 81 participants. In addition, average running speed of a competitive 1000 m run (S1k) was observed as criterion. The predictive value of running speed at VIP1 (SVIP1) and the speed range between VIP1 and VIP2 in relation to VIP2 (VIPSPAN) was analysed via regression analysis. VIPSPAN rather than running speed at VIP2 (SVIP2) was operationalised as a predictor to consider the covariance between SVIP1 and SVIP2. SVIP1 and VIPSPAN, respectively, provided 58.9% and 22.9% of explained variance in regard to S1k. Considering covariance, the timing of two ventilatory inflection points provides predictive value in regard to a competitive 1000 m run. This is the first study to apply computerised detection of ventilatory inflection points in a field setting independent on measurements of the respiratory gas exchange and without using any facemasks.  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