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   325篇
  免费   3篇
教育   190篇
科学研究   30篇
各国文化   1篇
体育   93篇
文化理论   4篇
信息传播   10篇
  2023年   1篇
  2022年   4篇
  2021年   10篇
  2020年   10篇
  2019年   27篇
  2018年   22篇
  2017年   28篇
  2016年   22篇
  2015年   9篇
  2014年   21篇
  2013年   49篇
  2012年   19篇
  2011年   11篇
  2010年   12篇
  2009年   4篇
  2008年   8篇
  2007年   9篇
  2006年   5篇
  2005年   6篇
  2004年   2篇
  2003年   3篇
  2002年   3篇
  2001年   2篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1996年   4篇
  1995年   3篇
  1994年   4篇
  1993年   1篇
  1992年   2篇
  1990年   2篇
  1989年   1篇
  1979年   2篇
  1977年   2篇
  1972年   1篇
  1968年   1篇
  1966年   1篇
  1963年   4篇
  1961年   1篇
  1960年   2篇
  1959年   3篇
  1956年   1篇
  1953年   1篇
  1892年   1篇
排序方式: 共有328条查询结果,搜索用时 15 毫秒
41.
International knowledge spillovers, especially through multinational companies (MNCs), have recently been a major topic of discussion among academics and practitioners. Most research in this field focuses on knowledge sharing activities of MNC subsidiaries. Relatively little is known about their capabilities for protecting valuable knowledge from spilling over to host country competitors. We extend this stream of research by investigating both formal protection strategies (e.g. patenting) as well as strategic ones (secrecy, lead time, complex design). We conceptualize the breadth of firm's knowledge protection strategies and relate it to the particular situation of MNC subsidiaries. Moreover, we argue that their approaches differ with regard to host country challenges and opportunities. We address these issues empirically, based on a harmonized survey of innovation activities of more than 1800 firms located in Portugal and Germany. We find evidence that MNCs prefer broader sets of knowledge protection strategies in a host country with fewer opportunities for knowledge sourcing (Portugal). In Germany, though, they opt for narrower sets of knowledge protection strategies if they invest in innovation activities themselves. We deduce that these results are due to a need for reciprocity in knowledge exchanges to benefit fully from promising host country knowledge flows.  相似文献   
42.
Language and country preponderance trends in MEDLINE and its causes.   总被引:3,自引:0,他引:3  
OBJECTIVE: The authors characterized the output of MEDLINE papers by language and country of publication during a thirty-four-year time period. METHODS: We classified MEDLINE's journal articles by country of publication (Anglos/Non-Anglos) and language (English/Non-English) for the years 1966 and from 1970 to 2000 at five-year intervals. Eight English-speaking countries were considered Anglos. Linear regression analysis of number of papers versus time was performed. RESULTS: The global number of papers increased linearly at a rate of 8,142 papers per year. Anglo and English papers also increased linearly (6,740 and 9,199, respectively). Journals of Non-Anglo countries accounted for 25% of the English language increase (2,438 per year). Only Non-English papers decreased at a rate of 1,056 fewer papers per year. These trends have led to overwhelming shares of English and Anglo papers in MEDLINE. In 2000, 68% of all papers were published in the 8 Anglo countries and 90% were written in English. CONCLUSIONS: The Anglo and English preponderances appear to be a consequence of at least two phenomena: (1) editorial policy changes in MEDLINE and in some journals from Non-Anglo countries and (2) factors affecting Non-Anglo researchers in the third world (publication constraints, migration, and undersupport). These are tentative conclusions that need confirmation.  相似文献   
43.
The purpose of this study was to examine the effects of a 10 week contrast training (CT) programme (isometric + plyometric) on jumping, sprinting abilities and agility performance in prepubertal basketball players. Fifty-eight children from a basketball academy (age: 8.72 ± 0.97 years; body mass index: 17.22 ± 2.48 kg/m2) successfully completed the study. Participants were randomly assigned to experimental groups (EG, n = 30) and control groups (CG, n = 28). The CT programme was included in the experimental group’s training sessions – twice a week – as part of their usual weekly training regime. This programme included 3 exercises: 1 isometric and 2 plyometric. Jumping, sprinting and agility performance were assessed before and after the training programme. Significant differences were found in posttest between EG and CG in sprint and T-test: EG showed better results than CG. Furthermore, there were significant differences in posttest-pretest between EG and CG in squat jump, countermovement jump, drop jump, sprint and T-test with the EG showing better results than CG. The CT programme led to increases in vertical jump, sprint and agility levels, so that the authors suggest that prepubertal children exhibit high muscular strength trainability.  相似文献   
44.
Many services can be self-provided. An individual user or a user firm can, for example, choose to do its own accounting - choose to self-provide that service - instead of hiring an accounting firm to provide it. Since users can ‘serve themselves’ in many cases, it is reasonable to suspect that they can also innovate with respect to the services they self-provide - possibly without the assistance of service providers.In this paper, we conduct the first quantitative exploration of the importance of services innovation by users, focusing on the field of commercial and retail banking services. We find that 55% of today's computerized commercial banking services were first developed and implemented by non-bank firms for their own use, and 44% of today's computerized retail banking services were first developed and implemented by individual service users rather than by commercial financial service providers. Manual precursors to these services - manual procedures that carried out functions similar to computerized services in our sample - were almost always developed by users as self-services.Our empirical findings differ significantly from prevalent producer-centered views of service development. We speculate that the patterns we have observed in banking with respect to the major role of users in service development will prove to be quite general. If so, this will be an important matter: on the order of 75% of GDP in advanced economies today is derived from services. We discuss the implications of our findings for research and practice in service development.  相似文献   
45.
Software must evolve in order to adapt to new demands and scenarios. In the case of packaged software that can be customized, this evolution implies the maintenance of both out-of-the-box and customized functionality alike. New user interface technologies provide a way to interact with applications that software vendors are forced to incorporate in order to meet new user and market requirements. Packaged software vendors are facing software evolution processes in order to attract more customers and conserve the existing ones. This case analysis describes the evolution of packaged software, Meta4 PeopleNet, towards the addiction of Rich Internet Applications features to a Human and Intellectual Capital Management tool. The findings and lessons learned presented in this case study provide useful insights for packaged software vendors facing software product evolution.  相似文献   
46.
47.
48.
This paper aims to extend understanding of the business and societal impact of academic research. From a business school perspective, it has taken stock of the role of academic research and relevance in business and society. The proposed conceptual framework highlights the forces influencing the pursuit of academic rigour and relevance in scholarly outputs. A theoretical model for measuring the societal impact of academic journal articles—the Academic Rigour and Relevance Index (AR2I)—was developed. This index comprises six key parameters, which are assessed by three stakeholder groups connected with academic research into business issues, these groups being: business practitioners, society and academics. The behaviour of the AR2I model was evaluated using the Monte Carlo simulation model. Taking into account the relationships between the standard deviations and the differences of classification between articles with different levels of rigour and relevance, it is demonstrated that the AR2I model is an effective tool.  相似文献   
49.
In this article, we analyze the variation in math achievement trajectories of Black male students to understand the different ways these students successfully or unsuccessfully navigate schools and the school characteristics that are associated with their trajectories. Using longitudinal student-level data from a large urban US city (n = 7,039), we analyze Black male students from one cohort to identify trajectories. We find a lack of growth in standardized math scores, suggesting that, on average, math proficiency among Black male students in our sample is declining over time. We found that the 4th-grade standardized math scores of subsidized-lunch students were somewhat lower than those of nonsubsidized students and those of retained students were substantially lower than their counterparts. The average math score of a Black male student's cohort appears to be the only variable amenable to policy manipulation that has a sizeable association with the growth of their standardized math scores, suggesting that putting Black male students in more challenging learning environments may be the best way to increase math proficiency over time. By themselves, other policy decisions (reducing student mobility, teacher turnover, or special education classification; increasing attendance or spending on after-school programming; or hiring more qualified or experienced teachers) all appear to have no or negligible associations with growth in math scores.  相似文献   
50.
In this paper we develop a new framework for time series segmentation based on a Hierarchical Linear Dynamical System (HLDS), and test its performance on monophonic and polyphonic musical note recognition. The center piece of our approach is the inclusion of constraints in the filter topology, instead of on the cost function as normally done in machine learning. Just by slowing down the dynamics of the top layer of an augmented (multilayer) state model, which is still compatible with the recursive update equation proposed originally by Kalman, the system learns directly from data all the musical notes, without labels, effectively creating a time series clustering algorithm that does not require segmentation. We analyze the HLDS properties and show that it provides better classification accuracy compared to current state-of-the-art approaches.  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