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   46970篇
  免费   1120篇
财政金融   8625篇
工业经济   3206篇
计划管理   7916篇
经济学   10734篇
综合类   693篇
运输经济   320篇
旅游经济   741篇
贸易经济   7722篇
农业经济   1975篇
经济概况   6051篇
信息产业经济   4篇
邮电经济   103篇
  2021年   284篇
  2020年   520篇
  2019年   701篇
  2018年   1534篇
  2017年   1560篇
  2016年   1249篇
  2015年   640篇
  2014年   1009篇
  2013年   4571篇
  2012年   1319篇
  2011年   1808篇
  2010年   1582篇
  2009年   1655篇
  2008年   1621篇
  2007年   1591篇
  2006年   1051篇
  2005年   1005篇
  2004年   1028篇
  2003年   1048篇
  2002年   920篇
  2001年   869篇
  2000年   874篇
  1999年   779篇
  1998年   799篇
  1997年   736篇
  1996年   713篇
  1995年   649篇
  1994年   697篇
  1993年   723篇
  1992年   692篇
  1991年   691篇
  1990年   600篇
  1989年   504篇
  1988年   490篇
  1987年   503篇
  1986年   518篇
  1985年   745篇
  1984年   725篇
  1983年   714篇
  1982年   676篇
  1981年   604篇
  1980年   567篇
  1979年   579篇
  1978年   511篇
  1977年   435篇
  1976年   372篇
  1975年   380篇
  1974年   323篇
  1973年   315篇
  1972年   248篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Portuguese Economic Journal - A set of RLS-type models with ARMA and ARFIMA dynamics is estimated and compared in a forecasting exercise with ARFIMA, GARCH and FIGARCH models. It is an extension of...  相似文献   
2.
This study maps the General Reporting Initiative (GRI) relations for a set of global enterprises. Enterprise interrelationships are built using the Mutual Information (MI) of the data reported by enterprises. From the MI topology, we describe interrelationships among the enterprises using chord diagrams to represent the inter- and intra-connectivity between geographical regions and economic sectors globally, by continent and country. Detailed maps are presented for European and Asian regions/sectors, including the relationship between Europe and Asia’s top reporting countries. Our findings reinforce previous research regarding the role of Europe as a driver of sustainability and its influence worldwide. We also determined that Spain is a major player in Europe and that Northern Europe does not have the assumed leading role mentioned in related studies. Eastern Asia is, by far, the leader of the region, and the GRI maps demonstrate the preponderant role of China in the region and the minimal role of India. MI topology maps outline the behavior of the economic sectors, for all the studied regions. Furthermore, a measure that relates the inter- to intra-connections is presented to describe the internal an external relationships among regions/sectors.  相似文献   
3.
This paper presents an approach to assessing the efficacy of public spending on research and development in state programs. At present, there is a need to develop a unified approach to the analysis and evaluation of the efficacy of such spending from the perspective of participants in state programs (federal executive bodies). The proposed approach does not allow evaluating the efficacy of public spending on the development of research areas assigned to the authors.  相似文献   
4.
5.
We propose a new framework exploiting realized measures of volatility to estimate and forecast extreme quantiles. Our realized extreme quantile (REQ) combines quantile regression with extreme value theory and uses a measurement equation that relates the realized measure to the latent conditional quantile. Model estimation is performed by quasi maximum likelihood, and a simulation experiment validates this estimator in finite samples. An extensive empirical analysis shows that high‐frequency measures are particularly informative of the dynamic quantiles. Finally, an out‐of‐sample forecast analysis of quantile‐based risk measures confirms the merit of the REQ.  相似文献   
6.
H. Bause  P. Henn 《Publizistik》2018,63(3):383-405
In 2016, German corporations invested 33.5 billion euros in on-the-job-trainings. Communication trainings, especially those for executives, play an important part in on-the-job-trainings and adult education. This study examines how basics of communication and media studies are used in the praxis of communication trainings. We ask which theories of interpersonal communication are being used in communication trainings for executives and for what reasons trainers choose specific theories. The answer can help us understand how executives view communication processes and which criteria make a theory praticable in the eyes of practitioners.First, we define communication trainings as part of on-the-job training and give an overview of research regarding the use of theories in trainings. Research shows that theories play an important role in communication trainings, but that the trainings lack theoretical depths and complexity. The existing research stems mostly from linguistics; the perspective of communication and media studies is missing. In addition, none of the existing studies considers criteria for a practicable theory.In a second step, the canon of theories of interpersonal communication in communication and media studies is identified via a content analysis of seven textbooks and encyclopedias. Overall, these books present 38 theories of interpersonal communication, but only eight theories are presented in three or more books. These eight theories, among them Symbolic Interactionism (Mead), the Theory of Social Systems (Luhmann) and the Four-Ears-Model (Schulz von Thun), build the canon of theories of interpersonal communication in this study.This canon is the basis for the main part of our study. Sixteen communication trainers were interviewed, using the method of qualitative expert interview. The trainers answered questions regarding their professional background, typical courses of training, their goals in trainings, the role of theories in trainings, requirements of the executives being trained and the exchange between colleagues in the occupational field.Results show that trainers use about 15 to 20% of the training time to convey theoretical basics. The Four-Ears-Model by Schulz von Thun dominates the examined trainings. Scientists regard this communication-psychological model as being rather popular scientific. Still, every interviewed trainer uses it. This finding shows that most trainers regard communicational misunderstandings as a result of the four-dimensional character of a message (Who is the sender? Why is he talking to me like that? What are the facts about? What shall I do, think, feel based on the message?). The Communication Axioms by Watzlawick are used as the second most common approach.Apart from theories of interpersonal communication, the trainers mentioned several psychological methods and approaches with therapeutic traits, like Transaction Analysis (Berne) or Active Listening (Rogers).The explorative findings suggest that the trainers chose the theories they use—especially the Four-Ears-Model and Communication Axioms—because it is easy to interlock these theories and the praxis of communication trainings, because they are comprehensible and easy to use in examples, and because they show the relativity of communication processes. Moreover, trainers use theories to explain human behavior and the sources for misunderstandings.These criteria alone do not explain the trainers’ theory choices, though. It became clear in the interviews that factors of socialization, like advanced training for the trainers, play a major role in influencing their training content. Trainers teach the theories which they themselves learned in further education programs becoming a trainer, and they barely look out for new and/or alternative theories.We recommend that communication trainers look for other theories in communication and media studies, like the Symbolic Interactionism. This theory complies with the trainers’ criteria for good theories. Communication and media scholars on the other hand should work together with educational institutions and advanced training to improve the transfer of their theories into the praxis of communication trainings.  相似文献   
7.
Differences in accrued gains and investors’ tax-sensitivity induce variation in a capital gains lock-in effect across mutual funds even for the same stock at the same time. Exploiting this variation, we show this effect influences funds’ governance decisions: higher capital gains decrease the likelihood a fund exits prior to contentious votes and increase the likelihood a fund votes against management. Consistent with tax motivation, these findings are concentrated among funds with tax-sensitive investors. Further, high aggregate capital gains across funds holding a stock predict a higher likelihood management loses a vote and a lower likelihood a contentious vote is proposed.  相似文献   
8.
Growing urbanisation in South Africa is reflected in burgeoning Working class and informal township settlements on the fringes of its major towns and cities. Paired with this is an increasing reliance on cash as the primary means of economic transaction, which has in turn stimulated the growth of micro-enterprise business activities within the township context. This article discusses the findings of an eight-township small-area census which occurred between 2010 and 2013 in Cape Town, Johannesburg, Ekurhuleni and Durban townships representing 250 000 residents. The researchers were able to establish the scope and scale of informal food and drink retailing in these localities. Of the 10 049 micro-enterprises located in the study, some 3966 (or 39% of the total) trade in food. These include enterprises in primary production, fresh produce retailing, grocery retailing from house and spaza shops, and informal foodservice enterprises. Food is the basis for much township informal business and plays an important role in making food increasingly affordable and locally accessible, and in creating cash employment. The article builds on the knowledge base of the township informal economy role in bolstering food security needs for the marginalised.  相似文献   
9.
Without guaranteed compensation, granted by the German Renewable Energy Sources Act (Erneuerbare Energien Gesetz/EEG), biogas plants compete with all other plant types on the market for electrical energy. However, exchange-based electricity products do not currently permit an economically viable operation of biogas plants owing to their cost situation.  相似文献   
10.
Making as a design-centered learning activity has recently received significant attention in education. We use literacies—how individuals use representations to learn—to explore the STEM literacy practices of experienced designers and makers. Describing makers’ representational practices in STEM contexts can inform the design of literacy supports for young makers that can encourage their use of representations to connect STEM disciplines and design practices. We interviewed experienced makers to describe one literacy practice central to design: identifying, organizing, and integrating information. Makers enacted this practice within specific making processes—e.g., designing—with the purpose of sourcing and navigating information related to their chosen problems. The research supports efforts to bridge learning while making with learning in schools by positioning STEM literacies as central practices involved in the processes of designing and making.  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