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   35183篇
  免费   537篇
  国内免费   1篇
财政金融   6036篇
工业经济   2265篇
计划管理   5732篇
经济学   8003篇
综合类   673篇
运输经济   162篇
旅游经济   296篇
贸易经济   7363篇
农业经济   916篇
经济概况   3630篇
信息产业经济   46篇
邮电经济   599篇
  2021年   112篇
  2020年   215篇
  2019年   283篇
  2018年   2672篇
  2017年   2437篇
  2016年   1612篇
  2015年   356篇
  2014年   502篇
  2013年   1972篇
  2012年   1020篇
  2011年   2591篇
  2010年   2347篇
  2009年   2122篇
  2008年   2027篇
  2007年   2393篇
  2006年   584篇
  2005年   805篇
  2004年   906篇
  2003年   1002篇
  2002年   674篇
  2001年   434篇
  2000年   419篇
  1999年   321篇
  1998年   352篇
  1997年   326篇
  1996年   339篇
  1995年   291篇
  1994年   300篇
  1993年   300篇
  1992年   329篇
  1991年   300篇
  1990年   253篇
  1989年   221篇
  1988年   207篇
  1987年   237篇
  1986年   245篇
  1985年   338篇
  1984年   372篇
  1983年   311篇
  1982年   286篇
  1981年   284篇
  1980年   292篇
  1979年   278篇
  1978年   189篇
  1977年   178篇
  1976年   143篇
  1975年   152篇
  1974年   116篇
  1973年   121篇
  1971年   97篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Replanning is often used to optimize results of an activity in an ever changing world. To address the challenge of preparing future engineers for success, a special course was created for all engineering freshmen of the Faculty of Engineering of the University of Porto, in Portugal. Presented as a case study, this special course underwent a careful replanning as a result of several years of experience in teaching practice alongside with a theoretical deepening in pedagogical and technological issues, under the aegis of the action-research methodology. Within the context of the case study course, the mentioned replanning was also based on a theoretical approach that clearly identifies teaching–learning-assessment methodologies that promote regulation from those that foster emancipation, using a specific instrument: a taxonomy of educational processes. The replanning was designed to globally boost results regarding the educational aims of the course such as furthering freshmen’s integration into work environment and preparing them for success by fostering transversal skills (needed for study and work). Technology is seen as a mean of education enrichment as well as a productivity tool. The introduced innovations include fun-but-educational activities, several types of assessment over time and specific technological tools which were critical for the educational impact/achievement of this course. Success is demonstrated by encouraging feedback from the stakeholders, high students’ classifications and a steady reduction in retention. It is advocated that large portions of the reasoning behind the replanning can be extrapolated to other courses.  相似文献   
42.
Ecosystem transformation and climate change evolve over long time scales. The effects of the economic decisions on the natural environment are also of a long-run character because they relate to investment decisions and capital stocks. At the same time, the economy is short-sighted and subject to different kinds of market failures. The time it takes to notice the changes and adequately address the associated problems affects the dynamics and inertia of the process. We discuss some recent contributions and new research questions that deal with time and timing in environmental and resource economics.  相似文献   
43.
This paper examines the pattern of settlements, investor wins and state wins in investor-state dispute settlement cases, focusing on the impact of arbitration rules, the resources and experience of the litigants, the type of treaty breach under investigation, and the pattern of state intervention. Logistic regression results show that settlements are more likely when investors do not disclose their allegations publicly, when the host state has been involved in a greater number of past cases, and when the respondent state has a higher control-of-corruption rating. Panel awards to investors are more likely in cases of alleged direct expropriation and less likely for indirect expropriation. Panel decisions favoring the state increase with higher per capita income and rule-of-law ratings.  相似文献   
44.
45.
The main objective of this paper it to model the dynamic relationship between global averaged measures of Total Radiative Forcing (RTF) and surface temperature, measured by the Global Temperature Anomaly (GTA), and then use this model to forecast the GTA. The analysis utilizes the Data-Based Mechanistic (DBM) approach to the modelling and forecasting where, in this application, the unobserved component model includes a novel hybrid Box-Jenkins stochastic model in which the relationship between RTF and GTA is based on a continuous time transfer function (differential equation) model. This model then provides the basis for short term, inter-annual to decadal, forecasting of the GTA, using a transfer function form of the Kalman Filter, which produces a good prediction of the ‘pause’ or ‘levelling’ in the temperature rise over the period 2000 to 2011. This derives in part from the effects of a quasi-periodic component that is modelled and forecast by a Dynamic Harmonic Regression (DHR) relationship and is shown to be correlated with the Atlantic Multidecadal Oscillation (AMO) index.  相似文献   
46.
Supersaturated designs (SSDs) constitute an important class of fractional factorial designs that could be extremely useful in factor screening experiments. Most of the existing studies have focused on balanced designs. This paper provides a new lower bound for the \(E(f_{NOD})\)-optimality measure of SSDs with general run sizes. This bound is a generalization of existing bounds since it is applicable to both balanced and unbalanced designs. Optimal multi and mixed-level, balanced and nearly balanced SSDs are constructed by applying a k-circulant type methodology. Necessary and sufficient conditions are introduced for the generator vectors, in order to pre-ensure the optimality of the constructed k-circulant SSDs. The provided lower bounds were used to measure the efficiency of the generated designs. The presented methodology leads to a number of new families of improved SSDs, providing tools for directly constructing optimal or nearly-optimal k-circulant designs by just checking the corresponding generator vector.  相似文献   
47.
Flash sale (FS) is a new business model that offers discounted products in limited numbers over a short period. In this paper we discuss the impact of strategic consumers on advance selling (AS) of new products on FS platforms. We first study the impact of strategic consumers on competing retailers adopting AS to sell a homogeneous new product. And find that the retailers’ AS profits and inventory quantities decrease with the strategic customers’ valuation and valuation decreasing rate. Then we analyse whether FS can mitigate the impact of strategic customers on retailers adopting AS for new products. We consider a newsvendor model involving only one retailer adopting AS to sell a new product. We derive the results by comparing this model with two counterpart models, namely the classical newsvendor model with no strategic customers and a newsvendor model with strategic customers where the retailer does not use FS under AS.  相似文献   
48.
Nowadays, the economic activities have become increasingly digital since hundreds of millions of Internet users are using crowdsourcing platforms either to work at an online job as workers, or as a model of problem-solving and production as requesters. This growing workforce makes it necessary from the perspective of the online platforms, to fully understand the business dimensions of this emerging and innovative “online labor” phenomenon, which can rapidly change the future of work and work organization in the online world. This paper aims to investigate and analyze the visits of online labor platforms that offer crowdsourcing and crowdfunding services. Using websites’ metrics data drawn from Alexa for the time period 2012-2016 the paper uses Ordinary Least Squares (OLS) and Fixed Effects (FE) regression analysis to examine correlations between visits and website characteristics. The research shows that the sessions of an online labor marketplace website from mobile devices have an increasing trend to be positively correlated to the quality mechanisms a website deploys as well as on location-dependent factors. The results are expected to provide insights on how the online labor website characteristics affect their traffic and thus inform about their evolution and improvement.  相似文献   
49.
In this paper, while focusing on the impact that the global financial crisis had on the stock markets of China, Japan, and the United States, the stock-price volatilities and linkage between these three countries are analyzed. In addition, the relationships between macroeconomic variables (real-economy variables and monetary-policy variables) and stock price volatility in each country are investigated. The estimation results of the EGARCH model revealed that although China’s stock price volatility was far greater than those of Japanese and US stock prices, China was less affected by the global financial crisis in 2007 than Japan and the United States. For China, stock price volatility was greater in the early 1990s, shortly after the stock market had been established, than in 2007 when the global financial crisis occurred. Furthermore, it has been revealed that the linkage of Chinese, Japanese, and US stock prices has increased since the global financial crisis. Moreover, Granger causality testing revealed China’s real-economy variables and monetary-policy variables do not affect China’s stock price volatility.  相似文献   
50.
Luxury marketing research has moved from functional product attributes to a ‘democratized’ view in emerging economies. This seems to be based on the development of interactive and digital communications. Luxury research studies have historically focused on the brand's and marketer's perspectives. Thus, little attention has been given to the consumer's view of what we consider to be the individual drivers, i.e., the ‘inner and outer self’ and how that impacts luxury consumption. This paper presents a framework of luxury and self, using concepts such as interdependent or outer, independent or inner, and a new concept of ‘digital self’. These appear as three levels of luxury consumption, i.e., conspicuous, individual, and interactive. The interdependent self is influenced by the external motives and leads to conspicuous luxury behavior. Individual self is affected by internal motives and thus influences individual luxury consumption. Digital self affects the networks of motive and relationships and thereby impacts interactive luxury consumption and behavior.  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