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   11045篇
  免费   79篇
财政金融   2008篇
工业经济   913篇
计划管理   2079篇
经济学   2329篇
综合类   135篇
运输经济   81篇
旅游经济   171篇
贸易经济   1700篇
农业经济   536篇
经济概况   1150篇
信息产业经济   1篇
邮电经济   21篇
  2021年   84篇
  2020年   146篇
  2019年   217篇
  2018年   212篇
  2017年   239篇
  2016年   270篇
  2015年   153篇
  2014年   221篇
  2013年   1055篇
  2012年   317篇
  2011年   349篇
  2010年   314篇
  2009年   355篇
  2008年   314篇
  2007年   292篇
  2006年   265篇
  2005年   225篇
  2004年   220篇
  2003年   222篇
  2002年   250篇
  2001年   232篇
  2000年   257篇
  1999年   226篇
  1998年   233篇
  1997年   210篇
  1996年   225篇
  1995年   184篇
  1994年   171篇
  1993年   192篇
  1992年   197篇
  1991年   188篇
  1990年   195篇
  1989年   146篇
  1988年   130篇
  1987年   124篇
  1986年   144篇
  1985年   207篇
  1984年   168篇
  1983年   153篇
  1982年   125篇
  1981年   147篇
  1980年   126篇
  1979年   131篇
  1978年   129篇
  1977年   73篇
  1976年   101篇
  1975年   78篇
  1974年   75篇
  1973年   75篇
  1972年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
    
This paper examines the international mixed duopoly behaviour with research spillovers. Using a two‐stage game with Research and Development (R&D) and output, we investigate the effects of imperfectly appropriable R&D on optimal R&D strategies of a domestic public firm and a foreign private firm across different market interactions: (i) international R&D competition, (ii) only the foreign firm conducts R&D, (iii) only the domestic public firm conducts R&D, (iv) no firm conducts R&D, and (v) research joint venture. The results show that firms' research performances are determined by the degree of spillovers and the optimal R&D strategies involve R&D competition. Spillovers are shown to be socially beneficial and their absence can prove to be a strategic deterrent, with the public firm monopolising the market. Some of these findings contrast with the traditional models of oligopoly (with or without R&D) and mixed oligopoly (without R&D).  相似文献   
82.
    
Sufficient dimension reduction (SDR) methods are effective tools for handling high dimensional data. Classical SDR methods are developed under the assumption that the data are completely observed. When the data are incomplete due to missing values, SDR has only been considered when the data are randomly missing, but not when they are nonignorably missing, which is arguably more difficult to handle due to the missing values' dependence on the reasons they are missing. The purpose of this paper is to fill this void. We propose an intuitive, easy-to-implement SDR estimator based on a semiparametric propensity score function for response data with non-ignorable missing values. We refer to it as the dimension reduction-based imputed estimator. We establish the theoretical properties of this estimator and examine its empirical performance via an extensive numerical study on real and simulated data. As well, we compare the performance of our proposed dimension reduction-based imputed estimator with two competing estimators, including the fusion refined estimator and cumulative slicing estimator. A distinguishing feature of our method is that it requires no validation sample. The SDR theory developed in this paper is a non-trivial extension of the existing literature, due to the technical challenges posed by nonignorable missingness. All the technical proofs of the theorems are given in the Appendix S1.  相似文献   
83.
Static tradeoff theories, which do not explicitly treat the impact of transaction costs, do not explain the policy of asymmetry between frequent small debt transactions and infrequent large equity transactions. Nor do these theories explain why the debt ratio is allowed to wander a considerable distance from its alleged static optimum, or how much of a distance should be tolerated. We offer a class of diffusion models that mimic this behaviour in a stochastic-dynamic framework and are designed to optimize a financing strategy using any static tradeoff theory as input. The models developed reveal the determinants of the size and frequency of equity transactions and the range of values over which leverage variations are tolerated in four generic scenarios. They also yield a new formulation of the cost of capital that recognizes stochastic transaction costs and a penalty for deviation from any static-optimal leverage. Our class of models augments the pecking order theory, provides a flexible quantitative framework for its implementation as a decision tool, and facilitates the formulation of additional hypotheses for its empirical validation. Symmetrically, our results show the importance of dynamic factors in designing and interpreting empirical tests of static tradeoff theories. The results presented have important implications for the role played by static tradeoff theories in a stochastic-dynamic framework. One such implication is that the static-optimal leverage has no direct effect on the firm's leverage policy in this setting. The target leverage for refinancing transactions is different from the static-optimal leverage, and the mean leverage is generally different from both. As a consequence, the latter cannot be used to estimate the former. Another implication is that even when the mean leverage equals the static optimum, mean reversion is not an optimal behaviour and therefore not a legitimate test for the existence of a static tradeoff in a dynamic context. Still another implication is that wide variations in leverage ratios cannot be interpreted as evidence of leverage indifference. It follows that the pecking order theory is consistent with static tradeoff theories and does not require the assumption of leverage indifference.  相似文献   
84.
    
The Färe‐Primont index is used to evaluate total factor productivity (TFP) change and its components for a sample of French suckler cow farms in grassland areas in 1985–2014. The results reveal an increase in TFP of 6.6 per cent over the whole observation period, with technological progress being the major source of productivity growth. Meanwhile, efficiency decreased. Farms experienced great technological progress from 1991 to 2000. From a methodological point of view, the comparison with results obtained with Malmquist indexes shows similar trends but different magnitudes, with the Malmquist index overestimating the TFP and technological changes compared to the Färe‐Primont index. In addition, the use of a sequential approach that restricts technological change to being positive or null allows for the precise calculation of technology changes, disregarding the effects of external conditions that are captured in efficiency changes. Finally, the estimation of full dimensional efficient facets (FDEFs) that guarantees the positivity of all shadow prices used to assess the mix efficiency component of TFP change is promising.  相似文献   
85.
An Infant Feeding Practices Study (IFPS) in 1982 in Kenya, which included a cross-sectional survey of a weighted sample of 980 low and middle income Nairobi mothers who had given birth in the previous 18 months, found that most women breastfeed their infants for long periods, but many introduce alternate feeding, especially infant formula, in the 1st 4 months (86 and 50% of the infants were breastfed at 6 and 15 months respectively, but 50% of the 2 month-olds and 63% of the 4 month-olds were receiving substitutes, mostly formula). This is done largely out of the belief that infant formula is an additional health benefit. A workshop to discuss the findings of the IFPS and other available data, and to make policy recommendations urged the adoption of a policy of protection, support and promotion of breastfeeding. Since breastfeeding is already widely prevalent in Kenya, protection of breastfeeding should receive the 1st priority in policy related to infant feeding. Attention should be directed at at least 2 influences which help undermine breastfeeding: widespread availability and promotion of breast milk substitutes. Support for breastfeeding is viewed as the 2nd policy priority. Situations where support can play a helpful role are, women's paid employment outside the home, hospital practices, maternal morbidity, and difficulties in breastfeeding. Since promotion is the least cost effective of the 3 options, and most Kenyan women are already motivated to breastfeed, this should be the last priority. Promotion includes reeduction of mothers to make them better aware of the benefits of breastfeeding. The workshop recommended the dissemination of appropriate information, consisting of standarized messages based on clearcut guidelines, using mass media techniques.  相似文献   
86.
Contrary to the widely held attitude towards the necessity of immediately raising the retirement age, this article demonstrates the absence of demographic conditions for changing the existing regulations in granting pension insurance. The demographic factors are recognized as the basic development conditions of the state pension system; however, they have a multichannel impact on it, which requires a holistic and qualified analysis of all the relevant parameters for the governmental regulation. The pension age is viewed from the perspective of achieving the objectives of pension reform and strategic benchmarks in the long-term development of the Russian Pension system.  相似文献   
87.
    
Abstract: This study examines the impact of (real) demand shocks, (aggregate) supply shocks, and monetary shocks on real exchange rates in 13 West African countries. We observe that the real demand shocks explain most of the fluctuations in real exchange rates in all these countries. Accordingly, policymakers should adopt a careful demand management strategy by controlling government expenditure and taxes.  相似文献   
88.
High-contact service industries are characterized by close interaction between service employees and customers, and diverse customer needs. Such characteristics pose a great challenge to the delivery of services of superior quality. In this research we conceptually explore and empirically examine several attitudinal and motivational factors of customer-contact employees, and the management style of managers as antecedents to service quality in high-contact service sectors. Based on dyadic data collected from 230 service firms in Hong Kong, we examine the relationships among transformational leadership, transactional leadership, affective organizational commitment, learning goal orientation, performance goal orientation, and service quality. We find that learning goal orientation is more effective than performance goal orientation in fostering service quality in the high-contact service context. We also observe that transformational leadership tends to be more effective than transactional leadership in influencing employee attitude in high-contact service firms. This research pioneers theory-driven examination of service quality in high-contact service firms using data collected from service employees and shop managers for hypothesis testing.  相似文献   
89.
The emergence of technical subfields is a common phenomenon in dynamic as well as relatively stable industries. The proper strategic response to the emergence of a subfield, that is, the decision on whether to enter or not to enter, is a key determinant of future firm performance. We propose that this entry decision is not a simple one. The effects of subfield entry may be influenced by strategic factors related to the subfield as well as to the greater industry environment. In this study, we apply a population ecology framework to the study of subfield birth and evolution and use this perspective to develop and test several propositions related to the effects of subfield entry on performance. The data pertain to the evolution of the automatic teller machine subfield over the first 9 years of its existence for a population of over 3500 banks. Our results support the population ecology framework, generally emphasizing the positive performance consequences of early subfield entry. © 1997 by John Wiley & Sons, Ltd.  相似文献   
90.
    
Strategic management research has been characterized as placing less emphasis on construct measurement than other management subfields. In this work, we document the state of the art of measurement in strategic management research, and discuss the implications for interpreting the results of research in this field. To assess the breadth of measurement issues in the discipline, we conducted a content analysis of empirical strategic management articles published in leading journals in the period of 1998–2000. We found that few studies discuss reliability and validity issues, and empirical research in the field commonly relies on single‐indicator measures. Additionally, studies rarely address the problems of attenuation due to measurement error. We close with a discussion of the implications for future research and for interpreting prior work in strategic management. Copyright © 2004 John Wiley & Sons, Ltd.  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