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   33556篇
  免费   679篇
财政金融   6078篇
工业经济   2440篇
计划管理   5687篇
经济学   7568篇
综合类   332篇
运输经济   227篇
旅游经济   535篇
贸易经济   5398篇
农业经济   1631篇
经济概况   4234篇
信息产业经济   3篇
邮电经济   102篇
  2021年   220篇
  2020年   388篇
  2019年   593篇
  2018年   662篇
  2017年   712篇
  2016年   699篇
  2015年   493篇
  2014年   772篇
  2013年   3378篇
  2012年   1068篇
  2011年   1099篇
  2010年   967篇
  2009年   1064篇
  2008年   1011篇
  2007年   881篇
  2006年   835篇
  2005年   744篇
  2004年   637篇
  2003年   677篇
  2002年   621篇
  2001年   689篇
  2000年   653篇
  1999年   638篇
  1998年   665篇
  1997年   598篇
  1996年   590篇
  1995年   521篇
  1994年   523篇
  1993年   537篇
  1992年   533篇
  1991年   553篇
  1990年   477篇
  1989年   406篇
  1988年   396篇
  1987年   389篇
  1986年   370篇
  1985年   581篇
  1984年   569篇
  1983年   527篇
  1982年   472篇
  1981年   459篇
  1980年   473篇
  1979年   457篇
  1978年   365篇
  1977年   336篇
  1976年   314篇
  1975年   286篇
  1974年   269篇
  1973年   263篇
  1972年   184篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
An Empirical Look at Software Patents   总被引:4,自引:1,他引:4  
Software patents have grown rapidly in number and now comprise 15% of all patents. They are acquired primarily by large manufacturing firms in industries known for strategic patenting; only 5% belong to software publishers. The very large increase in software patent propensity over time is not adequately explained by changes in R&D investments, employment of computer programmers, or productivity growth. The residual increase in software patent propensity is consistent with a sizeable increase in the cost effectiveness of software patents during the 1990s, perhaps arising from changes in the application of patent law to computer software.  相似文献   
992.
To study the optimal age-specific labor demand and human capital investment at the firm level we extend the standard dynamic labor demand model by introducing ‘age’ as a second dynamic variable and distinguish between two types of workers: ‘low skilled’ and ‘high skilled’. Applying an age-structured optimal control model we derive qualitative features of the optimal age-specific hiring and training effort. For the case of a linear revenue and production function we prove that firms do not anticipate changes in adjustment costs in their optimal decisions. This result no longer holds if a nonlinear revenue or production function is considered.  相似文献   
993.
Environmental awareness and legislative pressures have made manufacturers responsible for the take-back and end-of-life treatment of their products. To competitively exploit these products, one option is to incorporate used components in “new” or remanufactured products. However, this option is partly limited by a firm's ability to assess the reliability of used components. A comprehensive two-step approach is proposed. The first stage phase statistically analyzes the behavior of components for reuse. A well-known reliability assessment method, the Weibull analysis, is applied to the time-to-failure data to assess the mean life of components. In the second phase, the degradation and condition monitoring data are analyzed by developing an artificial neural network (ANN) model. The advantages of this approach over traditional approaches employing multiple regression analysis are highlighted with empirical data from a consumer product. Finally, the Weibull analysis and the ANN model are then integrated to assess the remaining useful life of components for reuse. This is a critical advance in sustainable management of supply chains since it allows for a better understanding of not only service requirements of product, but the remaining life in a product and hence its suitability for reuse or remanufacture. Future work should assess: (1) reduction in downtime of process equipment through the implementation of this technique as a means to better manage preventative maintenance; (2) reduce field failure of remanufactured product; (3) selling-service strategy through implementation of the proposed methodology.  相似文献   
994.
A multilevel, identity-based approach to leadership development   总被引:1,自引:0,他引:1  
A frontier of leadership development is examined involving the respective roles of levels-of-analysis and identity in constructing an integrated development system. An approach is described in which individual and relational leadership identities are the focus of developmental efforts at lower organizational levels (e.g., individual contributor and first-level supervisor) but collective identities become the focus at higher levels (e.g., general manager and above). The separate areas of levels-of-analysis and leader identities are first discussed in terms of their respective relevance to leadership development. These are then discussed jointly in elaborating on a proposed development approach that integrates across organizational levels as well as levels of development (i.e., leader development and leadership development). In developing collective leadership identities, processes that involve participants in engaging across boundaries (functional, hierarchical, geographical) are recommended.  相似文献   
995.
This paper focuses on: (1) how a select set of financial and economic factors could set the path for interest rates and foreign exchange rates, and (2) whether the resultant realized interest and exchange rates would be in harmony or in disarray. Using post-euro data for the EU and the US, an array of monetary rules is examined. In particular, the paper investigates whether the original and the extended Taylor rules provide an explanation of the dynamics of the EU monetary system since the inception of the euro. Our findings indicate that the EU and the US monetary responses are not the same and that exchange rates play a significant role.  相似文献   
996.
We present a probabilistic model based on the one developed by Hernández Mendo and Anguera (Revista de Psicologíca Social, 16(1), 71–93, 2001). Here we have tried to break down the interaction contexts that the opposing teams are able to generate and transform during the game. We are aware that a given player or team does not produce consistent behaviour in similar situations. However, a degree of uncertainty is assumed to exist regarding whether the results obtained are a specific function of the analysis used. In order to carry out this research a category system which optimized that used in the previous model was developed. This system should enable the interaction between teams to be observed within the actual play of a soccer game. A lag sequential analysis was performed on the basis of a coding of the behavioural flow. After describing the behavioural patterns obtained a probabilistic model of the development of play in soccer is proposed.  相似文献   
997.
Progressive stress accelerated life tests under finite mixture models   总被引:1,自引:0,他引:1  
In this paper, progressive stress accelerated life tests are considered when the lifetime of a product under use condition follows a finite mixture of distributions. The experiment is performed when each of the components in the mixture follows a general class of distributions which includes, among others, the Weibull, compound Weibull, power function, Gompertz and compound Gompertz distributions. It is assumed that the scale parameter of each component satisfies the inverse power low, the progressive stress is directly proportional to time and the cumulative exposure model for the effect of changing stress holds. Based on type-I censoring, the maximum likelihood estimates (MLEs) of the parameters under consideration are obtained. A special attention is paid to a mixture of two Rayleigh components. Simulation results are carried out to study the precision of the MLEs and to obtain confidence intervals for the parameters involved.  相似文献   
998.
With the current political environment (such as new legislation recognising gay and lesbian couples) and societal changes (such as increasing disclosure of sexual identity in the workplace) in countries such as the USA and Australia, organizations are increasingly recognising the existence of their gay and lesbian employees. This paper reports on an on-line survey of 581 working gay men, examining their quality of work life and career attitudes. The findings of the research provide a strong indication that contextual factors affect the quality of work life and work attitudes of gay men.  相似文献   
999.
In this paper characterizations of negative multinomial distributions based on conditional distributions have been studied.  相似文献   
1000.
In this paper, we propose an estimator for the population mean when some observations on the study and auxiliary variables are missing from the sample. The proposed estimator is valid for any unequal probability sampling design, and is based upon the pseudo empirical likelihood method. The proposed estimator is compared with other estimators in a simulation study.  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