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   6234篇
  免费   166篇
  国内免费   1篇
财政金融   1099篇
工业经济   539篇
计划管理   1003篇
经济学   1331篇
综合类   80篇
运输经济   36篇
旅游经济   87篇
贸易经济   946篇
农业经济   264篇
经济概况   1013篇
邮电经济   3篇
  2023年   39篇
  2021年   38篇
  2020年   81篇
  2019年   123篇
  2018年   153篇
  2017年   156篇
  2016年   159篇
  2015年   93篇
  2014年   151篇
  2013年   643篇
  2012年   186篇
  2011年   238篇
  2010年   192篇
  2009年   195篇
  2008年   186篇
  2007年   176篇
  2006年   145篇
  2005年   124篇
  2004年   122篇
  2003年   111篇
  2002年   116篇
  2001年   146篇
  2000年   142篇
  1999年   108篇
  1998年   118篇
  1997年   97篇
  1996年   88篇
  1995年   103篇
  1994年   73篇
  1993年   92篇
  1992年   88篇
  1991年   92篇
  1990年   83篇
  1989年   82篇
  1988年   75篇
  1987年   81篇
  1986年   82篇
  1985年   95篇
  1984年   105篇
  1983年   84篇
  1982年   78篇
  1981年   77篇
  1980年   89篇
  1979年   76篇
  1978年   61篇
  1977年   65篇
  1976年   46篇
  1975年   52篇
  1974年   40篇
  1973年   44篇
排序方式: 共有6401条查询结果,搜索用时 93 毫秒
101.
Multinomial Logit Model has analyzed the relationship between the frequency of visits to recreation areas and the motivational factors affecting the visits. Kastro Environment Preserving Site that is located in the Black Sea coast of Marmara region in Turkey, has been chosen as the site for this study. Kastro bay is a natural park that is visited only for recreational visits. The study has been conducted on a photogenic study group due to the proximity factor of Kastro bay close to Istanbul. Kastro bay is a popular recreational park due to its characteristic advantages such as a 200 m wide and approximately 2.5 km long beach and with its high quality vegetation. The vegetation type includes ash tree, oak tree, black pine, sand lily etc. Kastro bay is also the site for the Mediterranean seals (Monachus-monachus) which are at the level of extinction. Approximately 50,000 visitors visit the region during the months of July and August. It has been concluded that there is high direct correlation between the frequency of visits and the motivational factors. It has been determined that the visits are mostly based on the sea and the ecological tourism.Jel: O13, Q20, Q26, Q51, Q56, Q57  相似文献   
102.
103.
Seven computerprograms for non-linear regression or curve fitting problems are compared. The comparison of the programs, running in different computing centra, is restricted to the fit performance. Six model functions are fitted according to the least squares criterion to data series, arising from practical work. The special least squares minimization programs turned out to be better suited for these problems than general optimizing programs.  相似文献   
104.
A Stochastic Frontier Production Function with Flexible Risk Properties   总被引:1,自引:1,他引:1  
This paper considers a stochastic frontier production function which has additive, heteroscedastic error structure. The model allows for negative or positive marginal production risks of inputs, as originally proposed by Just and Pope (1978). The technical efficiencies of individual firms in the sample are a function of the levels of the input variables in the stochastic frontier, in addition to the technical inefficiency effects. These are two features of the model which are not exhibited by the commonly used stochastic frontiers with multiplicative error structures.An empirical application is presented using cross-sectional data on Ethiopian peasant farmers. The null hypothesis of no technical inefficiencies of production among these farmers is accepted. Further, the flexible risk models do not fit the data on peasant farmers as well as the traditional stochastic frontier model with multiplicative error structure.  相似文献   
105.
Selection and execution of site decontamination projects is often best left to local authorities, in accordance with the subsidiarity principle, even though the budget for such projects is made available through a central authority. In this paper we suggest a practical budget allocation policy which a central authority can employ to allocate budgets to local authorities, while still optimising the central authority's environmental objective function. The procedure is fully consistent with the principle of decentralisation of responsibility for selection and execution of projects, and requires a minimum information exchange between local and central levels. Despite the information asymmetry between local and central levels, incentive compatibility problems can be (partially) prevented by choosing an appropriate evaluation mechanism. At the same time, the procedure is computationally effective and efficient, and can guarantee a fair budget allocation, making it easy to implement and politically acceptable.  相似文献   
106.
107.
This paper examines differences in earnings by occupations, and within occupations by sex and by race, on the basis of the 1/100 Public Use Samples of the 1960 and 1970 U.S. Population Censuses. It employs interval analysis to establish 32 categories of occupations with similar characteristics. Little relation was found between mean earnings of occupational groups and the degree of earnings inequality within them. When the figures are examined by sex, it was found that men, on average, earned over twice as much as women in both years, but women's earnings were more unequally distributed (as measured by the Gini coefficient). Women are concentrated in the traditional “female” occupations, which tend to be those at the bottom of the earnings scale, and men have a monopoly of the higher paid occupations. But mean earnings for men exceeded those for women in all occupational groups except one, even in the primarily female occupations. Standardizing first for occupational distribution and then for earnings by occupation, it was found that earnings differences between males and females within occupation had a greater impact on the overall male-female earnings ratio than did differences in occupational distribution by sex. In contrast, when the figures are examined by race, the change in occupational distribution (primarily the movement of blacks out of farming and of blacks and Spanish speakers out of personal services) was the major factor. There was also a considerable degree of earnings inequality within demographic groups. The degree of inequality was in the main reduced when the demographic groups were subdivided into occupations, but it was still substantial. Additional factors like time worked, schooling, and experience must be taken into consideration in understanding this phenomenon.  相似文献   
108.
A bstract Bills introduced in the 100th and 101st Congresses would amend the Sherman Act in regard to retail competition Their two key provisions would seek to (1) alter the standard of proof currently used for the establishment of illicit vertical price arrangements and (2) codify into law the judicially-established per se rule against resale price maintenance agreements The first provision seeks to overcome the effect of the establishment by the Supreme Court , in its Monsanto decision, of what is viewed as an illogical and impossible burden of proof on plantiffs seeking damages in resale price maintenance cases The second merely incorporates into statutory law the court's declarations in the Dr Miles case of the per se illegality of resale price maintenance agreements Arguments for and against this legislation are discussed and recent developments are examined  相似文献   
109.
In questo lavoro viene fornita una nuova caratterizzazione dell'ammissibilità attraverso un adeguato uso della nozione di ammissibilità parziale. Questa caratterizzazione consente di affrontare le questioni riguardanti la completezza della classe delle decisioni ammissibiliti sotto condizioni «maneggevoli». Fornisce inoltre un approccio unificante al problema della completezza che consente di derivare, come casi particolari, alcuni risultati già noti nella letteratura sull'argomento.
In this paper a new characterization of admissibility is given for general decision problems. It is based on an adequate use of the notion of partial admissibility.A general decision problem is usually synthetized by a triplet (, , ) where is the states (or parameters) space, the set of available decisions and is a family of real valued functions defined on and expressing numerically the consequences of choosing when the state is . The set is regarded as a subset of the space of all real valued functions on endowed with the topology of pointwise convergence.As for as admissibility is concerned all the pertinent information about decisions are contained in the corresponding functionsW .This allows to introduce a notion of partial admissibility through the neigh-bourhoods of this topology. Admissibile decisions are then shown to be limits of monotone non increasing sequences of partially admissible decisions.Moreover this topological characterization allows to prove the completeness of classes of admissible decisions under acceptable systems of conditions which contain as special cases, known results in literature.


Lavoro svolto nell'ambito del Gruppo Nazionale per l'Analisi Funzionale e le sue Applicazioni del C.N.R.  相似文献   
110.
Regulatory agencies are often legally obliged to use a cost-benefit rule in revising environmental standards to reflect improvements in pollution-control techniques, but have considerable discretion over the timing of such revision. How should the agency use this discretion? Longer lags tend to encourage more intense R&;D effort by the regulated industry itself whilst discouraging parallel effort by external developers. Optimal implementation lags are characterized. The analysis calls into question the conventional view that “footdragging” by agencies is necessarily evidence of incompetence or regulatory capture. More generally, whether or not subject to conscious manipulation by regulatory agencies, the delays routinely observed in implementation may enhance welfare.  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