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141.
This paper deals with the collective qualification of members of society as belonging to a certain category or group based on a fixed attribute. Our model contains three main features: the existence of individual gradual opinions, the notion of elitism (only the opinions of certain individuals are taken into account to delineate the reference group), and the idea of sequentiality (elites are successively created by using the previous elites’ opinions on a social decision scheme). The main results of the paper characterize when this sequential procedure converges for some intuitive ways of aggregating individual opinions. Finally, we analyze the role of convergence for two extra basic properties (symmetry and contractiveness) that elitist rules should possess.  相似文献   
142.
In this paper, we determine the density functions of nonsymmetrised doubly noncentral matrix variate beta type I and II distributions. The nonsymmetrised density functions of doubly noncentral and noncentral bimatrix variate generalised beta type I and II distributions are also obtained.  相似文献   
143.
We analyze the statistical properties of three price discovery measures: The variance ratio, the weighted price contribution (WPC), and the R2 of unbiasedness regressions. We find that, if the price process is a driftless martingale, only the WPC is an unbiased estimator for the return variance explained during a time interval. For autocorrelated processes with a drift, only the R2 of the unbiasedness regression is consistent, but it is biased for small samples.  相似文献   
144.
We examine the change of the gender wage gap in Austria between 2002 and 2007 using Juhn et al. (Workers and their wages, AEI Press, Washington DC, pp 107–143, 1991) decomposition. We analyze data from Austrian tax records which we merge with social security records and Austrian micro-censuses of the years 2002 and 2007. We find that the gender wage gap declined from 21 % in 2002 to 18 % in 2007. The main determinant of this decline is the relative improvement of women’s unobserved characteristics. The decline of the gender wage gap is also due to women having attained more formal education and to a convergence of men’s and women’s returns to education. Women’s improved educational attainments were partly offset by a shift in the demand for skilled workers that disadvantaged unskilled workers, most of whom are women, resulting in a moderate decrease of the gender pay gap over these years. Robustness checks confirm our results.  相似文献   
145.
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   
146.
The short‐time asymptotic behavior of option prices for a variety of models with jumps has received much attention in recent years. In this work, a novel second‐order approximation for at‐the‐money (ATM) option prices is derived for a large class of exponential Lévy models with or without Brownian component. The results hereafter shed new light on the connection between both the volatility of the continuous component and the jump parameters and the behavior of ATM option prices near expiration. In the presence of a Brownian component, the second‐order term, in time‐t, is of the form , with d2 only depending on Y, the degree of jump activity, on σ, the volatility of the continuous component, and on an additional parameter controlling the intensity of the “small” jumps (regardless of their signs). This extends the well‐known result that the leading first‐order term is . In contrast, under a pure‐jump model, the dependence on Y and on the separate intensities of negative and positive small jumps are already reflected in the leading term, which is of the form . The second‐order term is shown to be of the form and, therefore, its order of decay turns out to be independent of Y. The asymptotic behavior of the corresponding Black–Scholes implied volatilities is also addressed. Our method of proof is based on an integral representation of the option price involving the tail probability of the log‐return process under the share measure and a suitable change of probability measure under which the pure‐jump component of the log‐return process becomes a Y‐stable process. Our approach is sufficiently general to cover a wide class of Lévy processes, which satisfy the latter property and whose Lévy density can be closely approximated by a stable density near the origin. Our numerical results show that the first‐order term typically exhibits rather poor performance and that the second‐order term can significantly improve the approximation's accuracy, particularly in the absence of a Brownian component.  相似文献   
147.
This paper presents the results of an empirical study into the efficiency of the currency options market. The methodology derives from a simple model often applied to the spot and forward markets for foreign exchange. It relates the historic volatility of the underlying asset to the implied volatility of an option on the underlying at a specified prior time and then proceeds to test obvious hypotheses about the values of the coefficients. The study uses panel regression to address the problem of overlapping data which leads to dependence between observations. It also uses volatility data directly quoted on the market in order to avoid the biases which may occur when ‘backing out’ volatility from specific option pricing models. In general, the evidence rejects the hypothesis that the currency option market is efficient. This suggests that implied volatility is not the best predictor of future exchange rate volatility and should not be used without modification: the models presented in this paper could be a way of producing revised forecasts.  相似文献   
148.
Alterations in the institutional environment, as a result of the markets integration process and the consequent alterations in stakeholders’ conduct are one of the important vectors of changes in companies’ behavior. In that context, in addition to their yields those companies happen to worry about their attitudes in relation to social and environmental factors. Thus, the corporate social responsibility (CSR) is seen as one more strategy to maintain or increase their income and to harness the enterprise development. The main purpose of this study is the verification of the existing relation between Social Responsibility and the economic and financial performance of two companies in the business of Petroleum, Gas and Bio-combustibles. The investigation was based on a comparison of social-environmental practices developed by Petrobras S/A (Brazil) and Repsol S/A (Spain). For the purpose of verification of the relation between social-environmental performance and the economic-financial one, a linear regression analysis was carried out.  相似文献   
149.

In this paper, we derive two-sided bounds for the ruin probability in the compound Poisson risk model when the adjustment coefficient of the individual claim size distribution does not exist. These bounds also apply directly to the tails of compound geometric distributions. The upper bound is tighter than that of Dickson (1994). The corresponding lower bound, which holds under the same conditions, is tighter than that of De Vylder and Goovaerts (1984). Even when the adjustment coefficient exists, the upper bound is, in some cases, tighter than Lundberg's bound. These bounds are applicable for any positive distribution function with a finite mean. Examples are given and numerical comparisons with asymptotic formulae for the ruin probability are also considered.  相似文献   
150.
The paper proposes in a regime-shift framework, an arbitrage-free term structure model based on the target and Fed Funds Rates. Empirical observations suggest that a three-state regime-shift environment associated with FOMC monetary actions is justified. Then, a closed-form solution for zero-coupon bonds is derived where regime-shift risk is priced. The solution is flexible enough to incorporate additional state variables.  相似文献   
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