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951.
This paper deals with the estimation of the mean of a spatial population. Under a design‐based approach to inference, an estimator assisted by a penalized spline regression model is proposed and studied. Proof that the estimator is design‐consistent and has a normal limiting distribution is provided. A simulation study is carried out to investigate the performance of the new estimator and its variance estimator, in terms of relative bias, efficiency, and confidence interval coverage rate. The results show that gains in efficiency over standard estimators in classical sampling theory may be impressive. 相似文献
952.
New Neural Network Methods for Forecasting Regional Employment: an Analysis of German Labour Markets
《Spatial Economic Analysis》2013,8(1):7-30
Abstract In this paper, a set of neural network (NN) models is developed to compute short-term forecasts of regional employment patterns in Germany. Neural networks are modern statistical tools based on learning algorithms that are able to process large amounts of data. Neural networks are enjoying increasing interest in several fields because of their effectiveness in handling complex data sets when the functional relationship between dependent and independent variables is not specified explicitly. The present paper compares two NN methodologies. First, it uses NNs to forecast regional employment in both the former West and East Germany. Each model implemented computes single estimates of employment growth rates for each German district, with a 2-year forecasting range. Next, additional forecasts are computed, by combining the NN methodology with shift-share analysis (SSA). Since SSA aims to identify variations observed among the labour districts, its results are used as further explanatory variables in the NN models. The data set used in our experiments consists of a panel of 439 German (NUTS 3) districts. Because of differences in the size and time horizons of the data, the forecasts for West and East Germany are computed separately. The out-of-sample forecasting ability of the models is evaluated by means of several appropriate statistical indicators. RÉSUMÉ Nouvelles Méthodes de Prévisions Fondées sur les Réseaux Neuronaux Appliquées l'Emploi Régional: Une Analyse des Marchés du travail dans l'Allemagne Réunifiée Dans cet article, les auteurs ont développé une série de modèles utilisant les réseaux neuronaux (RN) pour calculer des prévisions à court terme des paramètres de l'emploi, par région allemande. Les RN sont des outils statistiques modernes fondés sur des algorithmes d'apprentissage, capables de traiter de grandes quantités de données. On s'intéresse de plus en plus aux RN car ils permettent de gérer efficacement des séries de données complexes, bien que la relation fonctionnelle entre les variables dépendantes et indépendantes n'est pas définie explicitement. Cet article compare deux méthodologies fondées sur les RN. D'abord, il utilise les RN pour prévoir l'emploi régional dans les deux régions anciennement appelées Allemagne de l'Ouest et Allemagne de l'Est. Chaque modèle réalisé calcule de simples estimations des taux de croissance d'emploi pour chaque district allemand, sur une durée de 2 ans. Puis, il calcule des prévisions complémentaires, en combinant la méthodologie RN avec une analyse shift-share (ASS). Comme l'ASS a pour but d'identifier les variations relevées sur le marché local du travail, on emploie les résultats obtenus comme variables indépendantes complémentaires dans les modèles RN. Notre échantillon de données utilisé dans nos expériences se compose de 439 districts allemands. Comme les districts composant l’échantillon présentent de grandes différences en matière de taille et d'horizon temporel, les prévisions pour l'Allemagne de l'Ouest et l'Allemagne de l'Est sont calculées séparément. La capacité des modèles à établir des prévisions hors – échantillon est évaluée avec différents indicateurs statistiques appropriés. RESUMEN Nuevos métodos de redes neurales para la previsión de empleo regional: un análisis para los mercados laborales de Alemania En este documento desarrollamos una serie de modelos de redes neurales (RN) para calcular las previsiones a corto plazo de los modelos de empleo regional en Alemania. Las RN son modernas herramientas de estadísticas basadas en algoritmos de aprendizaje capaces de procesar un gran número de datos. Las RN se están popularizando cada vez más en diferentes campos porque son capaces de manejar grupos de datos complejos cuando la relación funcional entre las variables dependientes e independientes no está explícitamente especificada. En este artículo comparamos dos metodologías de RN. Primero, utilizamos las RN para pronosticar el empleo regional en Alemania del oeste y del este. Cada modelo aplicado computa por separado los cálculos de las tasas de crecimiento de empleo para cada distrito alemán, con un intervalo de previsión de 2 años. Luego se calculan las previsiones adicionales combinando la metodología de las RN con el análisis shift-share. Dado que los análisis shift-share identifican las variaciones observadas entre los distritos laborales, sus resultados se utilizan como otras variables explicatorios en los modelos de RN. El grupo de datos utilizado en nuestros experimentos abarca un panel de 439 distritos alemanes. Las previsiones para Alemania del oeste y este se computan por separado debido a las diferencias en los horizontes de tamaño y tiempo de los datos. La capacidad de previsión a partir de las muestras en los modelos es evaluada mediante varios indicadores adecuados de estadísticas. 相似文献
953.
Consider a linear regression model and suppose that our aim is to find a confidence interval for a specified linear combination of the regression parameters. In practice, it is common to perform a Durbin–Watson pretest of the null hypothesis of zero first‐order autocorrelation of the random errors against the alternative hypothesis of positive first‐order autocorrelation. If this null hypothesis is accepted then the confidence interval centered on the ordinary least squares estimator is used; otherwise the confidence interval centered on the feasible generalized least squares estimator is used. For any given design matrix and parameter of interest, we compare the confidence interval resulting from this two‐stage procedure and the confidence interval that is always centered on the feasible generalized least squares estimator, as follows. First, we compare the coverage probability functions of these confidence intervals. Second, we compute the scaled expected length of the confidence interval resulting from the two‐stage procedure, where the scaling is with respect to the expected length of the confidence interval centered on the feasible generalized least squares estimator, with the same minimum coverage probability. These comparisons are used to choose the better confidence interval, prior to any examination of the observed response vector. 相似文献
954.
This paper proposes an extension to the regional econometric input–output model (REIM) [Conway, R.S. (1990) The Washington Projection and Simulation Model: A Regional Interindustry Econometric Model. International Regional Science Review, 13, 141–165; Israilevich, P.R., G.J.D. Hewings, M. Sonis and G.R. Schindler (1997) Forecasting Structural Change with a Regional Econometric Input–Output Model. Journal of Regional Science, 37, 565–590]. We integrate a demand system with age and income parameters into the REIM. The extended model thus addresses concerns about the effects of household heterogeneity. The initial testing is conducted with a model for the Chicago metropolitan area. First, using aggregate expenditure data by income and age groups, the almost ideal demand system with group fixed effects is constructed. Next, the estimated demand system is linked to the REIM to reflect long-term changes in the age and income distribution of households. The long-range simulation from the extended model takes into account structural changes in expenditure type stemming from changing demographic composition. The extended model further broadens the scope of impact analysis under various scenarios associated with age and income changes. 相似文献
955.
《International Journal of Forecasting》2023,39(2):967-980
Real-time state estimation and forecasting are critical for the efficient operation of power grids. In this paper, a physics-informed Gaussian process regression (PhI-GPR) method is presented and used for forecasting and estimating the phase angle, angular speed, and wind mechanical power of a three-generator power grid system using sparse measurements. In standard data-driven Gaussian process regression (GPR), parameterized models for the prior statistics are fit by maximizing the marginal likelihood of observed data. In the PhI-GPR method, we propose to compute the prior statistics offline by solving stochastic differential equations (SDEs) governing the power grid dynamics. The short-term forecast of a power grid system dominated by wind generation is complicated by the stochastic nature of the wind and the resulting uncertainty in wind mechanical power. Here, we assume that the power grid dynamics are governed by swing equations, with the wind mechanical power fluctuating randomly in time. We solve these equations for the mean and covariances of the power grid states using the Monte Carlo simulation method.We demonstrate that the proposed PhI-GPR method can accurately forecast and estimate observed and unobserved states. For the considered problem, PhI-GPR has computational advantages over the ensemble Kalman filter (EnKF) method: In PhI-GPR, ensembles are computed offline and independently of the data acquisition process, whereas for EnFK, ensembles are computed online with data acquisition, rendering real-time forecast more challenging. We also demonstrate that the PhI-GPR forecast is more accurate than the EnKF forecast when the random mechanical wind power is non-Markovian. In contrast, the two methods produce similar forecasts for the Markovian mechanical wind power.For observed states, we show that PhI-GPR provides a forecast comparable to the standard data-driven GPR; both forecasts are significantly more accurate than the autoregressive integrated moving average (ARIMA) forecast. We also show that the ARIMA forecast is more sensitive to observation frequency and measurement errors than the PhI-GPR forecast. 相似文献
956.
B.J.T. Morgan 《Statistica Neerlandica》1988,42(4):253-272
There is much current interest in trying to improve the fit of the classical logit and probit models for quantal response data. This is done through transforming the dose scale and/or embedding a classical model in a richer parametric family. This paper provides an historical review of the development of this work, and attempts to make practical recommendations. Much of the work extends directly to the case of logistic regression. 相似文献
957.
文章以52个国家级高新区作为样本,基于Malqmquist指数对中国高新区技术赶超进行分解测度,并采用后向逐步回归方法提炼出关键影响因素。结果显示:中国高新区技术赶超主要是由技术前沿面上移和管理效率提升推动的;资本推进战略对全要素生产率改善起到了抑制作用,而资本深化起到了推动作用;专业化集聚和母城科技投入未促进高新区技术赶超。根据上述研究结果,高新区应该进一步强化创新资源集聚、增进创新孵化功能及优化空间资源。 相似文献
958.
本文对基金市场的进入次序优势进行了实证研究。选取54只封闭式基金作为样本,以基金净值增长率为因变量,以基金设立时间、基金规模、证券指数变化、利率等为自变量,进行回归分析。结果显示基金市场存在先动优势,即基金设立时间越早,平均净值增长率越高。 相似文献
959.
Suwen Pan Roderick M Xiurong He 《中国与世界经济(英文版)》2009,17(4):72-87
This paper investigates the impacts of financial intermediary (or banking) development on village-level per capita income using a Chinese dataset for selected years between 1993 and 2006. The empirical results from a random effect regression model indicate that mean per capita income in rural villages follows an inverted U-shaped path as financial intermediation develops. However, using a pooled quantile regression approach, we find that median per capita income in rural villages follows a positive linear path, rather than an inverted U-shaped path, as financial intermediation develops. The positive linear effect of financial intermediary development is observed at the lower and higher ends of the conditional per capita income distribution. This suggests that development of financial intermediation in China might not have statistically significant differential effects in low-income or high-income rural villages. 相似文献
960.
This paper revisits the long‐run determinants of house prices, and analyzes the house price dynamics using Korean data taking into account the close relationship between house prices and household debt. The results of cointegrating regression indicate that the major portion of the rise in house prices in Korea over the last 15 years can be explained by changes in macro variables such as household income, the demographic structure, the user cost of home ownership and the housing stock supply. The results also confirm that house prices are, indeed, closely linked to the steep increase in household debt seen over this period. Estimation of an error correction model shows that the extent of convergence of actual house prices to their long‐run equilibrium path has weakened somewhat since the global financial crisis while the speed of convergence has slowed, indicating structural changes in the Korean housing market. Finally, a forecast for house prices over the next several years suggests that they are unlikely to rise as sharply as they did in the 2000s, given the likely changes in the macro‐financial environment, and that their future path will be closely associated with that of the household debt‐to‐income ratio. 相似文献