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341.
342.
Stefan Rayer 《Population research and policy review》2007,26(2):163-184
Population projections are judged primarily by their accuracy. The most commonly used measure for the precision component
of accuracy is the mean absolute percent error (MAPE). Recently, the MAPE has been criticized for overstating forecast error
and other error measures have been proposed. This study compares the MAPE with two alternative measures of forecast error,
the Median APE and an M-estimator. In addition, the paper also investigates forecast bias. The analysis extends previous studies
of forecast error by examining a wide range of trend extrapolation techniques using a dataset that spans a century for a large
sample of counties in the US. The main objective is to determine whether the choice of summary measure of error makes a difference
from a practitioner’s standpoint. The paper finds that the MAPE indeed produces error values that exceed the robust measures.
However, except for situations where extreme outliers rendered the MAPE meaningless, and which are rare in real world applications,
there was not a single instance where using an alternative summary measure of error would have led to a fundamentally different
evaluation of the projections. Moreover, where differences existed, it was not always clear that the values and patterns provided
by the robust measures were necessarily more correct than those obtained with the MAPE. While research into refinements and
alternatives to the MAPE and mean algebraic percent error are worthwhile, consideration of additional evaluation procedures
that go beyond a single criterion might provide more benefits to producers and users of population forecasts.
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Stefan RayerEmail: |
343.
Stefan Hoderlein Enno Mammen 《Econometrica : journal of the Econometric Society》2007,75(5):1513-1518
Nonseparable models do not impose any type of additivity between the unobserved part and the observable regressors, and are therefore ideal for many economic applications. To identify these models using the entire joint distribution of the data as summarized in regression quantiles, monotonicity in unobservables has frequently been assumed. This paper establishes that in the absence of monotonicity, the quantiles identify local average structural derivatives of nonseparable models. 相似文献
344.
345.
Prof. Dr. Stefan Kühl 《Organisationsberatung, Supervision, Coaching》2008,15(3):260-294
There is a general agreement that central roles in organizations like manager and consultants cannot be professionalized. However, the development of coaching and supervision seem to show a slightly different picture. Because of their focus on persons the pressure to professionalize seems to be comparable to service providers in law, medicine, religion and education. This article reconstructs the professionalization pressure on coaching and supervision and analyzes their professionalization process. 相似文献
346.
Stefan Nygaard Hansen Per Kragh Andersen Erik Thorlund Parner 《Lifetime data analysis》2014,20(4):584-598
A method based on pseudo-observations has been proposed for direct regression modeling of functionals of interest with right-censored data, including the survival function, the restricted mean and the cumulative incidence function in competing risks. The models, once the pseudo-observations have been computed, can be fitted using standard generalized estimating equation software. Regression models can however yield problematic results if the number of covariates is large in relation to the number of events observed. Guidelines of events per variable are often used in practice. These rules of thumb for the number of events per variable have primarily been established based on simulation studies for the logistic regression model and Cox regression model. In this paper we conduct a simulation study to examine the small sample behavior of the pseudo-observation method to estimate risk differences and relative risks for right-censored data. We investigate how coverage probabilities and relative bias of the pseudo-observation estimator interact with sample size, number of variables and average number of events per variable. 相似文献
347.
This paper presents an experimental study of common consequence effects in binary choice, willingness-to-pay (WTP) elicitation, and willingness-to-accept (WTA) elicitation. We find strong evidence in favor of the fanning out hypothesis (Machina, Econometrica 50:277–323, 1982) for both WTP and WTA. In contrast, the choice data do not show a clear pattern of violations in the absence of certainty effects. Our results underline the relevance of differences between pricing and choice tasks, and their implications for models of decision making under risk. 相似文献
348.
You can go your own way! The long‐term effectiveness of a self‐employment programme for welfare recipients in Germany 下载免费PDF全文
Joachim Wolff Anton Nivorozhkin Stefan Bernhard 《International Journal of Social Welfare》2016,25(2):136-148
In this study, we examined the long‐term effects of supporting welfare recipients by means of a subsidy to start their own business. We used administrative data and propensity score matching to estimate the impact of the subsidy on the probability of receiving welfare benefits and on unemployment status up to 72 months after programme start. We supplemented our estimation results with the results of a qualitative survey which provided insights into the diversity of entrepreneurial activities and the recipients' motivation for starting a business. Our results are encouraging. We found a stable positive effect on the outcomes of interest. We further found that foreign nationals and the long‐term unemployed benefit the most. We conclude that the subsidy allows some people to successfully start a business who would not have otherwise done so and who would have been less successful by choosing the alternative of continued job search. 相似文献
349.
This article introduces a feasible estimation method for a large class of semi and nonparametric models. We present the family
of generalized structured models which we wish to estimate. After highlighting the main idea of the theoretical smooth backfitting
estimators, we introduce a general estimation procedure. We consider modifications and practical issues, and discuss inference,
cross validation, and asymptotic theory applying the theoretical framework of Mammen and Nielsen (Biometrika 90: 551–566,
2003). An extensive simulation study shows excellent performance of our method. Furthermore, real data applications from environmetrics
and biometrics demonstrate its usefulness. 相似文献
350.
In a methodological study recently published in this journal (No. 3, Vol. 51, 1999: 550–564), Klein and Arzheimer compared two competing methods for the measurement of personal value orientations, namely, rating and ranking. Focussing on postmaterialist value orientations, they concluded that ratings are superior. In this article, it is argued that this conclusion is based on a misleading interpretation of findings and a questionable research design. In particular, the authors do not address the validity of the two measurement methods, implicitly assuming that they both capture the same cognitive dimension. Since it is unclear whether or not this assumption holds, a broader research approach is suggested here, which allows assessment of both the validity and the reliability of the competing methods. Given the lack of empirical evidence regarding these points, theoretical considerations, briefly outlined in the last section, are crucial for the selection of an appropriate measurement strategy. 相似文献