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31.
Crucial to the long-term contribution of immigration to a receiving country's population is the extent to which the immigrants reproduce themselves in subsequent, native-born generations. Using conventional projection methodologies, this fertility contribution may be poorly estimated primarily because of problems in projecting the number of immigrants who are at risk of childbearing. We propose an alternative method that obviates the need to project the number of immigrants by using the full sending-country birth cohort as the risk group to project their receiving-country childbearing. This "sending-country birth cohort" method is found to perform dramatically better than conventional methods when projecting to 1999 from base years both before and after the large increase in inflows of Mexican immigrants to the United States in the late 1980s. Projecting forward from 1999, we estimate a cumulative contribution of Mexican immigrant fertility from the 1980s to 2040 of 36 million births, including 25% to 50% more births after 1995 than are projected using conventional methods. 相似文献
32.
Over the past 20 years, the internet has provided an expedient mode of communication and access to a wealth of information. The internet is a valuable tool; however, it can also be detrimental to the wellbeing of children due to numerous online hazards. There is the potential for children to be abused via cyberspace through online sexual solicitation and access to pornography. Indeed, the internet is replete with inappropriate material, including pornography, chatrooms with adult themes and access to instant messaging wherein others could misrepresent themselves. Because children are actively utilizing the internet where unknown others can have access to them or where they can be exposed to inappropriate sexual materials, they require safeguarding and education in safe internet use. The purpose of this article is to provide a discussion of how to safeguard children from and educate them about online sexual solicitation and pornography. We contend that society needs an overall conceptual shift in its attitude towards young people's internet use. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Projections of total population have been evaluated extensively, but few studies have investigated the performance of projections by age. Of those that did, most focused on projections for countries or other large areas. In this article, we evaluate projections by age for Florida and its counties, as produced and published between 1996 and 2010 by the Bureau of Economic and Business Research at the University of Florida. We first compare the precision and bias of projections of total population with the precision and bias of projections by age, at both the state and county levels. This is followed by a more detailed examination of county-level projection errors for individual age groups, first in the aggregate and then disaggregated by sex and population size. The second part of the analysis focuses on a number of adjustments that were implemented in projections published in 2006 and 2009. Intended to improve accuracy, these adjustments involved updates to the base population, fertility rates, and survival rates. We compare the accuracy of projections incorporating these adjustments with the accuracy of projections excluding them. We believe this study offers a unique opportunity to examine a variety of characteristics regarding the forecast accuracy of small-area population projections by age. 相似文献
37.
This paper experimentally investigates a preference condition for loss aversion in the framework of cumulative prospect theory (CPT). We propose the concepts of absolute and relative loss premiums in order to measure the extent of loss aversion and to derive notions of increasing, constant, and decreasing loss aversion. While in only one of the 28 choice situations analyzed loss neutrality and loss seeking can be rejected, about 51% of all choices are loss averse and, due to the large extent of loss aversion revealed by these choices, the average loss premium is positive for most choice situations. Female subjects exhibit both a more frequent occurrence and a larger extent of loss aversion. 相似文献
38.
Stefan Gre 《International social security review》2006,59(3):27-47
The objectives guiding healthcare reforms in Germany, Switzerland and the Netherlands were to increase efficiency and consumer satisfaction in the provision of healthcare services. This paper reviews the incentives for and instruments of competition for consumers, sickness funds and healthcare providers in these three countries which are necessary to fulfil these objectives. Incentives for risk selection of sickness funds are high in Germany and Switzerland while they are low in the Netherlands. Incentives for consumer choice are also highest in Germany and Switzerland. In all three countries sickness funds have only a few instruments of competition. The effects of competition have been disappointing so far. The objectives of competitive healthcare reforms can be achieved only if incentives for and instruments of competition consistently support competitive behaviour on the part of market actors. 相似文献
39.
Klaus Schneeberger Matthias Huttenlau Benjamin Winter Thomas Steinberger Stefan Achleitner Johann Sttter 《Risk analysis》2019,39(1):125-139
This article presents a flood risk analysis model that considers the spatially heterogeneous nature of flood events. The basic concept of this approach is to generate a large sample of flood events that can be regarded as temporal extrapolation of flood events. These are combined with cumulative flood impact indicators, such as building damages, to finally derive time series of damages for risk estimation. Therefore, a multivariate modeling procedure that is able to take into account the spatial characteristics of flooding, the regionalization method top‐kriging, and three different impact indicators are combined in a model chain. Eventually, the expected annual flood impact (e.g., expected annual damages) and the flood impact associated with a low probability of occurrence are determined for a study area. The risk model has the potential to augment the understanding of flood risk in a region and thereby contribute to enhanced risk management of, for example, risk analysts and policymakers or insurance companies. The modeling framework was successfully applied in a proof‐of‐concept exercise in Vorarlberg (Austria). The results of the case study show that risk analysis has to be based on spatially heterogeneous flood events in order to estimate flood risk adequately. 相似文献
40.
Martin Becker Ralph Friedmann Stefan Klößner Walter Sanddorf-Köhle 《AStA Advances in Statistical Analysis》2007,91(1):3-21
New tests are proposed for the specification of the intraday price process of a risky asset,
based on open, high, low, and close prices. Under the null of a Brownian process we derive two stochastically
independent, unbiased volatility estimators. For a Hausman specification test we prove its equivalence
with an F-test, consider its robustness against variation in drift and volatility, and analyze the power
against an Ornstein–Uhlenbeck process, as well as a random walk with alternative distributions. 相似文献