全文获取类型
收费全文 | 29079篇 |
免费 | 833篇 |
国内免费 | 3篇 |
专业分类
管理学 | 4153篇 |
民族学 | 135篇 |
人才学 | 4篇 |
人口学 | 2731篇 |
丛书文集 | 149篇 |
教育普及 | 2篇 |
理论方法论 | 2766篇 |
现状及发展 | 1篇 |
综合类 | 470篇 |
社会学 | 14586篇 |
统计学 | 4918篇 |
出版年
2021年 | 164篇 |
2020年 | 425篇 |
2019年 | 601篇 |
2018年 | 694篇 |
2017年 | 959篇 |
2016年 | 725篇 |
2015年 | 542篇 |
2014年 | 706篇 |
2013年 | 4647篇 |
2012年 | 951篇 |
2011年 | 936篇 |
2010年 | 721篇 |
2009年 | 628篇 |
2008年 | 703篇 |
2007年 | 747篇 |
2006年 | 722篇 |
2005年 | 703篇 |
2004年 | 650篇 |
2003年 | 562篇 |
2002年 | 633篇 |
2001年 | 754篇 |
2000年 | 726篇 |
1999年 | 649篇 |
1998年 | 498篇 |
1997年 | 461篇 |
1996年 | 453篇 |
1995年 | 428篇 |
1994年 | 422篇 |
1993年 | 421篇 |
1992年 | 475篇 |
1991年 | 456篇 |
1990年 | 411篇 |
1989年 | 419篇 |
1988年 | 402篇 |
1987年 | 382篇 |
1986年 | 344篇 |
1985年 | 410篇 |
1984年 | 407篇 |
1983年 | 375篇 |
1982年 | 328篇 |
1981年 | 262篇 |
1980年 | 264篇 |
1979年 | 299篇 |
1978年 | 265篇 |
1977年 | 240篇 |
1976年 | 212篇 |
1975年 | 244篇 |
1974年 | 200篇 |
1973年 | 167篇 |
1972年 | 143篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
191.
This study investigates the extent and nature of housing affordability for elderly nonmetropolitan female heads of household
using data from the Panel Study of Income Dynamics. The results indicate that over one-third of elderly nonmetropolitan female
heads of household experience housing poverty and that those who rent, who have fair to poor health, and who are minorities
are particularly vulnerable. Housing affordability, measured by the concept of housing poverty, identifies households struggling
to meet basic needs while the conventional 25% of income for housing expenditures ratio identifies a larger population. The
findings suggest the need for multifaceted public policies to address the problem of housing poverty.
Her research interests include housing affordability, housing and community vitality, and decision making. She received her
Ph.D. from Purdue University.
Sooyoun Park is in the same department as a Project Assistant on a USDA-funded research project entitled “Housing Affordability
in Rural Areas,” which is a joint project between Nebraska and Wisconsin. Her research interests focus on housing management
behavior in relation to housing expenditure burden. She received her Ph.D. from the University of Nebraska-Lincoln. 相似文献
192.
193.
UNDERSTANDING MAIL SURVEY RESPONSE BEHAVIOR A META-ANALYSIS 总被引:5,自引:0,他引:5
YAMMARINO FRANCIS J.; SKINNER STEVEN J.; CHILDERS TERRY L. 《Public opinion quarterly》1991,55(4):613-639
A meta-analysis of prior studies of techniques designed to inducemail survey response rates was conducted. Research encompassing184 effects (study outcomes) in 115 studies (articles) for 17predictors of response rate was examined. The average effectsize across all manipulations was r=.065, indicating an averageincrease of about 6.5 percent in response rates for manipulations.Effect sizes for specific predictors and two potential moderatorsof effects were examined. Results indicated that repeated contactsin the form of preliminary notification and follow-ups, appeals,inclusion of a return envelope, postage, and monetary incentives,were effective in increasing survey response rates. Significanteffect sizes for the predictors ranged from an increase in responseof 2 percent to 31 percent. Implications of the results forthe conduct of mail surveys and future research on mail surveyresponse behavior are discussed. 相似文献
194.
John E. Roemer 《Social Choice and Welfare》1994,11(4):355-380
Voter preferences are characterized by a parameter s (say, income) distributed on a set S according to a probability measure F. There is a single issue (say, a tax rate) whose level, b, is to be politically decided. There are two parties, each of which is a perfect agent of some constituency of voters, voters with a given value of s. An equilibrium of the electoral game is a pair of policies, b 1 and b 2, proposed by the two parties, such that b i maximizes the expected utility of the voters whom party i represents, given the policy proposed by the opposition. Under reasonable assumptions, the unique electoral equilibrium consists in both parties proposing the favorite policy of the median voter. What theory can explain why, historically, we observe electoral equilibria where the ‘right’ and ‘left’ parties propose different policies? Uncertainty concerning the distribution of voters is introduced. Let {F(t)} t ε T be a class of probability measures on S; all voters and parties share a common prior that the distribution of t is described by a probability measure H on T. If H has finite support, there is in general no electoral equilibrium. However, if H is continuous, then electoral equilibrium generally exists, and in equilibrium the parties propose different policies. Convergence of equilibrium to median voter politics is proved as uncertainty about the distribution of voter traits becomes small. 相似文献
195.
E. Reschenhofer 《Statistical Papers》1994,35(1):309-322
The suitability of autoregressive fractionally integrated moving average (ARFIMA) processes for the modeling of US aggregate output is examined. We consider the two most widely used methods for the estimation of the fractionally differencing parameter and discuss the empirical results obtained by applying these methods to the quarterly post-war real GNP as well as to the quarterly post-war real GNP per capita. Contrary to previous findings, we conclude that evidence for a fractional degree of integration is poor. 相似文献
196.
197.
This article introduces a new model for transaction prices in the presence of market microstructure noise in order to study the properties of the price process on two different time scales, namely, transaction time where prices are sampled with every transaction and tick time where prices are sampled with every price change. Both sampling schemes have been used in the literature on realized variance, but a formal investigation into their properties has been lacking. Our empirical and theoretical results indicate that the return dynamics in transaction time are very different from those in tick time and the choice of sampling scheme can therefore have an important impact on the properties of realized variance. For RV we find that tick time sampling is superior to transaction time sampling in terms of mean-squared-error, especially when the level of noise, number of ticks, or the arrival frequency of efficient price moves is low. Importantly, we show that while the microstructure noise may appear close to IID in transaction time, in tick time it is highly dependent. As a result, bias correction procedures that rely on the noise being independent, can fail in tick time and are better implemented in transaction time. 相似文献
198.
V. Scott H. Solberg Aaron H. Carlstrom Kimberly A. S. Howard Janice E. Jones 《The Career development quarterly》2007,55(4):313-327
Using cluster analysis, 789 predominately Latino and African American high school youth were classified into varying academic at‐risk profiles using self‐reported levels of academic confidence, motivation to attend school, perceived family support, connections with teachers and peers, and exposure to violence. Six clusters emerged, 5 of which were identified as “at‐risk.” The clusters were examined in relation to academic stress, health status, grades, and school retention. Exposure to violence was one distinguishing feature of youth identified as most vulnerable, vulnerable, and resilient; however, youth identified as resilient recorded better academic outcomes. 相似文献
199.
Catriona M. Queen Ben J. Wright Casper J. Albers 《Australian & New Zealand Journal of Statistics》2007,49(3):221-239
The problem of modelling multivariate time series of vehicle counts in traffic networks is considered. It is proposed to use a model called the linear multiregression dynamic model (LMDM). The LMDM is a multivariate Bayesian dynamic model which uses any conditional independence and causal structure across the time series to break down the complex multivariate model into simpler univariate dynamic linear models. The conditional independence and causal structure in the time series can be represented by a directed acyclic graph (DAG). The DAG not only gives a useful pictorial representation of the multivariate structure, but it is also used to build the LMDM. Therefore, eliciting a DAG which gives a realistic representation of the series is a crucial part of the modelling process. A DAG is elicited for the multivariate time series of hourly vehicle counts at the junction of three major roads in the UK. A flow diagram is introduced to give a pictorial representation of the possible vehicle routes through the network. It is shown how this flow diagram, together with a map of the network, can suggest a DAG for the time series suitable for use with an LMDM. 相似文献
200.
Terrorist actions are aimed at maximizing harm (health, psychological, economical, and political) through the combined physical impacts of the act and fear. Immediate and effective response to a terrorist act is critical to limit human and environmental harm, effectively restore facility function, and maintain public confidence. Though there have been terrorist attacks in public facilities that we have learned from, overall our experiences in restoration of public facilities following a terrorist attack are limited. Restoration of public facilities following a release of a hazardous material is inherently far more complex than in industrial settings and has many unique technical, economic, social, and political challenges. For example, there may be a great need to quickly restore the facility to full operation and allow public access even though it was not designed for easy or rapid restoration, and critical information is needed for quantitative risk assessment and effective restoration must be anticipated to be incomplete and uncertain. Whereas present planning documents have substantial linearity in their organization, the “adaptive management” paradigm provides a constructive parallel paradigm for restoration of public facilities that anticipates and plans for uncertainty, inefficiencies, and stakeholder participation. Adaptive management grew out of the need to manage and restore natural resources in highly complex and changing environments with limited knowledge about causal relationships and responses to restoration actions. Similarities between natural resource management and restoration of a public facility after a terrorist attack suggest that integration of adaptive management principles explicitly into restoration processes will result in substantially enhanced and flexible responses necessary to meet the uncertainties of potential terrorist attacks. 相似文献