全文获取类型
收费全文 | 5201篇 |
免费 | 127篇 |
专业分类
管理学 | 738篇 |
民族学 | 41篇 |
人才学 | 1篇 |
人口学 | 480篇 |
丛书文集 | 38篇 |
理论方法论 | 573篇 |
综合类 | 45篇 |
社会学 | 2519篇 |
统计学 | 893篇 |
出版年
2023年 | 40篇 |
2021年 | 45篇 |
2020年 | 106篇 |
2019年 | 163篇 |
2018年 | 163篇 |
2017年 | 202篇 |
2016年 | 174篇 |
2015年 | 137篇 |
2014年 | 146篇 |
2013年 | 1006篇 |
2012年 | 162篇 |
2011年 | 172篇 |
2010年 | 162篇 |
2009年 | 130篇 |
2008年 | 170篇 |
2007年 | 155篇 |
2006年 | 115篇 |
2005年 | 121篇 |
2004年 | 121篇 |
2003年 | 127篇 |
2002年 | 131篇 |
2001年 | 99篇 |
2000年 | 96篇 |
1999年 | 76篇 |
1998年 | 70篇 |
1997年 | 69篇 |
1996年 | 58篇 |
1995年 | 63篇 |
1994年 | 60篇 |
1993年 | 61篇 |
1992年 | 59篇 |
1991年 | 56篇 |
1990年 | 51篇 |
1989年 | 48篇 |
1988年 | 63篇 |
1987年 | 59篇 |
1986年 | 28篇 |
1985年 | 42篇 |
1984年 | 51篇 |
1983年 | 59篇 |
1982年 | 36篇 |
1981年 | 39篇 |
1980年 | 32篇 |
1979年 | 34篇 |
1978年 | 40篇 |
1977年 | 31篇 |
1976年 | 35篇 |
1975年 | 29篇 |
1974年 | 19篇 |
1973年 | 19篇 |
排序方式: 共有5328条查询结果,搜索用时 0 毫秒
91.
Kyungmin Kim Philipp Kircher 《Econometrica : journal of the Econometric Society》2015,83(5):1849-1875
We consider a large market where auctioneers with private reservation values compete for bidders by announcing cheap‐talk messages. If auctioneers run efficient first‐price auctions, then there always exists an equilibrium in which each auctioneer truthfully reveals her type. The equilibrium is constrained efficient, assigning more bidders to auctioneers with larger gains from trade. The choice of the trading mechanism is crucial for the result. Most notably, the use of second‐price auctions (equivalently, ex post bidding) leads to the nonexistence of any informative equilibrium. We examine the robustness of our finding in various dimensions, including finite markets and equilibrium selection. 相似文献
92.
Christiane Baumeister James D. Hamilton 《Econometrica : journal of the Econometric Society》2015,83(5):1963-1999
This paper makes the following original contributions to the literature. (i) We develop a simpler analytical characterization and numerical algorithm for Bayesian inference in structural vector autoregressions (VARs) that can be used for models that are overidentified, just‐identified, or underidentified. (ii) We analyze the asymptotic properties of Bayesian inference and show that in the underidentified case, the asymptotic posterior distribution of contemporaneous coefficients in an n‐variable VAR is confined to the set of values that orthogonalize the population variance–covariance matrix of ordinary least squares residuals, with the height of the posterior proportional to the height of the prior at any point within that set. For example, in a bivariate VAR for supply and demand identified solely by sign restrictions, if the population correlation between the VAR residuals is positive, then even if one has available an infinite sample of data, any inference about the demand elasticity is coming exclusively from the prior distribution. (iii) We provide analytical characterizations of the informative prior distributions for impulse‐response functions that are implicit in the traditional sign‐restriction approach to VARs, and we note, as a special case of result (ii), that the influence of these priors does not vanish asymptotically. (iv) We illustrate how Bayesian inference with informative priors can be both a strict generalization and an unambiguous improvement over frequentist inference in just‐identified models. (v) We propose that researchers need to explicitly acknowledge and defend the role of prior beliefs in influencing structural conclusions and we illustrate how this could be done using a simple model of the U.S. labor market. 相似文献
93.
We measure the relative ideological positions of newspapers, voters, interest groups, and political parties, using data on ballot propositions. We exploit the fact that newspapers, parties, and interest groups take positions on these propositions, and the fact that citizens ultimately vote on them. We find that, on average, newspapers in the United States are located almost exactly at the median voter in their states—that is, they are balanced around the median voter. Still, there is a significant amount of ideological heterogeneity across newspapers, which is smaller than the one found for interest groups. However, when we group propositions by issue area, we find a sizable amount of ideological imbalance: broadly speaking, newspapers are to the left of the state‐level median voter on many social issues, and to the right on many economic issues. To complete the picture, we use two existing methods of measuring bias and show that the news and editorial sections of newspapers have almost identical partisan positions. 相似文献
94.
Many firms that sell digital copies of copyrighted materials online face a common dilemma: the use of digital rights management (DRM) to impede pirates can impose restrictions on legitimate use. We introduce a two‐period model in which the use of DRM in the first period affects the probability that a consumer finds a pirated copy in the second period; the threat of legal action reduces consumers’ consumption of pirated copies; and firms choose whether to sell, and at what prices, either strongly or weakly DRM‐protected products, or both. Furthermore, we incorporate the role of uncertainty concerning future levels of piracy. Using a two‐period model with uncertainty, we investigate a firm's optimal DRM strategies and present the optimal pricing strategy as well as product launch strategy under different market conditions. We find that one important characteristic of the optimal strategy is that it is optimal to maintain the same product line configuration strategy for both periods. We also characterize the conditions under which each strategy is optimal. 相似文献
95.
In this paper, we investigate the problem of determining the relationship, represented by similarity of the homologous gene configuration, between paired circular genomes using a regression analysis. We propose a new regression model for studying two circular genomes, where the Möbius transformation naturally arises and is taken as the link function, and propose the least circular distance estimation method, as an appropriate method for analyzing circular variables. The main utility of the new regression model is in identification of a new angular location of one of a homologous gene pair between two circular genomes, for various types of possible gene mutations, given that of the other gene. Furthermore, we demonstrate the utility of our new regression model for grouping of various genomes based on closeness of their relationship. Using angular locations of homologous genes from the five pairs of circular genomes (Horimoto et al. in Bioinformatics 14:789–802, 1998), the new model is compared with the existing models. 相似文献
96.
A problem of using a non‐convex penalty for sparse regression is that there are multiple local minima of the penalized sum of squared residuals, and it is not known which one is a good estimator. The aim of this paper is to give a guide to design a non‐convex penalty that has the strong oracle property. Here, the strong oracle property means that the oracle estimator is the unique local minimum of the objective function. We summarize three definitions of the oracle property – the global, weak and strong oracle properties. Then, we give sufficient conditions for the weak oracle property, which means that the oracle estimator becomes a local minimum. We give an example of non‐convex penalties that possess the weak oracle property but not the strong oracle property. Finally, we give a necessary condition for the strong oracle property. 相似文献
97.
In this paper, a hypothesis test for heteroscedasticity is proposed in a nonparametric regression model. The test statistic, which uses the residuals from a nonparametric fit of the mean function, is based on an adaptation of the well-known Levene's test. Using the recent theory for analysis of variance when the number of factor levels goes to infinity, the asymptotic distribution of the test statistic is established under the null hypothesis of homocedasticity and under local alternatives. Simulations suggest that the proposed test performs well in several situations, especially when the variance is a nonlinear function of the predictor. 相似文献
98.
One in five students report experimenting with tobacco before the age of 13 and most prevention efforts take place in the school setting. This study measures the effect of a single-lesson tobacco prevention curriculum, conducted by a health education center, focusing on knowledge of tobacco, ability to identify refusal techniques, and intent not to smoke. Data were collected, via electronic keypads, from students visiting a non-school, health education center in Michigan (n = 704 intervention and 85 comparison). Contingency table Chi-squared tests and t-tests demonstrated that a single lesson can improve general knowledge and ability to identify appropriate refusal techniques. Improvement in intent not to smoke was not significant because both groups had very high intent prior to implementation. Similar to results from other programs, multivariate logistic regression of gender, general knowledge, and skill identification revealed that only the skill variable was associated with intent not to smoke at pretest. Recommendations are given for further research and for designing more effective curricula or programs. 相似文献
99.
Domestic violence screening and service acceptance among adult victims in a dependency court setting
Many child welfare systems are unable to effectively identify and address co-occurring domestic violence and child maltreatment. In response, the Dependency Court Intervention Program for Family Violence implemented a protocol to identify indicators of domestic violence in families involved with child protection proceedings. This article highlights data that demonstrate the ability of an outreach and screening process to identify adult victims of domestic violence in dependency court and to offer them appropriate intervention services. 相似文献
100.
Weinstock J Whelan JP Meyers AW Watson JM 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2007,23(1):13-24
This study investigated the prevalence of gambling, gambling related NCAA violations, and disordered gambling in student-athletes
(n = 736) with a comparison cohort of students (n = 1,071) at four universities. Student-athletes reported similar rates of gambling frequency, use of a bookmaker, and disordered
gambling as students. After accounting for demographic differences, student-athletes were less likely to engage in sports
wagering than students. Several risk factors for disordered gambling were identified, including being male and reporting at
least one parent with a history of gambling problems. These findings suggest that problems associated with gambling are a
university-wide issue with student-athletes meriting additional attention because of implications for the integrity of intercollegiate
sports. Improved prevention and intervention efforts for collegiate gambling are recommended. 相似文献