全文获取类型
收费全文 | 90812篇 |
免费 | 2964篇 |
国内免费 | 18篇 |
专业分类
管理学 | 12370篇 |
民族学 | 554篇 |
人才学 | 25篇 |
人口学 | 6910篇 |
丛书文集 | 605篇 |
理论方法论 | 9457篇 |
综合类 | 2670篇 |
社会学 | 42418篇 |
统计学 | 18785篇 |
出版年
2023年 | 504篇 |
2021年 | 575篇 |
2020年 | 1519篇 |
2019年 | 2201篇 |
2018年 | 2081篇 |
2017年 | 3167篇 |
2016年 | 2378篇 |
2015年 | 2057篇 |
2014年 | 2643篇 |
2013年 | 18907篇 |
2012年 | 2446篇 |
2011年 | 2252篇 |
2010年 | 2060篇 |
2009年 | 2244篇 |
2008年 | 2148篇 |
2007年 | 1972篇 |
2006年 | 2189篇 |
2005年 | 2359篇 |
2004年 | 2177篇 |
2003年 | 1886篇 |
2002年 | 2005篇 |
2001年 | 1997篇 |
2000年 | 1769篇 |
1999年 | 1682篇 |
1998年 | 1493篇 |
1997年 | 1331篇 |
1996年 | 1289篇 |
1995年 | 1321篇 |
1994年 | 1290篇 |
1993年 | 1272篇 |
1992年 | 1260篇 |
1991年 | 1198篇 |
1990年 | 1175篇 |
1989年 | 1025篇 |
1988年 | 1123篇 |
1987年 | 990篇 |
1986年 | 891篇 |
1985年 | 1067篇 |
1984年 | 1124篇 |
1983年 | 1006篇 |
1982年 | 939篇 |
1981年 | 865篇 |
1980年 | 801篇 |
1979年 | 865篇 |
1978年 | 759篇 |
1977年 | 685篇 |
1976年 | 650篇 |
1975年 | 633篇 |
1974年 | 525篇 |
1973年 | 433篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
771.
772.
Ranked set sampling is a sampling approach that leads to improved statistical inference in situations where the units to be sampled can be ranked relative to each other prior to formal measurement. This ranking may be done either by subjective judgment or according to an auxiliary variable, and it need not be completely accurate. In fact, results in the literature have shown that no matter how poor the quality of the ranking, procedures based on ranked set sampling tend to be at least as efficient as procedures based on simple random sampling. However, efforts to quantify the gains in efficiency for ranked set sampling procedures have been hampered by a shortage of available models for imperfect rankings. In this paper, we introduce a new class of models for imperfect rankings, and we provide a rigorous proof that essentially any reasonable model for imperfect rankings is a limit of models in this class. We then describe a specific, easily applied method for selecting an appropriate imperfect rankings model from the class. 相似文献
773.
In the paper we present a new method of calculating sampling intervals, so-called windows, allowing an experimenter some flexibility in timing the sample collection, while a minimum required design efficiency for parameter estimation is assured. The method is based on the Equivalence Theorem for D-optimality what makes the length of each window related to the parameter sensitivities. An example of calculating the windows in a pharmacokinetic study is presented. Some other methods of calculating efficient sampling windows are briefly discussed. 相似文献
774.
Peltzman [Peltzman, S., 1984. Constituent interest and congressional voting. Journal of Law and Economics 27, 181–210] argues that if constituents’ economic interests have well-defined “winners and losers” and are appropriately measured, then constituents’ economic interests, and not legislator ideology, are the most important determinates of legislator voting. We test Peltzman's theory by examining senatorial voting on three mandated spending limitation bills. We find, consistent with Peltzman's theory, that the ratio of federal spending in a senator's state to federal taxes paid by that state, and not a senator's personal ideology, matters on legislation where there are well-defined economic “winners and losers.” This is particularly important because unlike other constituents’ economic interest measures that only impact a fraction of the constituency, the ratio of federal spending to federal taxes in a state represents the economic interests of all the constituents in a state. 相似文献
775.
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
776.
The training of medical practitioners to improve the practitioner/patient relationship may be difficult, as limitations often exist on the choice of patients included in the study. A specific study of this type of training is given. It is proposed that a simple modification and generalization of Yates' plaid-square designs be used. It is shown that a replicated plaid-design incorporates as a special case the criss-cross or strip-plot design. The usefulness of these designs in studies of the training of medical practitioners is illustrated. The basic characteristics of their analysis are outlined. 相似文献
777.
778.
779.
The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software. 相似文献
780.
Gay affirmative practice has recently been introduced into the social work literature as a culturally sensitive model for
working with gay, lesbian, and bisexual (GLB) adults, however, this model has rarely been applied to practice with GLB youth.
In this article, the authors review the literature to present the main tenets of gay affirmative practice, outline the challenges
that GLB youth face, and delineate the environmental and individual strengths that can be enhanced to promote well-being.
The authors then apply the gay affirmative practice model to GLB youth, offering concrete information about the specific knowledge,
attitudes, and skills that social workers should acquire to better serve the unique, yet diverse, needs of GLB youth. 相似文献