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81.
Tim Wylie Michael A. Schuh Rafal A. Angryk 《Journal of Combinatorial Optimization》2016,32(4):1107-1132
Many modern search applications are high-dimensional and depend on efficient orthogonal range queries. These applications span web-based and scientific needs as well as uses for data mining. Although k-nearest neighbor queries are becoming increasingly common due to mobile and geospatial applications, orthogonal range queries in high-dimensional data remain extremely important and relevant. For efficient querying, data is typically stored in an index optimized for either kNN or range queries. This can be problematic when data is optimized for kNN retrieval and a user needs a range query or vice versa. Here, we address the issue of using a kNN-based index for range queries, as well as outline the general computational geometry problem of adapting these systems to range queries. We refer to these methods as space-based decompositions and provide a straightforward heuristic for this problem. Using iDistance as our applied kNN indexing technique, we also develop an optimal (data-based) algorithm designed specifically for its indexing scheme. We compare this method to the suggested naïve approach using real world datasets. The data-based algorithm consistently performs better. 相似文献
82.
The Internet is providing an opportunity to revenue management practitioners to exploit the potential of auctions as a new price distribution channel. We develop a stochastic model for a high‐level abstraction of a revenue management system (RMS) that allows us to understand the potential of incorporating auctions in revenue management in the presence of forecast errors associated with key parameters. Our abstraction is for an environment where two market segments book in sequence and revenue management approaches consider auctions in none, one, or both segments. Key insights from our robust results are (i) limited auctions are best employed closest to the final sale date, (ii) counterbalancing forecast errors associated with overall traffic intensity and the proportion of customer arrivals in a segment is more important if an auction is adopted in that segment, and (iii) it is critically important not to err on the side of overestimating market willingness to pay. 相似文献
83.
Tim Williamson Sudharshan Canagarajah 《Development policy review : the journal of the Overseas Development Institute》2003,21(4):449-480
Various developing countries with weak public expenditure management systems are establishing virtual poverty funds (VPFs), drawing on the experience of Uganda's Poverty Action Fund. As a mechanism for tagging and tracking the performance of specific poverty‐reducing expenditures in the budget, a VPF can be useful. However, this article argues that such devices should be treated from the outset as transitional, and as part of wider processes of strengthening public expenditure management; otherwise, they can seriously distort public expenditure allocations and management systems, potentially undermining growth. Emphasis needs to be placed on identifying the right balance of expenditures in the entire budget; improving the effectiveness and efficiency of existing allocations; and developing better public‐sector policies for promoting pro‐poor private sector growth. 相似文献
84.
85.
Tim Hetherington 《Child Abuse Review》1999,8(2):120-132
This paper argues the case for an integrated approach to child protection services, embracing children's safety, risk and needs and incorporating formal assessment instruments. It then provides a brief overview of the new child protection system in South Australia. The steady rise in child abuse/neglect reports raises questions about how best to provide child protection services. Analysis of South Australian data suggests that much of the rise can be attributed to an increase in reports of neglect and emotional abuse and an increase in re‐notifications. This in turn raises questions about the traditional investigative approach. In 1995 Messages from Research advocated that agencies re‐focus on children's needs and concentrate less on investigations into safety and risk. The critical question is how to distinguish families requiring investigation from those needing support. The latest research suggests that such decision‐making in child protection is generally inconsistent and unreliable. This paper argues that statutory agencies should use formal assessment tools to determine the level and nature of their interventions. These arguments have been critical in the development of the new child protection model in SA, which relies on a centralized intake, differential response to reports and the structured decision‐making system. Initial evaluation of the new model indicates improvements in consistency of initial screening and responses to children in danger. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
86.
Baseline adjusted analyses are commonly encountered in practice, and regulatory guidelines endorse this practice. Sample size calculations for this kind of analyses require knowledge of the magnitude of nuisance parameters that are usually not given when the results of clinical trials are reported in the literature. It is therefore quite natural to start with a preliminary calculated sample size based on the sparse information available in the planning phase and to re‐estimate the value of the nuisance parameters (and with it the sample size) when a portion of the planned number of patients have completed the study. We investigate the characteristics of this internal pilot study design when an analysis of covariance with normally distributed outcome and one random covariate is applied. For this purpose we first assess the accuracy of four approximate sample size formulae within the fixed sample size design. Then the performance of the recalculation procedure with respect to its actual Type I error rate and power characteristics is examined. The results of simulation studies show that this approach has favorable properties with respect to the Type I error rate and power. Together with its simplicity, these features should make it attractive for practical application. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
87.
88.
Tim Lomas 《Journal for the theory of social behaviour》2018,48(1):134-152
Linguists have often remarked upon the polysemous nature of love, whereby the term encompasses a wide diversity of emotional relationships. Several typologies have been constructed to account for this diversity. However, these tend to be restricted in scope, and fail to fully represent the range of experiences signified by the term ‘love’ in discourse. In the interest of generating an expanded typology of love, encompassing its varied forms, an enquiry was conducted into relevant concepts found across the world's cultures, focusing on so‐called untranslatable words. Through a quasi‐systematic search of published and internet sources, 609 relevant words were identified. These were organised through a version of grounded theory into 14 categories, representing 14 different forms or ‘flavours’ of love. The result is an expanded theoretical treatment of love, allowing us to better appreciate the nuances of this most cherished and yet polysemous of concepts. 相似文献
89.
Tim Legrand 《Policy Studies》2016,37(5):440-455
ABSTRACTThe prominent corridor of bilateral policy transfer between Australia and the UK is underpinned by a long-standing cultural and political proximity. While ad hoc cases of transfer have in recent years been the subject to concerted attention from transfer theorists, much less attention has been given to the rise of multilateral, or transgovernmental, policy networks based on similar cultural and political amity amongst the ‘Anglosphere’ group of states including Australia, Canada, New Zealand, the UK and the US. Populated by policy elites and regularly interacting, these networks represent potentially important modes of policy transfer yet little is known about how they operate, with what purposes or what outcomes. This article therefore sets out research findings that offer an insight into 23 identified networks, suggesting that understanding the emergence of these networks are crucial to explaining any bilateral transfer between Anglosphere states in general, and specifically Australia and the UK. The article contends that a consideration of these networks provides insight into (i) the substantive landscape of Anglosphere policy learning and collaboration, (ii) the attendant dynamics of collaborative policy networks as elite, elusive and exclusive and (iii) iterative policy transfers. 相似文献
90.
Tim Mahoney 《经理人》2009,(11):104-105
什么是“利基品牌”(Niche brand)?作为美国斯巴鲁(Subaru)汽车公司的营销总监,我需要了解这个问题。斯巴鲁只占美国汽车市场份额的2%——显然,至少从数量上来讲,这就是一个利基市场。但数量本身还不足以说明问题。我认为,每个产品品牌都可以是利基品牌。人们绝对不会说,“我想买一辆通用(企业品牌)”,相反,他们会说,“我想买一辆雪佛兰”。 相似文献