首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   473篇
  免费   19篇
  国内免费   1篇
管理学   85篇
民族学   7篇
人口学   36篇
丛书文集   4篇
理论方法论   46篇
综合类   6篇
社会学   132篇
统计学   177篇
  2023年   9篇
  2022年   11篇
  2021年   13篇
  2020年   22篇
  2019年   32篇
  2018年   28篇
  2017年   51篇
  2016年   20篇
  2015年   13篇
  2014年   35篇
  2013年   99篇
  2012年   24篇
  2011年   14篇
  2010年   13篇
  2009年   9篇
  2008年   12篇
  2007年   13篇
  2006年   7篇
  2005年   8篇
  2004年   4篇
  2003年   7篇
  2002年   9篇
  2001年   7篇
  1999年   5篇
  1998年   3篇
  1995年   1篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1986年   3篇
  1985年   3篇
  1983年   1篇
  1981年   2篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
  1967年   1篇
排序方式: 共有493条查询结果,搜索用时 578 毫秒
91.
Ali MM  Cleland J  Shah IH 《Demography》2003,40(4):659-673
Using "calendar" data for single women aged 15-24 from successive Demographic and Health Surveys (DHS) conducted in Colombia and Peru during the 1990s, we document trends, year by year, in sexual activity, the use of contraceptives, and subsequent reproductive outcomes. We provide evidence of the important and hitherto largely untapped potential of DHS calendar data to draw complete sexual and reproductive profiles when data from various surveys are integrated. Over the period 1985-1999, young single women in both Colombia and Peru became sexually active at younger ages. The use of contraceptives, especially the use of condoms, increased but did not fully offset the rise in sexual activity, and thus the incidence of premarital conceptions rose among young single women. In both countries, sharp declines occurred in the proportion of premaritally conceived births that were reported as being wanted.  相似文献   
92.
This article is aimed at applying Taguchi method in Kansei engineering and explores a way to integrate it into an industrial product design stage. Emotional customer needs are derived using Kansei image word pairs. The Taguchi-based approach is validated by a case study with mobile phones. Experimental work in implementing the proposed approach was able to suggest design attributes of a mobile phone that are essential to be considered at the product design stage to satisfy the customers’ expectations and hence to increase the company's sales.  相似文献   
93.

In this paper, an extension of the minimum cost flow problem is considered in which multiple incommensurate weights are associated with each arc. In the minimum cost flow problem, flow is sent over the arcs of a graph from source nodes to sink nodes. The goal is to select a subgraph with minimum associated costs for routing the flow. The problem is tractable when a single weight is given on each arc. However, in many real-world applications, several weights are needed to describe the features of arcs, including transit cost, arrival time, delay, profit, security, reliability, deterioration, and safety. In this case, finding an optimal solution becomes difficult. We propose a heuristic algorithm for this purpose. First, we compute the relative efficiency of the arcs by using data envelopment analysis techniques. We then determine a subgraph with efficient arcs using a linear programming model, where the objective function is based on the relative efficiency of the arcs. The flow obtained satisfies the arc capacity constraints and the integrality property. Our proposed algorithm has polynomial runtime and is evaluated in rigorous experiments.

  相似文献   
94.
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - This article analyzes various roles of development practitioners (called outsiders) in five different cases of...  相似文献   
95.
Analysis of incomplete durations with application to contraceptive use   总被引:1,自引:0,他引:1  
Models for analysing incomplete durations obtained from cross-sectional surveys are presented. The aim of the paper is to develop a framework for analysing the incomplete duration of episodes in progress at the time of the survey by formulating generalized linear models and fitting and assessing them by using standard statistical packages. The maximum quasi-likelihood method is used for model fitting. The choice of the distribution and the diagnostic procedures are discussed. Simulated data from two distributions (the Weibull and log-logistic distributions) are used to evaluate the methodology developed and to assess model misspecifications. A data set on the current use of the contraceptive pill from a cross-sectional survey in Egypt is analysed.  相似文献   
96.
Abstract

Innovation has become a core driver for the success and survival of organizations regardless of their size and nature. A plethora of literature has discussed the importance of innovation in profit-based organizations, while nonprofit organizations (NPOs) have generally been ignored in research. This study examines the influence of the sub-dimensions of innovation on the performance of NPOs. Data were collected through structured questionnaires using a sample size of 309 NPOs operating in the emerging market Pakistan. The hypotheses were tested through structural equation modeling (SEM) in AMOS.21. The results indicate that process innovation and organization innovation have significant positive influence on the performance of NPOs, while product innovation and marketing innovation have insignificant influence on the performance of NPOs. NPOs are advised to give enough attention to process and organization innovation in order to boost their performance. Future researchers are encouraged to test the model in other environmental settings. Implications for practice were discussed.  相似文献   
97.
Ethnography has become a useful method in procuring sensitive information from the ‘hidden population’ who may not be accessed with quantitative survey techniques. Researchers are generating huge amounts of qualitative/textual data. Qualitative data require careful planning in storage, coding, retrieval, and analysis. Personal computers have solved data management problems, but data analysis remains problematic. The paper describes some qualitative data management and analytic problems faced by a team of ethnographers engaged in a longitudinal epidemiological study of cocaine and crack distribution/abuse in New York City. Ethnographic data was collected through multi-session open-ended interviews with more than one hundred cocaine/crack dealers and extensive field-notes were kept. Compared to other programs, a hypertext software — Folio Views — was more useful in solving (a) data management and (b) analytical problems. Authors used this software to handle more than twenty-five thousand pages of texts; search and sort the database by any words or codes; and retrieve relevant textual materials needed to complete comparative and thematic analysis. Authors analyzed the data from outsiders’ point of view (etic) as well as from the viewpoint of the subject populations (emic).  相似文献   
98.
Covariance matrices, or in general matrices of sums of squares and cross-products, are used as input in many multivariate analyses techniques. The eigenvalues of these matrices play an important role in the statistical analysis of data including estimation and hypotheses testing. It has been recognized that one or few observations can exert an undue influence on the eigenvalues of a covariance matrix. The relationship between the eigenvalues of the covariance matrix computed from all data and the eigenvalues of the perturbed covariance matrix (a covariance matrix computed after a small subset of the observations has been deleted) cannot in general be written in closed-form. Two methods for approximating the eigenvalues of a perturbed covariance matrix have been suggested by Hadi (1988) and Wang and Nyquist (1991) for the case of a perturbation by a single observation. In this paper we improve on these two methods and give some additional theoretical results that may give further insight into the problem. We also compare the two improved approximations in terms of their accuracies.  相似文献   
99.
ABSTRACT

This phenomenological study used individual, semistructured, face-to-face interviews to explore motherhood experiences among 15 women receiving public assistance in a large urban area on the West coast. A primary phenomenon observed was that motherhood was described as an experience of identity change, with resulting emotional, behavioral, and sense-of-self changes. Within this broad theme, two categories emerged: the experience and process of change, and consequences of change. It was concluded that motherhood may serve as an important catalyst for change in some women and that the context of poverty is essential for understanding the motherhood experience. These results suggest that interventions aimed at leveraging emerging motherhood identities may be beneficial in setting women on the path out of poverty, drug addiction, and incarceration. Future research should examine the consequences of maternal change within the specific context of the stages of change documented in the recovery process from drug addiction.  相似文献   
100.
This paper studies a class of shrinkage estimators of the vector of regression coefficients. The small disturbance approximations for the bias and the mean squared error matrix of the estimator are derived. In the sense of mean squared error, these estimators dominate the least squares estimator and the generalized Stein estimator developed by Hosmane (1988).  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号