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   1896篇
  免费   80篇
  国内免费   14篇
管理学   193篇
民族学   7篇
人口学   52篇
丛书文集   149篇
理论方法论   110篇
综合类   603篇
社会学   193篇
统计学   683篇
  2024年   5篇
  2023年   18篇
  2022年   20篇
  2021年   21篇
  2020年   52篇
  2019年   62篇
  2018年   71篇
  2017年   76篇
  2016年   62篇
  2015年   63篇
  2014年   97篇
  2013年   283篇
  2012年   108篇
  2011年   117篇
  2010年   102篇
  2009年   86篇
  2008年   101篇
  2007年   89篇
  2006年   82篇
  2005年   72篇
  2004年   87篇
  2003年   62篇
  2002年   62篇
  2001年   44篇
  2000年   38篇
  1999年   20篇
  1998年   17篇
  1997年   13篇
  1996年   11篇
  1995年   5篇
  1994年   5篇
  1993年   4篇
  1992年   6篇
  1991年   5篇
  1990年   4篇
  1989年   2篇
  1988年   5篇
  1986年   3篇
  1985年   4篇
  1984年   1篇
  1983年   5篇
排序方式: 共有1990条查询结果,搜索用时 31 毫秒
101.
We study the influence of frequent survey measurement on behavior. Widespread access to the Internet has made important breakthroughs in frequent measurement possible—potentially revolutionizing social science measurement of processes that change quickly over time. One key concern about using such frequent measurement is that it may influence the behavior being studied. We investigate this possibility using both a population-based experiment with random assignment to participation in a weekly journal for twelve months (versus no journal) and a large-scale, population-based, journal-keeping study with weekly measurement for 30 months. Results reveal few of the measured behaviors are correlated with assignment to frequent measurement. Theoretical reasoning regarding the likely behavioral response to frequent measurement correctly predicts domains most vulnerable to this possibility. Overall, however, we found little evidence of behavioral response to frequent measurement.  相似文献   
102.
103.
Since the implementation of the International Conference on Harmonization (ICH) E14 guideline in 2005, regulators have required a “thorough QTc” (TQT) study for evaluating the effects of investigational drugs on delayed cardiac repolarization as manifested by a prolonged QTc interval. However, TQT studies have increasingly been viewed unfavorably because of their low cost effectiveness. Several researchers have noted that a robust drug concentration‐QTc (conc‐QTc) modeling assessment in early phase development should, in most cases, obviate the need for a subsequent TQT study. In December 2015, ICH released an “E14 Q&As (R3)” document supporting the use of conc‐QTc modeling for regulatory decisions. In this article, we propose a simple improvement of two popular conc‐QTc assessment methods for typical first‐in‐human crossover‐like single ascending dose clinical pharmacology trials. The improvement is achieved, in part, by leveraging routinely encountered (and expected) intrasubject correlation patterns encountered in such trials. A real example involving a single ascending dose and corresponding TQT trial, along with results from a simulation study, illustrate the strong performance of the proposed method. The improved conc‐QTc assessment will further enable highly reliable go/no‐go decisions in early phase clinical development and deliver results that support subsequent TQT study waivers by regulators.  相似文献   
104.
The multiple non symmetric correspondence analysis (MNSCA) is a useful technique for analyzing a two-way contingency table. In more complex cases, the predictor variables are more than one. In this paper, the MNSCA, along with the decomposition of the Gray–Williams Tau index, in main effects and interaction term, is used to analyze a contingency table with two predictor categorical variables and an ordinal response variable. The Multiple-Tau index is a measure of association that contains both main effects and interaction term. The main effects represent the change in the response variables due to the change in the level/categories of the predictor variables, considering the effects of their addition, while the interaction effect represents the combined effect of predictor categorical variables on the ordinal response variable. Moreover, for ordinal scale variables, we propose a further decomposition in order to check the existence of power components by using Emerson's orthogonal polynomials.  相似文献   
105.
Parenting may be particularly challenging for substance‐dependent mothers who have grown up with parents who themselves had substance use disorders (SUDs). The aim of this study was to explore how substance‐dependent mothers describe their childhood experiences with substance‐abusing parents and the association between these earlier experiences and their own role as caregivers. Using purposeful sampling, mothers admitted for 1 year to a family ward at a substance abuse clinic were approached. Through in‐depth, qualitative interviews, nine substance‐dependent mothers described their lives in the form of present, past and future tense. The findings indicate that substance‐dependent women, who have experienced SUDs in their families of origin, face several major challenges when they become mothers. Some describe having lived their whole lives ‘on the edge of society'. This makes their rehabilitation process more complex. All mothers work to abstain from substances, process traumatic experiences and integrate their family into society. They need help to build supportive social networks and to establish a safe and predictable family environment for themselves and their children. The therapeutic implications of these findings will be discussed.  相似文献   
106.
Our study aims at describing mortality among reported elder abuse experiences in rural Malaysia. This is a population-based cohort study with a multistage cluster sampling method. Older adults in Kuala Pilah (n = 1,927) were interviewed from November 2013 to May 2014. Mortality was traced after 2 years using the National Registration Department database. Overall, 139 (7.2%) respondents died. Fifteen (9.6%) abuse victims died compared to 124 (7.0%) not abused. Mortality was highest with financial abuse (13%), followed by psychological abuse (10.8%). There was a dose-response relationship between mortality and clustering of abuse: 7%, 7.7%, and 14.0% for no abuse, one type, and two types or more, respectively. Among abuse victims, 40% of deaths had ill-defined causes, 33% were respiratory-related, and 27% had cardiovascular and metabolic origin. Results suggest a link between abuse and mortality. Death proportions varied according to abuse subtypes and gender.  相似文献   
107.
The problem of interaction selection in high-dimensional data analysis has recently received much attention. This note aims to address and clarify several fundamental issues in interaction selection for linear regression models, especially when the input dimension p is much larger than the sample size n. We first discuss how to give a formal definition of “importance” for main and interaction effects. Then we focus on two-stage methods, which are computationally attractive for high-dimensional data analysis but thus far have been regarded as heuristic. We revisit the counterexample of Turlach and provide new insight to justify two-stage methods from the theoretical perspective. In the end, we suggest new strategies for interaction selection under the marginality principle and provide some simulation results.  相似文献   
108.
We consider hypothesis testing and estimation of carry-over effects in continuous data under an incomplete block crossover design when comparing two experimental treatments with a placebo. We develop procedures for testing differential carry-over effects based on the weighted-least-squares (WLS) method. We apply Monte Carlo simulations to evaluate the performance of these test procedures in a variety of situations. We use the data regarding the forced expiratory volume in one second (FEV1) readings taken from a double-blind crossover trial comparing two different doses of formoterol with a placebo to illustrate the use of test procedures proposed here.  相似文献   
109.
Children typically receive investments from their fathers, but absent fathers often invest at low levels. In a father's absence, what types of nonfathers invest heavily in children? This article investigates educational participation as a reflection of childhood investments on Ibo Island, Mozambique, where only one third of school‐aged children live with their biological fathers. Father‐present children generally attended school at the highest rates. Stepchildren and father‐absent relatives (e.g., grandchildren, nieces) attended school at comparably high rates if any coresiding children were father‐present. This may signal high altruism among present fathers toward some nonoffspring. Consistent with this result, a fixed effects model indicates that, within the same household, adult males invested equally in their own children, relatives, and stepchildren. Prejudicially lower investments were made in children who were unrelated to the household's adult males, however; this result has strong negative implications for the well‐being of African children fostered by nonrelatives.  相似文献   
110.
Although much research examines the association between fathers' relationship aggression and mothers' parenting, little attention is given to mothers' aggression, mutual aggression, or fathers' parenting. Using a sample of coresiding couples from the Fragile Families and Child Wellbeing Study (N = 973), the authors examine the association between mothers' and fathers' relationship aggression, measured as frequency and perpetration–victimization types (mutual, mother only, father only), and mothers' and fathers' parenting. Fixed effects regression models show that fathers' aggression is positively related to mothers' parenting stress, whereas father‐only or mother‐only aggression is related to fathers' stress. For both parents, aggression perpetration is negatively related to their own engagement with children. Mother‐only aggression is negatively related to mothers' spanking and positively related to fathers' spanking. These findings suggest the importance of examining both parents' aggression and perpetrators' as well as victims' parenting to better understand the link between relationship aggression and parenting.  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