全文获取类型
收费全文 | 5573篇 |
免费 | 712篇 |
国内免费 | 4篇 |
专业分类
管理学 | 1133篇 |
劳动科学 | 1篇 |
民族学 | 17篇 |
人口学 | 103篇 |
丛书文集 | 73篇 |
理论方法论 | 1003篇 |
综合类 | 414篇 |
社会学 | 2423篇 |
统计学 | 1122篇 |
出版年
2024年 | 12篇 |
2023年 | 43篇 |
2022年 | 14篇 |
2021年 | 127篇 |
2020年 | 217篇 |
2019年 | 381篇 |
2018年 | 252篇 |
2017年 | 436篇 |
2016年 | 408篇 |
2015年 | 379篇 |
2014年 | 403篇 |
2013年 | 963篇 |
2012年 | 436篇 |
2011年 | 317篇 |
2010年 | 305篇 |
2009年 | 200篇 |
2008年 | 239篇 |
2007年 | 163篇 |
2006年 | 153篇 |
2005年 | 146篇 |
2004年 | 142篇 |
2003年 | 118篇 |
2002年 | 108篇 |
2001年 | 117篇 |
2000年 | 102篇 |
1999年 | 14篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有6289条查询结果,搜索用时 15 毫秒
1.
The authors use an ecological framework and grounded theoretical analysis to explore the circumstances in which working‐class and low‐income custodial African American fathers gain custody of their children, their transition from part‐time to full‐time parents, and the role of support networks in enhancing or inhibiting these men's parenting. Twenty‐four men from an impoverished Midwestern urban area participated in the study. The findings suggest that these men, and perhaps others sharing their demographic profiles, generally become parents by default and are often reluctant to take on a full‐time, single parenting role. Adaptation to the role seems to be enhanced by these men's use of extended kin support networks and shared living arrangements. However, low wages, a lack of sufficient assistance from public assistance programs, and informal custody arrangements often inhibit their fathering. 相似文献
2.
Craig H. Mallinckrodt Christopher J. Kaiser John G. Watkin Michael J. Detke Geert Molenberghs Raymond J. Carroll 《Pharmaceutical statistics》2004,3(3):171-186
The last observation carried forward (LOCF) approach is commonly utilized to handle missing values in the primary analysis of clinical trials. However, recent evidence suggests that likelihood‐based analyses developed under the missing at random (MAR) framework are sensible alternatives. The objective of this study was to assess the Type I error rates from a likelihood‐based MAR approach – mixed‐model repeated measures (MMRM) – compared with LOCF when estimating treatment contrasts for mean change from baseline to endpoint (Δ). Data emulating neuropsychiatric clinical trials were simulated in a 4 × 4 factorial arrangement of scenarios, using four patterns of mean changes over time and four strategies for deleting data to generate subject dropout via an MAR mechanism. In data with no dropout, estimates of Δ and SEΔ from MMRM and LOCF were identical. In data with dropout, the Type I error rates (averaged across all scenarios) for MMRM and LOCF were 5.49% and 16.76%, respectively. In 11 of the 16 scenarios, the Type I error rate from MMRM was at least 1.00% closer to the expected rate of 5.00% than the corresponding rate from LOCF. In no scenario did LOCF yield a Type I error rate that was at least 1.00% closer to the expected rate than the corresponding rate from MMRM. The average estimate of SEΔ from MMRM was greater in data with dropout than in complete data, whereas the average estimate of SEΔ from LOCF was smaller in data with dropout than in complete data, suggesting that standard errors from MMRM better reflected the uncertainty in the data. The results from this investigation support those from previous studies, which found that MMRM provided reasonable control of Type I error even in the presence of MNAR missingness. No universally best approach to analysis of longitudinal data exists. However, likelihood‐based MAR approaches have been shown to perform well in a variety of situations and are a sensible alternative to the LOCF approach. MNAR methods can be used within a sensitivity analysis framework to test the potential presence and impact of MNAR data, thereby assessing robustness of results from an MAR method. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
3.
Latina female (n= 97) and Latino male (n= 69) college students (M age = 21.4 years) completed self‐report surveys regarding family of origin experiences, including sexual communication with parents while growing up. Latino parents of this comparatively highly educated sample tended to use direct rather than indirect strategies for communicating about sexuality with their children. Young women reported higher levels of sexual communication with mothers while growing up than did young men, and respondents reported less communication with fathers than mothers. Among young women, sexual communication with mother was positively associated with non‐Mexican origin and negatively associated with having older brothers living at home. In contrast, maternal education was positively associated with mother‐son communication about sex. Paternal education and the absence of older brothers positively predicted communication with both sons and daughters. The analyses provide novel information regarding sexual communication in Latino families and suggest directions for future research. 相似文献
4.
Craig H. Mallinckrodt John G. Watkin Geert Molenberghs Raymond J. Carroll 《Pharmaceutical statistics》2004,3(3):161-169
Missing data, and the bias they can cause, are an almost ever‐present concern in clinical trials. The last observation carried forward (LOCF) approach has been frequently utilized to handle missing data in clinical trials, and is often specified in conjunction with analysis of variance (LOCF ANOVA) for the primary analysis. Considerable advances in statistical methodology, and in our ability to implement these methods, have been made in recent years. Likelihood‐based, mixed‐effects model approaches implemented under the missing at random (MAR) framework are now easy to implement, and are commonly used to analyse clinical trial data. Furthermore, such approaches are more robust to the biases from missing data, and provide better control of Type I and Type II errors than LOCF ANOVA. Empirical research and analytic proof have demonstrated that the behaviour of LOCF is uncertain, and in many situations it has not been conservative. Using LOCF as a composite measure of safety, tolerability and efficacy can lead to erroneous conclusions regarding the effectiveness of a drug. This approach also violates the fundamental basis of statistics as it involves testing an outcome that is not a physical parameter of the population, but rather a quantity that can be influenced by investigator behaviour, trial design, etc. Practice should shift away from using LOCF ANOVA as the primary analysis and focus on likelihood‐based, mixed‐effects model approaches developed under the MAR framework, with missing not at random methods used to assess robustness of the primary analysis. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
5.
Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances. 相似文献
6.
Beryllium is the strongest of the lightweight metals. Used primarily in military applications prior to the end of the Cold War, beryllium is finding new applications in many commercial products, including computers, telecommunication equipment, and consumer and automotive electronics. The use of beryllium in nondefense consumer applications is of concern because beryllium is toxic. Inhalation of beryllium dust or vapor causes a chronic lung disease in some individuals at concentrations as low as 0.01 microg/m3 in air. As beryllium enters wider commerce, it is prudent to ask what risks this might present to the general public and to workers downstream of the beryllium materials industry. We address this question by evaluating the potential for beryllium exposure from the manufacturing, use, recycle, and disposal of beryllium-containing products. Combining a market study with a qualitative exposure analysis, we determine which beryllium applications and life cycle phases have the largest exposure potential. Our analysis suggests that use and maintenance of the most common types of beryllium-containing products do not result in any obvious exposures of concern, and that maintenance activities result in greater exposures than product use. Product disposal has potential to present significant individual risks, but uncertainties concerning current and future routes of product disposal make it difficult to be definitive. Overall, additional exposure and dose-response data are needed to evaluate both the health significance of many exposure scenarios, and the adequacy of existing regulations to protect workers and the public. Although public exposures to beryllium and public awareness and concern regarding beryllium risks are currently low, beryllium risks have psychometric qualities that may lead to rapidly heightened public concern. 相似文献
7.
This study examines housing quality among three groups of single-parent women: white, African-American, and Hispanic. Three
indicators of housing quality—crowding, affordability, and satisfaction—are used to discover the extent to which these groups
experience housing problems. This study also explores differences and similarities in the factors that precipitate problems
in housing quality for these three groups of single parents. Findings suggest important differences and similarities in the
nature of housing quality problems among white, African-American, and Hispanic single-parent women. The specified variables
explained about 20% of the variance in crowding, housing affordability, and housing satisfaction. On measures of objective
and subjective housing quality, white single mothers are better housed than their African-American or Hispanic counterparts.
Hispanic single mothers have the largest housing cost burden and average more persons per household than the other groups.
African-Americans are twice as likely as either group to live in low-quality housing and reported the lowest average satisfaction
with their housing.
Her research interests include housing and neighborhood assessment and women and public policy issues. She has recently published
articles inUrban Affairs Quarterly andHousing and Society on housing and neighborhood assessment criteria among black urban households and the housing cost burden of various groups
of female-headed households. She received her Ph.D. from Ohio State University.
Her research interests include the housing adjustment behavior of women and public policy. She has recently completed her
thesis on the role of noncustodial parents in determining the quality of life of their children. She is also the recipient
of the Tessie Agan Award for research excellence from the American Association of Housing Educators for a paper titled “Unterstanding
Constraints and Residential Satisfaction among Low-Income Single-Parent Families.” 相似文献
8.
Chris Dockins Robin R Jenkins Nicole Owens Nathalie B Simon Lanelle Bembenek Wiggins 《Risk analysis》2002,22(2):335-346
This article explores two problems analysts face in determining how to estimate values for children's health and safety risk reductions. The first addresses the question: Do willingness‐to‐pay estimates for health risk changes differ across children and adults and, if so, how? To answer this question, the article first examines the potential effects of age and risk preferences on willingness to pay. A summary of the literature reporting empirical evidence of differences between willingness to pay for adult health and safety risk reductions and willingness to pay for health and safety risk reductions in children is also provided. The second dimension of the problem is a more fundamental issue: Whose perspective is relevant when valuing children's health effects—society's, children's, adults‐as‐children, or parents'? Each perspective is considered, followed ultimately by the conclusion that adopting a parental perspective through an intrahousehold allocation model seems closest to meeting the needs of the estimation problem at hand. A policy example in which the choice of perspective affects the outcome of a regulatory benefit‐cost analysis rounds out the article and emphasizes the importance of perspective. 相似文献
9.
This paper critically evaluates research and literature on childprotection social work practice with minority ethnic familieswho speak little or no English. Though the focus is on childprotection, many of the themes raised should be transferableacross to other areas and disciplines. Specifically, the paperfocuses on the limitations and difficulties of using professionalinterpreters in child protection work and covers themes likethe availability of interpreters, the role of interpreters,suitability of interpreters, the interpretation of particularwords and phrases, and manipulating the interpreting process.The paper then moves on to address the important but often neglectedarea of using children as interpreters, and ends by consideringthe broader issue of how language barriers can exacerbate discriminationagainst minority ethnic families. 相似文献
10.
Abstract: This article explores the relationship between social stratification and the division of household labor by examining how the contribution to housework by husbands in dual-earner families varies across the Japanese social stratification structure. First, I review previous studies concerning the determinants of husbands' participation in housework and construct four hypotheses regarding the relative resources explanation, the time constraints explanation, the ideology/sex role explanation, and the alternative manpower explanation. Second, I examine the empirical support for these hypotheses in dual-earner couples and the effect of social stratification on husband's participation in housework, which has not been studied thus far. Third, I investigate the effect of social stratification in more detail. According to the results of TOBIT regressions and other supplementary analyses, the principal findings are as follows:
- 1)
the relative resources explanation is not supported;