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   125篇
  免费   10篇
管理学   30篇
人口学   19篇
理论方法论   11篇
社会学   56篇
统计学   19篇
  2023年   3篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2018年   11篇
  2017年   10篇
  2016年   6篇
  2015年   5篇
  2014年   7篇
  2013年   26篇
  2012年   8篇
  2011年   5篇
  2010年   5篇
  2009年   4篇
  2008年   10篇
  2007年   4篇
  2006年   3篇
  2005年   3篇
  2004年   2篇
  2003年   1篇
  2002年   6篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   5篇
  1993年   1篇
  1985年   1篇
排序方式: 共有135条查询结果,搜索用时 31 毫秒
11.
We interpret gradients in population dynamics of the gray-sided vole from the southwestern part of the island of Hokkaido to its northeastern part within the framework of a phenomenological model involving the relative length of summer and winter. In Hokkaido, as in other northern regions, both spring and fall is considered as short transition periods between the two main seasons — summer (the primary breeding season) and winter (the non-reproductive or secondary breeding season). We show that the geographic transition in dynamics may be understood as the combined consequence of different patterns of density-dependence during summer and winter, and geographically varying season lengths. Differences are shown to exist between summer and winter with respect to strength of density-dependence. Direct density-dependence, in particular, is stronger during winter than during summer. A model is presented to show how relative lengths of seasons can induce both stable and periodically fluctuating population dynamics. The results are compared and contrasted with what is otherwise known about the gradient in rodent dynamics in Fennoscandia.  相似文献   
12.
This study investigated the relationship between aversive conditioning, heart rate variability suppression, behavioral activation system/behavioral inhibition system and risk-avoidance on the Iowa gambling task (IGT) in a nonclinical sample (29 male, 29 female, mean age = 20.7). A laboratory based Pavlovian aversive conditioning paradigm was used where a 1500 Hz tone (CS+) was followed by a burst of loud white noise (US), and a 850 Hz (CS−) tone was never followed by the US. In a subsequent extinction phase where the CS+ and CS− were presented without the US, conditioned skin conductance responses to the CS+ indicated aversive conditioning. The results showed that the participants who did not show aversive conditioning (N = 26) exhibited significantly less risk-avoidance compared to participants who did show aversive conditioning (N = 32). Regression analysis showed that among the study variables, only aversive conditioning contributed significantly to explaining variance in risk-avoidance. These results may have implications for understanding risk-taking in gambling in general, and may be a starting point understanding the role of aversive conditioning in the development and maintenance of gambling problems.  相似文献   
13.
Traceability is normally difficult to achieve in continuous processes, since there are no natural batch structures. In this article, we demonstrate flow-based simulation using process data to improve traceability in a continuous pelletising process. Using the simulation model, the engineers could test the impacts of process disturbances, identify cause and effect relations and aid control in case of process disturbances. In a field trial where the chemistry of an additive was varied during production of a special product, the simulation forecasts predicted the level of the chemical content after the plant within the errors that the engineers found acceptable.  相似文献   
14.
15.
Using insurance data, medically impairing injuries sustained by 111 firefighters were analyzed. The injury incidence per year among full-time working firefighters was 39 per 10 000, and among part-time working firefighters 6 per 10 000. More than half (51%) were injured during fitness training, 14% during job training, and 13% during emergency response, while 4% were injured in traffic crashes and 18% in other injury events. Soccer and floorball caused 82% of all fitness injuries, of which more than half were meniscal or sprain injuries of knees or ankles. None of those injured during emergency response suffered from burn injuries, however during job training 4 sustained burns. Less injurious fitness training and practice activities could greatly reduce impairing injuries among firefighters and consequently reduce economical losses and disability.  相似文献   
16.
The main aims of this study are to document whether an intervention for promoting evidence-based public health practice had been delivered as intended and to explore the reasons for its lack of impact. Process data from the implementation of the program and data from interviews with 40 public health physicians are analyzed. Although they expressed satisfaction with the service, the doctors experienced the program as rather irrelevant for their daily work. They did not perceive that they dealt with many issues relevant for the use of research information, and if they did, referring to research would not make any difference to the way others perceived their advice. There is a need to develop more overlying strategies for integrating evidence into decision making than addressing the individual level.  相似文献   
17.
This paper explores a wide range of cross-country determinants of life satisfaction exploiting a database of 90,000 observations in 70 countries. We distinguish four groups of aggregate variables as potential determinants of satisfaction: political, economic, institutional, and human development and culture. We use ordered probit to investigate the importance of these variables on individual life satisfaction and test the robustness of our results with Extreme Bounds Analysis. The results show that only a small number of factors, such as openness, business climate, postcommunism, the number of chambers in parliament, Christian majority, and infant mortality, robustly influence life satisfaction across countries while the importance of many variables suggested in the previous literature is not confirmed. This remains largely true when the analysis splits national populations according to gender, income, and political orientation also. We thank Stephen Lea, participants at the 30th IAREP conference in Prague and the referees of this journal for comments on earlier versions. Gilles Winkler provided excellent research assistance.  相似文献   
18.
What makes people perceive a leader as charismatic, and how do team leaders obtain performance outcomes from their followers? We examine leaders in times of organizational change and investigate the mechanisms through which leaders' change-promoting behaviors are associated with team performance. In a multilevel mediation model, we propose that the indirect relationship between change-promoting behaviors and team performance is sequentially transmitted through followers' perceptions of charisma and followers' commitment to change. A study of 33 leaders and 142 followers provides empirical support for the model, using multilevel structural equation modeling to analyze top-down relationships between leaders and followers and bottom-up relationships between followers and team outcomes. Results suggest that team leaders are perceived as more charismatic when they engage in change-promoting behaviors. These behaviors facilitate team performance through individual followers' perceived charisma and commitment to change.  相似文献   
19.
Die Forderung nach schwacher Wertadditivit?t von Sicherheits?quivalenten ist in Abh?ngigkeit des jeweiligen Bewertungszwecks zu diskutieren. W?hrend in der unternehmensexternen Bewertungssicht, z.B. bei der Unternehmensbewertung, die Forderung nach schwacher Wertadditivit?t gut begründbar ist, stellt sie im Bereich der unternehmensinternen Steuerungssicht eine „Nice to have“-Anforderung dar. Darüber hinaus werden in der bisherigen Literatur zur Anwendbarkeit von Sicherheits?quivalenten die Kernherausforderungen der unternehmensinternen Steuerung vernachl?ssigt. Insbesondere die ad?quate Berücksichtigung stochastischer Abh?ngigkeiten im Portfolioverbund bei der Bewertung von Einzelgesch?ften mittels Sicherheits?quivalenten stellt eine Forschungslücke dar.  相似文献   
20.
Swedish cross-sectional survey data on young individuals was used to analyse the determinants of perceived risks of alcohol use and how these perceptions relate to drinking behaviour. Three major conclusions were drawn: (1) that people overestimate the risks of alcoholism, (2) that these risk perceptions fall substantially with age, but nevertheless imply risk overestimation, and (3) that education about alcohol, narcotics and tobacco leads individuals to perceive risks more correctly and to have lower risk beliefs. An additional finding was that individuals with higher perceived risks were less likely to consume alcohol. Equations were estimated both separately and simultaneously.  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