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   22527篇
  免费   385篇
  国内免费   2篇
管理学   3000篇
民族学   112篇
人才学   4篇
人口学   1970篇
丛书文集   145篇
教育普及   2篇
理论方法论   2164篇
综合类   549篇
社会学   11284篇
统计学   3684篇
  2021年   113篇
  2020年   326篇
  2019年   450篇
  2018年   481篇
  2017年   700篇
  2016年   518篇
  2015年   410篇
  2014年   485篇
  2013年   3687篇
  2012年   703篇
  2011年   631篇
  2010年   467篇
  2009年   473篇
  2008年   501篇
  2007年   541篇
  2006年   467篇
  2005年   594篇
  2004年   521篇
  2003年   424篇
  2002年   463篇
  2001年   558篇
  2000年   498篇
  1999年   493篇
  1998年   358篇
  1997年   345篇
  1996年   356篇
  1995年   325篇
  1994年   339篇
  1993年   314篇
  1992年   363篇
  1991年   363篇
  1990年   348篇
  1989年   349篇
  1988年   314篇
  1987年   313篇
  1986年   285篇
  1985年   311篇
  1984年   344篇
  1983年   320篇
  1982年   277篇
  1981年   220篇
  1980年   237篇
  1979年   271篇
  1978年   223篇
  1977年   193篇
  1976年   186篇
  1975年   191篇
  1974年   177篇
  1973年   150篇
  1972年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The purpose of this paper is firstly to investigate the distribution of two parent low income families in England and Wales and Scotland for see to what extent they differ, and secondly to examine the relative importance of certain contributing factors in determining the distributions. From an analysis of Family Expenditure Survey data it is found that although it is difficult to arrive at statistically verifiable conclusions about the nature of the distributions, interesting qualitative observations can be made.  相似文献   
992.
Social interaction, particularly in older adolescents, increasingly involves computer‐mediated communication. Although studies of public computer‐mediated communication are increasingly common, studies of private text messaging remain rare. As approaches for obtaining such data evolve with technological advances, developmental scientists need designs in which to use such approaches that reduce sampling biases in both participants and text messages. In this study (n = 854; 46% male; 22% African American, 60% European American), we examined selection biases in the participant sample (i.e., factors associated with actual participation), procedural biases in the participant sample (i.e., factors related to failed data capture due to technological or procedural issues), and selection biases in the sample of text messages (i.e., based on self‐reported reasons for texting). Findings from our study suggest that studying human interaction directly through analysis of text message data is not only feasible, but also may be successfully undertaken with minimal biases regarding sample selection and text message selection among those who are engaged in research and engaged in text messaging outside of the study context. However, biases may occur depending on the type of platform (iPhone vs. Android) used by participants for texting.  相似文献   
993.
The transfer of advantage and disadvantage across multiple generations is receiving increasing attention in the international literature; however, transfers of resources across multiple generations in Australian families are less well understood. Using a longitudinal dataset of Australian children, we have the opportunity to not only investigate the transfer of educational resources across three generations in Australia, but also investigate the gendered nature of these transfers, which has been a limitation of other studies. We find no evidence of individual grandparent education effects on numeracy and reading scores for grandchildren in Year 3, independent of parent educational attainment and other covariates. However, significant effects on numeracy and reading scores were observed for children in families where both the grandmother and grandfather in maternal and paternal grandparent sets had high educational attainment (a diploma or university qualification), and where either or both the mother and father had a university qualification. These results suggest that the contribution of grandparents to the academic achievement of grandchildren cannot be fully explained by the parent generation and that the concentration of human capital in families contributes to educational inequalities across multiple generations that can be observed by eight years of age.  相似文献   
994.
Existing research demonstrates that parent and child gender may influence important aspects of family relationships; however, most research in this area has been conducted with non‐clinical samples. As clinicians, it is important to consider how gender impacts family relationships, particularly among vulnerable families. This study examined the intersections of gender role attitudes and parenting practices among 34 parents involved with the child welfare system and referred for clinical intervention. Using a mixed methods design, themes regarding gender role beliefs and parenting practices were found through qualitative interviews with parents. Findings suggested that fathers felt responsible for financially providing for their families and expressed challenges in communicating with mothers, and mothers described challenges they face because of a lack of father involvement. Parents also discussed a perceived need to monitor daughters closely while fostering the independence of their sons. Results of the qualitative analyses were supported by quantitative findings indicating significant differences in harsh and inconsistent discipline practices and clear expectations for girls compared to boys. The discussion addresses implications for clinicians, including how a feminist family therapy perspective may help promote client influence over traditional gender norms by questioning gender role attitudes and exploring alternate narratives that may impact family dynamics.  相似文献   
995.
Sexual harassment laws have led to important organizational changes in the workplace yet research continues to document resistance to their implementation and backlash against the people who mobilize such laws. Employing experimental research methods, this study proposes and tests a theory specifying the mechanisms through which sexual harassment policies affect gender beliefs. The findings show evidence that sexual harassment policies strengthen unequal gender beliefs among men and women most committed to traditional gender interaction norms. I also find that men and women’s different structural locations in the status hierarchy lead to different, but related sets of concerns about the status threats posed by sexual harassment policies. By specifying the social psychological processes through which sexual harassment law affects beliefs about men and women, this study sets the stage for investigating ways to make laws designed to reduce inequality between social groups more effective.  相似文献   
996.
Relatively few studies examine the relationship between racial residential segregation and educational or cognitive outcomes. Using data from the National Longitudinal Study of Adolescent Health and the institutional resources model of neighborhood effects, I investigate one account of how macrostructural arrangements between race, neighborhood segregation, and school quality interact to produce inequalities in test scores. Consistent with the institutional resources model, results suggest that school quality varies across neighborhoods based, in part, on their degree of racial concentration. Indeed, school quality and other school characteristics mediate the relationship between racial concentration and verbal skills, particularly among black males. These findings have implications not only for inequalities in cognitive skills among blacks across residential space, but also between blacks and whites given high levels of residential segregation in the United States. In sum, findings illustrate yet another way in which residential segregation contributes to, and not merely reflects, racial inequalities.  相似文献   
997.
Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives. Here, we implement and improve on a classic decision-analytical model (Van Dantzig 1956) to: (i) capture tradeoffs across conflicting stakeholder objectives, (ii) demonstrate the consequences of structural uncertainties in the sea-level rise and storm surge models, and (iii) identify the parametric uncertainties that most strongly influence each objective using global sensitivity analysis. We find that the flood adaptation model produces potentially myopic solutions when formulated using traditional mean-centric decision theory. Moving from a single-objective problem formulation to one with multiobjective tradeoffs dramatically expands the decision space, and highlights the need for compromise solutions to address stakeholder preferences. We find deep structural uncertainties that have large effects on the model outcome, with the storm surge parameters accounting for the greatest impacts. Global sensitivity analysis effectively identifies important parameter interactions that local methods overlook, and that could have critical implications for flood adaptation strategies.  相似文献   
998.
In the quest to model various phenomena, the foundational importance of parameter identifiability to sound statistical modeling may be less well appreciated than goodness of fit. Identifiability concerns the quality of objective information in data to facilitate estimation of a parameter, while nonidentifiability means there are parameters in a model about which the data provide little or no information. In purely empirical models where parsimonious good fit is the chief concern, nonidentifiability (or parameter redundancy) implies overparameterization of the model. In contrast, nonidentifiability implies underinformativeness of available data in mechanistically derived models where parameters are interpreted as having strong practical meaning. This study explores illustrative examples of structural nonidentifiability and its implications using mechanistically derived models (for repeated presence/absence analyses and dose–response of Escherichia coli O157:H7 and norovirus) drawn from quantitative microbial risk assessment. Following algebraic proof of nonidentifiability in these examples, profile likelihood analysis and Bayesian Markov Chain Monte Carlo with uniform priors are illustrated as tools to help detect model parameters that are not strongly identifiable. It is shown that identifiability should be considered during experimental design and ethics approval to ensure generated data can yield strong objective information about all mechanistic parameters of interest. When Bayesian methods are applied to a nonidentifiable model, the subjective prior effectively fabricates information about any parameters about which the data carry no objective information. Finally, structural nonidentifiability can lead to spurious models that fit data well but can yield severely flawed inferences and predictions when they are interpreted or used inappropriately.  相似文献   
999.
1000.
Determinations of significance play a pivotal role in environmental impact assessments because they point decision makers to the predicted effects of an action most deserving of attention and further study. Impact predictions are always subject to uncertainty because they rely on estimates of future consequences. Yet uncertainty is often neglected or treated in a perfunctory manner as part of the characterization, evaluation, and communication of anticipated consequences and their significance. Proposals to construct fossil fuel pipelines in North America provide a highly visible example; casual treatment of how uncertainty affects significance determinations has resulted in poorly informed stakeholders, frustrated industry proponents, and inconsistent choices on the part of public decision makers. Using environmental assessments for recent pipeline proposals as examples, we highlight five ways in which uncertainty is often neglected when determining impact significance and suggest that a mix of known methods, new guidelines, and appropriate oversight could greatly improve current practices.  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