全文获取类型
收费全文 | 1606篇 |
免费 | 39篇 |
专业分类
管理学 | 257篇 |
民族学 | 9篇 |
人才学 | 2篇 |
人口学 | 130篇 |
丛书文集 | 12篇 |
理论方法论 | 151篇 |
综合类 | 20篇 |
社会学 | 909篇 |
统计学 | 155篇 |
出版年
2023年 | 7篇 |
2020年 | 26篇 |
2019年 | 20篇 |
2018年 | 26篇 |
2017年 | 47篇 |
2016年 | 29篇 |
2015年 | 21篇 |
2014年 | 40篇 |
2013年 | 254篇 |
2012年 | 42篇 |
2011年 | 48篇 |
2010年 | 44篇 |
2009年 | 38篇 |
2008年 | 60篇 |
2007年 | 44篇 |
2006年 | 42篇 |
2005年 | 45篇 |
2004年 | 56篇 |
2003年 | 40篇 |
2002年 | 56篇 |
2001年 | 21篇 |
2000年 | 28篇 |
1999年 | 38篇 |
1998年 | 29篇 |
1997年 | 20篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 24篇 |
1993年 | 22篇 |
1992年 | 22篇 |
1991年 | 24篇 |
1990年 | 29篇 |
1989年 | 23篇 |
1988年 | 27篇 |
1987年 | 19篇 |
1986年 | 27篇 |
1985年 | 18篇 |
1984年 | 15篇 |
1983年 | 23篇 |
1982年 | 14篇 |
1981年 | 24篇 |
1980年 | 18篇 |
1979年 | 20篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1976年 | 19篇 |
1975年 | 16篇 |
1974年 | 11篇 |
1971年 | 6篇 |
1970年 | 8篇 |
排序方式: 共有1645条查询结果,搜索用时 15 毫秒
991.
992.
Charles L. Baum 《Journal of population economics》2012,25(4):1307-1340
With over 66% of Americans overweight, expectant mothers are unusual because they are encouraged to gain weight while pregnant. Food stamp receipt (FSR) may facilitate recommended weight gain by providing resources for food and nutrition. I examine the effects of FSR on the amount of weight gained by low-income expectant mothers using NLSY79 data. Results indicate FSR decreases the probability gaining insufficient weight but does not exacerbate the probability of gaining too much weight. Examining the effects of FSR on pregnancy weight gain is important because low birth weight is more likely when expectant mothers gain insufficient weight. 相似文献
993.
Reward‐Modulated Response Inhibition,Cognitive Shifting,and the Orbital Frontal Cortex in Early Adolescence 下载免费PDF全文
Zu Wei Zhai Stefan Pajtek Beatriz Luna Charles F. Geier Ty A. Ridenour Duncan B. Clark 《Journal of research on adolescence》2015,25(4):753-764
Immaturities in cognitive shifting are associated with adolescent risk behaviors. The orbital frontal cortex (OFC) regulates reward processing and response inhibition. This study tested the relationship between cognitive shifting, OFC activity, and reward‐modulated response inhibition in young adolescents. An fMRI antisaccade (AS) paradigm examined the effects of reward conditions on inhibitory response and OFC processing. A validated self‐report inventory assessed cognitive shifting. Compared with neutral, reward trials showed better AS performance and increased OFC activation. Cognitive shifting positively associated with AS performance in reward and neutral trials. Poorer cognitive shifting predicted greater OFC activation. Results indicate lower OFC efficiency, as greater activation to achieve correct performance, underlies cognitive shifting problems. These neurocognitive impairments are relevant for understanding adolescent risk behaviors. 相似文献
994.
Charles E. Cunningham Robert B. Zipursky Bruce K. Christensen Peter J. Bieling Victoria Madsen Heather Rimas 《Journal of American college health : J of ACH》2017,65(6):389-399
Objective: We modeled design factors influencing the intent to use a university mental health service. Participants: Between November 2012 and October 2014, 909 undergraduates participated. Method: Using a discrete choice experiment, participants chose between hypothetical campus mental health services. Results: Latent class analysis identified three segments. A Psychological/Psychiatric Service segment (45.5%) was most likely to contact campus health services delivered by psychologists or psychiatrists. An Alternative Service segment (39.3%) preferred to talk to peer-counselors who had experienced mental health problems. A Hesitant segment (15.2%) reported greater distress but seemed less intent on seeking help. They preferred services delivered by psychologists or psychiatrists. Simulations predicted that, rather than waiting for standard counseling, the Alternative Service segment would prefer immediate access to E-Mental health. The Usual Care and Hesitant segments would wait 6 months for standard counseling. Conclusions: E-Mental Health options could engage students who may not wait for standard services. 相似文献
995.
Pool screening is a widely used study design to make inference about the probability of a subject being positive for an infection when the probability is extremely low. When the pool sizes are unequal, outcomes of pool screening follow independent nonidentical Bernoulli distributions. This paper presents different calculation methods for the probability distribution of T, the number of positive pools. Marcus and Lopes recursive method is recommended. 相似文献
996.
997.
The prevalence of obesity has doubled over the last 25 years. We estimate the effects of multiple socio-environmental factors (e.g., physical demands at work, restaurants, food prices, cigarette smoking, food stamps, and urban sprawl) on obesity using NLSY data. Then we use the Oaxaca–Blinder decomposition technique to approximate the contribution of each socio-environmental factor to the increase during this time. Many socio-environmental factors significantly affect weight, but none are able to explain a large portion of the obesity increase. Decreases in cigarette smoking consistently explains about 2–4 % of the increase in obesity and BMI. Food stamp receipt also consistently affects the measures of weight, but the small decrease in food stamp program participation during the period we examine actually dampened the increases in obesity and BMI. Collectively, the socio-environmental factors we examine never explain more than about 6.5 % of the weight increases. 相似文献
998.
999.
This paper will provide information on a recent Breakthrough Series Collaborative (BSC) conducted by the National Child Traumatic Stress Network on Using Trauma-Informed Child Welfare Practice to Improve Foster Care Placement Stability. Information on this particular BSC will be provided, followed by initial findings gathered from an evaluation of the BSC and metrics gathered by each of the nine participating teams throughout the BSC process. Specific trauma-informed promising strategies adopted by teams are presented along with recommendations for next steps. 相似文献
1000.
Donald J. Baumann Charles Grigsby Janess Sheets J. Christopher GrahamJason Holoubek James FarrisEugene Wang 《Children and youth services review》2011,33(9):1648-1657
This article presents a concept-guided approach to the assessment of risk in the life situations of children alleged to be maltreatment victims. This concept-guided risk assessment is theoretically based and is the first to use a nomological hierarchy which can yield itself to systematic testing for construct validity. Data were collected on 1199 cases referred for investigations of child maltreatment. Reliability was examined by applying Cronbach's alpha coefficient to the 25 risk features and the 18 risk category constructs within the seven risk areas. Convergent validity coefficients for seven risk area constructs and eighteen risk category constructs were computed and structural validity was examined using an analysis technique adapted from the multitrait-multimethod technique of Campbell and Fiske (1959). Predictive validity was assessed using a multivariate measure assessing rated risk, seriousness, and concern. In general, the results support construct validity. Improvements are needed in assessments of child vulnerability and caregiver stress. The overall psychometric evidence, combined with the model's hierarchical and theoretical nature, suggests a promising direction for future research on understanding and preventing child maltreatment. 相似文献