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   13177篇
  免费   402篇
  国内免费   15篇
管理学   1621篇
民族学   82篇
人才学   1篇
人口学   1148篇
丛书文集   143篇
理论方法论   1234篇
综合类   691篇
社会学   6999篇
统计学   1675篇
  2023年   70篇
  2021年   108篇
  2020年   209篇
  2019年   254篇
  2018年   331篇
  2017年   480篇
  2016年   325篇
  2015年   265篇
  2014年   314篇
  2013年   2065篇
  2012年   482篇
  2011年   468篇
  2010年   394篇
  2009年   334篇
  2008年   405篇
  2007年   418篇
  2006年   419篇
  2005年   365篇
  2004年   288篇
  2003年   255篇
  2002年   269篇
  2001年   339篇
  2000年   282篇
  1999年   274篇
  1998年   202篇
  1997年   170篇
  1996年   158篇
  1995年   174篇
  1994年   160篇
  1993年   163篇
  1992年   185篇
  1991年   186篇
  1990年   183篇
  1989年   161篇
  1988年   167篇
  1987年   191篇
  1986年   149篇
  1985年   160篇
  1984年   176篇
  1983年   152篇
  1982年   152篇
  1981年   122篇
  1980年   113篇
  1979年   122篇
  1978年   95篇
  1977年   80篇
  1976年   93篇
  1975年   110篇
  1974年   85篇
  1972年   62篇
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
921.
Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.  相似文献   
922.
In evaluating family preservation services, it is important not only to study the service outcomes and the family characteristics, but also what actually happens during the treatment. This requires a program model. This article describes how a program model works, prescribes how workers should carry it out, and describes how researchers should measure the program's characteristics. The authors use data from Families First in The Netherlands to test the model. Results show that the method of the program meets the specified characteristics. The results are important for treatment, policy, education, and evaluation research.  相似文献   
923.
This study describes depressive symptoms among caregivers following bereavement and connects these trajectories to earlier features of caregiving using life course and stress process theory. Data are from a six-wave longitudinal survey (five years) of spouses and adult children caring for someone with Alzheimer's Disease. The analytic subsample (N = 291) is defined by death of the care-recipient after the baseline interview. A latent class mixture model is used to identify distinctive clusters of depressive symptoms over time. Of the four trajectories identified, three represent stable symptom levels over time, with two-thirds being repeatedly symptomatic (medium symptom levels), compared to two smaller groups of repeatedly asymptomatic (effectively absent of symptoms) and repeatedly distressed (severe symptoms). In contrast, about one in five caregivers experiences improved emotional well-being over time, the temporarily distressed, who progress from severe to moderate symptom levels. Caregivers with few symptoms before bereavement tend to maintain these states afterwards, but emotionally distressed caregivers tend to become more distressed. Role overload before bereavement substantially increases the odds of following an unfavorable trajectory afterwards, whereas self-esteem and socioemotional support play protective roles. These results demonstrate that caregivers are not uniform in their emotional responses to bereavement, but follow several distinct trajectories. These trajectories are linked to their previous experiences as caregivers, in particular exposure to stressors and access to resources. These findings suggest that intervention during caregiving may facilitate adaptation following death of a loved one.  相似文献   
924.
This research project examined the individual and combined effectiveness of an HIV prevention workshop and a free condom distribution program in four high schools in Tijuana, Mexico. Adolescents (N = 320) completed baseline measures on sexual practices and theoretical correlates and participated in a two-part study. In Study 1, students were randomly assigned to an HIV prevention workshop or a control condition, with a 3-month follow-up assessment. Results indicate three significant workshop benefits regarding HIV transmission by altering sexual initiation, access to condoms, and traditional beliefs regarding condoms. In Study 2, we set up a condom distribution program at two of the participating schools, and students completed a 6-month follow-up assessment. Results indicate that exposure to the workshop followed by access to the condom distribution program yielded two beneficial results for reducing HIV transmission: moderating sexual initiation and increasing condom acquisition. Access to the condom distribution program alone had no effects on behavioral and psychosocial correlates of HIV transmission. We discuss implications of these results.  相似文献   
925.
This research is based on in-depth ethnographic interviews and focus groups with 88 African American family caregivers from various regions of the United States during a stressful time in their family development--caregiving at the end-of-life--and the grieving during the aftermath. The study employed a stratified purposeful sampling strategy. Subjects were African Americans from the Northern, Southern, and Midwestern United States. Formal care is complicated by the distrust that many African Americans hold toward the health care system, which has resulted from years of exclusion, racism and discrimination. The findings highlight the importance of hearing from African American families to gain an understanding of what services, including family therapy and other psychotherapy, they will need during this process.  相似文献   
926.
There is limited guidance for conducting competent and responsive cross-cultural evaluation research with American Indian communities. The authors draw on Fisher and Ball's Tribal Participatory Research Model to highlight ways in which this project is attempting to be culturally appropriate and sensitive as they partner with an American Indian community to implement and evaluate a youth-based initiative. Challenges encountered during the evaluation are shared, as well as the authors' collective responses to such challenges. Implications for future cross-cultural evaluation researchers are also discussed in light of these experiences.  相似文献   
927.
Using data from 2,170 individuals who participated in Waves 8 (age 23) and 9 (age 29) of a multiyear panel study, this study examined whether alcohol and marijuana use in young adulthood increase one's risk for experiencing subsequent sexual or physical assault victimization, whether victims' own violent behavior or involvement in the sale of drugs explain any effects of substance use on victimization, and whether these associations differ by gender. Controlling for prior victimization, we found that marijuana use, but not alcohol use, predicted women's and men's subsequent sexual victimization and men's subsequent physical assault victimization, and that heavy alcohol use, but not marijuana use, predicted women's subsequent physical assault victimization. Whereas the links from marijuana use to victimization were explained by users' own violent behavior, the link from alcohol use to women's physical assault victimization was not.  相似文献   
928.
One of the most prominent interventions developed to protect victims in domestic abuse cases is the temporary restraining order or "TRO," the purpose of which is to restrain an alleged defendant from further harassment or abuse against a plaintiff. This report analyzes 397 restraining order petitions, and subsequent arrest and conviction data for TRO defendants from 1996 to 1998. Findings confirm that TRO petitioners report many types of abuse and while half of TRO defendants do not re-offend, a small percent of defendants are responsible for multiple police reports, arrests, and criminal violations. Outcome data are discussed for program and policy implications.  相似文献   
929.
The authors identified the number, type, and frequency of protective behaviors that undergraduate college students who consume alcohol use to prevent alcohol-related consequences. Their hypothesis was that students who engage in more types of protective behaviors with greater frequency would be less likely to experience alcohol-related consequences. Participants consisted of a randomly selected sample of 1,355 undergraduates aged 18 years and older at a large public university. Students completed a mailed questionnaire on alcohol and health behaviors in spring 2002. The findings (after adjustment for covariates) indicated that self-protective behaviors are inversely associated with alcohol-related problems for women but not for men. The influences of gender and racial and ethnic differences are considered in relation to prevention and intervention programs aimed at reducing alcohol-related consequences on college campuses.  相似文献   
930.
The authors examined the impact of pharmaceutical companies' advertisements on college students' perceptions of depression and concomitant treatment with antidepressants among 13 male and 31 female undergraduates from a midwestern university. The students were randomly assigned to groups that read either pharmaceutical company advertisements or scientific information about depression and its treatment. The analysis revealed that 40% of the women in the advertisement condition as opposed to 1 woman (6%) in the scientific condition rated themselves as having mild, moderate, or severe depression on the Beck Depression Inventory, second edition. Women in the advertisement condition were significantly more likely to believe that depression required treatment with antidepressant medication and were more willing than women in the scientific condition to suggest antidepressant treatment to others.  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