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   8681篇
  免费   133篇
各国政治   255篇
工人农民   751篇
世界政治   497篇
外交国际关系   305篇
法律   5276篇
中国政治   51篇
政治理论   1662篇
综合类   17篇
  2021年   40篇
  2020年   70篇
  2019年   103篇
  2018年   543篇
  2017年   549篇
  2016年   437篇
  2015年   83篇
  2014年   122篇
  2013年   585篇
  2012年   225篇
  2011年   485篇
  2010年   528篇
  2009年   390篇
  2008年   439篇
  2007年   418篇
  2006年   140篇
  2005年   144篇
  2004年   186篇
  2003年   148篇
  2002年   105篇
  2001年   310篇
  2000年   277篇
  1999年   193篇
  1998年   81篇
  1997年   85篇
  1996年   63篇
  1995年   77篇
  1994年   64篇
  1993年   38篇
  1992年   121篇
  1991年   139篇
  1990年   131篇
  1989年   126篇
  1988年   113篇
  1987年   125篇
  1986年   100篇
  1985年   95篇
  1984年   102篇
  1983年   90篇
  1982年   61篇
  1981年   73篇
  1980年   34篇
  1979年   79篇
  1978年   45篇
  1977年   31篇
  1975年   37篇
  1974年   49篇
  1973年   54篇
  1972年   39篇
  1971年   34篇
排序方式: 共有8814条查询结果,搜索用时 15 毫秒
301.
302.
303.
There is widespread evidence that individuals select information that supports their convictions and worldviews. This behavior yields the formation of echo chambers – environments in which an individual’s own political beliefs are repeated and amplified and dissenting opinions are screened out. Recent research demonstrates that social networking sites such as Facebook or Twitter can facilitate this selection into homogenous networks. Using data from a representative nation-wide online survey, we consider the degree to which respondents’ social media networks resemble virtual echo chambers. We then analyze the effect of these social media echo chambers on satisfaction with democracy among Democrats and Republicans in the aftermath of the 2016 US elections. Our findings reveal that virtual echo chambers boost democratic satisfaction among Republicans but they do not have an effect on system support by self-identified Democrats. Our paper therefore adds to a growing literature linking online behaviors to mass attitudes about politics.  相似文献   
304.
Climate change adaptation refers to altering infrastructure, institutions or ecosystems to respond to the impacts of climate change. Least developed countries often lack the requisite capacity to implement adaptation projects. The Global Environment Facility’s Least Developed Countries Fund (LDCF) is a scheme where industrialised countries have disbursed $934.5 million in voluntary contributions to support 213 adaptation projects across 51 least developed countries. But how effective are its efforts—and what sort of challenges have arisen as it implements projects? To provide some answers, this article documents the presence of four “political economy” attributes of adaptation projects—processes we have termed enclosure, exclusion, encroachment and entrenchment—cutting across economic, political, ecological and social dimensions. Based on extensive field research, we find the four processes at work simultaneously in our case studies of five LDCF projects being implemented in Bangladesh, Bhutan, Cambodia, the Maldives and Vanuatu. The article concludes with a discussion of the broader implications of the political economy of adaptation for analysts, program managers and climate researchers at large. In sum, the politics of adaptation must be taken into account so that projects can maximise their efficacy and avoid marginalising those most vulnerable to the impacts of climate change.  相似文献   
305.
The One Laptop per Child (OLPC) project aims to make low-cost computers accessible to the “world’s poorest children,” presuming that the gadgets will support their empowerment via education. The project’s success globally, however, has been mixed at best, with many countries terminating their purchases due to cost, inadequate infrastructure, and negative side effects. In October 2010, Ghana suspended the country’s 3-year participation. This study examines the complex history and failure of OLPC Ghana in two pilot schools, one urban and one rural, with particular attention to gender bias. The analysis draws on interviews with government personnel, students, and teachers in the pilot classes. Despite lacking electric power in the rural community, UNDP’s Millennium Villages Project played a strong support role, making OLPC somewhat more effective with less of a gender divide in the rural school than in the urban school in Accra. Both pilot schools faced severe sustainability challenges raising decade-old questions about modernity and technological determinism. Further, in both schools, particularly the urban school, a digital divide by gender was evident.  相似文献   
306.
Are internalizing and externalizing behavior problems interrelated via mutually reinforcing relationships (with each behavior leading to increases over time in levels of the other behavior) or mutually suppressing relationships (with each behavior leading to decreases over time in levels of the other behavior)? Past research on the directionality of these relationships has led to ambiguous results, particularly in adolescence. Furthermore, the extent to which prior results will generalize to adolescents with low levels of cognitive abilities remains unknown. This second limit is particularly important, given that these adolescents are known to present higher levels of externalizing and internalizing behaviors than their peers with average-to-high levels of cognitive abilities, and that the mechanisms involved in the reciprocal relationships between these two types of behaviors may differ across both populations. This study examines the directionality of the longitudinal relationships between externalizing and internalizing behavior problems as rated by teachers across three measurement waves (corresponding to Grades 8–10) in matched samples of 138 adolescents (34.78?% girls) with low levels of cognitive abilities and 556 adolescents (44.88?% girls) with average-to-high levels of cognitive abilities. The results showed that the measurement structure was fully equivalent across time periods and groups of adolescents, revealing high levels of developmental stability in both types of problems, and moderately high levels of cross-sectional associations. Levels of both internalizing and externalizing behaviors were higher among adolescents with low levels of cognitive abilities relative to those with average-to-high levels of cognitive abilities. Finally, the predictive analyses revealed negative reciprocal longitudinal relationships (i.e., mutually suppressing relationships) between externalizing and internalizing problems, a result that was replicated within samples of adolescents with low, and average-to-high levels of cognitive ability.  相似文献   
307.
Early alcohol use is associated with multiple negative outcomes later in life, including substance use disorders. Identification of factors related to this very early risk indicator can help inform early prevention efforts. This study prospectively examined the relationship between childhood adversities and early initiation of alcohol use (by age 14) among Puerto Rican youth, the Latino subgroup at highest risk for alcohol use disorders in adulthood. The data come from the Boricua Youth Study, a longitudinal study of Puerto Rican youth in two sites (South Bronx, New York, and the standard metropolitan area of San Juan, Puerto Rico). We focus on youth who were ages 10 and older at Wave 1 [M age at Wave 1 (SE)?=?11.64(0.05), N?=?1259, 48.85?% females]. Twelve childhood adversities were measured at Wave 1 and include 10 adverse childhood experiences commonly studied and two additional ones (exposure to violence and discrimination) that were deemed relevant for this study’s population. Early initiation of alcohol use was determined based on youth report at Waves 1 through 3 (each wave 1 year apart). Cox proportional hazards models showed that, when considered individually, adversities reflecting child maltreatment, parental maladjustment, and sociocultural stressors were related to early initiation of alcohol use. Significant gender interactions were identified for parental emotional problems and exposure to violence, with associations found among girls only. Adversities often co-occurred, and when they were considered jointly, physical and emotional abuse, parental antisocial personality, and exposure to violence had independent associations with early alcohol use, with a stronger influence of exposure to violence in girls compared to boys. The accumulation of adversities, regardless of the specific type of exposure, increased the risk for starting to drink at a young age in a linear way. The associations between childhood adversities and early alcohol use were generally consistent across sociocultural contexts, in spite of differences in the prevalence of exposure to adversity. Our findings highlight the importance of targeting multiple adversities and expanding the notion of adversity to capture the experiences of specific groups more adequately.  相似文献   
308.
In light of its associations with child and adolescent health and well-being, there remains a need to better understand the etiological underpinnings and developmental course of internalizing symptomatology in children and adolescents. This study leveraged intensive longitudinal data (N?=?959; 49.6?% females) to test the hypothesis that internalizing symptoms in childhood may be driven more strongly by family experiences whereas internalizing symptoms in adolescence may derive more uniquely from familial loading for affective disorders (i.e., maternal depression). We evaluated the relative contributions of (a) family experiences (b) maternal depression, and (c) peer influences in testing this hypothesis. The results indicated that family predictors were more strongly correlated with childhood (relative to adolescent) internalizing symptoms. In contrast to previous findings, maternal depression also exhibited stronger associations with childhood internalizing symptoms. Although often overlooked in theories concerning potential differential origins of childhood vs. adolescent internalizing symptomatology, peer experiences explained unique variation in both childhood and adolescent internalizing problems.  相似文献   
309.
Although research consistently suggests that adolescents in single-mother families are at increased risk for depression, the mechanisms that explain this relationship are unclear. In a community sample of adolescents (N?=?368; ages 12–16; 50?% female; 50?% White) and their mothers (42?% single), adolescents completed measures of depressive symptoms, rumination, and depressogenic inferential style at baseline and two yearly follow-ups. Mothers reported on stressful events that occurred in the child’s life from birth until baseline. Adolescents raised by single mothers, relative to partnered mothers, experienced more childhood stressors and higher rumination levels at 1-year follow-up. Additionally, higher rumination mediated the relationship between single motherhood and greater youth depressive symptoms at the 2-year follow-up. Clinical implications and developmental considerations are discussed.  相似文献   
310.
Youth’s career attainment is associated with socioeconomic background, but may also be related to their beliefs about causes of success. Relationships between 17-year-olds’ socioeconomic status (SES) and causal beliefs about success, and whether these beliefs predict career attainment after completing a vocational or university degree were examined using data from the German Socio-Economic Panel Study (n?=?997, 48.5% female). Youth with higher SES parents and those who attended higher levels of high schools were less likely to believe that success in society is due to external causes, but SES was unrelated to the belief that success is due to personal merit or ability. Youth who believe that success is due to external causes attained lower income, occupational prestige, and job autonomy, and slower increases in income over time. There were also significant indirect effects of youth’s parents’ SES and their own high school levels on career attainment through such external causal beliefs; merit beliefs, by contrast, were largely unrelated to career attainment. These results suggest that beliefs about external causes of success may uniquely contribute to the transmission and maintenance of SES across generations and over time.  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