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   24935篇
  免费   1159篇
各国政治   893篇
工人农民   1742篇
世界政治   1290篇
外交国际关系   793篇
法律   16479篇
中国共产党   2篇
中国政治   104篇
政治理论   4702篇
综合类   89篇
  2023年   76篇
  2021年   86篇
  2020年   427篇
  2019年   444篇
  2018年   1736篇
  2017年   1687篇
  2016年   1589篇
  2015年   557篇
  2014年   546篇
  2013年   1798篇
  2012年   643篇
  2011年   1349篇
  2010年   1467篇
  2009年   1086篇
  2008年   1181篇
  2007年   1132篇
  2006年   519篇
  2005年   488篇
  2004年   594篇
  2003年   487篇
  2002年   426篇
  2001年   672篇
  2000年   606篇
  1999年   479篇
  1998年   246篇
  1997年   182篇
  1996年   208篇
  1995年   213篇
  1994年   187篇
  1993年   176篇
  1992年   303篇
  1991年   312篇
  1990年   294篇
  1989年   275篇
  1988年   305篇
  1987年   261篇
  1986年   321篇
  1985年   316篇
  1984年   254篇
  1983年   233篇
  1982年   181篇
  1981年   154篇
  1980年   143篇
  1979年   224篇
  1978年   123篇
  1977年   99篇
  1975年   94篇
  1974年   124篇
  1973年   79篇
  1972年   80篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
861.
At the turn of the first millennium, the rise of autonomous communes and city-states in northern Italy coincided with the development of a particular sense of attachment to land and city, which is widely labeled as civic patriotism. Neither the transformation of these collective identities across time nor the macrostructural dynamics behind this transformation has received much attention. Through an examination of these communes and city-states from the eleventh to the sixteenth century, this paper unpacks different forms of collective identities that prevailed in northern Italy in different periods of time, all of which have previously been labeled as “patriotism” in the literature. The differentiation I propose between “communal patriotism,” “civic nationalism,” and “city-state chauvinism” presents a more nuanced picture which highlights the differences in the ways these collective identities are produced, reproduced, and transformed. My analysis also discusses the role played by macrostructural dynamics (e.g., changing climate in the macropolitical economy as well as inter-city-state system in the peninsula) in transforming these collective identities. Alongside a longue durée evolutionary transformation, there were two conjunctural moments which created ruptures in the transformation of collective identities in northern Italy: The first took place during the territorialization of the communes and the conquest of the contado in the mid-twelfth century and the second occurred in the aftermath of the crisis of the fourteenth century.  相似文献   
862.
Research on coparenting documents that mothers’ and fathers’ coordination and mutual support in their parenting roles is linked to their offspring’s adjustment in childhood, but we know much less about the coparenting of adolescents. Taking a family systems perspective, this study assessed two dimensions of coparenting, parents’ shared decision-making and joint involvement in activities with their adolescents, and examined bidirectional associations between these coparenting dimensions and boys’ and girls’ risky behaviors and depressive symptoms across four time points (6 years) in adolescence. Participants were 201 mothers, fathers, and adolescents (M = 11.83, SD = .55 years of age at Time 1; 51 % female). Parents of sons shared more decisions, on average, than parents of daughters. On average, shared decision-making followed an inverted U shaped pattern of change, and parents’ joint involvement in their adolescents’ activities declined. Cross-lagged findings revealed that risky behavior predicted less shared decision-making, and shared decision-making protected against increased risky behavior for boys. For girls and boys, parents’ joint involvement predicted fewer risky behaviors, and lower levels of risky behavior predicted higher levels of joint involvement. In contrast, boys’ and girls’ depressive symptoms predicted less joint involvement. The discussion centers on the nature and correlates of coparenting during adolescence, including the role of child effects, and directions for future research on coparenting during this developmental period.  相似文献   
863.
Recent advancements in technology (e.g., social networking, texting) have created new ways for dating youth to relate to one another, including in abusive ways via “cyber dating abuse.” Cyber dating abuse is a form of teen dating violence that overlaps with other types of abuse (e.g., psychological) but also has several unique characteristics. Given the phenomenon’s limited presence in dating violence literature, we focus on identifying how experiencing cyber dating abuse relates to youths’ individual behaviors and experiences (e.g., substance use, sexual activity), psychosocial adjustment, school connection, family relationships, and partner relationships. A total of 3,745 youth (52 % female, 74 % White) in three northeastern states participated in the survey and reported currently being in a dating relationship or having been in one during the prior year. We found that experiences of cyber dating abuse were most significantly correlated with being female, committing a greater variety of delinquent behaviors, having had sexual activity in one’s lifetime, having higher levels of depressive symptoms, and having higher levels of anger/hostility. Further, cyber dating abuse appeared somewhat more strongly related to depressive symptoms and delinquency than did other forms of teen dating violence and abuse.  相似文献   
864.
Peer victimization is a well-known national and international problem, contributing to a range of emotional, social, and behavioral consequences. Using structural equation modeling, the authors tested a theoretical model suggesting that psychological distress and student engagement mediate the association between the experience of victimization and concurrent academic achievement. Participants were 469 (46.4 % male, 53.6 % female) 6th to 8th grade students, from randomly selected classrooms in 11 middle schools in a southeastern school district. Structural equation models of the hypothesized effects demonstrated adequate fit to the data, with both symptoms of psychological distress and engagement mediating the relationship between victimization and academic achievement. In general, the results suggest that victimization predicts diminished academic achievement by way of psychological distress and poorer engagement in classroom and academic tasks. However, the direct relationship between victimization and measures of achievement lacked significance across many correlational and path analyses conducted. These findings have implications for researchers and practitioners in understanding how psychological distress and student engagement are associated with the academic performance of students who experience peer victimization.  相似文献   
865.
866.
Intravascular lymphoma (IVL) is a rare subtype of extranodal lymphomas that is characterized by the selective growth of neoplastic cells within the lumen of small vessels. Authors document the case of an unexpected death caused by an undiagnosed intravascular large B-cell lymphoma with multi-organ involvement, which had initially manifested as an infection and then as an unclarified central nervous system pathology. Histological examination showed a diffuse intravascular large B-cell brain lymphoma with prominent cerebral involvement. The relevance of the case report reveals the importance of an autopsy of an extremely rare and threatening pathology that in most cases is diagnosed only postmortem. As a result, the role of the forensic pathologist becomes particularly important. When specifically performing an in-depth autopsy evaluation with a specific histologic analysis, it is possible to identify the intravascular lymphoma and declare a more accurate cause of death.  相似文献   
867.
868.
Through the measurement of ethyl glucuronide in hair (hETG), it is possible to assess chronic alcohol abuse over time. In this paper, we present a study on hETG in Italian prison inmates. Analyses were performed by LC-MS according to a previously published method. Results were evaluated using the cut-offs established by the Society of Hair Testing. Positives samples (ETG > 30 pg/mg) accounted for 6% of all subjects, with concentrations ranging from 42 pg/mg up to 270 pg/mg, abstinent subjects (ETG < 7 pg/mg) accounted for 88%, and moderate alcohol consumption (7 < ETG < 30 pg/mg) for 6% of the subjects. No females displayed ETG values above 30 pg/mg. Among positive samples, only two subjects did not declare heavy alcohol consumption and were found strongly positive at 210 and 270 pg/mg. To the best of our knowledge, this represents the first study on ETG hair concentration on prison inmates.  相似文献   
869.
870.
Many studies in the literature have highlighted the utility of virtual 3D databanks as a substitute for real skeletal collections and the important application of radiological records in personal identification. However, none have investigated the accuracy of virtual material compared to skeletal remains in nonmetric variant analysis using 3D models. The present study investigates the accuracy of 20 computed tomography (CT) 3D reconstruction models compared to the real crania, focusing on the quality of the reproduction of the real crania and the possibility to detect 29 dental/cranial morphological variations in 3D images. An interobserver analysis was performed to evaluate trait identification, number, position, and shape. Results demonstrate a false bone loss in 3D models in some cranial regions, specifically the maxillary and occipital bones in 85% and 20% of the samples. Additional analyses revealed several difficulties in the detection of cranial nonmetric traits in 3D models, resulting in incorrect identification in circa 70% of the traits. In particular, pitfalls included the detection of erroneous position, error in presence/absence rates, in number, and in shape. The lowest percentages of correct evaluations were found in traits localized in the lateral side of the cranium and for the infraorbital suture, mastoid foramen, and crenulation. The present study highlights important pitfalls in CT scan when compared with the real crania for nonmetric analysis. This may have crucial consequences in cases where 3D databanks are used as a source of reference population data for nonmetric traits and pathologies and during bone-CT comparisons for identification purposes.  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