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   18511篇
  免费   512篇
管理学   2201篇
民族学   102篇
人才学   6篇
人口学   1757篇
丛书文集   109篇
教育普及   2篇
理论方法论   1708篇
现状及发展   1篇
综合类   236篇
社会学   9256篇
统计学   3645篇
  2023年   92篇
  2022年   79篇
  2021年   95篇
  2020年   285篇
  2019年   458篇
  2018年   462篇
  2017年   645篇
  2016年   459篇
  2015年   354篇
  2014年   437篇
  2013年   3158篇
  2012年   668篇
  2011年   574篇
  2010年   464篇
  2009年   442篇
  2008年   504篇
  2007年   504篇
  2006年   460篇
  2005年   416篇
  2004年   417篇
  2003年   387篇
  2002年   391篇
  2001年   467篇
  2000年   388篇
  1999年   381篇
  1998年   312篇
  1997年   281篇
  1996年   289篇
  1995年   274篇
  1994年   263篇
  1993年   249篇
  1992年   291篇
  1991年   291篇
  1990年   261篇
  1989年   258篇
  1988年   245篇
  1987年   234篇
  1986年   221篇
  1985年   247篇
  1984年   237篇
  1983年   235篇
  1982年   181篇
  1981年   157篇
  1980年   173篇
  1979年   170篇
  1978年   144篇
  1977年   141篇
  1976年   122篇
  1975年   115篇
  1974年   96篇
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
801.
With survey data from 243 Latina/o early adolescent language brokers, latent profile analyses were conducted to identify different types (i.e., profiles) of brokers. Profiles were based on how often Latina/o early adolescents brokered for family members, as well as their levels of family‐based acculturation stress, negative brokering beliefs, parentification, and positive brokering beliefs. Three brokering profiles emerged: (1) infrequent‐ambivalents, (2) occasional‐moderates, and (3) parentified‐endorsers. Profile membership was significantly predicted by ethnic identification and brokering in a medical context. Respect, brokering at school, and brokering at home did not significantly predict profile membership. In addition, parentified‐endorsers had more frequent perceived ethnic/racial discrimination and depressive symptoms than other profiles. In contrast, infrequent‐ambivalents engaged in risky behaviors less frequently than other profiles.  相似文献   
802.
In the current research, we examined whether the known link between relative deprivation and disordered gambling (via delay discounting; i.e., preferences for immediate smaller rewards relative to delayed larger rewards) is moderated by the extent to which gamblers have a financially focused self-concept. Specifically, we hypothesized that delay discounting would be a strong predictor of disordered gambling among those who base their self-worth on their financial success. To test this moderated-mediation model, a community sample of gamblers (N = 239) completed measures that assessed relative deprivation, delay discounting, financially focused self-concept, and disordered gambling severity. As predicted, people who felt more relative deprivation reported more severe symptoms of disordered gambling and this association was mediated by delay discounting. Importantly, this mediated relationship was moderated by the extent to which participants’ self-concept was focused on financial success. Among participants whose self-concept was high in financial focus, greater delay discounting (stemming from relative deprivation) was a strong predictor of disordered gambling. Among people whose self-concept was low in financial focus, delay discounting (stemming from relative deprivation) was a weak predictor of disordered gambling. Thus, the magnitude of the indirect effect of relative deprivation on disordered gambling severity was larger among people with a more financially focused self-concept—an effect mediated by delay discounting. These findings suggest that targeting gamblers’ financial focus in prevention and treatment interventions may be instrumental in curtailing the development and maintenance of disordered gambling.  相似文献   
803.
The goal of this study was to advance understanding of how adolescent conflict appraisals contribute uniquely, and in combination with interparental conflict behavior, to individual differences in adolescent physiological reactivity. Saliva samples were collected from 153 adolescents (52% female; ages 10–17 years) before and after the Trier Social Stress Test. Saliva was assayed for cortisol and alpha‐amylase. Results revealed interactive effects between marital conflict and conflict appraisals. For youth who appraised parental conflict negatively (particularly as threatening), negative marital conflict predicted dampened reactivity; for youth who appraised parental conflict less negatively, negative marital conflict predicted heightened reactivity. These findings support the notion that the family context and youth appraisals of family relationships are linked with individual differences in biological sensitivity to context.  相似文献   
804.
ABSTRACT

Numerous mental health disorders plague our veterans when they return from deployment including anxiety and depressive disorders, which have been linked to elevated suicide risk when left untreated. Family factors, such as parenthood status, may serve as a protective factor against these mental health issues. This study examined the role of parenthood status of male veterans (N = 234) based on age of the child in order to determine whether a child’s age (minor children v. adult children) affects the likelihood of meeting diagnosis criteria for anxiety, depression, and suicide ideation after controlling for marital status. Three hierarchical binary logistic regression models were constructed to assess the predictive influence of children 18 years old and younger, children older than 18, and no children with the results indicating that parenthood status did meaningfully enhance the prediction of suicide ideation. Complete findings, clinical implications, and future considerations are discussed.  相似文献   
805.
This study explores the conversion of cultural capital into economic capital, and specifically financial capital in the form of parental financial planning for children’s college education, including reported financial preparations and savings. Using data from the Education Longitudinal Study (ELS:2002), logistic regression-based analyses of aspects of cultural capital indicated that parental involvement exhibited the most prevalent relationship with financial planning and the amount saved, and that parents’ expectations, but not their aspirations, corresponded to engagement in financial planning. Findings support the conclusion that some parents convert part of their cultural capital to financial capital in preparation for paying for their child’s college education, perhaps representing a typically hidden facet of social class reproduction.  相似文献   
806.
Urban areas are understood to be extraordinarily spatially heterogeneous. Spatial heterogeneity, and its causes, consequences, and changes, are central to ecological science. The social sciences and urban design and planning professions also include spatial heterogeneity as a key concern. However, urban ecology, as a pursuit that integrates across these disciplines, lacks a theoretical framework that synthesizes the diverse and important aspects of heterogeneity. This paper presents the concept of dynamic heterogeneity as a tool to explore how social and ecological heterogeneities interact and how they together act as both an outcome of past interactions and a driver future heterogeneity and system functions. To accomplish this goal, we relate heterogeneity to the fundamental concept of the human ecosystem. The human ecosystem concept identifies key processes that require operationalized models of dynamic heterogeneity in three process realms: the flow of materials, the assembly of urban ecosystem biota, and the locational choices humans make concerning land. We exemplify a specific dynamic model of heterogeneity in each of these realms, and indicate a range of complementary statistical approaches to integrate the drivers and outcomes of dynamic heterogeneity across the three realms. We synthesize a hierarchical framework for a theory of dynamic urban heterogeneity, noting its complementarity to other major urban theories and general model approaches. We hypothesize that human actions and structures amplify the dynamics of heterogeneity in urban systems.  相似文献   
807.
With a growing number of people living in urban areas, city residents are more frequently exposed to stresses related to the built environment including elevated summer surface temperatures contributing to the urban heat island (UHI) effect. This study examines the role of urban tree density in moderating surface temperature variation in a densely populated city (Toronto, Canada). By applying parallel aspatial (OLS) and spatial regression (GWR) approaches with satellite derived data describing tree canopy density and surface temperature, one dimension of tree canopy quality (i.e., canopy density) is shown to contribute directly to a reduction in the surface urban heat island (SUHI) effect at a local scale. Though the model fit differed between the two regression approaches, both exhibited moderately strong explanatory power and demonstrated that observed surface temperature decreases in locations with increasing high-density and closed tree canopy. Study findings provide an empirical basis to recommend that municipal urban forest strategies embrace canopy quality metrics, such as increasing the density of existing urban forest stands, as a part of tree planting objectives seeking to effectively deliver temperature moderation as a valuable ecosystem service.  相似文献   
808.
The objective of this study was to evaluate the relative effects of watershed land-use on streambed substrate composition in eight low-order tropical streams. Data were collected at 24 sampling sites for eight wadeable streams in the Pirapó River Basin, southern Brazil. According to the percentage of impervious surfaces in the watershed, we defined the streams as either urban or rural. We estimate the percentages of the different streambed substrates, hydrological variables, and the rainfall intensity. The results showed that silt, sand and coarse particulate organic matter (CPOM) contributed to significant differences in streambed substrate composition between urban and rural streams. Silt, sand and CPOM were found in a higher mean proportion in the rural streams. Probably the urban streams have a greater bed load, promoted by precipitation and discharge, than rural streams, especially fine sediment. Rural streams have soft hydrographs, with stream flow slowly increasing during a rainstorm and subsequently decreasing over a long period after the rain event is over. These characteristics can provide the lixiviation of fine sediments into the stream channels due to land-surface clearance for agricultural activities and their accumulation in the streambed due to the moderate discharge regime.  相似文献   
809.
Urbanization and other land cover changes have been particularly detrimental to wetlands throughout the planet. One wetland specialist that may be sensitive to land cover changes surrounding wetlands is the round-tailed muskrat (Neofiber alleni; hereafter RTM). The RTM is a wetland obligate rodent that appears to have declined over the last half century and is a species of concern in Florida, where it is a near endemic. To determine if urbanization or other land cover influenced the distribution of RTMs we took a multi-scaled approach to examine the occurrence of RTMs and their associated vegetation in North-Central Florida. We detected RTMs on 19 of 72 sample plots and used a Classification And Regression Tree (CART) to determine that dogfennel (Eupatorium capillifolium) was negatively associated with RTMs and maidencane (Panicum hemitomon) was positively associated with their occurrence on sampling plots. Examining the influence of landscape composition for 2 km surrounding our plots we found that RTM occurrence was negatively related to urban land cover. Further, we found that dogfennel increased and maidencane decreased as urbanization increased in the surrounding landscape. Our research suggests that conservation of RTMs and their associated vegetation should focus on limiting urban sprawl at least within 2 km of wetlands.  相似文献   
810.
The Nuestro Futuro Saludable partnership designed a critical service-learning intervention focused on health equity and action. The 10-week afterschool intervention was implemented in a Boston middle school. Youths who took part in the intervention were knowledgeable about the social determinants of health in their communities, as well as to the barriers to health. Our findings indicate that engaging young people in a meaningful way will be critical if health improvement efforts are to be realized. We found that a critical service-learning framework that incorporates elements of applied inquiry and critical pedagogy was effective as a health intervention and provided opportunities for action.  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