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   20602篇
  免费   366篇
  国内免费   2篇
管理学   3096篇
民族学   77篇
人才学   1篇
人口学   1959篇
丛书文集   85篇
教育普及   2篇
理论方法论   1797篇
现状及发展   1篇
综合类   323篇
社会学   9782篇
统计学   3847篇
  2023年   104篇
  2021年   124篇
  2020年   306篇
  2019年   416篇
  2018年   507篇
  2017年   689篇
  2016年   560篇
  2015年   382篇
  2014年   514篇
  2013年   3154篇
  2012年   716篇
  2011年   659篇
  2010年   495篇
  2009年   414篇
  2008年   487篇
  2007年   516篇
  2006年   509篇
  2005年   487篇
  2004年   447篇
  2003年   404篇
  2002年   455篇
  2001年   544篇
  2000年   559篇
  1999年   468篇
  1998年   343篇
  1997年   314篇
  1996年   328篇
  1995年   307篇
  1994年   290篇
  1993年   289篇
  1992年   345篇
  1991年   322篇
  1990年   288篇
  1989年   295篇
  1988年   288篇
  1987年   253篇
  1986年   246篇
  1985年   280篇
  1984年   268篇
  1983年   253篇
  1982年   220篇
  1981年   184篇
  1980年   168篇
  1979年   197篇
  1978年   179篇
  1977年   161篇
  1976年   138篇
  1975年   159篇
  1974年   121篇
  1973年   119篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
This study is the first to comprehensively examine the effect of state anti-bullying laws (ABLs) on school safety and youth violence. Using existing data from the Youth Risk Behavior Surveys and the Uniform Crime Reports, and newly-collected data on school shootings, we find little evidence that the typical state ABL is effective in improving school safety and student well-being. However, this null finding masks substantial policy heterogeneity. State mandates that require school districts to implement strong, comprehensive anti-bullying policies are associated with a 7 to 13 % reduction in school violence and an 8 to 12 % reduction in bullying. In addition, our results show that strong anti-bullying policy mandates are associated with a reduction in minor teen school shooting deaths and violent crime arrests, suggesting potentially important spillover effects.  相似文献   
992.
This study compared the development of clinical assessment and intervention skills between students enrolled in a face-to-face (F2F) or an asynchronous online clinical social work class. All students from three semesters of F2F (n = 74) and online (n = 78) sections of an MSW clinical class taught by the same instructor were included. Two assignments were used to compare students: an assessment and treatment plan of a fictional case and a digital role-play. A doctoral student who was blinded to the course delivery mechanism graded the role-play. After controlling for baseline differences in age, there were no differences between online and F2F students in skill demonstration. It appears clinical skills can be taught as effectively online as in F2F situations based on blinded review of role-plays.  相似文献   
993.
This study used data from Waves 1 (1987–1989) and 2 (1992–1994) of the National Survey of Families and Households in the United States and a series of regression models, some of which included individual-specific fixed effects, to estimate associations of particular types and levels of debt with adult depressive symptoms. Results suggest that household debt is positively associated with greater depressive symptoms. However, this association appears to be driven by short-term (unsecured) debt; we found little evidence of associations with depressive symptoms for mid- or long-term debt. The link between short-term debt and depressive symptoms persisted with alternative estimation strategies, including defining debt in absolute and relative terms. Furthermore, this association was particularly concentrated among 51–64 year-old adults, those with a high school education or less, and those who were not stably married throughout the observation period. These findings suggest that short-term debt may have an adverse influence on psychological wellbeing, particularly for those who are less educated, approaching retirement age, or unmarried.  相似文献   
994.
Pettinga  D.  Kennedy  J.  Proppe  D. S. 《Urban Ecosystems》2016,19(1):373-382

Recent studies suggest that songbird communication is negatively affected by anthropogenic noise. However, much of the current literature focuses on inter- and intra-sexual communication. Songbirds also use acoustic cues for many other functional behaviors. One example associated with fitness consequences is the identification of predatory threats through acoustic cues. To test the effect of anthropogenic noise on detection of acoustic cues, we compared the rates of seven anti-predator behavioral responses in urban dwelling songbirds foraging at bird feeders when exposed to playback of calls from predatory Cooper’s hawks under quiet conditions, and when overlapped with road noise. Only a single behavior, freeze response, decreased significantly when calls were overlapped with noise. However, freeze responses occurred in only a small percentage of playback trials, raising some question regarding the biological relevance of this observed difference. Overall, our results suggest that common urban songbirds are relatively successful at perceiving acoustic signals associated with predator presence. Whether this ability is commonplace amongst songbird species is unknown and warrants additional study. However, if this trait is not widespread, it may be an additional characteristic determining which bird species can inhabit noisy areas.

  相似文献   
995.
Urban Ecosystems - Many street trees in urban areas are deciduous and drop leaves during autumn. These leaves are a potential growing substrate for fungi, which when aerosolized and inhaled, can...  相似文献   
996.
997.
Urbanization has been identified as a threat to biodiversity due to landscape modifications. Studies of parasite ecology in urbanized areas lagged behind those made on macro organisms. Here we studied infection prevalence of haemosporidian parasites in an avian community of an urban forest from Germany, and its relationship with bird abundance and body mass. We used PCR to amplify a fragment of the mtDNA cyt b gene to determine the infection status of birds, and bird point counts to determine bird relative abundances. The avifauna was dominated by two small sized insectivore passerines (Parus major, Cyanistes caeruleus), representing ~40 % of the total bird records. The highest haemosporidian prevalence was recorded for Turdus philomelos (100 %) and for Fringilla coelebs (75 %). Bird abundance and body mass were positively associated with infection status for two haemosporidian genera: Plasmodium and Leucocytozoon. Infection rate was lower in juveniles compared to adult birds. We recorded a total of 7 Plasmodium, 26 Haemoproteus, and 10 Leucocytozoon lineages. Avian malaria (P. relictum) was detected infecting 5 individuals of P. major, the most abundant species in the community. These results, together with those of previous studies at the same site, suggest that potentially any of the genetic haemosporidian lineages detected in this urban forest can be transmitted across native and pet bird species, and to species of conservation concern housed at aviaries.  相似文献   
998.
Analyses of disordered gambling assessment data have indicated that commonly used screens appear to measure latent categories. This stands in contrast to the oft-held assumption that problem gambling is at the extreme of a continuum. To explore this further, we report a series of latent class analyses of a number of prevalent problem gambling assessments (PGSI, SOGS, DSM-IV Pathological Gambling based assessments) in nationally representative British surveys between 1999 and 2012, analysing data from nearly fifty thousand individuals. The analyses converged on a three class model in which the classes differed by problem gambling severity. This identified an initial class of gamblers showing minimal problems, a additional class predominantly endorsing indicators of preoccupation and loss chasing, and a third endorsing a range of disordered gambling criteria. However, there was considerable evidence to suggest that classes of intermediate and high severity disordered gamblers differed systematically in their responses to items related to loss of control, and not simply on the most ‘difficult’ items. It appeared that these differences were similar between assessments. An important exception to this was one set of DSM-IV criteria based analyses using a specific cutoff, which was also used in an analysis that identified an increase in UK problem gambling prevalence between 2007 and 2010. The results suggest that disordered gambling has a mixed latent structure, and that present assessments of problem gambling appear to converge on a broadly similar construct.  相似文献   
999.
1000.
Transformational leaders are known to inspire and motivate their followers, thereby leading to enhanced job satisfaction. Job satisfaction is an intellectual concept regarding individuals’ attitudes toward their jobs. This study asserts that the underlying mechanisms for transformational leadership to affect employee satisfaction are trust in the community, including the leader (that is, organization) and trust in the self, namely self‐efficacy. Leadership is specifically associated with continual transformations in the higher educational context, and collectivist cultures may manifest different processes underlying the transformational leadership–satisfaction relationship. This study investigated the mediating effects of trust and self‐efficacy on the relationship between transformational leadership and job satisfaction. The study sample included academicians from a nonprofit higher education institution in Turkey. The data were analyzed using structural equation modeling. The results showed that the relationship between transformational leadership and job satisfaction is fully mediated by both trust and self‐efficacy. The mediator effect of trust was shown to be stronger than self‐efficacy, which is assumed to be the result of the cultural context. The results are discussed in the context of employee satisfaction and cultural determinants of employee satisfaction.  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