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   49815篇
  免费   825篇
  国内免费   168篇
教育   35186篇
科学研究   4627篇
各国文化   532篇
体育   4505篇
综合类   61篇
文化理论   416篇
信息传播   5481篇
  2022年   302篇
  2021年   510篇
  2020年   828篇
  2019年   1215篇
  2018年   1654篇
  2017年   1708篇
  2016年   1550篇
  2015年   947篇
  2014年   1336篇
  2013年   9432篇
  2012年   1279篇
  2011年   1379篇
  2010年   1046篇
  2009年   1066篇
  2008年   1140篇
  2007年   1034篇
  2006年   974篇
  2005年   879篇
  2004年   1032篇
  2003年   950篇
  2002年   999篇
  2001年   1148篇
  2000年   883篇
  1999年   801篇
  1998年   473篇
  1997年   492篇
  1996年   530篇
  1995年   492篇
  1994年   447篇
  1993年   432篇
  1992年   679篇
  1991年   626篇
  1990年   660篇
  1989年   652篇
  1988年   585篇
  1987年   587篇
  1986年   551篇
  1985年   666篇
  1984年   541篇
  1983年   529篇
  1982年   448篇
  1981年   417篇
  1980年   380篇
  1979年   561篇
  1978年   433篇
  1977年   360篇
  1976年   331篇
  1975年   276篇
  1974年   288篇
  1973年   273篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
As medical programs place increasing importance on competency-based training and surgical simulations for residents, anatomy laboratories, and body donation programs find themselves in a position of adapting to changing demands. To better assess the demand for “life-like” cadaveric specimens and evaluate the possible impacts that competency-based medical education could have upon the body donation program of McGill University, Canada, the authors tracked, over the course of the last 10 years, the number of soft-embalmed specimens, along with the number of teaching sessions and the residents enrolled in competency-based programs that are using cadaveric material. The results reveal that the number of soft-embalmed specimens used within residency training increased from 5 in 2009 to 35 in 2019, representing an increase from 6% of bodies to 36.5% of the total number of body donors embalmed in this institution. Correspondingly, the number of annual teaching sessions for residents increased from 19 in 2012 to 116 in 2019. These increases in teaching are correlated with increasing number of residents enrolled in competency-based programs over the last 3 years (Pearson r ranging from 0.9705 to 0.9903, and R2 ranging from 0.9418 to 0.9808). Those results suggest that the new skill-centered curricula which require residents to perform specific tasks within realistic settings, exhibit a growing demand for “life-like” cadaveric specimens. Institutions’ body donation programs must, therefore, adapt to those greater need for cadaveric specimens, which presents many challenges, ranging from the logistical to the ethical.  相似文献   
2.
Research in Higher Education - Given the significant need to increase and diversify graduate enrollments within computing fields, it is vital to understand what shapes students’ pathways to...  相似文献   
3.
ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   
4.
Genetic variation in the angiotensin II type 1 receptor (AT1R) has an important effect on the outcome of acute coronary syndrome (ACS) initiated treatment with captopril. This study aims to investigate the impact of genetic polymorphism of AT1R (rs5186 and rs275651) on the ACS outcome in Iraqi patients treated with captopril. A total of 250 Iraqi individuals with ACS were included in this case—control study and they were divided into two study groups; Study group 1 included 125 participants who were prescribed captopril, 25 mg twice daily and study group 2 included 125 participants who received no captopril as part of their ACS treatment (control study). The AT1R gene (rs5186) CC genotype was found to be associated with ST-elevation myocardial infarction (STEMI) (Odd’s ratio (O.R) = 1.2, P = 0.7), while AC was associated with Non-ST-elevation myocardial infarction (NSTEMI) and unstable angina (UA) (O.R = 1.2, P = 0.8). AC genotype is more prone to have Percutaneous coronary intervention (PCI) after ACS attack (O.R = 1.2, P = 0.6). CC genotype had a risk to get less improvement (O.R = 1.6, P = 0.5), so might require higher doses of captopril during acute coronary insult. The AT1R gene (rs275651) AA genotype was associated with UA (O.R = 1.3, P = 0.9). AA and AT genotypes were more prone to have PCI after ACS attack (O.R = 3.9 P = 0.2, O.R = 3.5, P = 0.3 respectively) and thus requiring higher doses of captopril. We conclude that the AT1R rs5186, rs275651 genetic polymorphisms might partially affect the clinical outcome of ACS patients treated with captopril and might have captopril resistance which requires higher doses.  相似文献   
5.
ABSTRACT

For many forcefully displaced people worldwide, notions around one’s sense of “home” and “place” in the world are perpetually unsettled. This article explores how digital technologies interact with embodied, material experiences within the geographical location refugees are residing in. Empirical examples from ethnographic research conducted among Iraqi urban refugees, living in prolonged uncertainty in Jordan, shows how situated experiences of legal, material, and social uncertainty reinforce particular mediated socialities. Pivotal studies have shown how digital connections engender virtual home-making practices and a wide variety of connected presences. This study points to the other side of the same coin: the cultivation of “absent presence.” “Absent presence” refers to feelings—the ambivalence that experiences of prolonged displacement bring about—but also to active disengagement and affective tactics in response. These engender a further separation from the physical world where forced migrants are not deemed welcome.  相似文献   
6.
7.
The emerging creative practices of digital collections are increasing in prominence thanks to the access to, and appeal of, data visualizations. Interactive data visualizations, such as a map, timeline, chart, graph, or artist’s rendering of data, enable users to pursue their own research interests within a collection and participate in new areas of research. Use of these data visualizations enhances the scope of the collection and enables a modern and diverse thematic collection to emerge. This article considers the question: Does the addition of data visualizations affect how users participate with a research collection? Impacts on collection development, application of user-centered design, and analysis of users’ exploratory strategies are discussed. Examples of data visualizations used in digital humanities projects and digital collections are presented as case studies.  相似文献   
8.
Cultural Studies of Science Education - The retention of underrepresented students remains a significant challenge in the STEM (Science, Technology, Engineering and Math) disciplines. A broad range...  相似文献   
9.
10.
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