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   123664篇
  免费   1863篇
  国内免费   280篇
教育   86254篇
科学研究   13400篇
各国文化   1988篇
体育   9393篇
综合类   204篇
文化理论   1064篇
信息传播   13504篇
  2021年   965篇
  2020年   1652篇
  2019年   2558篇
  2018年   3066篇
  2017年   3344篇
  2016年   3386篇
  2015年   2324篇
  2014年   3202篇
  2013年   27301篇
  2012年   2433篇
  2011年   2797篇
  2010年   2414篇
  2009年   2694篇
  2008年   2454篇
  2007年   2188篇
  2006年   2482篇
  2005年   2451篇
  2004年   3033篇
  2003年   2350篇
  2002年   2156篇
  2001年   2081篇
  2000年   1684篇
  1999年   1568篇
  1998年   1462篇
  1997年   1517篇
  1996年   1696篇
  1995年   1469篇
  1994年   1468篇
  1993年   1467篇
  1992年   1503篇
  1991年   1417篇
  1990年   1440篇
  1989年   1329篇
  1988年   1193篇
  1987年   1130篇
  1986年   1162篇
  1985年   1421篇
  1984年   1295篇
  1983年   1274篇
  1982年   1255篇
  1981年   1187篇
  1980年   1157篇
  1979年   1250篇
  1978年   1216篇
  1977年   1122篇
  1976年   1000篇
  1975年   810篇
  1974年   813篇
  1973年   784篇
  1971年   637篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
ABSTRACT

The length of telomeres is an objective measure of biologic ageing. This study evaluated the extent minutes of walking per week are associated with leukocyte telomere length (LTL) in a random sample of 5,823 U.S. adults. The investigation was cross-sectional and data were obtained from the National Health and Nutrition Examination Survey (NHANES). LTL was measured by the quantitative polymerase chain reaction method. Walking minutes was calculated from walking frequency and duration measures. Results showed that for each year of chronological age, telomeres were 15.6 base pairs shorter (P < 0.0001). With walking minutes and LTL treated as continuous variables, the relationship was quadratic, not linear (F = 11.2, P = 0.0023). With walking time divided into three categories, adults who performed ≥ 150 minutes of walking per week had longer telomeres than those who did no regular walking, and those who did some, but less than the recommendation (F = 5.0, P = 0.0137). Regular walkers were estimated to have a biologic ageing advantage associated with 6.5–7.6 years less biologic ageing compared to non-walkers, after adjusting for covariates. Additional investigations designed to study causality and the mechanisms associated with the walking and LTL relationship are needed.  相似文献   
872.
ABSTRACT

Amid rising controversy around the alleged distinctions between merit and excellence lies a familiar refrain, scarcity. The narrative of academic scarcity, proclaiming the insufficient numbers of scholars and academics of color, permeates conversations in higher education. We suggest that the academic scarcity narrative, a remnant of stagnant logics of diversity, circulates as a contemporary mechanism of what we name disciplinary containment. Extending disciplinary conversations around rhetorical containment, we argue that disciplinary containment perpetuates whiteness.  相似文献   
873.
Current conceptions of accountability imply that, in order for teachers to be able to hold themselves to account, they need first to have cultivated certain ‘professional dispositions’. But these conceptions fail to acknowledge the extent to which teachers are first and foremost accountable ‘as such’. For the early existentialist thought of the philosopher Jean‐Paul Sartre, this relates to a kind of responsibility premised on the ways in which we are always and inevitably responding to the world in which we find ourselves (with others). In this paper, I offer a reconceptualisation of teacher accountability in light of this, one that recognises implicit responses in classroom situations as underpinned by the subjectivity of those who bring these situations to light—often in subtle and immeasurable ways.  相似文献   
874.
875.
876.
877.
This article focuses on counseling research in the community college context. The article suggests the need for a robust community college knowledge base, describes some limitations of the current community college literature, and suggests a framework for more effective work in this area. The authors’ own experiences and selected examples of published studies are used as illustrations of the hurdles encountered and solutions available when examining counseling theories, practices, and outcomes in 2‐year settings.  相似文献   
878.
This paper demonstrates the application of module arithmetic for controlling the level of information security by a new technique referred as integer splitting. The basic definitions and concepts of the method are provided. The mathematical function of arising transformation is described in detail; its properties were studied and the basic theorems were proven that justify the use of splitting in practical applications. An active system was designed and characteristic cases of its operation are considered.  相似文献   
879.
880.
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