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   15440篇
  免费   189篇
  国内免费   119篇
教育   10575篇
科学研究   2044篇
各国文化   109篇
体育   1350篇
综合类   11篇
文化理论   120篇
信息传播   1539篇
  2020年   209篇
  2019年   307篇
  2018年   424篇
  2017年   370篇
  2016年   383篇
  2015年   242篇
  2014年   315篇
  2013年   2618篇
  2012年   297篇
  2011年   337篇
  2010年   242篇
  2009年   240篇
  2008年   252篇
  2007年   286篇
  2006年   274篇
  2005年   270篇
  2004年   254篇
  2003年   247篇
  2002年   238篇
  2001年   255篇
  2000年   271篇
  1999年   274篇
  1998年   142篇
  1997年   149篇
  1996年   183篇
  1995年   169篇
  1994年   131篇
  1993年   142篇
  1992年   216篇
  1991年   222篇
  1990年   230篇
  1989年   258篇
  1988年   209篇
  1987年   225篇
  1986年   219篇
  1985年   250篇
  1984年   222篇
  1983年   211篇
  1982年   176篇
  1981年   168篇
  1980年   157篇
  1979年   244篇
  1978年   190篇
  1977年   180篇
  1976年   148篇
  1975年   132篇
  1974年   151篇
  1973年   132篇
  1972年   107篇
  1971年   119篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
This paper analyses the publication patterns of researchers in the field of applied sciences at Universities of Technology in South Africa. Aspects investigated include publications in SCOPUS-listed journals; number of citations and countries of publication. Collaborative research patterns at national and international levels were also investigated. A bibliometric analysis approach was followed using SCOPUS as the main source of data and analysing the articles published in selected applied science disciplines. Results show that researchers in the field of applied sciences in universities of technology have increased their number of publications over the past 10?years and are also working in conjunction with other researchers both nationally and internationally. The analysis is an important addition to the field in South Africa which helps in measuring how institutions are positively responding to government incentives in research. The results are also important to information professionals who are increasingly playing an important role in research impact assessments.  相似文献   
42.
In 2008 Meier and Conkling first tested Google Scholar's coverage of the engineering literature against citations gathered from the Compendex database. Since that time, other studies have used the same methodology and found improvement in Google Scholar's coverage. This study uses engineering dissertations from Proquest Dissertations & Theses to create a data set of citations for the comparison of fee-based databases, Compendex and Scopus, against Google Scholar. From 1950 to 2017 Google Scholar outperformed both Compendex and Scopus in discoverability of citations in nine engineering subjects. These results have implications for collection management and information literacy program planning for librarians.  相似文献   
43.
The purpose of this study was to examine the outcomes of information literacy instruction for the Design first year students at the Temasek Polytechnic Library. Also of interest was whether or not the librarian was being seen as easily approachable, and if the students were deeming the lessons to be worthwhile. A participant action research approach was used, with the data being collected from multiple choice tests delivered via the institutional learning management system, group exercises, and a diagnostic assessment that was delivered before the workshops. It was found that the students did see the librarian as someone who was eminently approachable, and the majority of them found the lessons to be of value. It was concluded that the use of a diagnostic tool can be very useful in highlighting the gaps in students' knowledge, and that it would be beneficial to use it for all information literacy instruction at TP. Suggested future research could include a study of how much the students retain of IL skills into their third year of study.  相似文献   
44.
This article analyzes the Supreme Court decision in Obergefell v. Hodges, showing that a subset of the dissent constructed devout religious groups as victims to rearticulate power relations between the state, LGBT groups, and religious entities. This rearticulation is possible as a consequence of ambiguity in the legal concept of religious liberty, which is explored in depth. That ambiguity is employed to mount an argument against the decision, moving LGBT individuals from oppressed to oppressor of religious groups. The study contextualizes this inversion against the material and symbolic conditions of both the LGBT and devout Christian communities in the United States.  相似文献   
45.
Against the backdrop of Spain’s Transparency Act, this article discusses the presence or otherwise of a series of document types, proposed as management-related transparency indicators, on 61 (8 national and 53 provincial) historic archive websites. Although examples of good practice were identified, the information provided was found to be scant, in particular as regards lines of action, organisational objectives and yearly reports. The information most commonly provided on the websites included the collection classification chart, service use regulations and citizen charters. The inference drawn was that archives, so intently focused on their role in the application of the Act by the organisations they serve, neglect their own administrative obligations in respect of its provisions. The recommendation is that as government-funded and subsidised public service institutions, historic archives should exercise transparency by furnishing the information stipulated in the Act on their websites.  相似文献   
46.
47.
48.
49.
50.
BackgroundConsidering the potential cumulative effects of repetitive head impact (HI) exposure, we need sensitive biomarkers to track short- and long-term effects. Circulating small extracellular vesicles (sEVs) (<200 nm) traffic biological molecules throughout the body and may have diagnostic value as biomarkers for disease. The purpose of this study was to identify the microRNA (miRNA) profile in circulating sEVs derived from human plasma following repetitive HI exposure.MethodsHealthy adult (aged 18–35 years) soccer players were randomly assigned to one of 3 groups: the HI group performed 10 standing headers, the leg impact group performed 10 soccer ball trapping maneuvers over 10 min, and the control group did not participate in any soccer drills. Plasma was collected before testing and 24 h afterward, and sEVs were isolated and characterized via nanoparticle tracking analysis. Next-generation sequencing was utilized to identify candidate miRNAs isolated from sEVs, and candidate microRNAs were analyzed via quantitative polymerase chain reaction. In silico target prediction was performed using TargetScan (Version 7.0; targetscan.org) and miRWalk (http://mirwalk.umm.uni-heidelberg.de/) programs, and target validation was performed using luciferase reporter vectors with a miR-7844-5p mimic in human embryonic kidney (HEK) 293T/17 cells.ResultsPlasma sEV concentration and size were not affected across time and group following repetitive HI exposure. After 24 h, the HI read count from next-generation sequencing showed a 4-fold or greater increase in miR-92b-5p, miR-423-5p, and miR-24-3p and a 3-fold or greater decrease in miR-7844-5p, miR-144-5p, miR-221-5p, and miR-22-3p. Analysis of quantitative polymerase chain reaction revealed that leg impact did not alter the candidate miRNA levels. To our knowledge, miR-7844-5p is a previously unknown miRNA. We identified 8 miR-7844-5p mRNA targets: protein phosphatase 1 regulatory inhibitor subunit 1B (PPP1R1B), LIM and senescent cell antigen-like domains 1 (LIMS1), autophagy-related 12 (ATG12), microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), integrin subunit alpha-1 (ITGA1), mitogen-activated protein kinase 1 (MAPK1), glycogen synthase kinase 3β (GSK3β), and mitogen-activated protein kinase 8 (MAPK8).ConclusionCollectively, these data indicate repetitive HI exposure alters plasma sEV miRNA content, but not sEV size or number. Furthermore, for the first time we demonstrate that previously unknown miR-7844-5p targets mRNAs known to be involved in mitochondrial apoptosis, autophagy regulation, mood disorders, and neurodegenerative disease.  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