全文获取类型
收费全文 | 28521篇 |
免费 | 242篇 |
国内免费 | 119篇 |
专业分类
教育 | 20536篇 |
科学研究 | 3333篇 |
各国文化 | 123篇 |
体育 | 1745篇 |
综合类 | 13篇 |
文化理论 | 525篇 |
信息传播 | 2607篇 |
出版年
2021年 | 121篇 |
2020年 | 239篇 |
2019年 | 356篇 |
2018年 | 2610篇 |
2017年 | 2519篇 |
2016年 | 2023篇 |
2015年 | 412篇 |
2014年 | 481篇 |
2013年 | 3095篇 |
2012年 | 562篇 |
2011年 | 1127篇 |
2010年 | 1135篇 |
2009年 | 701篇 |
2008年 | 939篇 |
2007年 | 1470篇 |
2006年 | 366篇 |
2005年 | 683篇 |
2004年 | 729篇 |
2003年 | 636篇 |
2002年 | 388篇 |
2001年 | 273篇 |
2000年 | 317篇 |
1999年 | 300篇 |
1998年 | 157篇 |
1997年 | 170篇 |
1996年 | 197篇 |
1995年 | 177篇 |
1994年 | 145篇 |
1993年 | 155篇 |
1992年 | 229篇 |
1991年 | 238篇 |
1990年 | 240篇 |
1989年 | 266篇 |
1988年 | 219篇 |
1987年 | 232篇 |
1986年 | 224篇 |
1985年 | 264篇 |
1984年 | 227篇 |
1983年 | 219篇 |
1982年 | 188篇 |
1981年 | 175篇 |
1980年 | 167篇 |
1979年 | 255篇 |
1978年 | 203篇 |
1977年 | 187篇 |
1976年 | 156篇 |
1975年 | 142篇 |
1974年 | 154篇 |
1973年 | 139篇 |
1971年 | 124篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Creating Access to Invisible Special Collections: Using Participatory Management to Reduce a Backlog
The University of Colorado at Boulder Libraries used participatory management to reduce a special collections backlog. Without an increase in budget or staffing, technical and public services departments designed a pilot project to redeploy internal human resources in a collaborative manner. The process of backlog management is discussed. 相似文献
102.
Subjective Social Location: Data From 21 Nations 总被引:1,自引:0,他引:1
103.
104.
E Diane Johnson Paul E Pancoast Joyce A Mitchell Chi-Ren Shyu 《Journal of the Medical Library Association》2004,92(4):438-444
PURPOSE: This study describes the system architecture and user acceptance of a suite of programs that deliver information about newly updated library resources to clinicians' personal digital assistants (PDAs). DESCRIPTION: Participants received headlines delivered to their PDAs alerting them to new books, National Guideline Clearinghouse guidelines, Cochrane Reviews, and National Institutes of Health (NIH) Clinical Alerts, as well as updated content in UpToDate, Harrison's Online, Scientific American Medicine, and Clinical Evidence. Participants could request additional information for any of the headlines, and the information was delivered via e-mail during their next synchronization. Participants completed a survey at the conclusion of the study to gauge their opinions about the service. RESULTS/OUTCOME: Of the 816 headlines delivered to the 16 study participants' PDAs during the project, Scientific American Medicine generated the highest proportion of headline requests at 35%. Most users of the PDA Alerts software reported that they learned about new medical developments sooner than they otherwise would have, and half reported that they learned about developments that they would not have heard about at all. While some users liked the PDA platform for receiving headlines, it seemed that a Web database that allowed tailored searches and alerts could be configured to satisfy both PDA-oriented and e-mail-oriented users. 相似文献
105.
Techtarget Todd R. Weiss 《信息系统工程》2005,(3):16
keystone公司长期停滞的ERP项目终于宣告成功, 系统将 130 个厂房,全美国2000 多员工连接在一起。回首keystone 信息化历程,其经验教训值得我们深思。 相似文献
106.
107.
Question classification systems play an important role in question answering systems and can be used in a wide range of other domains. The goal of question classification is to accurately assign labels to questions based on expected answer type. Most approaches in the past have relied on matching questions against hand-crafted rules. However, rules require laborious effort to create and often suffer from being too specific. Statistical question classification methods overcome these issues by employing machine learning techniques. We empirically show that a statistical approach is robust and achieves good performance on three diverse data sets with little or no hand tuning. Furthermore, we examine the role different syntactic and semantic features have on performance. We find that semantic features tend to increase performance more than purely syntactic features. Finally, we analyze common causes of misclassification error and provide insight into ways they may be overcome. 相似文献
108.
109.
Bast fibres have been commonly used as a textile material in Northern Europe since Neolithic times. However, the process of identifying the different species has been problematic, and many important questions related to their cultural history are still unanswered. For example, a modified Herzog test and the presence of calcium oxalate crystals have both been used in identification. In order to generate more reliable results, further research and advancement in multi-methodological methods is required. This paper introduces a combination of methods which can be used to identify and distinguish flax (Linum usitatissimum), hemp (Cannabis sativa), and stinging nettle (Urtica dioica). The research material consisted of reference fibres and 25 fibre samples obtained from 12 textiles assumed to be made of nettle. The textiles were from the Finno-Ugric and Historical Collections of The National Museum of Finland. The fibre samples were studied by observing the surface characteristics and cross sections with transmitted light microscopy, and by using a modified Herzog test with polarized light, in order to identify the distinguishable features in their morphological structures. The study showed that five out of 25 samples were cotton, 16 nettle, one flax, and one hemp. Findings from two samples were inconsistent. The results show that it is possible to distinguish common north European bast fibres from each other by using a combination of microscopic methods. Furthermore, by utilizing these combined methods, new and more reliable information could be obtained from historical ethnographic textiles, which creates new vistas for the interpretation of their cultural history. 相似文献
110.
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