全文获取类型
收费全文 | 35832篇 |
免费 | 306篇 |
国内免费 | 14篇 |
专业分类
教育 | 26113篇 |
科学研究 | 3200篇 |
各国文化 | 265篇 |
体育 | 2638篇 |
综合类 | 7篇 |
文化理论 | 576篇 |
信息传播 | 3353篇 |
出版年
2021年 | 241篇 |
2020年 | 375篇 |
2019年 | 573篇 |
2018年 | 2840篇 |
2017年 | 2738篇 |
2016年 | 2259篇 |
2015年 | 563篇 |
2014年 | 675篇 |
2013年 | 4511篇 |
2012年 | 735篇 |
2011年 | 1313篇 |
2010年 | 1270篇 |
2009年 | 881篇 |
2008年 | 1141篇 |
2007年 | 1607篇 |
2006年 | 509篇 |
2005年 | 763篇 |
2004年 | 875篇 |
2003年 | 683篇 |
2002年 | 472篇 |
2001年 | 485篇 |
2000年 | 539篇 |
1999年 | 449篇 |
1998年 | 267篇 |
1997年 | 273篇 |
1996年 | 321篇 |
1995年 | 255篇 |
1994年 | 266篇 |
1993年 | 232篇 |
1992年 | 358篇 |
1991年 | 379篇 |
1990年 | 348篇 |
1989年 | 367篇 |
1988年 | 339篇 |
1987年 | 327篇 |
1986年 | 331篇 |
1985年 | 374篇 |
1984年 | 296篇 |
1983年 | 308篇 |
1982年 | 241篇 |
1981年 | 252篇 |
1980年 | 260篇 |
1979年 | 352篇 |
1978年 | 260篇 |
1977年 | 238篇 |
1976年 | 201篇 |
1975年 | 181篇 |
1974年 | 182篇 |
1973年 | 176篇 |
1971年 | 174篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
The views of specialists (academics, librarians, publishers and information scientists) on trends in scholarly communications were canvassed by means of structured questions. A greater commonality of views was found than might have been expected. 相似文献
82.
83.
Jürgen Ebert Franz Lehner Volker Riediger und Andreas Winter 《Informatik - Forschung und Entwicklung》2005,19(3):125-126
Ohne Zusammenfassung 相似文献
84.
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
85.
OBJECTIVES: Medical Library Association (MLA) members were surveyed to gather background about the current state of expert searching in institutions. The survey results were intended to guide the recommendations of the Task Force on Expert Searching for promoting the importance of expert searching and implementing those recommendations. METHODS: MLA members were surveyed, and data obtained from the survey were compiled and analyzed to answer three general questions: what is the perceived value of searching skills to the institution, how do health sciences librarians maintain and improve their searching skills, and how are searching services promoted and/or mandated in the institution. RESULTS: There were 256 responses to the survey. Over 95% of the respondents saw their expert-searching skills were of value to their institutions, primarily through performing mediated searches and search consultations. Over 83% of the respondents believed that their searching skills had improved over the past 10 years. Most indicated that continued training was very important in maintaining and improving their skills. Respondents promoted searching services most frequently through orientations, brochures, and the libraries' Web pages. No respondent's institution mandated expert searching. Less than 2% of respondents' institutions had best practice guidelines related to expert searching, and only about 8% had guidelines or policies that identified situations where expert searching was recommended. CONCLUSIONS: The survey supports the belief that health sciences librarians still play a valuable role in searching, particularly in answering questions about treatment options and in providing education. It also highlights the need for more expert searching courses. There has been minimal discussion about the perceived need for expert-searching guidelines in the institutions represented by survey respondents. 相似文献
86.
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
87.
Carmen Cole Angela R. Davis Vanessa Eyer John J. Meier 《The Journal of Academic Librarianship》2018,44(3):419-425
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
88.
John J. Riemer 《Cataloging & classification quarterly》2018,56(2-3):118-127
ABSTRACTThe career path and significant professional accomplishments of librarian Valerie Bross (1954–2016) are described in this article. The awards and recognition she received are recounted and the influence of outside activities on her career is assessed. An attempt is made to capture what she was like as a professional, as well as what her unique characteristics were. A bibliography of her writings and a photograph are included. 相似文献
89.
Yu. N. Schuko 《Scientific and Technical Information Processing》2018,45(3):163-167
Although the USSR and the United States had a comparable number of employees in the field of scientific information, there was a substantial difference in funding, which resulted in a lack of information support for Soviet scientists. While 90% of the publications in the United States were available almost immediately after their release, in the USSR they were delayed by 1.5 to 2 years. Since the publication of the Abstracts Journal by VINITI (AJ), its content was consistently expanding and reached its peak in 1990 (1.5 million documents per year). The next quarter of a century was characterized by a decline in both the composition of the AJ and the time required for its document coverage. The steps for restructuring VINITI activities are discussed. The focus is made on improving the limited coverage of the Russian-language part of the global flow of scientific information by Western information systems. 相似文献
90.
P. A. Kalachikhin 《Scientific and Technical Information Processing》2018,45(1):28-34
The issues related to funding of public research organizations are explored. The history of scientometric information systems is outlined. The advantages and disadvantages of a bibliometric approach to financing of research organizations are analyzed. The link between the assessment of the scientific and technological potential of an institution and the optimal allocation of funds is investigated. Recommendations on how to improve the efficiency of public resources allocated for scientific research are presented. 相似文献