全文获取类型
收费全文 | 7416篇 |
免费 | 45篇 |
国内免费 | 8篇 |
专业分类
教育 | 5095篇 |
科学研究 | 1006篇 |
各国文化 | 19篇 |
体育 | 392篇 |
综合类 | 9篇 |
文化理论 | 154篇 |
信息传播 | 794篇 |
出版年
2022年 | 22篇 |
2021年 | 26篇 |
2020年 | 57篇 |
2019年 | 78篇 |
2018年 | 805篇 |
2017年 | 835篇 |
2016年 | 598篇 |
2015年 | 127篇 |
2014年 | 136篇 |
2013年 | 624篇 |
2012年 | 193篇 |
2011年 | 419篇 |
2010年 | 400篇 |
2009年 | 232篇 |
2008年 | 288篇 |
2007年 | 418篇 |
2006年 | 70篇 |
2005年 | 167篇 |
2004年 | 212篇 |
2003年 | 152篇 |
2002年 | 84篇 |
2001年 | 99篇 |
2000年 | 89篇 |
1999年 | 69篇 |
1998年 | 61篇 |
1997年 | 53篇 |
1996年 | 58篇 |
1995年 | 26篇 |
1994年 | 39篇 |
1993年 | 24篇 |
1992年 | 55篇 |
1991年 | 50篇 |
1990年 | 34篇 |
1989年 | 47篇 |
1988年 | 40篇 |
1987年 | 33篇 |
1986年 | 43篇 |
1985年 | 49篇 |
1984年 | 44篇 |
1983年 | 30篇 |
1982年 | 35篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 35篇 |
1978年 | 42篇 |
1977年 | 24篇 |
1976年 | 22篇 |
1974年 | 29篇 |
1972年 | 27篇 |
1971年 | 18篇 |
排序方式: 共有7469条查询结果,搜索用时 194 毫秒
41.
42.
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
43.
Previous studies have shown that weeding a library collection benefits patrons and increases circulation rates. However, the time required to review the collection and make weeding decisions presents a formidable obstacle. This study empirically evaluated methods for automatically classifying weeding candidates. A data set containing 80,346 items from a large-scale weeding project running from 2011 to 2014 at Wesleyan University was used to train six machine learning classifiers to predict a weeding decision of either ‘Keep’ or ‘Weed’ for each candidate. The study found statistically significant agreement (p?=?0.001) between classifier predictions and librarian judgments for all classifier types. The naive Bayes and linear support vector machine classifiers had the highest recall (fraction of items weeded by librarians that were identified by the algorithm), while the k-nearest-neighbor classifier had the highest precision (fraction of recommended candidates that librarians had chosen to weed). The variables found to be most relevant were: librarian and faculty votes for retention, item age, and the presence of copies in other libraries. 相似文献
44.
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
45.
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
46.
I. I. Potapov 《Scientific and Technical Information Processing》2018,45(2):63-69
Modern global eco-dynamics problems are discussed. It is noted that global changes are mostly characterized by several key features, such as their multicomponent nature, as well as interactivity and nonlinearity. These features challenge various forecast estimates in such a way that the concept of forecasting has been replaced over the last few years by a much more ambiguous concept of scenarios. The vagueness of scenarios is due to the problem of global climate change. A global climate–nature–society system model is outlined. 相似文献
47.
I. V. Zibareva L. Yu. Ilina B. L. Alperin 《Scientific and Technical Information Processing》2018,45(2):106-109
The current state of the Russian Science Citation Index is analyzed. Several areas for its further development identified by long-standing active users, such as data searching, refinement, and storage; current user alerts; data input with the Science Index license; patent information; and the application programming interface (API) are investigated. 相似文献
48.
Textbook vetting and evaluation process intends to ensure that the materials provided are relevant, of the required quality, suitable ad would enhance learning efficiency and effectiveness. The paper investigates the role of publishers and Tanzania Institute of Education (TIE) in the textbooks vetting and evaluation process; examines factors used to vet, evaluate and approve primary and secondary school textbooks in Tanzania and proposes Strategies that would enhance the textbook vetting, evaluation and process. The study used a mixed method research design. Respondents were selected educational publishers; MoEVT, Baraza la Kiswahili Tanzania, TIE, and Publishers Association of Tanzania. Questionnaire and semi- structured interview were used to collect data which were analysed qualitatively and quantitatively. Major findings of the study were; textbooks vetting and evaluation process is not professionally conducted although standard criteria have been established; there is not well established roles among key players involved in the vetting and evaluation process leading to conflict of interest between TIE and the publishers. The study recommends establishing an independent professional evaluation board and a well-defined timetable and effective communication among various players; enacting a book policy and adopting a limited multiple-textbook publishing system. 相似文献
49.
50.