全文获取类型
收费全文 | 27615篇 |
免费 | 396篇 |
国内免费 | 17篇 |
专业分类
教育 | 19816篇 |
科学研究 | 2137篇 |
各国文化 | 287篇 |
体育 | 2821篇 |
综合类 | 7篇 |
文化理论 | 303篇 |
信息传播 | 2657篇 |
出版年
2022年 | 180篇 |
2021年 | 338篇 |
2020年 | 541篇 |
2019年 | 812篇 |
2018年 | 1066篇 |
2017年 | 1003篇 |
2016年 | 921篇 |
2015年 | 580篇 |
2014年 | 682篇 |
2013年 | 5183篇 |
2012年 | 638篇 |
2011年 | 640篇 |
2010年 | 501篇 |
2009年 | 523篇 |
2008年 | 546篇 |
2007年 | 505篇 |
2006年 | 487篇 |
2005年 | 413篇 |
2004年 | 428篇 |
2003年 | 356篇 |
2002年 | 360篇 |
2001年 | 490篇 |
2000年 | 531篇 |
1999年 | 463篇 |
1998年 | 284篇 |
1997年 | 267篇 |
1996年 | 337篇 |
1995年 | 268篇 |
1994年 | 282篇 |
1993年 | 241篇 |
1992年 | 361篇 |
1991年 | 388篇 |
1990年 | 363篇 |
1989年 | 383篇 |
1988年 | 356篇 |
1987年 | 341篇 |
1986年 | 338篇 |
1985年 | 378篇 |
1984年 | 302篇 |
1983年 | 309篇 |
1982年 | 249篇 |
1981年 | 256篇 |
1980年 | 265篇 |
1979年 | 359篇 |
1978年 | 270篇 |
1977年 | 246篇 |
1976年 | 207篇 |
1975年 | 191篇 |
1974年 | 190篇 |
1973年 | 180篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
122.
123.
124.
125.
126.
127.
128.
Krister Lindén 《Information Retrieval》2006,9(3):295-310
Technical term translations are important for cross-lingual information retrieval. In many languages, new technical terms
have a common origin rendered with different spelling of the underlying sounds, also known as cross-lingual spelling variants
(CLSV).
To find the best CLSV in a text database index, we contribute a formulation of the problem in a probabilistic framework, and
implement this with an instance of the general edit distance using weighted finite-state transducers. Some training data is
required when estimating the costs for the general edit distance. We demonstrate that after some basic training our new multilingual
model is robust and requires little or no adaptation for covering additional languages, as the model takes advantage of language
independent transliteration patterns.
We train the model with medical terms in seven languages and test it with terms from varied domains in six languages. Two
test languages are not in the training data. Against a large text database index, we achieve 64–78 % precision at the point
of 100% recall. This is a relative improvement of 22% on the simple edit distance. 相似文献
129.
130.
Tuomo Korenius Jorma Laurikkala Martti Juhola Kalervo Järvelin 《Information Retrieval》2006,9(1):33-53
Search facilitated with agglomerative hierarchical clustering methods was studied in a collection of Finnish newspaper articles
(N = 53,893). To allow quick experiments, clustering was applied to a sample (N = 5,000) that was reduced with principal components analysis. The dendrograms were heuristically cut to find an optimal partition,
whose clusters were compared with each of the 30 queries to retrieve the best-matching cluster. The four-level relevance assessment
was collapsed into a binary one by (A) considering all the relevant and (B) only the highly relevant documents relevant, respectively.
Single linkage (SL) was the worst method. It created many tiny clusters, and, consequently, searches enabled with it had high
precision and low recall. The complete linkage (CL), average linkage (AL), and Ward's methods (WM) returned reasonably-sized
clusters typically of 18–32 documents. Their recall (A: 27–52%, B: 50–82%) and precision (A: 83–90%, B: 18–21%) was higher
than and comparable to those of the SL clusters, respectively. The AL and WM clustering had 1–8% better effectiveness than
nearest neighbor searching (NN), and SL and CL were 1–9% less efficient that NN. However, the differences were statistically
insignificant. When evaluated with the liberal assessment A, the results suggest that the AL and WM clustering offer better
retrieval ability than NN. Assessment B renders the AL and WM clustering better than NN, when recall is considered more important
than precision. The results imply that collections in the highly inflectional and agglutinative languages, such as Finnish,
may be clustered as the collections in English, provided that documents are appropriately preprocessed. 相似文献