全文获取类型
收费全文 | 10715篇 |
免费 | 2383篇 |
国内免费 | 2235篇 |
专业分类
电工技术 | 934篇 |
技术理论 | 2篇 |
综合类 | 1231篇 |
化学工业 | 179篇 |
金属工艺 | 90篇 |
机械仪表 | 442篇 |
建筑科学 | 181篇 |
矿业工程 | 142篇 |
能源动力 | 144篇 |
轻工业 | 198篇 |
水利工程 | 116篇 |
石油天然气 | 128篇 |
武器工业 | 77篇 |
无线电 | 1482篇 |
一般工业技术 | 484篇 |
冶金工业 | 944篇 |
原子能技术 | 18篇 |
自动化技术 | 8541篇 |
出版年
2024年 | 97篇 |
2023年 | 275篇 |
2022年 | 453篇 |
2021年 | 519篇 |
2020年 | 583篇 |
2019年 | 513篇 |
2018年 | 535篇 |
2017年 | 563篇 |
2016年 | 630篇 |
2015年 | 675篇 |
2014年 | 804篇 |
2013年 | 761篇 |
2012年 | 1015篇 |
2011年 | 1133篇 |
2010年 | 950篇 |
2009年 | 906篇 |
2008年 | 952篇 |
2007年 | 962篇 |
2006年 | 676篇 |
2005年 | 523篇 |
2004年 | 422篇 |
2003年 | 323篇 |
2002年 | 266篇 |
2001年 | 184篇 |
2000年 | 101篇 |
1999年 | 80篇 |
1998年 | 49篇 |
1997年 | 41篇 |
1996年 | 38篇 |
1995年 | 28篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 14篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1966年 | 9篇 |
1965年 | 9篇 |
1964年 | 10篇 |
1963年 | 8篇 |
1962年 | 8篇 |
1960年 | 13篇 |
1959年 | 12篇 |
1957年 | 9篇 |
1956年 | 6篇 |
1955年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
J. L. Díez J. L. Navarro A. Sala 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2007,11(10):973-983
In this work, simple modifications on the cost index of particular local-model fuzzy clustering algorithms are proposed in
order to improve the readability of the resulting models. The final goal is simultaneously providing local linear models (reasonably
close to the plant’s Jacobian) and clustering in the input space so that desirable characteristics (regarding final model
accuracy, and convexity and smoothness of the cluster membership functions) are improved with respect to other proposals in
literature. Some examples illustrate the proposed approach. 相似文献
3.
Abstract. This paper examines the capacity of the research designs of 37 empirical studies of information systems (IS) effectiveness to provide a basis for the development of theories about behaviour related to IS effectiveness. The power of each study to support causal inference was evaluated in terms of (a) its handling of the time dimension, (b) its ability to weigh differences and (c) its resistance to internal validity threats that pose alternative explanations for its reported findings. Of the reviewed studies, 29.7% could account for the time dimension, 32.4% employed a comparison group and 16.2% were not susceptible to any internal validity threats. Only 13.5% of the studies combined an accounting for the time dimension with the use of a comparison group. Of these, however, only 5.4% were also invulnerable to internal validity threats. The research designs of nearly 95% of these published studies were deficient in supporting causal inference. In those studies, suggestions that one variable was causally related to another variable could not be substantiated. Encouragement for the future capacity of IS effectiveness research to support causal inference was found in a trend towards the use of quasiexperimental designs. Recommendations are made regarding ways to increase the inferential capacity of research designs employed in the study of IS effectiveness. 相似文献
4.
Thomas L. Landers Melinda K. Beavers Malik Sadiq Don E. Stuart 《Computers & Industrial Engineering》1994,27(1-4):245-248
This paper describes an approach, conceptual framework, and software architecture for dynamic reconfiguration of the order picking system. The research and development project was sponsored by the Material Handling Research Center (MHRC), a National Science Foundation sponsored Cooperative Industry/University Research Center. The storage configuration is assumed to be an in-the-aisle order picking system in which stockkeeping units (SKUs) can occupy variable capacity storage locations and stock-splitting is allowed among zones (clusters). The product mix may include multiple product families with different life cycles, correlated demand within families and commonality of demand across families. 相似文献
5.
Non-redundant data clustering 总被引:6,自引:6,他引:0
Data clustering is a popular approach for automatically finding classes, concepts, or groups of patterns. In practice, this
discovery process should avoid redundancies with existing knowledge about class structures or groupings, and reveal novel,
previously unknown aspects of the data. In order to deal with this problem, we present an extension of the information bottleneck
framework, called coordinated conditional information bottleneck, which takes negative relevance information into account by maximizing a conditional mutual information score subject to
constraints. Algorithmically, one can apply an alternating optimization scheme that can be used in conjunction with different
types of numeric and non-numeric attributes. We discuss extensions of the technique to the tasks of semi-supervised classification
and enumeration of successive non-redundant clusterings. We present experimental results for applications in text mining and
computer vision. 相似文献
6.
The aim of this study was to examine the reliability and validity of a French version of the Revised Children's Manifest Anxiety Scale (RCMAS). A sample of 2,666 school-age French-Canadian children completed the questionnaire. With regard to factor structure, the 5-factor model found in U.S. normative samples was confirmed. The internal consistency of the 5 scales and of the 2 global scales was good to excellent. Test-retest reliabilities after a 6-month period were also similar to those of the original version. Finally, the concurrent validity, assessed by a correlation with the State-Trait Anxiety Inventory for Children, was also found to be good. Results of the present study show that the French version of the RCMAS is a good instrument to assess anxiety in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
There is a growing trend of research in neuropsychological assessment in Asia: The mean number of published studies increased from 1.8 in the 1980s to 16.0 in 2 recent years. About 40% of the studies reviewed concerned test development or adaptation, with the latter greatly outnumbering the former. To facilitate the test selection for clinical use, 36 clinical measures were evaluated based on some statistical criteria. The results showed that only 8 neuropsychological tests (5 Chinese. 2 Korean, and 1 Japanese) met the criteria. Given that Asian and Western populations differ on certain cognitive processes, future development of neuropsychological assessment measures in Asia should move from the adaptation of Western tests toward the construction of original tests with better ecological validity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
9.
10.
模糊聚类在三维地震参数处理中的应用 总被引:1,自引:1,他引:0
三维地震参数是一个庞大的三维数据体,能从不同侧面反映储集层的特征。通过对三维地震参数的分析,可以评估油藏表征的参数(沉积相、构造、生长历史、流体饱和度等)。针对传统的聚类方法不能很好地综合考虑各个参数之间的相似程度,提出了用模糊C-均值聚类(fuzzy c-means clustering,简称FCM)对三维地震参数进行处理。从三维地震参数和油藏表征参数之间的关系出发,采用模糊C-均值聚类方法对三维地震参数进行处理,依此评估油藏表征的参数。测试结果表明,模糊C-均值聚类方法能够对三维地震参数进行较为准确的分类,并为储集层的研究提供了很好的依据。 相似文献