全文获取类型
收费全文 | 11771篇 |
免费 | 2624篇 |
国内免费 | 2378篇 |
专业分类
电工技术 | 1065篇 |
技术理论 | 2篇 |
综合类 | 1442篇 |
化学工业 | 209篇 |
金属工艺 | 112篇 |
机械仪表 | 540篇 |
建筑科学 | 283篇 |
矿业工程 | 165篇 |
能源动力 | 148篇 |
轻工业 | 229篇 |
水利工程 | 141篇 |
石油天然气 | 141篇 |
武器工业 | 94篇 |
无线电 | 1745篇 |
一般工业技术 | 716篇 |
冶金工业 | 140篇 |
原子能技术 | 26篇 |
自动化技术 | 9575篇 |
出版年
2024年 | 118篇 |
2023年 | 318篇 |
2022年 | 535篇 |
2021年 | 587篇 |
2020年 | 647篇 |
2019年 | 588篇 |
2018年 | 603篇 |
2017年 | 653篇 |
2016年 | 703篇 |
2015年 | 751篇 |
2014年 | 953篇 |
2013年 | 930篇 |
2012年 | 1156篇 |
2011年 | 1202篇 |
2010年 | 991篇 |
2009年 | 940篇 |
2008年 | 979篇 |
2007年 | 1018篇 |
2006年 | 674篇 |
2005年 | 557篇 |
2004年 | 417篇 |
2003年 | 308篇 |
2002年 | 259篇 |
2001年 | 181篇 |
2000年 | 130篇 |
1999年 | 114篇 |
1998年 | 74篇 |
1997年 | 62篇 |
1996年 | 58篇 |
1995年 | 45篇 |
1994年 | 30篇 |
1993年 | 26篇 |
1992年 | 17篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 16篇 |
1988年 | 11篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 13篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
This paper considers the principles of algorithmic and software implementation of the software system NADRA 3D designed to
analyze processes in three-dimensional multicomponent soil media. The principles of operation of NADRA 3D are described.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 157–174, November–December 2006. 相似文献
2.
3.
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
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.
试论就业形势与战略 总被引:5,自引:1,他引:4
刘庆唐 《重庆理工大学学报(自然科学版)》2005,19(1):7-10
论述了就业的特殊重要性、目前我国就业形势的极端严重性,以及所应当采取的战略和措施。 相似文献
6.
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
7.
8.
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
9.
Tao Li 《Machine Learning》2006,62(3):199-215
Clustering is the problem of identifying the distribution of patterns and intrinsic correlations in large data sets by partitioning
the data points into similarity classes. This paper studies the problem of clustering binary data. Binary data have been occupying
a special place in the domain of data analysis. A unified view of binary data clustering is presented by examining the connections
among various clustering criteria. Experimental studies are conducted to empirically verify the relationships. 相似文献
10.
Xin Song Xiaoyu Qi Bin Hao Yinbo Qu 《European Journal of Lipid Science and Technology》2008,110(12):1095-1101
Although lipases are widely applied in a wide variety of reactions, available information on the factors that are responsible for the substrate specificities of lipases from different sources is scarce. In this paper, nine lipase‐producing microorganism strains were isolated from oil‐containing samples. The properties of these enzymes, including pH optima, temperature optima, thermal stability, and pH stability, vary significantly with the different sources from which these lipases were isolated. The substrate specificities of the nine lipases, including fatty acid and positional specificities, were also studied. The fatty acid specificities of the nine lipases were observably different toward 15 substrates with different carbon chain lengths, different saturation degrees and different side chains. The lipases from S3 Penicillium citrinum (PCL), MJ1 Aspergillus niger (ANL), MJ2 Aspergillus oryzae (AOL), YM Bacillus coughing (BCL), S9 Geotrichum candidum (GCL), and S11 Candida lypolytica (CLL) showed the strongest specificities to short‐chain esters, and the other lipases showed strong selectivity for medium‐ or long‐chain and branched esters. The positional specificities were examined by analyzing the hydrolytic products of triolein catalyzed by the nine lipases, using TLC. The lipases can be mainly classified into two groups by their specificities for the ester bond at position 2 of triglycerides; one group can selectively hydrolyze the ester bond at position 2 of the triglycerides, the other group cannot. All these nine lipases were divided into four groups by hierarchical clustering analysis on the basis of the results of fatty acid and positional specificities. 相似文献