全文获取类型
收费全文 | 14727篇 |
免费 | 1680篇 |
国内免费 | 885篇 |
专业分类
电工技术 | 1084篇 |
综合类 | 1299篇 |
化学工业 | 2677篇 |
金属工艺 | 746篇 |
机械仪表 | 891篇 |
建筑科学 | 1007篇 |
矿业工程 | 387篇 |
能源动力 | 670篇 |
轻工业 | 1361篇 |
水利工程 | 348篇 |
石油天然气 | 469篇 |
武器工业 | 99篇 |
无线电 | 1784篇 |
一般工业技术 | 1658篇 |
冶金工业 | 588篇 |
原子能技术 | 218篇 |
自动化技术 | 2006篇 |
出版年
2024年 | 30篇 |
2023年 | 161篇 |
2022年 | 340篇 |
2021年 | 485篇 |
2020年 | 353篇 |
2019年 | 379篇 |
2018年 | 386篇 |
2017年 | 415篇 |
2016年 | 428篇 |
2015年 | 613篇 |
2014年 | 760篇 |
2013年 | 924篇 |
2012年 | 1043篇 |
2011年 | 1044篇 |
2010年 | 992篇 |
2009年 | 914篇 |
2008年 | 922篇 |
2007年 | 885篇 |
2006年 | 824篇 |
2005年 | 677篇 |
2004年 | 638篇 |
2003年 | 732篇 |
2002年 | 1010篇 |
2001年 | 832篇 |
2000年 | 442篇 |
1999年 | 305篇 |
1998年 | 123篇 |
1997年 | 144篇 |
1996年 | 116篇 |
1995年 | 88篇 |
1994年 | 39篇 |
1993年 | 51篇 |
1992年 | 34篇 |
1991年 | 28篇 |
1990年 | 19篇 |
1989年 | 28篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 12篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1972年 | 3篇 |
1966年 | 2篇 |
1959年 | 3篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
81.
82.
介绍了ADSS光缆的力学计算,给出了光缆弧垂、张力、应变和悬长等计算公式,并对普遍采用的“悬链线”和“抛物线”两种计算方法加以比较。 相似文献
83.
Kok Wai Wong Chun Che Fung Eren H. Gedeon T. 《IEEE transactions on instrumentation and measurement》2003,52(6):1865-1869
Fuzzy rule-based systems have been very popular in many engineering applications. In mineral engineering, fuzzy rules are normally constructed using some fuzzy rule extraction techniques to establish the determination model in predicting the d50c of hydrocyclones. However, when generating fuzzy rules from the available information, it may result in a sparse fuzzy rule base. The use of more than one input variable is also common in hydrocyclone data analysis. This paper examines the application of fuzzy interpolation to resolve the problems using sparse fuzzy rule bases, and to perform analysis of fuzzy interpolation in multidimensional input spaces. 相似文献
84.
This paper considers determination of the optimal number of periodic preventive maintenance operations during the warranty period. The hazard rate after preventive maintenance lies between as good as new and as bad as old. After minimal repair, the hazard rate of the system remains unchanged. Free and modified warranty policies are considered with a numerical example using the Weibull case. 相似文献
85.
86.
利用U矩阵对SOM网络的处理 总被引:1,自引:0,他引:1
自组织神经网络的最大优点是能够保持原始数据的拓扑结构。但是当数据量很大的时候,自组织神经网络的神经元的数据也随之增大。因此为了更好地对数据进行分析,需要将自组织神经网络中相似的神经元进行分组,也就是聚类。在对SOM网络进行再次分析之前,为了减少“噪音”数据和孤立点对聚类结构的影响,用U矩阵的变型方法对自组织神经网络分析的结果进行预处理。 相似文献
87.
This paper presents results of numerical simulations for impact effects in panel-like structures using solid and shell element modeling techniques. Three examples from experiments in literature have been numerically analyzed. The nonlinear transient dynamic analysis code, LS-DYNA is used in the simulations to model projectiles and panel-like targets. It is found that models established for panel-like targets using solid shell elements cannot only save significant computational effort, but also produce good results as long as the panel-like targets satisfy certain conditions. A criterion that governs the validity of modeling panel-like targets with shell elements is proposed in the paper. 相似文献
88.
Hsu‐Wei Fang Hsien‐Chieh Wang Teh‐Hua Tsai Wei‐Bor Tsai Shao‐Yi Hou Hsuan‐Liang Liu Wun‐Hsing Lee Yung‐Chang Lu Chun‐Hsiung Huang 《应用聚合物科学杂志》2008,108(4):2428-2437
Wear of ultrahigh‐molecular‐weight polyethylene (UHMWPE) and wear‐particle‐induced osteolysis and bone resorption are the major factors causing the failure of total joint replacements. It is feasible to improve the lubrication and reduce the wear of artificial joints. We need further understanding of the lubrication mechanism of the synovial fluid. The objective of this study is to evaluate the lubricating ability of three major components in the synovial fluid: albumin, globulin, and phospholipids. An accelerated wear testing procedure in which UHMWPE is rubbed against a microfabricated surface with controlled asperities has been developed to evaluate the lubrication behavior. An analysis of the wear particle dimensions and wear amount of the tests has provided insights for comparing their lubrication performance. It is concluded that the presence of biomolecules at the articulating interface may reduce friction. A higher concentration of a biological lubricant leads to a decrease in the wear particle width. In addition, in combination with the wear results and mechanical analysis, the roles of individual biomolecules contributing to friction and wear at the articulating interface are discussed. These results can help us to identify the role of the biomolecules in the boundary lubrication of artificial joints, and further development of lubricating additives for artificial joints may be feasible. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
89.
Han‐Lang Wu Chen‐Chi M. Ma Chun‐Chieh Lin Yie‐Chan Chiu Chih‐Yuan Chen Chin‐Lung Chiang 《应用聚合物科学杂志》2008,107(5):3236-3243
Poly(arylene ether benzonitrile) (PAEBN) was synthesized with 2,6‐dichlorobenzonitrile and biphenol. PAEBNs with various molecular weights (MWs), 1,640,000 and 185,000 g/mol, were synthesized by control of the stoichiometry of the monomers and were blended with sulfonated poly(ether ether ketone) (SPEEK). The effects of MW on the water uptake, swelling, methanol permeability, and proton conductivity of the SPEEK/PAEBN blend membranes were investigated. The molecular mobility of the SPEEK/PAEBN blends was also examined in this study. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
90.