全文获取类型
收费全文 | 19036篇 |
免费 | 2073篇 |
国内免费 | 904篇 |
专业分类
电工技术 | 1132篇 |
综合类 | 1301篇 |
化学工业 | 3948篇 |
金属工艺 | 881篇 |
机械仪表 | 1149篇 |
建筑科学 | 1079篇 |
矿业工程 | 398篇 |
能源动力 | 878篇 |
轻工业 | 1815篇 |
水利工程 | 350篇 |
石油天然气 | 488篇 |
武器工业 | 99篇 |
无线电 | 2481篇 |
一般工业技术 | 2653篇 |
冶金工业 | 663篇 |
原子能技术 | 293篇 |
自动化技术 | 2405篇 |
出版年
2024年 | 47篇 |
2023年 | 215篇 |
2022年 | 454篇 |
2021年 | 640篇 |
2020年 | 463篇 |
2019年 | 489篇 |
2018年 | 552篇 |
2017年 | 605篇 |
2016年 | 615篇 |
2015年 | 811篇 |
2014年 | 988篇 |
2013年 | 1219篇 |
2012年 | 1377篇 |
2011年 | 1463篇 |
2010年 | 1271篇 |
2009年 | 1171篇 |
2008年 | 1137篇 |
2007年 | 1059篇 |
2006年 | 999篇 |
2005年 | 822篇 |
2004年 | 765篇 |
2003年 | 858篇 |
2002年 | 1117篇 |
2001年 | 898篇 |
2000年 | 521篇 |
1999年 | 357篇 |
1998年 | 188篇 |
1997年 | 188篇 |
1996年 | 155篇 |
1995年 | 117篇 |
1994年 | 71篇 |
1993年 | 69篇 |
1992年 | 55篇 |
1991年 | 42篇 |
1990年 | 34篇 |
1989年 | 40篇 |
1988年 | 19篇 |
1987年 | 20篇 |
1986年 | 15篇 |
1985年 | 19篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1971年 | 3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 15 毫秒
41.
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
42.
43.
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
44.
JaeHyunKim JounHoLee JiChulLim ChangHoonLee MooHyoungSong JuYeonYoon HeeDongChoi JeomJaeKim ChangHoOh SangDeogYeo 李路海 《现代显示》2004,31(5):31-33
薄膜晶体管液晶电视(TFT-LCD TV)因为具有薄、轻、紧凑和可随意放置的特点,已经占据了大部分电视机市场。除了这些物理特性以外,最重要的特性是已具有了良好像质的对比度。为了将对比度提高到1:600以上,对偏振片膜、背光源板、滤色片树脂、电极锥角和摩擦条件等都进行了研究。优化的背光板组合,光滑的电极锥角和摩擦方法的控制是提高对比度的主要控制因素。应用新开发的滤色片树脂,对获得高对比度最为有效。 相似文献
45.
46.
T. Jeevananda Siddaramaiah Taek Su Lee Joong Hee Lee O. M. Samir R. Somashekar 《应用聚合物科学杂志》2008,109(1):200-210
Polyaniline/carboxylated multi-walled carbon nanotube (PAni/c-MWNT) nanocomposites have been synthesized by micellar aided emulsion polymerization with various c-MWNTs compositions, viz., 0.5, 1, 5, and 10 wt %. The microcrystalline parameters such as the nanocrystal size (〈N〉), lattice strain (g), interplanar distance (dhkl), width of the crystallite size distribution, surface weighted crystal size (Ds), and volume of the ordered regions were calculated from the X-ray data by using two mathematical models, namely the Exponential distribution and Reinhold distribution methods. The effects of heat ageing on the microcrystalline parameters of the PAni/c-MWNT nanocomposites were also studied and the results are correlated. The thermal stability and electrical resistivity of the PAni/c-MWNT nanocomposites were examined with thermogravimetric analysis (TGA) and a conventional two-probe method. The TGA data indicate that the thermal stability of the nanocomposites improved after the incorporation of c-MWNTs. The influence of temperature on the resistivity of the nanocomposites was also measured. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
47.
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
48.
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
49.
为了改善筛分机械的使用环境,降低筛分机械的噪声,从噪声源入手,从内因和外因两个方面分析了筛分机噪声的形成原因。论述了USL和USK系列振动筛在降低噪声方面所采取的先进技术措施。 相似文献
50.