全文获取类型
收费全文 | 529篇 |
免费 | 24篇 |
国内免费 | 4篇 |
学科分类
工业技术 | 557篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 19篇 |
2021年 | 31篇 |
2020年 | 33篇 |
2019年 | 31篇 |
2018年 | 34篇 |
2017年 | 32篇 |
2016年 | 36篇 |
2015年 | 27篇 |
2014年 | 36篇 |
2013年 | 43篇 |
2012年 | 32篇 |
2011年 | 39篇 |
2010年 | 24篇 |
2009年 | 25篇 |
2008年 | 21篇 |
2007年 | 13篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有557条查询结果,搜索用时 0 毫秒
551.
Intumescent flame retardant polyurethane/starch composites: Thermal,mechanical, and rheological properties 下载免费PDF全文
Jaber Nasrollah Gavgani Hossein Adelnia Gity Mir Mohamad Sadeghi Farhad Zafari 《应用聚合物科学杂志》2014,131(23)
Intumescent flame retardant polyurethane/starch (IFRPU/starch) composites were prepared by means of melt blending. Microencapsulated ammonium polyphosphate (MCAPP) was added to improve its compatibility with matrix, retardation of reaction between acid and carbon source, and its water resistancy. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of hydrogen bonding and entangled network between IFR system and PU matrix. Further, scanning electron microscopy (SEM) illustrated homogeneity of starch in matrix. By addition of 10 wt % of starch and 20 wt % of IFR, limiting oxygen index (LOI) increased from 22.0 to 40.0 and UL94 V0 rating was achieved. Differential scanning calorimetry (DSC) detected three endothermic transitions and one glass transition (Tg). The temperature of transition III and Tg increased with starch due to crosslinking between PU and starch. The improved thermal stability in the presence of starch was confirmed by thermogravimetric analysis (TGA). Beside the fact that starch was used as a carbonization agent to improve flame retardancy, it also effectively led to enhanced mechanical and viscoelastic properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41158. 相似文献
552.
Farhad ANSARI 《中国科学E辑(英文版)》2009,52(3):647-650
The creep properties of optical fiber used in fiber optical sensors were studied in this paper. A low co- herent white light double interferometer system was designed and calibrated and the creep deforma- tions of optical fibers under static and cyclic loadings were measured with this device. The research results showed that polymer coated optical fibers crept at the beginning when they were under static or cyclic load. As the number of the cyclic loading or the static loading times increased the creep tend... 相似文献
553.
Investigation of the ConXL moment connection cyclic behavior in box columns without filling concrete with different arrangement of collar bolts 下载免费PDF全文
Farhood Shahidi Alireza Rezaeian Majid Jamal‐Omidi Farhad Shahidi 《The Structural Design of Tall and Special Buildings》2015,24(5):317-350
The aim of this study was to study numerically the seismic behavior of ConXL connection without filler concrete of columns and reduce the number of collar bolts with different arrangement. For this purpose, to verify the modeling and analyzing, we compared the numerical results of specimens (reduced beam section, end plate and Kaiser bolted bracket (KBB) connections) with the experimental results and observed a good agreement. Afterward, 18 specimens of ConXL moment connections in box columns not filled with concrete with axial force in single, planar and bi‐axial loading conditions with different arrangement of bolts were studied, and their performances were evaluated. Results show that seismic behavior of specimens with beam section depth less than W30 series under cyclic loading, even with reduces of number of bolts to 16 numbers, are suitable in the over 0.04 rad rotations. In addition, the use of 16 bolts in W30 series beams connections is suitable provided they are used in the corner connections (with single sided loading) and the material specifications ASTM‐A36 are used for the beams. Moreover, the closer the position of bolts related to the outer side of collar flange, the more axial strain of bolts shank and the lesser slippage. The most optimum of bolt position is the surface middle of the collar flange and collar corner. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
554.
Microbiological Investigation of O‐Serogroups,Virulence Factors and Antimicrobial Resistance Properties of Shiga Toxin‐Producing Escherichia Coli Isolated from Ostrich,Turkey and Quail Meats 下载免费PDF全文
555.
556.
557.
Abbas Ghareghashi Farhad Shahraki Kiyanoosh Razzaghi Sattar Ghader Mohammad Ali Torangi 《Korean Journal of Chemical Engineering》2017,34(1):87-99
A two-stage, one-dimensional configuration model including the steam reforming of methane (SRM) and Fischer-Tropsch (FT) synthesis has been developed for the production of hydrocarbons. This configuration is used to investigate hydrocarbon product distribution, such as gasoline. The first SRM reactor is fed by methane and steam, and the products are converted to hydrocarbons by the second FT reactor. The model was solved numerically by applying the finite difference approximation, and the set of first-order ODEs was solved in the axial direction. The results show that complete conversion of hydrogen in the second reactor can be achieved although a small amount of carbon monoxide remains. Furthermore, at higher H2O/CH4 ratio (and low CO in feed), lower C2-C5 yield and selectivity is obtained. 相似文献