全文获取类型
收费全文 | 668篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 253篇 |
金属工艺 | 26篇 |
机械仪表 | 18篇 |
建筑科学 | 37篇 |
矿业工程 | 5篇 |
能源动力 | 19篇 |
轻工业 | 51篇 |
水利工程 | 8篇 |
石油天然气 | 2篇 |
无线电 | 27篇 |
一般工业技术 | 114篇 |
冶金工业 | 30篇 |
原子能技术 | 7篇 |
自动化技术 | 90篇 |
出版年
2022年 | 24篇 |
2021年 | 32篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 19篇 |
2017年 | 23篇 |
2016年 | 24篇 |
2015年 | 13篇 |
2014年 | 29篇 |
2013年 | 57篇 |
2012年 | 24篇 |
2011年 | 43篇 |
2010年 | 19篇 |
2009年 | 46篇 |
2008年 | 26篇 |
2007年 | 27篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 16篇 |
2003年 | 20篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1970年 | 2篇 |
1956年 | 2篇 |
排序方式: 共有695条查询结果,搜索用时 15 毫秒
81.
Zbigniew J. Lata Peter B. Aronhime 《Analog Integrated Circuits and Signal Processing》1997,13(3):275-284
New procedures are presented that yield cascadable, opamp based current-mode biquads from voltage-mode biquads without the use of voltage-mode to current-mode transformations. The opamps in the resulting current-mode circuits can be replaced by current-mode devices, such as current conveyors, producing circuits that are fully current-mode. The procedures are applied to several multi-opamp voltage-mode circuits to achieve current-mode lowpass, highpass, bandpass, notch, and allpass filters. The procedures are also applied to a single opamp circuit. Experimental results are given. 相似文献
82.
A numerical model for the hopping conductivity in 3-D disordered systems is presented. The relation between variable-range hopping conductivity and temperature for the low-temperature range is found. The advantage of the proposed model is that the size of the system investigated is not limited by the computer memory. 相似文献
83.
We have studied thin films of Ti-Al for use as resistance elements. It was found that Ti-40 wt.% Al thin films with a resistivity of 10 ω/□ possess stable characteristics. We have also studied the structure of Ti-Al thin films. Analysis of electron and X-ray diffraction patterns showed that Ti-40 wt.% Al films contained a fine-grained disordered intermetallic face-centred cubic TiAl phase whereas bulk TiAl had a tetragonal CuAu-type structure. 相似文献
84.
85.
Nitrogen base fractions were prepared from a heavy coal-derived liquid via two commonly accepted laboratory procedures and partially characterized. Significant differences in the composition of the two fractions suggest strongly that extreme caution should be exercised in interpreting and comparing the results of base characterization studies in which different base isolation procedures are used. 相似文献
86.
Zbigniew Lewandoswki 《Water research》1982,16(1):19-22
The rate of a waste water dentification process depends amongst others upon the temperature and the kind of compound used as electron donor. The results of measurements of denitrification kinetics using methanol, acetone and acetic acid have been presented. 相似文献
87.
88.
Zbigniew Jedliński Andrej Stolarzewicz Pawel Szewczyk Ryszard Tymczyński 《Polymer Bulletin》1980,2(8):555-563
Summary Polymerization of p-chlorophenyl glycidyl ether initiated by potassium glycolates (ethylene, propylene and 2-methyl propylene glycolatea) in DMSO containing some 18-crown-6 ether or glycol was investigated. For the reaction system containing the propylene glycolate asymmetrically substituted with a methyl group, relatively high polymerization rates were obtained as compared with those found for the other systems studied, the resultant polymers also having higher molecular weights and comparatively low polydispersities. Aliphatic double bonds were found to be absent in the polymers synthesized, which would suggest that in the anionic polymerization process studied the growing chain is not transferred to the monomer.Dedicated to Prof. C.I. Simionescu on the occasion of the 60th anniversary of his birthday 相似文献
89.
In this study, the influence of pH on interfacial energy distributed over the phospholipids-bilayer surface model and the effect of hydrophobicity on coefficient of friction (f) were investigated by using microelectrophoresis. An important clinical implication of deficiency in hydrophobicity is the loss of phospholipids that is readily observed in osteoarthritis joints. This paper establishes the influence of pH on interfacial energy upon an increase f, which might be associated with a decrease of hydrophobicity of the articular surface. 相似文献
90.
Marta Legawiec-Jarzyna Wojciech Juszczyk Magdalena Bonarowska Zbigniew Kaszkur Leszek Kępiński Zbigniew Kowalczyk Zbigniew Karpiński 《Topics in Catalysis》2009,52(8):1037-1043
A series of Pt/Al2O3 catalysts were prepared by the impregnation method and were characterized by TEM, XRD, H2 and CO chemisorptions, and investigated in the hydrodechlorination of tetrachloromethane. Three Pt-rich, Pt–Au/Al2O3 catalysts (Pt100, Pt95Au5 and Pt90Au10) showed a similar metal particle size (~2.5–2.7 nm), so observed changes in the catalytic behavior are ascribed to alloying
effect, especially because a considerable degree of Pt–Au mixing was achieved in the bimetallic samples. It appeared that
by introducing very small amount of gold (10 at.%) to platinum, the catalytic activity is increased. It is argued that the
occurrence of this moderate synergistic effect is associated with a decreased tendency of surface chloriding when platinum
is alloyed with gold.
Zbigniew Kowalczyk—deceased. 相似文献