全文获取类型
收费全文 | 1176篇 |
免费 | 34篇 |
专业分类
电工技术 | 102篇 |
综合类 | 4篇 |
化学工业 | 268篇 |
金属工艺 | 19篇 |
机械仪表 | 35篇 |
建筑科学 | 30篇 |
能源动力 | 79篇 |
轻工业 | 65篇 |
水利工程 | 3篇 |
无线电 | 107篇 |
一般工业技术 | 258篇 |
冶金工业 | 74篇 |
原子能技术 | 31篇 |
自动化技术 | 135篇 |
出版年
2023年 | 4篇 |
2022年 | 16篇 |
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 19篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 26篇 |
2015年 | 15篇 |
2014年 | 35篇 |
2013年 | 72篇 |
2012年 | 50篇 |
2011年 | 48篇 |
2010年 | 60篇 |
2009年 | 52篇 |
2008年 | 62篇 |
2007年 | 53篇 |
2006年 | 40篇 |
2005年 | 52篇 |
2004年 | 35篇 |
2003年 | 40篇 |
2002年 | 29篇 |
2001年 | 33篇 |
2000年 | 22篇 |
1999年 | 24篇 |
1998年 | 31篇 |
1997年 | 32篇 |
1996年 | 36篇 |
1995年 | 22篇 |
1994年 | 21篇 |
1993年 | 31篇 |
1992年 | 12篇 |
1991年 | 21篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 16篇 |
1985年 | 16篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1974年 | 4篇 |
1972年 | 2篇 |
排序方式: 共有1210条查询结果,搜索用时 15 毫秒
1.
2.
Yoshihiro Iida Toshikatsu Tsuyuki Takao Mashima Takeo Takashima Kunito Okuyama 《亚洲传热研究》2002,31(1):28-41
This paper presents a series of experimental results on a passive augmentation technique of boiling heat transfer by supplying solid particles in liquid. A cylindrical heater 0.88 mm in diameter is placed in saturated water, in which a lot of mobile particles exist, and the nucleate and film boiling heat transfer characteristics are measured. Particle materials used were alumina, glass, and porous alumina, and the diameter ranged from 0.3 mm to 2.5 mm. Particles are fluidized by the occurrence of boiling without any additive power, and the heat transfer is augmented. The maximum augmentation ratio obtained in this experiment reaches about ten times the heat transfer coefficient obtained in liquid alone. The augmentation ratio is mainly affected by the particle material, diameter, and the height of the particle bed set at no boiling condition. The augmentation mechanism is discussed on the basis of the experimental results. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 28–41, 2002 相似文献
3.
Masami Ikeda Susumu Fukumoto Hiroshi Takao Shinya Ohtsuka Eiichi Haginomori Masayuki Hikita 《Electrical Engineering in Japan》2002,141(4):16-24
This paper describes the dielectric breakdown characteristics of oil and oil‐impregnated paper for very fast transient (VFT) voltages. Blumlein circuits generate VFT voltages of 60 and 300 ns in a pulse width that simulates disconnecting switching surges in gas‐insulated switch gears. We measured the breakdown voltages of needle‐to‐plane, plane‐to‐plane oil gaps and several pieces of paper between plane electrodes for VFT and lightning impulse voltages. The measured data were formulated in V‐t characteristics and Weibull probability distributions. The inclination n of V‐t characteristics of insulating paper is 150, which is less than n = 13.7 of the plane‐to‐plane oil gap in the VFT time range. The shape parameters of Weibull distribution obtained in this study show that the scattering of breakdown voltages of paper is much less than that of oil. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 16–24, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10043 相似文献
4.
Theoretical analysis based on the calculation of phase diagrams was employed for Fe-Si-Co and Fe-Si-Al ordering systems to
clarify the necessity for the occurrence of phase separation in Fe-base ternary ordering systems. The free energy of Fe-base
ternary ordering alloys where B2 and D03 ordered structures are formed is evaluated statistically using a pairwise interaction approximation up to second nearest
neighbours, taking into account not only the atomic interaction but also the magnetic interaction, based on the Bragg-Williams-Gorsky
model. The calculated phase diagrams are consistent with the experimentally obtained ones. The phase diagram calculation in
this work is useful to predict the equilibrium states of the ternary ordering systems. The phase separation in ordering alloys
is caused by the contribution of excess free energies due to ordering. The influences of ferromagnetism on the two-phase regions
are also demonstrated. 相似文献
5.
The objectives of this paper are to quantify the effect of Marangini convection on the absorption performance for the ammonia–water absorption process, and to visualize Marangoni convection that is induced by adding a heat transfer additive, n-octanol. A real-time single-wavelength holographic interferometer is used for the visualization using a He–Ne gas laser. The interface temperature is always the highest due to the absorption heat release near the interface. It was found that the thermal boundary layer (TBL) increased faster than the diffusion boundary layer (DBL), and the DBL thickness increased by adding the heat transfer additive. At 5 s after absorption started, the DBL thickness for 5 mass% NH3 without and with the heat transfer additive was 3.0 and 4.5 mm, respectively. Marangoni convection was observed near the interface only in the cases with heat transfer additive. The Marangoni convection was very strong just after the absorption started and it weakened as time elapsed. It was concluded that the absorption performance could be improved by increasing the absorption driving potential (xvb−xvi) and by increasing the heat transfer additive concentration. The absorption heat transfer was enhanced as high as 3.0–4.6 times by adding the heat transfer additive that generated Marangoni convection. 相似文献
6.
7.
Hiroyuki Miki Takanori Takeno Toshiyuki Takagi Alexei Bozhko Mikhail Shupegin Hideya Onodera Takao Komiyama Takashi Aoyama 《Diamond and Related Materials》2006,15(11-12):1898
Superconductivity in a tungsten-containing carbon-oxide film was reported. The film with 500 nm thickness was deposited onto polycrystalline silicon oxides using chemical vapor deposition and the co-sputtering of a tungsten metal target. The bonding state of the carbon atoms and the macroscopic and microscopic crystal structure of the film were investigated by Raman spectroscopy, X-ray diffraction and transmission electron microscopy measurements. From the experimental results, we determined that this film essentially had an amorphous structure. The temperature dependence on resistivity was measured in the temperature range of 2–300 K. Resistive superconducting transition was observed at 3.8 K. The dc magnetizations were measured in the temperature range of 1.8–6.5 K. The diamagnetism resulting from a superconductive state was observed below 3.75 K, which is consistent with a resistive superconducting transition. It is thought that the finite sized clusters of the different superconductive transition temperatures cooperatively produce a macroscopic superconducting phenomenon. 相似文献
8.
9.
Drawing plane graphs nicely 总被引:3,自引:0,他引:3
Summary This paper presents two efficient algorithms for drawing plane graphs nicely. Both draw all edges of a graph as straight line segments without crossing lines. The first draws a plane graph convex if possible, that is, in a way that every inner face and the complement of the outer face are convex polygons. The second, using the first, produces a pleasing drawing of a given plane graph that satisfies the following property as far as possible: the complements of 3-connected components, together with inner faces and the complement of the outer face, are convex polygons. The running time and storage space of both algorithms are linear in the number of vertices of the graph. 相似文献
10.
For the purpose of synthesizing standards to be used in the quantification of TAG hydroperoxides, three TAG (1,2-dioleoyl-3-palmitoylglycerol,
1-oleoyl-2-linoleoyl-3-palmitoylglycerol, and triolein) monohydroperoxides were chemically synthesized as authentic specimens.
TAG were prepared by using a simple condensation in pyridine of glycerol and the corresponding acid chlorides. These TAG were
then converted into monohydroperoxides by a photosensitized peroxidation. The synthesized monohydroperoxides were analyzed
by normal-phase and RP-HPLC. The results of normal-phase HPLC analysis showed that monohydroperoxides from a corresponding
TAG were a mixture of regioisomers. In RP-HPLC, however, the regioisomers of monohydroperoxides were not separated and gave
a single peak, which may improve the sensitivity for the detection of TAG monohydroperoxides. In this study TAG monohydroperoxide
standards were synthesized; these will be useful for the study of yet unknown biological and pathological roles of TAG hydroperoxides. 相似文献