全文获取类型
收费全文 | 700篇 |
免费 | 10篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 7篇 |
综合类 | 2篇 |
化学工业 | 111篇 |
金属工艺 | 97篇 |
机械仪表 | 5篇 |
建筑科学 | 13篇 |
能源动力 | 27篇 |
轻工业 | 14篇 |
水利工程 | 1篇 |
无线电 | 89篇 |
一般工业技术 | 126篇 |
冶金工业 | 156篇 |
原子能技术 | 1篇 |
自动化技术 | 70篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 14篇 |
2021年 | 19篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2014年 | 19篇 |
2013年 | 37篇 |
2012年 | 37篇 |
2011年 | 44篇 |
2010年 | 53篇 |
2009年 | 38篇 |
2008年 | 40篇 |
2007年 | 39篇 |
2006年 | 26篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 14篇 |
2002年 | 21篇 |
2001年 | 16篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 21篇 |
1997年 | 37篇 |
1996年 | 25篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有719条查询结果,搜索用时 62 毫秒
51.
52.
This study theoretically investigates Fano resonances and dips of an Au-SiO2-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green''s functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes. 相似文献
53.
54.
Shinn-Shyong Tzeng Yang-Li Fang Ya-Ko Chih Yi-Ching Lin Chin-Fen Tuan 《Diamond and Related Materials》2010,19(7-9):783-786
DLC films were synthesized by RF plasma enhanced chemical vapor deposition and the effects of nitrogen plasma post-treatment at different pressures on the structure and properties of DLC films were investigated. Higher roughness was obtained after plasma post-treatment at higher pressures (0.3 and 0.9 torr) and plasma post-treatment at a lower pressure (0.15 torr) resulted in lower roughness than that of original films. The hardness of DLC films decreased with the decrease of post-treatment pressure, which is consistent with the Raman results of ID/IG ratio and G peak position. Compared to the original DLC film, the residual stress after plasma post-treatment decreased slightly due to the relatively thin region involved in the plasma post-treatment. 相似文献
55.
In this paper, the state-of-the-art progress in research on novel mechanical properties of nanocrystalline materials and carbon
nanotubes is reviewed. There is evidence that the relation between the strength of nanocrystalline materials and grain size
does not observe the classic Hall-Petch plot. Lowtemperature and high-strain rate superplasticity have been found in some
nanocrystalline materials. Theoretical prediction and experimental data indicate that carbon nanotubes are materials with
high stiffness, high strength, great toughness, and low density. There are already some application examples for novel mechanical
properties of nanocrystalline materials and carbon nanotubes.
For more information, contact P.K. Liaw, University of Tennessee at Knoxville, Materials Science and Engineering Department,
427-B Dougherty Engineering Building, Knoxville, Tennessee 37996; (865) 974-6356; fax (865) 974-4115; e-mail pliaw@utk.edu. 相似文献
56.
W. H. Peter P. K. Liaw R. A. Buchanan C. T. Liu C. R. Brooks J. A. Horton Jr. C. A. Carmichael Jr. J. L. Wright 《Intermetallics》2002,10(11-12)
In the present study, fatigue tests were conducted on a zirconium-based bulk metallic glass (BMG), BMG-11 (Zr–10Al–5Ti–17.9Cu–14.6Ni, atomic percent), in air and vacuum to elucidate the possible environmental effects. In air, the fatigue endurance limit and the fatigue ratio were found to be 907 MPa and 0.53, respectively. These values are better than many conventional high-strength crystalline alloys. Unexpectedly, the fatigue lifetimes in vacuum were found to be lower than in air. Additional testing indicated that dissociation of residual water vapor to atomic hydrogen in the vacuum via a hot-tungsten-filament ionization gauge, and subsequent hydrogen embrittlement of the BMG-11, could have been a factor causing the lower fatigue lifetimes observed in vacuum. 相似文献
57.
K. T. Chiang D. H. Loh P. K. Liaw E. S. Diaz 《Metallurgical and Materials Transactions A》1995,26(12):3249-3255
Flexural fatigue behavior was investigated on titanium (Ti-15V-3Cr) metal matrix composites reinforced with cross-ply, continuous
silicon carbide (SiC) fibers. The titanium composites had an eightply (0, 90, +45, -45 deg) symmetric layup. Mechanistic investigation
of the fatigue behavior is presented in Part I of this series. In Part II, theoretical modeling of the fatigue behavior was
performed using finite element techniques to predict the four stages of fatigue deflection behavior. On the basis of the mechanistic
understanding, the fiber and matrix fracture sequence was simulated from ply to ply in finite element modeling. The predicted
fatigue deflection behavior was found to be in good agreement with the experimental results. Furthermore, it has been shown
that the matrix crack initiation starts in the 90 deg ply first, which is in agreement with the experimental observation.
Under the same loading condition, the stress in the 90 deg ply of the transverse specimen is greater than that of the longitudinal
specimen. This trend explains why the longitudinal specimen has a longer fatigue life than the transverse specimen, as observed
in Part I.
This article is based on a presentation made in the symposium entitled “Creep and Fatigue in Metal Matrix Composites” at the
1994 TMS/ASM Spring meeting, held February 28–March 3, 1994, in San Francisco, California, under the auspices of the Joint
TSM/SMD/ASM-MDS Composite Materials Committee. 相似文献
58.
Yo-Sheng Lin Huan-Tsung Huang Chung-Cheng Wu Ying-Keung Leung Hsu-Yang Pan Tse-En Chang Wei-Ming Chen Jung-Jih Liaw Diaz C.H. 《Electron Devices, IEEE Transactions on》2002,49(3):442-448
This paper describes a leading-edge 0.13 μm low-leakage CMOS logic technology. To achieve competitive off-state leakage current (I off) and gate delay (Td) performance at operating voltages (Vcc) of 1.5 V and 1.2 V, devices with 0.11 μm nominal gate length (Lg-nom) and various gate-oxide thicknesses (Tox) were fabricated and studied. The results show that low power and memory applications are limited to oxides not thinner than 21.4 Å in order to keep acceptable off-state power consumption at Vcc=1.2 V. Specifically, two different device designs are introduced here. One design named LP (Tox=26 Å) is targeted for Vcc=1.5 V with worst case Ioff <10 pA/μm and nominal gate delay 24 ps/gate. Another design, named LP1 (Tox=22 Å) is targeted for Vcc =1.2 V with worst case Ioff<20 pA/μm and nominal gate delay 27 ps/gate. This work demonstrates n/pMOSFETs with excellent 520/210 and 390/160 μA/μm nominal drive currents at Vcc for LP and LP1, respectively. Process capability for low-power applications is demonstrated using a CMOS 6T-SRAM with 2.43 μm2 cell size. In addition, intrinsic gate-oxide TDDB tests of LP1 (T ox=22 Å) demonstrate that gate oxide reliability far exceeding 10 years is achieved for both n/pMOSFETs at T=125°C and V cc=1.5 V 相似文献
59.
STAR-SVT Collaboration R. Bellwied R. Beuttenmuller W. Chen D. DiMassimo L. Dou H. Dyke A. French J. R. Hall G. W. Hoffmann T. J. Humanic I. V. Kotov H. W. Kraner Z. Li C. J. Liaw J. Lopez D. Lynn V. L. Rykov S. U. Pandey C. Pruneau J. Schambach J. Sedlmeir E. Sugarbaker J. Takahashi W. K. Wilson 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1997,400(2-3):279-286
Electron collection at the anodes of large-area silicon drift detectors was studied with STAR2 prototypes. Results of measurements of anode leakage currents, signal dependence on focusing voltages, anode uniformity, and model simulations are reported. A design of the anode region is presented. The design optimization is discussed. 相似文献
60.
P. K. Liaw M. G. Burke A. Saxena J. D. Landes 《Metallurgical and Materials Transactions A》1991,22(2):455-468
Elevated-temperature fracture toughness properties were developed on ex-service 2-l/4Cr-1Mo steel weldments. Fracture toughness
was measured on both base and heat-affected zone (HAZ) metals. A composite specimen consisting of base, HAZ, and weld metals
was used to develop fracture toughness properties in the HAZ area. It was observed that the J-R curve of the HAZ was significantly
lower than that of the base metal. Increasing crack extension increased the difference between theJ-R curves of the base metal and the HAZ. Dimpled fracture was the prime fracture mode in the base metal specimen, and a mixed-mode
(ductile and “granular”) fracture was found in the HAZ specimens. Scanning transmission electron microscopy (STEM) examination
revealed significant intergranular carbide precipitation and agglomeration within the HAZ. The lower fracture toughness of
the HAZ, as compared to the base metal, was attributed to the large accumulation of carbides in the grain boundaries of the
HAZ, which weakened the grain boundaries and caused “granular” fracture. 相似文献