全文获取类型
收费全文 | 819篇 |
免费 | 97篇 |
国内免费 | 39篇 |
专业分类
电工技术 | 11篇 |
综合类 | 14篇 |
化学工业 | 190篇 |
金属工艺 | 52篇 |
机械仪表 | 18篇 |
建筑科学 | 10篇 |
矿业工程 | 4篇 |
能源动力 | 28篇 |
轻工业 | 68篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 263篇 |
一般工业技术 | 239篇 |
冶金工业 | 18篇 |
原子能技术 | 3篇 |
自动化技术 | 30篇 |
出版年
2024年 | 5篇 |
2023年 | 12篇 |
2022年 | 19篇 |
2021年 | 22篇 |
2020年 | 21篇 |
2019年 | 26篇 |
2018年 | 10篇 |
2017年 | 38篇 |
2016年 | 35篇 |
2015年 | 39篇 |
2014年 | 36篇 |
2013年 | 48篇 |
2012年 | 55篇 |
2011年 | 58篇 |
2010年 | 34篇 |
2009年 | 44篇 |
2008年 | 40篇 |
2007年 | 39篇 |
2006年 | 50篇 |
2005年 | 42篇 |
2004年 | 30篇 |
2003年 | 28篇 |
2002年 | 30篇 |
2001年 | 32篇 |
2000年 | 28篇 |
1999年 | 16篇 |
1998年 | 12篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有955条查询结果,搜索用时 15 毫秒
91.
Koichi Nagamoto Kunihisa Kato Satoshi Naganawa Takeshi Kondo Yasushi Sato Hisao Makino Naoki Yamamoto Tetsuya Yamamoto 《Thin solid films》2011,520(5):1411
We investigated the characteristics of highly transparent conductive Ga-doped ZnO (GZO) polycrystalline films of 100 nm thickness deposited on glass and polymer substrates. GZO films were deposited by ion plating with dc-arc discharge. We developed multiple-deposition method to obtain various deposition process temperatures lower than 100 °C. Cross-sectional SEM images show that all the GZO films have columnar structure. Analysis of data obtained by XRD measurements shows that all the GZO films with wurtzite structure exhibit highly (002) orientation perpendicular to the substrate. The resistivity of the GZO films deposited on polyester and glass substrates were 5.0 × 10-4 Ω · cm. The mechanical bending properties of the GZO films were investigated by comparing the sheet resistance determined before and after a bending test with various bending diameters. For the bending diameter of more than 30 mm, all the GZO films exhibited excellent bending properties with no change in sheet resistance. For the bending diameter of less than 20 mm, we found the sheet resistance affected by the bending. We demonstrated that our multiple-deposition method to achieve different controllable polyester substrate temperatures is highly suitable for improving the bending properties of GZO films. 相似文献
92.
Heterojunction solar cells have been manufactured by depositing n-type a-Si: H on p-type 1–2Ω cm CZ single crystalline silicon substrates. Although our cell structure is very simple - neither a BSF nor a surface texturing is used - a conversion efficiency of 13.1% has been achieved on an area of 1 cm2. In this paper the technology is described and the dependence of the solar cell parameters on the properties of the n-type a-Si: H layer is discussed. It is shown that this cell type exhibits no degradation under light exposure. 相似文献
93.
A mold was designed to create various strains in polyethylene terephthalate (PET) substrates before the deposition of TiO2 film to simulate deposition process on a cylindrical drum. The residual stress of the PET substrate with TiO2 film significantly increased with increasing strain, decreasing the radius of curvature. Compared to the as-received PET substrate, there was a noticeable increase in the surface roughness in the PET/TiO2 specimens when a large strain was applied. The formation of voids or cavities in the TiO2 layer significantly increased the roughness of the specimen. The mean cavity size and depth increased with increasing strain. For strains ≦ 4%, the specimen's hardness and Young's modulus factored by the voids/cavities increased with increasing surface roughness. The optical absorption increased with increasing surface roughness before becoming asymptotic to a constant value. The strain applied to the PET substrate before TiO2 deposition greatly affects the optical reflection, transmittance, and absorption. 相似文献
94.
95.
《Organic Electronics》2014,15(7):1672-1677
In this paper organic thin film transistors (OTFTs) are directly fabricated on fabric substrates consisting of Polyethylene Terephthalate (PET) fibers. A key process is coating the polymer layers on the fabric in order to reduce the large surface roughness of the fabric substrate. Two polymers, i.e. polyurethane (PU) and photo-acryl (PA), are used to reduce the large surface roughness and simultaneously improve the process compatibility of the layers with the subsequent OTFTs processes while also retaining the original flexibility of the fabric. The surface roughness of the PU/PA-coated fabric is significantly reduced to 0.3 μm. Furthermore, the original flexibility of the PET fabric remained after coating of the PU/PA polymer layers. The mobility of the OTFTs fabricated on the PU-PA coated fabric substrate is 0.05 ± 0.02 cm2/V s when three PA layers and 90 nm thick pentacene layer were used. The performance does not vary even after 30,000 bending test. 相似文献
96.
The growth of epitaxial films on featured substrates has an important device application in junction-confinement, double hetero-structure
light emitting diodes. These devices are presently grown by a liquid phase epitaxy process but growth by metalorganic chemical
vapor deposition is desirable because of MOCVD's superior surface quality, uniformity, and throughput. This paper describes
the effect of growth parameters on AlGaAs films deposited by atmospheric-pressure MOCVD into substrate holes typically made
in the fabrication of junction-confinement LEDs. MOCVD growth replicates the substrate features; it does not give a planar
surface over the holes. The behavior of epitaxy filling into holes is strongly dependent on growth temperature and total gas
flow and largely independent of substrate misorientation and the thickness of the layer grown. Wet-etched holes formed (ll0)-oriented
V-groove and dovetail-groove features on the hole circumference. Faceting of the MOCVD growth was seen on the wall with the
(111)A feature while smooth growth was seen on the etched (111)B surface.
Deceased. 相似文献
97.
Chakrapani V. Varanasi Leon Chuck Lyle Brunke Jack Burke Andrew D. Chaney Paul N. Barnes 《Journal of Electronic Materials》2007,36(10):1265-1269
A simple testing method is used to compare the yield strengths (YS) of biaxially textured metallic substrates (Ni and its
alloys) presently under development for YBa2Cu3O7−x
coated conductors. This method is based on a retired ASTM D3379 tensile test standard method that was originally recommended
for single filament materials. Several common textured substrates, such as Ni, Ni-3at.%W, and Ni-5at.%W, procured from different
manufacturers, were tested using this method, and the data were compared with the values reported in the literature. A new
alloy substrate (constantan (Cu55-Ni44-Mn1wt.%)) that is biaxially textured in-house was also tested using this method, and
the YS data were compared with those of other substrates. For the substrates used in this study, the data obtained using this
method indicated that Ni substrates have YS of ∼52 MPa, Ni-3at.%W substrates have YS of ∼106 MPa, Ni-5at.%W substrates have
YS 163 MPa, and Cu55-Ni44-Mn1 wt.% substrates have YS of 74 MPa. 相似文献
98.
99.
100.
The effects of the process parameters of ultrasonic power and normal bonding force on bond formation at ambient temperatures
have been investigated with scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis. A model was developed
based on classical microslip theory1 to explain the general phenomena observed in the evolution of bond footprints left on the substrate. Modifications to the
model are made due to the inherent differences in geometry between ball-bonding and wedge-bonding. Classical microslip theory
describes circular contacts undergoing elastic deformation. It is shown in this work that a similar microslip phenomenon occurs
for elliptical wire-to-flat contacts with plastically deformed wire. It is shown that relative motion exists at the bonding
interface as peripheral microslip at lower powers, transitioning into gross sliding at higher powers. With increased normal
bonding forces, the transition point into gross sliding occurs at higher ultrasonic bonding powers. These results indicate
that the bonding mechanisms in aluminum wire wedge-bonding are very similar to those of gold ball-bonding, both on copper
substrate. In ultrasonic wedge-bonding onto copper substrates, the ultrasonic energy is essential in forming bonding by creating
relative interfacial motion, which removes the surface oxides. 相似文献