全文获取类型
收费全文 | 362篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 142篇 |
金属工艺 | 12篇 |
机械仪表 | 44篇 |
建筑科学 | 5篇 |
能源动力 | 16篇 |
轻工业 | 9篇 |
无线电 | 40篇 |
一般工业技术 | 84篇 |
冶金工业 | 13篇 |
原子能技术 | 3篇 |
自动化技术 | 22篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 26篇 |
2012年 | 20篇 |
2011年 | 31篇 |
2010年 | 29篇 |
2009年 | 29篇 |
2008年 | 30篇 |
2007年 | 15篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 3篇 |
2002年 | 10篇 |
2001年 | 12篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有396条查询结果,搜索用时 15 毫秒
71.
Dong-Gil Lee Kyeung-Cheun Jang Jung-Min Kuk Ill-Soo Kim 《The International Journal of Advanced Manufacturing Technology》2005,26(7-8):896-908
A rotary bending fatigue test was carried out with two kinds of materials, S43C and S50C, using the front engine and front
driveshaft (F.F. shaft) of the vehicle. The specimens were heat-treated using the high frequency induction method (about 1 mm
depth and HRC56∼60) and the test environment temperatures were -30 °C (-22 °F), +25 °C (+77 °F), and +80 °C (+176 °F) in order
to determine the influence of the heat treatment and the temperatures.
The fatigue life increased on the order of +80 °C, +25 °C, and -30 °C regardless of heat treatment. In comparison of the fatigue
lives with the basis of the tested result at +25 °C, the fatigue lives of non-heated specimens decreased about 35%, but that
of heat-treated specimens decreased by only about 5% at +80 °C, more than at +25 °C. And fatigue life of non-heated and heat-treated
specimens were about 110% and 120% higher at -30 °C than that of +25 °C. The initiation of surface microcracks was observed
at 0.2 fatigue life ratio in as-received S43C and S50C, but the average crack length in S50C was about 14% longer than that
of S43C at the same fatigue life ratio. 相似文献
72.
Kim NK Cho S Lee SH Park HR Lee CS Cho YM Choy YH Yoon D Im SK Park EW 《Meat science》2008,80(4):1068-1073
Proteomic profiling by two-dimensional gel electrophoresis and mass spectrometry of longissimus dorsi muscle tissue from Korean native cattle identified seven proteins that are differentially expressed in animals producing low and high quality grade beef. The expression level of alpha actin is increased in high quality grade beef and the expression levels of T-complex protein 1 (TCP-1), heat shock protein beta-1 (HSP27), and inositol 1,4,5-triphosphate receptor type1 (IP3R1), a new protein to be associated with meat quality, are increased in low quality grade beef. In particular, the quantitation of HSP27 and IP3R1 by both silver staining and immunoblotting correlated well with intramuscular fat content, meat tenderness, and free calcium levels. The data suggest that HSP27 and IP3R1 are potential meat quality biomarkers and their identification provides new insight into the molecular mechanisms and pathways associated with overall beef quality. 相似文献
73.
Jeong-Hyun Sohn Wan-Suk Yoo Keum-Shik Hong Kwang-Suk Kim 《Journal of Mechanical Science and Technology》2002,16(6):810-818
When the contribution of lightweight components to the total energy of a system is small, the inertia effects are sometimes
ignored by replacing them to massless links. For example, a revolute-spherical massless link generates two kinematic constraint
equations between adjacent bodies and allows four relative degrees of freedom. In this paper, to implement a massless link
systematically in a computer program using the velocity transformation technique, the velocity transformation matrix of massless
links is derived and numerically implemented. The velocity transformation matrix for a revolute-spherical massless link and
a revolute-universal massless link are appeared as a 6X4 matrix and a 6X3 matrix, respectively. A massless link model in a
suspension composite joint transmitting external forces is also developed and the numerical efficiency of the proposed model
is compared to a conventional multibody model. For a massless link transmitting external forces, forces acting on links are
resolved and transmitted to the attached points with a quasi-static assumption. Numerical examples are presented to verify
the formulation. 相似文献
74.
The properties of carbon black-filled thermoplastic elastomers were studied. We compared the extrudate swell behavior and the rheological properties of carbon black-filled polymers with those of raw polymers. The shear viscosity increases with increasing amount of carbon black. The extrudate swell becomes smaller with increasing carbon black amount, indicated by the decreased elasticity of the material when adding carbon black. © 1993 John Wiley & Sons, Inc. 相似文献
75.
Photoelectrochemical Cells: Carbon Nanotube–Graphitic Carbon Nitride Hybrid Films for Flavoenzyme‐Catalyzed Photoelectrochemical Cells (Adv. Funct. Mater. 24/2018) 下载免费PDF全文
76.
77.
78.
The development of lithium metal anodes for next generation batteries remains a challenge. Uncontrolled Li dendrite growth not only induces severe safety issues but also leads to capacity fading by continuously consuming the electrolyte. This study demonstrates the design and fabrication of a composite protective layer composed of a high dielectric polymer, inorganic particles, and an electrolyte to overcome these obstacles. This layer not only suppresses dendrite growth, but also prevents LiPF6 degradation. The electrolyte introduced in the protective layer remains within the coating layer after solvent removal and acts as an ion transport channel at the interface. This enables the protective layer to exhibit high ionic conductivity and mechanical strength. The composite protective layer, which exhibits synergistic soft‐rigid characteristics, is placed on the Li metal anode and facilitates superior interfacial stability during long‐term cycles. LiMn2O4/coated lithium full cells using the composite protective layer show a superior rate capability and enhanced capacity retention compared to the cells using a bare lithium anode. The proposed strategy opens new avenues to fabricate a sustainable composite protective layer that affords superior performance in lithium metal batteries. 相似文献
79.
C. J. Kim H. G. Lee I. H. Kuk I. S. Chang C. S. Rim P. S. Han D. Y. Won 《Journal of Materials Science》1990,25(4):2165-2169
The phase transition YBa2(Cu1–x
Fe
x
)3O7–y (0x0.05) prepared through solid-state reaction was studied with X-ray diffraction analysis and optical microscope. It was found that the orthorhombic-to-tetragonal phase change was induced between x=0.02 and x=0.03 by X-ray diffraction. The phase transition was also identified by the disappearance of striations in plate-like grains under polarized light. The microstructures of the specimens with compositions of x=0.01 and x=0.02 showed faint striation images. It is considered that a mixture of the orthorhombic and tetragonal phase exists in these compositions. 相似文献
80.
Process engineering economic evaluation of the ethanol extraction of cottonseed: Preliminary analysis 总被引:1,自引:0,他引:1
G. Abraham K. M. Decossas R. J. Hron M. S. Kuk 《Journal of the American Oil Chemists' Society》1991,68(6):418-421
This preliminary analysis was undertaken to determine if the operations being developed for the aqueous ethanol extraction
of cottonseed oil are economical and whether further research of this process should be pursued. Results of the conversion
of hypothetical hexane extraction plants to ethanol extraction, in the plant capacity range of 300-600 tons of cottonseed
flakes/day and operating 150-350 days annually, show that two unconventional operations, namely, chill-separation of miscella
exiting the extractor and reduction of oil in recycled ethanol by reverse osmosis, require less energy and are less expensive
than conventional alternatives. However, additional work is needed to determine the overall efficiency of an alcohol process
as compared to a conventional hexane process. 相似文献