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991.
Jeong-Sun Oh Joon-Hyung An Sun-Ok Lee Yeon-Hum Yun Bo-An Kang Sang-Bok Kim Kyu-Seog Hwang 《Metals and Materials International》2002,8(5):459-462
We prepared zirconia thin films on (100) Si wafer by using a chemical solution deposition with a zirconium naphthenate as
a starting material. The films were pyrolyzed at 500°C for 10 min and finally annealed for 30 min in air at 500°C. Amorphous
films after annealing had no distinct structure and were uniform along the cross section line.In vitro formation of the calcium phosphate was evaluated by the field emission-scanning electron microscope, energy dispersive X-ray
spectrometer and Fourier transform infrared spectroscopy. 相似文献
992.
Keiichiro Oh-ishi John Boydon Terry R. McNelley 《Journal of Materials Engineering and Performance》2004,13(6):710-719
The importance of grain size refinement in enabling superplasticity is reviewed, and the current understanding of grain boundary
characteristics is summarized. The application of orientation-imaging microscopy (OIM) methods to the processing response
and the deformation and failure modes in superplastic aluminum alloys are illustrated through microtexture analysis and determination
of grain boundary characteristics in selected commercial materials. Continuous and discontinuous recrystallization reactions
exhibit distinct microtextures and grain boundary characteristics. The application of OIM and microtexture analysis to the
evaluation of both deformation and failure mechanisms during superplastic forming is illustrated.
This paper was presented at the International Symposium on Superplasticity and Superplastic Forming, sponsored by the Manufacturing
Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium
was organized by Daniel G. Sanders, The Boeing Company. 相似文献
993.
Different metallurgical processing, including the standard heat treatment, heat treatment without β aging, addition of high
amount of Cr, and long-term isothermal exposure, was conducted on superalloy Inconel 783. For these processed materials, the
tensile property and hardness at room temperature and stress relaxation behavior at 650 °C were examined. The testing results
showed that isothermal exposure and heat treatment without β aging slightly enhanced the yield strength of alloy 783 at room
temperature as well as all metallurgical processing in this study produced an identical stress relaxation behavior at 650
°C. The microstructure variation with different processing was analyzed using optical microscope, scanning electron microscopy
(SEM), and transmission electron microscopy (TEM). 相似文献
994.
995.
996.
Daniel G. Sanders Mamidala Ramulu 《Journal of Materials Engineering and Performance》2004,13(6):744-752
Superplastic forming (SPF) combined with diffusion bonding (DB) has been used successfully for the fabrication of titanium
aerospace hardware. Many of these applications have been for military aircraft, whereby a complex built-up structure has been
replaced with monolithic parts. Several methods for applying the two- and four-sheet titanium SPF/DB processes have been devised,
including the welding of sheets prior to forming and the use of silk-screened stop-off (yttria) to prevent bonding where it
is undesirable. Very little progress has been made in the past few years toward understanding and modeling the SPF/DB process
using constitutive equations and data by laboratory testing. Concerns that engineers face in designing for fatigue life, acceptable
design loads, and damage tolerance are currently being studied, but the database is very limited. This is a summary of past
work found in the literature and forms the foundation for additional research.
This paper was presented at the International Symposium on Superplasticity and Superplastic Forming sponsored by the Manufacturing
Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium
was organized by Daniel G. Sanders, The Boeing Company. 相似文献
997.
Yang Gao Lian-Tong An Cheng-Qi Sun Zhi-Jun Yan 《Journal of Thermal Spray Technology》2004,13(4):521-525
The effects of the composition of plasma gases (Ar-N2, Ar-H2), arc current, and voltage on the temperature and velocity of a low-power (5 kW) plasma torch in the arc field free region
has been investigated using an enthalpy probe. Coatings of Al2O3-13TiO2 were deposited under different conditions. The results show that in the Ar-N2 plasma, the enthalpy, temperature, and velocity change little with arc current and voltage when regulating the nitrogen proportion
in the plasma gas. The hardness of the resulting coatings is 800 to 900 kg/mm2 HV.300. For Ar-H2 plasma, however, increases in the H2 content in the mixture of the gases remarkably enhanced the velocity and heat transfer ability of the plasma jet, with the
result that the coatings showed high hardness up to 1200 HV. 相似文献
998.
Uma Batra S. Ray S. R. Prabhakar 《Journal of Materials Engineering and Performance》2003,12(5):597-601
A ductile iron containing 0.6% copper as the main alloying element was austempered at a fixed austempering temperature of
330 °C for a fixed austempering time of 60 min after austenitization at 850 °C for different austenitization periods of 60,
90, and 120 min. The austempering process was repeated after changing austenitization temperature to 900 °C. The effect of
austenitization temperature and time was studied on the carbon content and its distribution in the austenite after austenitization.
The effect of austenitization parameters was also studied on austempered microstructure, structural parameters like volume
fraction of austenite, X
γ
, carbon content C
γ
, and X
γ
C
γ
, and bainitic ferrite needle size, d
α
after austempering. The average carbon content of austenite increases linearly with austenitization time and reaches a saturation
level. Higher austenitization temperature results in higher carbon content of austenite. As regards the austempered structure,
the lowering austenitization temperature causes significant refinement and more uniform distribution of austempered structure,
and a decrease in the volume fraction of retained austenite. 相似文献
999.
Désirée Risch Alexander Brosius Matthias Kleiner 《Journal of Materials Engineering and Performance》2007,16(3):327-330
Electromagnetic sheet metal forming is a high speed forming process using pulsed magnetic fields to form metals with high
electrical conductivity such as aluminum. Thereby, workpiece velocities of more than 300 m/s are achievable, which can cause
difficulties when forming into a die. The kinetic energy, which is related to the workpiece velocity, must be dissipated in
a short time slot when the workpiece hits the die; otherwise undesired effects, for example rebound can occur. One possibility
to handle this shortcoming is to locally increase the stiffness of the workpiece. A modal analysis is carried out in order
to determine the stiffness of specific regions of the workpiece so that an estimation concerning the feasibility of the desired
geometry is possible in advance without doing cost and time consuming experiments. Thereby, the desired geometry of the workpiece
will be fractionized in significant sectors. This approach has to define the internal force variables acting on the cutting
edge, which are required to constrain the numerical model. Finally, a method will be developed with the objective of calculating
the stiffness of each sector. The numerical results will be verified by experiments.
This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati,
OH, October 15-19, 2006. 相似文献
1000.
Zhongning Shi Junli Xu Zhuxian Qiu Zhaowen Wang Bingliang Gao 《JOM Journal of the Minerals, Metals and Materials Society》2003,55(11):63-65
The superalloys Cu-Ni-Al, Cu-Ni-Fe, and Cu-Ni-Cr were studied as anodes for aluminum electrolysis. The alloys were tested
for corrosion in acidic electrolyte molten salt and for oxidation in both air and oxygen. The results showed that the Cu-Ni-Al
anodes possess excellent resistance to oxidation and corrosion, and the oxidation rates of Cu-Ni-Fe and Cu-Ni-Al anodes were
slower than those of pure copper or nickel. During electrolysis, the cell voltage of the Cu-Ni-Al anode was affected most
by the concentration of alumina in cryolite molten salt. The Cu-Ni-Fe anode exhibited corrosion resistance in electrolyte
molten salt. Comparatively, the Cu-Ni-Cr anode showed poor resistance to oxidation and corrosion. The testing found that further
study is warranted on the use of Cu-Ni-Al and Cu-Ni-Fe as inert alloy anodes.
For more information, contact Zhongning Shi, Northeastern University, School of Materials and Metallurgy, WenhuiRoad No. 3,
Shenynag, Liaoning 110004 China; e-mail znshi@163.com 相似文献