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101.
Jae-Sung Oh Min-Chul Shim Man-Ho Park Kee-Ahn Lee 《Metals and Materials International》2014,20(5):915-921
This study investigated the high temperature oxidation behavior of newly developed Ni-Cr-Al powder porous metal. High temperature isothermal oxidation tests were conducted at 900, 1000 and 1100 °C temperatures for 24 h under an atmosphere of 79% N2 + 21% O2 gas. Oxidation weight gain vs. time curves represented typical oxidation behavior of parabolic shape. Weight gain increased with increasing oxidation temperature. Ni-Cr-Al porous metal mainly created oxides such as α-Al203, Cr2O3, NiCr2O4. The α-Al203 oxide could be still maintained up to 1100 °C oxidation temperature as a thick and stable protective layer. It was noted that Ni-Cr-Al porous metal had better high temperature oxidation resistance than those of other Ni-based and Fe-based porous metals. The catastrophic degradation of oxidation resistance especially at very high temperature was not observed up to 1100 °C in this porous metal. The micro-mechanism of high temperature oxidation of Ni-Cr-Al porous metal was also discussed. 相似文献
102.
Herein, we fabricated MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers by electrospinning and dip coating method. The amount of MWCNT–OH adsorbed to the pure electrospun nylon 6,6 nanofibers was 0.056 wt%. The electrical conductivity of MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers was 5.24 × 10?3 S cm?1. We also investigated the sensing properties of MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers by measuring its response upon exposure to low molecular weight alcohol vapours such as methanol, ethanol, 1-propanol, and 1-butanol. The changes of the electrical resistance of MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers were demonstrated on the basis of hydrogen bonds among the alcohol vapours and hydroxyl groups (–OH) on MWCNT–OH, and amide groups (–NHCO–) in nylon 6,6. The fabricated sensor showed good reversible and reproducible responses upon the cyclic test. 相似文献
103.
Jinseob Shin Kyomin Shin Hanna Lee Jeong‐Beom Nam Jae‐Eun Jung Jee‐Hyun Ryu Joo‐Hyun Han Kyung‐Do Suh Yong‐Jin Kim Jongwon Shim Junoh Kim Sang‐Hoon Han Kookheon Char Yeon Kyung Kim Jin Ho Chung Min Jung Lee Byeong Cheol Kang Jin‐Woong Kim 《Advanced materials (Deerfield Beach, Fla.)》2010,22(6):739-743
104.
A magnet wheel is chosen as the driving method to transfer a conductive plate without mechanical contact in space, due to its high force density. When permanent magnets (hereafter PMs) constituting the magnet wheel rotate below the conductive plate, not only a repulsive type of normal force but also a traction torque is generated on the plate. To utilize the torque as a thrust force, the magnetic fields from PMs are covered partially using a magnetic shield plate. So, in-plane positions of the conductive plate are controlled by turning the shield plate opened partially. In this paper, the operating principle of the noncontact conveyance system using a magnet wheel is discussed, including experimental verification. Specially, the resulting force from the suggested magnet wheel is AC force with oscillation, but it can be minimized through varying entry or exit shape of the open area of the magnetic shield plate. 相似文献
105.
Focused ion beam (FIB) milling is the typical method used to fabricate micropillars to study small-scale plasticity and size effects in uniaxial compression. However, FIB milling can introduce defects into the milled pillars. To investigate the effects of FIB damage on mechanical behavior, we tested Mo-alloy micropillars that were FIB milled following directional solidification, and compared their compressive response to pillars that were not FIB milled. We also FIB milled at glancing incidence a Mo-alloy single-crystal surface, and compared its nanoindentation response to an electropolished surface of the same crystal. Implications for the interpretation of data obtained from FIB-milled micropillars are discussed. 相似文献
106.
Seung-Wook Lee Daeyun Shim Yeon-Jae Jung Dong-Yun Lee Chang-Hyun Kim Wonchan Kim 《Electronics letters》1999,35(12):952-953
An output buffer is described which employs built-in load monitoring in order to bound the transition time over a wide range of load conditions. The adaptive control of driving current enables the switching-noise to be kept to a minimum value. The experimental chip, which was designed to bound the fall time within 6 ns for loading capacitance up to 100 pF, revealed a reduced switching-noise level, 15-35% of a conventional buffer 相似文献
107.
Ku-ho Chung Jong-in Shim 《Quantum Electronics, IEEE Journal of》1999,35(5):730-736
In a conventional polarization-insensitive multiquantum-well electroabsorption modulator, it is normal to apply tensile and compressive strain on the well and the barrier, respectively. But the main disadvantages of such a structure are a low conduction band offset (0.04-0.06 eV), a high heavy-hole band offset (0.20-0.24 eV), and a relatively large well thickness (110-120 Å). We propose a new method of overcoming these disadvantages by placing a tensile strain on both the well and the barrier and compensating for them with a compressive strained intrinsic layer 相似文献
108.
This article is the first of a four-part series by the authors that treats various aspects of digital signal processing applied to partial discharge detection. It is shown that manufacturers and users of high-voltage apparatus are interested in on-site, off-line and on-line analysis of partial discharge to identify and locate defects in insulation systems 相似文献
109.
Sang-Cheol Park Dirk Tuma Sunwook Kim Yong Rok Lee Jae-Jin Shim 《Korean Journal of Chemical Engineering》2010,27(1):299-309
C. I. Disperse Red 60 (DR60) was absorbed into polymer films and textile fibers in the presence of supercritical carbon dioxide
at pressures between 5 and 33MPa and at temperatures between 308.2 and 423.2 K. Polystyrene (PS) and poly(methyl methacrylate)
(PMMA) films and polyester (polyethylene terephthalate: PET) and Nylon 6 textiles were used as absorbents. The amount of equilibrium
sorption of dye increased both with pressure and temperature. The sorption behavior was successfully analyzed with the quasi
dual-mode sorption model. 相似文献
110.
Lithium-ion polymer cells composed of a carbon anode and a LiCoO2 cathode are assembled with a gel polymer electrolyte cured by in-situ chemical cross-linking with novel cross-linking agents. The strong interfacial adhesion between the electrodes and the porous polyethylene membrane by the chemical cross-linking results in the stable capacity retention of the cell. However, a reduction in the ionic mobility in both the electrolyte and the electrodes adversely affects the high rate performance of the cell. These results imply that proper control of the cross-linking density in the cell is imperative for achieving good capacity retention and high rate performance of the cell. 相似文献