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81.
82.
Toshitaka Idehara Kosuke Kosuga La Agusu Ryosuke Ikeda Isamu Ogawa Teruo Saito Yoh Matsuki Keisuke Ueda Toshimichi Fujiwara 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(7):775-790
A high frequency gyrotron with a 15 T superconducting magnet named Gyrotron FU CW VI has achieved continuous frequency tuning through the relatively wide range of 1.5 GHz near 400 GHz. The operation is at the fundamental cyclotron resonance of the TE06 cavity mode with many higher order axial modes. The output power measured at the end of the circular waveguide system ranges from 10 to 50 watts at the low acceleration voltage of 12 kV for beam electrons. The beam current is also low. It is around 250 mA. This gyrotron is designed as a demountable radiation source for the 600 MHz DNP-NMR spectroscopy. The design and operation results of the gyrotron FU CW VI are presented. 相似文献
83.
Muneyasu Suzuki Yasuyuki Kusaka Tetsuo Tsuchiya Hirobumi Ushijima Jun Akedo 《Journal of the American Ceramic Society》2020,103(6):3479-3492
Recently, the demand for flexible or stretchable Internet-of-things devices has increased with the rise in popularity of wearables. Also, research is progressing for the development of oxide-based all-solid-state lithium-ion batteries, which are expected to have improved safety and performance compared with current batteries. Room-temperature processes for the production of oxide films would facilitate the development of such novel devices. Press forming is a simple room-temperature process; however, conventional press forming cannot produce highly dense green compacts. Here, we developed a new press forming-based, room-temperature process, the mega-press forming (MF) method, that produces highly dense aggregate oxide films at a pressure below 1 GPa, which is lower than that at which oxide particles fracture, by taking advantage of the differences in cohesive force between microsized and nanosized particles. We used our novel process to produce highly dense lead zirconate titanate aggregate films on aluminum foil at room temperature, and found that when impregnated with silicone oil, these films exhibited low leakage current density and saturated polarization hysteresis properties. Furthermore, we were able to produce films with a porosity of only 6%, which is much lower than that of films produced by conventional press forming (20%). Thus, the MF method will be useful for the development of novel functional composite ceramics that are difficult to fabricate using high-temperature processes. 相似文献
84.
Yosuke Nishitani Kohei Ohashi Isamu Sekiguchi Chiharu Ishii Takeshi Kitano 《Polymer Composites》2010,31(1):68-76
To develop new tribomaterials for mechanical sliding parts, investigations were carried out on the influence of adding styrene–ethylene/butylene–styrene block copolymer (SEBS) on the rheological, mechanical, and tribological properties of polyamide 6 (PA6) nanocomposite, which is a commercial product of layered silicate (clay) filled polyamide 6 (PA6/Clay). Two kinds of block copolymers, unmodified SEBS (SEBS) and maleic anhydride‐grafted SEBS (SEBS‐g‐MA), were added with PA6/Clay nanocomposite. Dynamic viscoelastic properties in the molten state of these nanocomposites and their tensile, impact, and tribological properties of these nanocomposites were evaluated. Dynamic viscoelastic properties were found to increase with the addition of SEBS and were influenced, in particular, by block copolymers containing SEBS‐g‐MA. Influence of the addition of SEBS on mechanical properties of these systems differed for each mechanical property. Although tensile properties decreased with SEBS, Izod impact properties were improved with the addition of SEBS‐g‐MA. Tribological properties were improved with the addition of block copolymer, and the influence of the amount of addition was higher than the type of block copolymer used. These results indicate that new tribomaterials developed have sufficient balance amongst moldability, mechanical, and tribological properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers 相似文献
85.
86.
We performed a series of molecular dynamics (MD) simulations on Nafion® membranes containing various quantities of H2O and CH3OH. The simulations afforded diverse nanoscale phase-separated structures, such as clusters, channels, and cluster–channels. The calculated cluster–channel structure qualitatively agrees with the experimental results of X-ray diffraction studies. We also investigated the diffusion mechanisms for H2O, protons, CH3OH, H2, and O2 in these membranes. To reproduce the hopping transfer of protons, we employed a semi-classical MD approach using the empirical valence bond method. The estimated diffusion coefficients of H2O and proton in the membranes significantly depended on the H2O content, and these values showed qualitatively good agreement with the experimental results. The diffusion coefficient of proton in H2O-rich membranes was much larger than that of H2O, and the proton mainly formed H5O2+ complex. Furthermore, the simulation results indicate that the majority of CH3OH permeates through the H2O clusters, and the majority of H2 and O2 permeates through the hydrophobic region of the membrane. 相似文献
87.
Fatty acid α-hydroxylase, a cytochrome P450 enzyme, from Sphingomonas paucimobilis, utilizes various straight-chain fatty acids as substrates. We investigated whether a recombinant fatty acid α-hydroxylase is able to metabolize phytanic acid, a methyl-branched fatty acid. When phytanic acid was incubated with the recombinant enzyme in the presence of H2O2, a reaction product was detected by gas chromatography, whereas a reaction product was not detected in the absence of H2O2. When a heat-inactivated enzyme was used, a reaction product was not detected with any concentration of H2O2. Analysis of the methylated product by gas chromatography-mass spectrometry revealed a fragmentation pattern of 2-hydroxyphytanic acid methyl ester. By single-ion monitoring, the mass ion and the characteristic fragmentation ions of 2-hydroxyphytanic acid methyl ester were detected at the retention time corresponding to the time of the product observed on the gas chromatogram. The K m value for phytanic acid was approximately 50 μM, which was similar to that for myristic acid, although the calculated V max for phytanic acid was about 15-fold lower than that for myristic acid. These results indicate that a bacterial cytochrome P450 is able to oxidize phytanic acid to form 2-hydroxyphytanic acid. 相似文献
88.
The nuisance species Limnoperna fortunei is a freshwater mussel whose infestations have harmed water intake facilities, such as water supply systems. We investigated the changes in the drift and the settlement of L. fortunei along a headrace channel. The densities of the drift and the settlement both decreased dramatically with the downstream distance from the L. fortunei source (a reservoir). In comparison with larval densities in the reservoir, drift densities decreased by 10 to 25% at 0.5 km downstream from the reservoir, and were less than 2% at sites more than 4.8 km downstream. Although larval densities at midnight (0:00-2:00) were approximately 1.5 times higher than those at noon (12:00-14:00) in a shallow layer (3 m depth) of the reservoir, we found no diurnal variation of drift densities in the headrace channel. Settlement densities at the site nearest the intake gate were much higher than those of the other sites further downstream in the headrace channel. The L. fortunei adult population in the channel could reduce drift individuals by attracting the larva. The attraction probably induces the massive aggregation at the location of the channel immediately below the drift source, resulting in biofouling. 相似文献
89.
Saburo Akiyama Nikako Tsukiji Isamu Akiba Minoru Inoue Yoshihisa Kano 《Polymer International》2001,50(6):659-662
The relationship between the surface composition and the rate of solvent evaporation (R) in blend films of poly(vinylidene fluoride‐co‐hexafluoroacetone) (P(VDF‐HFA)) and poly(2‐ethylhexyl acrylate‐co‐acrylic acid‐co‐vinyl acetate) (P(2EHA‐AA‐VAc)) has been investigated. P(VDF‐HFA), a low‐surface tension component, was concentrated on the surface when R was relatively high. In contrast, when R was relatively low, P(2EHA‐AA‐VAc), a low‐density component, was concentrated on the surface. Therefore, it is speculated that the factors dominating surface enrichment in polymer blends were changed from surface tension differences to density differences between the components when R was decreased. In addition, the affinity between components and substrate strongly affects the dominant factors determining the surface composition. © 2001 Society of Chemical Industry 相似文献
90.
Ouji Y Yoshida-Terakura A Hayashi Y Maeda I Kawase M Yamato E Miyazaki J Yagi K 《Journal of Bioscience and Bioengineering》2002,94(1):81-83
In search of an efficient nonviral vector, polyethyleneimine (PEI)-based vectors were examined. In general, the transfection efficiency of nonviral vectors is suppressed by serum. Here we show that PEI based vectors, particularly, the chitosan hexamer-PEI vector, could perform efficient gene transfection into intestinal epithelial cells (IEC-6) in the presence of serum. The conjugation order of the two polymers with a plasmid (first, chitosan hexamer; second, PEI) was found to be an important factor in enhancing transfection efficiency. 相似文献