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91.
Yun-Chul Jung Takeo Sasaki Toru Tomimatsu Katsuyuki Matsunaga Takahisa Yamamoto Yutaka Kagawaba 《Science and Technology of Advanced Materials》2013,14(6):571-574
Distribution and arrangement of nanopores in an YSZ (7 wt% Y2O3–ZrO2)-thermal barrier coating (TBC) deposited by an electron beam-physical vapor deposition (EB-PVD) have been investigated by means of transmission electron microscopy. The YSZ-TBC deposited by the EB-PVD showed a typical columnar structure normal to the bond coat surface on the substrate. It has been generally believed that one column is a single crystal and grows continuously from the substrate. In the present study, however, it was found that each column consisted of a number of subcolumns with different misorientations and contained nanopores at the subcolumn boundaries. In addition to the nanopores at the subcolumn boundaries, nanopores with smaller size were observed within subcolumns, and were arranged periodically perpendicular to the growth direction of the subcolumns. Such arrangement and distribution of nanopores may be due to the misorientation of YSZ plate-like grains in the formation and coalescence processes of the YSZ subcolumns. 相似文献
92.
93.
Matsui J Akamatsu K Hara N Miyoshi D Nawafune H Tamaki K Sugimoto N 《Analytical chemistry》2005,77(13):4282-4285
Molecularly imprinted polymer gel with embedded gold nanoparticle was prepared on a gold substrate of a chip for a surface plasmon resonance (SPR) sensor for fabricating an SPR sensor sensitive to a low molecular weight analyte. The sensing is based on swelling of the imprinted polymer gel that is triggered by an analyte binding event within the polymer gel. The swelling causes greater distance between the gold nanoparticles and substrate, shifting a dip of an SPR curve to a higher SPR angle. The polymer synthesis was conducted by radical polymerization of a mixture of acrylic acid, N-isopropylacrylamide, N,N'-methylenebisacrylamide, and gold nanoparticles in the presence of dopamine as model template species on a sensor chip coated with allyl mercaptan. The modified sensor chip showed an increasing SPR angle in response to dopamine concentration, which agrees with the expected sensing mechanism. Furthermore, the gold nanoparticles were shown to be effective for enhancing the signal intensity (the change of SPR angle) by comparison with a sensor chip immobilizing no gold nanoparticles. The analyte binding process and the consequent swelling appeared to be reversible, allowing one the repeated use of the presented sensor chip. 相似文献
94.
Philip R. Onffroy Evan V. Miu William J. Confer Caleb M. Darkes-Burkey William C. Holler Katsuyuki Wakabayashi 《Polymer Engineering and Science》2020,60(3):503-511
Solid-state shear pulverization (SSSP) is a continuous polymer processing methodology based on a modified twin-screw extruder. The unique application of low barrel temperatures and mechanochemistry has contributed to the development of an extensive range of polymer-based materials, from environmentally responsible polymer blends to nanocomposites, for more than 30 years. The complex processing-structure-processing relationships in SSSP can be elucidated by way of integrated, measured covariants that capture the interplay between numerous processing parameters. Residence time distribution and specific mechanical energy are evaluated in a base case polypropylene (PP) study under a full factorial experiment involving screw design, screw speed, and throughput parameters. These factors are in turn correlated to dispersion morphology and thermal property results from a parallel study based on a model PP/carbon black composite. This investigation highlights the tunability of SSSP processing parameters for tailored output with desired purposes and applications. In particular, enhanced residence distribution can be achieved with low screw speed and high throughput settings, leading to high levels of material mixing and shear. POLYM. ENG. SCI., 60:503–511, 2020. © 2019 Society of Plastics Engineers 相似文献
95.
Takae Nagasawa Katsuyuki Sato Yasuhiro Shimada Takafumi Kasumi 《Journal of Applied Glycoscience》2016,63(2):39
D-Glucose and D-fructose are isomers of commonly consumed monosaccharides. The ratio of conversion of D-glucose to D-fructose by glucose isomerase (xylose isomerase) is not more than 50 %. However, addition of an equimolar ratio of the organogermanium compound poly-trans-[(2-carboxyethyl)germasesquioxane] (Ge-132) or its derivative increases the conversion ratio to 80 %. In contrast, use of the Lobry de Bruyn–Alberda van Ekenstein transformation with heating results in a lower conversion ratio, less than 30 %, whereas addition of an equimolar concentration of Ge-132 or its derivative to this reaction mixture increases the ratio to 73 %. Therefore, in this study, we aimed to further analyze the affinity between organogermanium compounds (i.e., Ge-132 and its derivatives) and sugar using 1H-nuclear magnetic resonance (NMR) spectrometry. For the dimethyl derivative of Ge-132, the complex formation ratios at 0.25 M (mixing ratio 1:1) were 19 and 74 % for D-glucose and D-fructose, respectively. Additionally, the complex formation constants between monosaccharides and Ge-132 were 1.2 and 46 M-1 for D-glucose and D-fructose, respectively. The complex formation capacity was approximately 40-fold higher for D-fructose than for D-glucose. Therefore, we concluded that the high affinity for the product of isomerization may promote isomerization, and that promotion of sugar isomerization using organogermanium compounds is an effective method for conversion of D-glucose to D-fructose. 相似文献
96.
Yoshio Iwai Shinji Miyamoto Katsuyuki Nakano Yasuhiko Arai 《Polymer Engineering and Science》1990,30(8):480-484
The mutual diffusion coefficients for styrene-butadiene rubber (SBR)-ethylbenzene systems were measured using a sorption apparatus with a quartz spring at 100 and 130°C for mass fractions of ethylbenzene ranging from 0 to 0.17. The mutual diffusion coefficients were correlated with good agreement by the free-volume theory. 相似文献
97.
Takeo Sasaki Katsuyuki Matsunaga Hiromichi Ohta Hideo Hosono Takahisa Yamamoto Yuichi Ikuhara 《Science and Technology of Advanced Materials》2003,4(6):4206-584
Interfacial atomic structures of Cu/Al2O3(0001) and Cu/Al2O3(11
0) systems prepared by a pulsed-laser deposition technique have been characterized by using high-resolution transmission electron microscopy (HRTEM). It was found that Cu metals were epitaxially oriented to the surface of Al2O3 substrates, and the following orientation relationships (ORs) were found to be formed: (111)Cu//(0001)Al2O3,
Cu//[1
00]Al2O3 in the Cu/Al2O3(0001) interface and (001)Cu//(11
0)Al2O3, [1
0]Cu//[0001]Al2O3 in the Cu/Al2O3(11
0) interface. Geometrical coherency of the Cu/Al2O3 system has been evaluated by the coincidence of reciprocal lattice points method, and the result showed that the most coherent ORs were (111)Cu//(0001)Al2O3, [11
]Cu//[1
00]Al2O3 and (1
0)Cu//(11
0)Al2O3, [111]Cu//[0001]Al2O3, which are equivalent to each other. These ORs were not consistent with the experimentally observed ORs, and it was possible that crucial factors to determine the ORs between Cu and Al2O3 were not only geometrical coherency, but also other factors such as chemical bonding states. Therefore, to understand the nature of the interface atomic structures, the electronic structures of the Cu/Al2O3 interfaces have been investigated by electron energy-loss spectroscopy. It was found that the pre-edge at the lower energy part of the main peak appeared in the O-K edge spectra at the interface region in both the Cu/Al2O3(0001) and Cu/Al2O3(11
0) systems. This indicates the existence of Cu–O interactions at the interface. In fact, HRTEM simulation images based on O-terminated interface models agreed well with the experimental images, indicating that O-terminated interfaces were formed in both systems. Since the overlapped Cu atomic density in the experimental ORs were larger than that in the most coherent OR, it is considered that the on-top Cu–O bonds stabilize the O-terminated Cu/Al2O3 interfaces. 相似文献
98.
Heterogeneous nucleation and crystallization data for polyethylene at a gold interface are reported. Isothermal crystallization is investigated by dilatometry. Avrami plots of the crystallization data suggest that the gold surface acts as a suitable nucleating agent resulting in heterogeneous nucleation and two-dimensional crystal growth at the polyethylene melt–gold interface. The deviation of measurements from Avrami's equation suggests the presence of intercrystalline links during the final growth stages of isothermal crystallization. A closely packed lamellar model is given for heterogeneous nucleation and two-dimensional crystallization which results in high density and rod-like crystals. 相似文献
99.
Hidero Unuma Katsuyuki Kawamura Naoya Sawaguchi Hideki Maekawa Toshio Yokokawa 《Journal of the American Ceramic Society》1993,76(5):1308-1312
The structure and properties of Na-Si-O-N oxynitride glasses have been studied by molecular dynamics calculations using a pair potential of the Busing approximation of the Born-Mayer-Huggins type. Nitrogen atoms bonded to one, two, and three silicon atoms coexist in the glass structure. The mean of the number of silicon atoms bonded to a nitrogen atom ranges from 2.4 to 2.1, decreasing with increasing Na2 O content from 15 to 30 mol%. It has been assumed that nitrogen atoms bonded to two or fewer silicon atoms are formed when nitrogen atoms substitute for non-bridging atoms. The bond angle ∠Si-N-Si exhibits a bimodal distribution around 105–135° and 140–170°, roughly corresponding to the nitrogen atoms bonded to three and two silicon atoms, respectively. The dependences of the density, the bulk thermal expansion, and the bulk modulus on the nitrogen content are consistent with those observed in real systems. 相似文献
100.
Side channel attacks are a very serious menace to embedded devices with cryptographic applications. To counteract such attacks many randomization techniques have been proposed. One efficient technique in elliptic curve cryptosystems randomizes addition chains with binary signed digit (BSD) representations of the secret key. However, when such countermeasures have been used alone, most of them have been broken by various simple power analysis attacks. In this paper, we consider combinations which can enhance the security of countermeasures using BSD representations by adding additional countermeasures. First, we propose several ways the improved countermeasures based on BSD representations can be attacked. In an actual statistical power analysis attack, the number of samples plays an important role. Therefore, we estimate the number of samples needed in the proposed attack. 相似文献