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排序方式: 共有152条查询结果,搜索用时 31 毫秒
51.
Yusaku Takita Kimiaki Inokuchi Osamu Kobayashi Fumiaki Hori Noboru Yamazoe Tetsuro Seiyama 《Journal of Catalysis》1984,90(2):232-240
The gas-phase oxidation of methyl ethyl ketone was studied on metal oxide catalysts in the presence of water vapor. Two types of competitive partial oxidations, i.e., biacetyl formation and oxidative scission reaction leading to acetaldehyde and acetic acid, took place on every oxide studied at 400–500 K. An approximate linear relationship was observed between the selectivity of each reaction and the acid-base property of the oxides; the former reaction was accelerated on the basic oxides such as Co3O4, while the latter reaction became predominant on the acidic oxides. As Co3O4 was the most effective biacetyl former of single-component oxides, modification of Co3O4 was examined to develop more effective catalysts for biacetyl synthesis. Scission reaction took the place of biacetyl formation over a catalyst where Co2+ ions were located in Y zeolite by an ion-exchanged method. Scission reaction was suppressed when Co oxide was supported on basic oxides such as MgO or CaO; however, the selectivity to biacetyl was slightly decreased due to the occurrence of a new reaction, acetone formation. The addition of Na2O or Li2O to Co3O4 was found to improve the selectivity to biacetyl without loss of catalytic activity. The maximum efficiency (13%) in biacetyl formation was attained at a Li content of ca. 7 at.%. 相似文献
52.
Fumiaki Miyaji Shinya Hasegawa Toshinobu Yoko Sumio Sakka 《Journal of the American Ceramic Society》1993,76(2):545-546
The mixed alkali effect on electrical conductivity, that is, the reduction of conductivity due to alkali mixing, was observed in Na2 O–K2 O–Ga2 O3 –TiO2 glasses, which are nonconventional in the sense that glass-forming oxides defined by Zachariasen are not involved. The magnitude of the reduction in conductivity of the present glasses due to alkali mixing was similar to that of corresponding mixed alkali silicate and phosphate glasses. The activation energy for electrical conduction showed a maximum around the composition Na/(Na + K) = 0.5, where the conductivity was at a minimum. 相似文献
53.
Synthesis of Ti3SiC2 polycrystals by hot-isostatic pressing of the elemental powders 总被引:4,自引:0,他引:4
Jing-Feng Li Fumiaki Sato Ryuzo Watanabe 《Journal of Materials Science Letters》1999,18(19):1595-1597
54.
Takeuchi F Negishi A Nakamura S Kanao T Kamimura K Sugio T 《Journal of Bioscience and Bioengineering》2005,99(6):586-591
Acidithiobacillus ferrooxidans MON-1 which is highly resistant to Hg2+ could grow in a ferrous sulfate medium (pH 2.5) with 0.1 microM p-chloromercuribenzoic acid (PCMB) with a lag time of 2 d. In contrast, A. ferrooxidans AP19-3 which is sensitive to Hg2+ did not grow in the medium. Nine strains of A. ferrooxidans, including seven strains of the American Type Culture Collection grew in the medium with a lag time ranging from 5 to 12 d. The resting cells of MON-1, which has NADPH-dependent mercuric reductase activity, could volatilize Hg0 when incubated in acidic water (pH 3.0) containing 0.1 microM PCMB. However, the resting cells of AP19-3, which has a similar level of NADPH-dependent mercuric reductase activity compared with MON-1, did not volatilize Hg0 from the reaction mixture with 0.1 microM PCMB. The activity level of the 11 strains of A. ferrooxidans to volatilize Hg0 from PCMB corresponded well with the level of growth inhibition by PCMB observed in the growth experiments. The resting cells of MON-1 volatilized Hg0 from phenylmercury acetate (PMA) and methylmercury chloride (MMC) as well as PCMB. The cytosol prepared from MON-1 could volatilize Hg0 from PCMB (0.015 nmol mg(-1) h(-1)), PMA (0.33 nmol mg(-1) h(-1)) and MMC (0.005 nmol mg(-1) h(-1)) in the presence of NADPH and beta-mercaptoethanol. 相似文献
55.
Guichen Ma ;Kazuhide Sawada ;Atsushi Yashima ;Fumiaki Uehan ;Osamu Murata ;Hideki Saito ;Yasunori Ootsuka 《土木工程与建筑:英文版》2014,(5):624-632
This paper examines a new method of evaluating the stability of a rock slope using a remotely positioned LDV (laser Doppler vibrometer). We conducted an experiment using physical models and performed a numerical analysis to evaluate the new method. The physical model included: (l) concrete blocks on an artificial soil slope with two block sizes and three slopes; (2) concrete blocks bonded to the concrete base with different contact area. The LDV measurements agreed with conventional seismometer measurements. The dominant frequency of the blocks varied with the stability and dominant frequency and the amplitude varied with the block size. The numerical model was used to examine a concrete block adhered to a concrete base with different contact areas. The dominant frequency of the blocks determined using the numerical model agreed with those obtained from the physical experiments. We analyzed different sized blocks to examine the scaling effects. The dominant frequency of the blocks was inversely related to the block size. These results demonstrated the effectiveness of LDV for evaluating the stability of rock slopes and cleared the block size scaling effects. 相似文献
56.
Yukiya Yamada Shuichi Wakayama Junji Ikeda Fumiaki Miyaji 《Journal of Materials Science》2011,46(18):6131-6139
Damage accumulation during compression testing of the alumina femoral head used in hip arthroplasty was monitored using an
acoustic emission (AE) technique. Because a number of mechanical noises due to friction disturbed the AE measurement during
the test using a conventional testing configuration standardized in ISO 7206, the testing apparatus was modified so that AE
signals from microdamage were detected successfully. During the compression tests of femoral heads, a rapid increase in AE
energy was observed before the final fracture. Dye penetration observations demonstrated that the rapid increase in AE energy
correlated with the formation of maincrack which leads to the final fracture. The stress distribution in femoral heads was
analyzed using finite element analysis (FEA). The critical stress for maincrack formation and the final fracture strength
were determined. Finally, fundamental insights into the development of a technique for assessing the long-term reliability
of ceramic femoral heads were obtained. 相似文献
57.
Miyashita K Nishikawa S Beppu F Tsukui T Abe M Hosokawa M 《Journal of the science of food and agriculture》2011,91(7):1166-1174
Obesity and type 2 diabetes are pathologies with rapidly growing prevalence throughout the world. A few molecular targets offer the most hope for anti-obesity and anti-diabetic therapeutics. One of the keys to success will be the induction of uncoupling protein 1 (UCP1) in abdominal white adipose tissue (WAT) and the regulation of cytokine secretions from both abdominal adipose cells and macrophage cells infiltrated into adipose tissue. Anti-obesity and anti-diabetic effects of fucoxanthin, a characteristic carotenoid found in brown seaweeds, have been reported. Nutrigenomic studies reveal that fucoxanthin induces UCP1 in abdominal WAT mitochondria, leading to the oxidation of fatty acids and heat production in WAT. Fucoxanthin improves insulin resistance and decreases blood glucose levels through the regulation of cytokine secretions from WAT. The key structure of carotenoids for the expression of anti-obesity effect is suggested to be the carotenoid end of the polyene chromophore, which contains an allenic bond and two hydroxyl groups. 相似文献
58.
Hyun-Min Kim Fumiaki Miyaji Tadashi Kokubo Chikara Ohtsuki Takashi Nakamura 《Journal of the American Ceramic Society》1995,78(9):2405-2411
Bioactivities of Na2 O-CaO-SiO2 glasses were evaluated by examining the formation of bonelike apatite, which is responsible for their bonding to living bone, on their surfaces in a simulated body fluid, using thin-film X-ray diffraction and Fourier-transform infrared reflection spectroscopy. It was found that glasses in a wide compositional region in the P2 O5 -free Na2 O-CaO-SiO2 system can show bioactivity, as those in the P2 O5 -containing system. The rate of apatite formation on the surfaces of glasses varied largely with the composition of the glasses. Under a constant SiO2 content of 50 mol%, a glass containing equimole of Na2 O and CaO showed the highest rate of the apatite formation. Variation in the rate of apatite formation with the glass composition corresponded well with the rate of increase in the degree of the supersaturation of the simulated body fluid with respect to the apatite due to dissolution of sodium and calcium ions from the glasses. Little difference was observed in the rates of ion dissolution and of apatite formation between P2 O5 -containing Bioglass 45S5-type and a corresponding P2 O5 -free Na2 O-CaO-SiO2 glass. It is believed that P2 Os -free Na2 O-CaO-SiO2 glasses also show bioactivity as high as that of Bioglass. 相似文献
59.
McArdle John J.; Ferrer-Caja Emilio; Hamagami Fumiaki; Woodcock Richard W. 《Canadian Metallurgical Quarterly》2002,38(1):115
Latent growth curve techniques and longitudinal data are used to examine predictions from the theory of fluid and crystallized intelligence (Gf-Gc theory; J. L. Horn & R. B. Cattell, 1966, 1967). The data examined are from a sample (N?–?1,200) measured on the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R). The longitudinal structural equation models used are based on latent growth models of age using two-occasion "accelerated" data (e.g., J. J. McArdle & R. Q. Bell, 2000; J. J. McArdle & R. W. Woodcock, 1997). Nonlinear mixed-effects growth models based on a dual exponential rate yield a reasonable fit to all life span cognitive data. These results suggest that most broad cognitive functions fit a generalized curve that rises and falls. Novel multilevel models directly comparing growth curves show that broad fluid reasoning (Gf) and acculturated crystallized knowledge (Gc) have different growth patterns. In all comparisons, any model of cognitive age changes with only a single g factor yields an overly simplistic view of growth and change over age. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
Transparent active matrix organic light-emitting diode displays driven by nanowire transistor circuitry 总被引:1,自引:0,他引:1
Ju S Li J Liu J Chen PC Ha YG Ishikawa F Chang H Zhou C Facchetti A Janes DB Marks TJ 《Nano letters》2008,8(4):997-1004
Optically transparent, mechanically flexible displays are attractive for next-generation visual technologies and portable electronics. In principle, organic light-emitting diodes (OLEDs) satisfy key requirements for this application-transparency, lightweight, flexibility, and low-temperature fabrication. However, to realize transparent, flexible active-matrix OLED (AMOLED) displays requires suitable thin-film transistor (TFT) drive electronics. Nanowire transistors (NWTs) are ideal candidates for this role due to their outstanding electrical characteristics, potential for compact size, fast switching, low-temperature fabrication, and transparency. Here we report the first demonstration of AMOLED displays driven exclusively by NW electronics and show that such displays can be optically transparent. The displays use pixel dimensions suitable for hand-held applications, exhibit 300 cd/m2 brightness, and are fabricated at temperatures suitable for integration on plastic substrates. 相似文献