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61.
Atsushi Iizuka Takeshi Sasaki Masato Honma Hiroyuki Yoshida Yasuyuki Hayakawa Yukio Yanagisawa 《Chemical Engineering Communications》2017,204(1):79-85
A pilot-scale plant to treat concrete sludge and produce calcium carbonate (CaCO3) and an environmental purification agent (phosphorus adsorbent derived from concrete sludge, PAdeCS®) was designed, constructed, and operated. Concrete sludge from a concrete pile and pole production plant, boiler gas containing CO2, and groundwater were used in the plant. The process involved calcium extraction from concrete sludge into water, followed by reaction of the calcium with CO2 to produce crystalline CaCO3. The pilot-scale plant was operated for 1 week, and the mass flows, conversion of CO2 to CaCO3, and net CO2 emissions of the process were estimated. High-purity CaCO3 (>97%) suitable for industrial use was obtained. Based on the power consumption of the process and the amount of CO2 sequestered into CaCO3, a net reduction in CO2 emissions can be achieved using this process. The produced PAdeCS can be used as an inexpensive substitute for calcium series environmental purification agents. 相似文献
62.
H Toyoda Y Fukuda Y Koyama J Takamatsu H Saito T Hayakawa 《Canadian Metallurgical Quarterly》1997,26(5):975-982
BACKGROUND/AIMS: To study the effects of the immunosuppression caused by the reduction of CD4 activity on the composition of hepatitis C virus (HCV) populations, we analyzed the number of HCV quasispecies clones and the nucleotide diversity of the hypervariable region 1 (HVR1) of HCV in 37 patients with hemophilia with persistent HCV infection, with or without human immunodeficiency virus (HIV). METHODS: The numbers of HCV quasispecies clones were measured by fluorescence single-strand conformation polymorphism analysis. Direct sequencing was used to analyze the degree of diversity of HVR1. We compared these values according to coinfection with HIV, and CD4 counts of patients. RESULTS: There were no differences in either the number of HCV clones or the diversity between patients with and without HIV coinfection. In HIV coinfected patients the diversity decreased in association with the decrease in CD4 count while the number of HCV clones did not. The diversity of HVR1 was 3.64 +/- 5.03% in patients with a CD4 count < 50/microliters and 14.92 +/- 6.03% in patients with a CD4 count > or = 50/microliters; it was significantly lower in the former (p = 0.0002). CONCLUSIONS: A severe reduction in the CD4 count, which is considered to cause a decline in the activity of helper T-lymphocytes, induced changes in the composition of HCV populations; one or a few quasispecies clones are predominant in the HCV population in the serum of individual patients. 相似文献
63.
64.
Yasuo Cho Teruaki Kasahara Koichi Fukuda 《Journal of the American Ceramic Society》1999,82(7):1720-1724
Two-dimensional images of the distribution showing the temperature coefficient of the dielectric constant for two types of two-phase composite ceramics composed of TiO2 -Bi2 Ti4 O11 and BaTi4 O9 -BaPr2 Ti4 O12 were obtained using scanning photothermal dielectric microscopy. The images of the TiO2 -Bi2 Ti4 O11 ceramic showed that the TiO2 and Bi2 Ti4 O11 grains had negative and positive temperature coefficients, respectively, and that the macroscopic averaged temperature coefficient of the ceramic was relatively low because of the cancellation of the opposite signs of the coefficients. On the other hand, the images of the BaTi4 O9 -BaPr2 Ti4 O12 ceramic showed that the temperature coefficient of both grains had the same sign (negative), although their absolute values were quite different. 相似文献
65.
Lithium-doped sulfated-zirconia catalysts for oxidative coupling of methane to give ethylene and ethane 总被引:1,自引:0,他引:1
Li-doped sulfated-zirconia catalysts were found to be effective for oxidative coupling of methane (OCM). The catalyst performances depend on the sulfate content and calcination temperature. A maximum C2 yield is attained over the catalysts, which contain 6 wt.% sulfate and calcined at 923–973 K, being closely related to the preparation conditions of sulfated-ZrO2 as solid super-acids. When the performances of the Li-doped sulfated-ZrO2 (Li/SZ) catalysts were tested at 1023 K as a function of reaction time, both the C2 and COx selectivities remained constant over the range of 8 h, but the CH4 conversion decreased from 17.5% to 11.9%. The nature of Li/SZ catalysts for the OCM was investigated by X-ray diffraction, XPS, and NH3 and CO2 TPD measurements. It could be postulated that the sulfated-ZrO2 surface could play an important role in the formation of a catalytically active structure by Li-doping. 相似文献
66.
Methanol decomposition to synthesis gas over supported Pd catalysts prepared from synthetic anionic clays 总被引:2,自引:0,他引:2
Ryuji Shiozaki Takashi Hayakawa Yan-yong Liu Tomoko Ishii Mikio Kumagai Satoshi Hamakawa Kunio Suzuki Tatehiko Itoh Tetsuya Shishido Katsuomi Takehira 《Catalysis Letters》1999,58(2-3):131-140
Supported Pd or Rh catalysts were prepared by the solid-phase crystallization method starting from hydrotalcite anionic clay minerals based on [Mg6Al2(OH)16CO 2 2− ]·4H2O as the precursors. The precursors were prepared by a coprecipitation method from the raw materials containing Pd2+ and various trivalent metal ions which can replace each site of Mg2+ and Al3+ in the hydrotalcite. Rh3+ was also used for preparing the catalyst as comparison. The precursors were then thermally decomposed and reduced to form supported Pd or Rh catalysts and used for the methanol decomposition to synthesis gas. Among the precursors tested, use of Mg–Cr hydrotalcite containing Pd2+ resulted in the formation of efficient Pd supported catalysts for the production of synthesis gas by selective decomposition of methanol at low temperature. Although Pd2+ cannot well replace the Mg2+ site in the hydrotalcite, the Pd supported catalyst (Pd/Mg–Cr) prepared by the solid-phase crystallization method formed highly dispersed Pd metal particles and showed much higher activity than that prepared by the conventional impregnation method. When the precursor was prepared under mild conditions, more fine particles of Pd metal were formed over the catalyst, resulting in high activity. It is likely that the high activity may be due to the highly dispersed and stable Pd metal particles assisted by the role of Cr as the co-catalyst. This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
67.
Shaobin Wang K Murata T Hayakawa S Hamakawa K Suzuki 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2001,76(3):265-272
The oxidative dehydrogenations of ethane and propane were investigated over a series of zirconia and nickel‐oxide supported on zirconia catalysts. It was found that zirconia, sulfated zirconia as well as NiO‐based zirconia catalysts showed high catalytic activities for oxidative dehydrogenation of ethane and propane. However, conversion and selectivity differed depending on the nature of the catalysts. Zirconia, sulfated zirconia (SZ) and their supported NiO catalysts showed high ethane conversions but lesser selectivities to olefins while NiO/Li2ZrO3 exhibited high selectivities to ethylene and propylene. Addition of an LiCl promoter in the NiO/SZ catalyst increased the catalytic activity and olefin selectivity, thus resulting in a higher olefin yield. In the oxidative dehydrogenations of ethane and propane NiO–LiCl/SZ exhibited 79% ethylene selectivity at 93% ethane conversion at 650 °C and 52% selectivity to propylene at 20% propane conversion at 600 °C, respectively. Characterization showed that the physico‐chemical properties of the catalysts determine the catalytic activity and selectivity. © 2001 Society of Chemical Industry 相似文献
68.
The catalytic activity in the polymerization of styrene has been examined using commercially available simple rare earth metal compounds such as Sm(OiPr)3, Sm(acac)3, Sm(OCOMe)3, SmI2(THF)2 or SmCl3 coupled with Et3Al or methylaluminoxane (MAO). Among these compounds, the Sm(OiPr)3/AlEt3 system shows the highest catalytic activity, especially in the presence of a minor amount of toluene at 60 °C. The random copolymerization of styrene with methyl methacrylate suggests that the present polymerization proceeds with a radical polymerization mechanism. (C5Me5)SmCl3Na(THF) and (C5Me5)SmCl3Li(THF) systems exhibit relatively low catalytic activity, even in the presence of AlEt3. © 2001 Society of Chemical Industry 相似文献
69.
H Sao K Kitaori M Kasai T Shimokawa H Kato M Hayakawa C Kato T Yamaguchi Y Kamiya M Yanada Y Morishima 《Canadian Metallurgical Quarterly》1998,39(7):473-480
In this study, we examined the ability of tumour necrosis factor-alpha (TNF) to stimulate the mitogen-activated protein (MAP) kinase homologues p42/44 MAP kinase, c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase and its effect upon DNA synthesis in primary cultures of bovine aortic endothelial cells (BAECs). TNF strongly stimulated p38 MAP kinase and JNK activity in both a time- and concentration-dependent manner. By contrast, TNF was a very poor activator of p42/44 MAP kinase relative to the known activator of p42/44 MAP kinase in endothelial cells, adenosine triphosphate (ATP). TNF-stimulated activation of p38 MAP kinase, and MAPKAP kinase-2, a known downstream target of p38 MAP kinase, was strongly inhibited by pre-incubation with the p38 MAP kinase inhibitor SB203580, whereas the minor activation of p42/44 MAP kinase was abolished by pre-incubation of the cell with the novel MAP kinase kinase 1 inhibitor PD098059. Addition of TNF resulted in a 50-60% decrease in DNA synthesis in BAECs. Pre-incubation with PD098059 or co-incubation with ATP failed to modify the inhibitory effect of TNF upon DNA synthesis. SB203580 reduced basal DNA synthesis by approximately 50%; however, if failed to modify the inhibition mediated by TNF. These results indicate that TNF strongly activates both p38 MAP kinase, JNK and, to a minor extent, p42/p44 MAP kinase. It is likely that only one of these kinases, JNK, plays a role in the regulation of DNA synthesis in these cells. 相似文献
70.
S. V. Koshevaya M. Tecpoyotl-T E. A. Gutiérrez-D M. Hayakawa V. V. Grimalsky 《Journal of Infrared, Millimeter and Terahertz Waves》1999,20(11):1925-1932
Theoretical and experimental analysis has been performed for surface oriented silicon plasma-based p,i,n structures used to control high power level, broadband devices. It is shown that these structures are very promising for their use as modulators in the millimeter and submillimeter wave range. 相似文献