全文获取类型
收费全文 | 895篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 37篇 |
综合类 | 2篇 |
化学工业 | 194篇 |
金属工艺 | 17篇 |
机械仪表 | 7篇 |
建筑科学 | 10篇 |
能源动力 | 23篇 |
轻工业 | 48篇 |
水利工程 | 3篇 |
石油天然气 | 5篇 |
无线电 | 98篇 |
一般工业技术 | 166篇 |
冶金工业 | 263篇 |
原子能技术 | 13篇 |
自动化技术 | 43篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 21篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 43篇 |
2012年 | 28篇 |
2011年 | 35篇 |
2010年 | 23篇 |
2009年 | 27篇 |
2008年 | 21篇 |
2007年 | 31篇 |
2006年 | 29篇 |
2005年 | 29篇 |
2004年 | 17篇 |
2003年 | 33篇 |
2002年 | 22篇 |
2001年 | 21篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 101篇 |
1997年 | 55篇 |
1996年 | 46篇 |
1995年 | 41篇 |
1994年 | 32篇 |
1993年 | 30篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有929条查询结果,搜索用时 0 毫秒
51.
Tetsuya Nanba Asima Sultana Shouichi Masukawa Masaaki Haneda Junko Uchisawa Akira Obuchi Hideaki Hamada 《Topics in Catalysis》2009,52(13-20):1766-1770
Selective catalytic reduction of NO x by NH3 over Cu–FER and Cu–ZSM-5 in the presence of n-decane and SO2 was investigated. NO x conversion over Cu–ZSM-5 decreased in the presence of n-decane, owing to inhibition of the active sites by coke formation. In contrast, coke formation was negligible over Cu–FER, which maintained its NO x conversion activity even in the presence of decane. Coke formation was negligible over H–ZSM-5 and H–FER supports, which suggests that Cu species were involved in coke formation. Temperature-programmed reduction by H2 and electron spin resonance spectroscopy indicated that [Cu–O–Cu]2+ was probably the Cu species involved in coke formation over Cu–ZSM-5. 相似文献
52.
The impregnation and sol–gel preparation methods were investigated to develop high activity catalysts and understand the significance of the indium–aluminium interaction on aluminasupported indium catalysts in NO
x
reduction with propene. Active In/alumina catalysts with a very high surface area (270 m2/g) and thermal stability were prepared in controlled conditions by sol–gel processing. When Al isopropoxide and In nitrate in ethyl glycol were used as precursors in aqua media, indium atoms were incorporated evenly distributed as a thermally stable form in the aluminium oxide lattice structure. In wet impregnation it was beneficial to use a certain excess of aqueous In solution (volumes of solution : pores = 2 : 1) to have the highest NO
x
reduction activity. The catalyst containing dispersed Al on In oxide (58 wt% In, phaseequilibrium preparation method) showed activity at lower temperatures than any other In–Al oxide catalyst or pure In2O3. The adsorption of different reaction intermediates on alumina and stable In2O3 sites were detected by FTIR studies. In/alumina catalysts have active sites to oxidize NO to NO2, partially oxidize HC, form the actual reductant which contains N–H or N–C bonding and react with NO to dinitrogen. The cooperation with indium and aluminium was evident even in the mechanical mixture of sol–gel prepared alumina (301 m2/g) and In2O3 powders (27 m2/g), where the probability for molecularscale intimate contact between indium and aluminium sites was very low (particle size 10–250 m). Shortlived gaseous intermediates and surface migration are the possible reasons for the high catalytic activities on the two physically separated active sites both necessary for the reaction sequence. 相似文献
53.
Hiroyuki Hamada Hiroyuki Kato Naoto Ito Yoshihiko Takase Hironobu Nanbu Shoko Mishima Hiromu Sakaki Kiyotaka Sato 《European Journal of Lipid Science and Technology》2010,112(12):1323-1330
Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures. 相似文献
54.
Claudia Paredes Francisco J. Martínez-Vázquez Hamada Elsayed Paolo Colombo Antonia Pajares Pedro Miranda 《Journal of the European Ceramic Society》2021,41(1):892-900
Bioactive ceramic scaffolds for bone regeneration consisting of a three-dimensional mesh of interpenetrating struts with square section were fabricated via Digital Light Processing (DLP). The ability of the technique to manufacture 3D porous structures from β-tricalcium phosphate (β-TCP) powders with different dimensions of struts and pores was evaluated, identifying the possibilities and limitations of the manufacturing process. Small pore sizes were found to seriously complicate the elimination of excess slurry from the scaffold’s innermost pores. The effect of the strut/pore size on the mechanical performance of the scaffolds under compressive stresses was also evaluated, but no significant influence was found. Under compressive stresses, the structures resulted weaker when tested perpendicularly to the printing plane due to interlayer shear failure. Interlayer superficial grooves are proposed as potential failure-controlling defects, which could also explain the lack of a Weibull size effect on the mechanical strength of the fabricated DLP scaffolds. 相似文献
55.
We have investigated fluid flow characteristics of film‐wise condensation on vertical plates with horizontal periodic grooves. Condensate stays at the edge of the grooves due to the surface tension. The condensate starts to flow, however, when the balance between the surface tension and the condensate's own weight is broken. It is found that the condensate flows downward successively and periodically from the top part of the plate as a group. In addition, we have obtained the relation between the frequencies of the periodic flow and the degree of sub‐cooling for two different pitches of the grooves. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20249 相似文献
56.
Hiroshi Kamimura Tsuyoshi Hamada Shun-ichi Matsuno Hideki Ushio 《Journal of Superconductivity》2002,15(5):379-385
The present novel approach consists of two stages: in the first stage the many-electron states of a CuO6 octahedron or a CuO5 pyramid are calculated by the first-principles variational method, by taking into account the local distortions of a CuO6 octahedron or a CuO5 pyramid. In the second stage a metallic state is constructed in the presence of the local AF ordering constructed by the localized spins. In this metallic state the local distortions are treated in the mean field approximation, so that a pseudopolaronic effect is taken into account. Based on this approach, the hole-concentration dependence of T
c and the isotope effect are calculated for LSCO, and compared with experimental results. This approach leads to d-wave pairing mechanism. 相似文献
57.
T Nishida TP Huang A Seiyama E Hamada W Kamiike S Ueshima H Kazuo H Matsuda 《Canadian Metallurgical Quarterly》1998,115(2):412-420
BACKGROUND & AIMS: Endothelin 1 is considered to be an important regulator of sinusoidal blood flow and increases during endotoxemia. The purpose of this study was to investigate the role of endothelin 1 in hepatic microcirculation, oxygen transport, and liver injury during endotoxemia. METHODS: Male Sprague-Dawley rats were continuously infused with 2.5 mL/h of saline, 0.8 mg . kg-1 . h-1 of lipopolysaccharide (LPS), 3 mg . kg-1 . h-1 of BQ-485, an endothelin A-receptor antagonist, or LPS plus BQ-485 for 7 hours. RESULTS: BQ-485 infusion had no significant effect on hepatic microcirculation and liver injury. LPS increased the plasma levels of aspartate aminotransferase (AST) and total bilirubin and decreased the hepatic adenosine triphosphate (ATP) level and bile flow rate. LPS + BQ-485 infusion further increased the plasma levels of AST and total bilirubin and decreased the bile flow rate and the hepatic ATP level. Dual-spot microspectroscopy revealed mild decreases in sinusoidal erythrocyte velocity and oxygen transport in the LPS group and profound decreases in these parameters in the LPS + BQ-485 group. Histological examinations revealed massive necrotic changes in the pericentral regions of the LPS + BQ-485 group. CONCLUSIONS: These results suggest that blockade of endothelin A receptors disturbs hepatic microcirculation and oxygen transport and aggravates the necrotic injury induced by endotoxin. 相似文献
58.
K Ueda M Konishi K Maeda K Hamada M Sakamoto E Yoshimoto T Majima K Mikasa E Kita R Sano T Masutani N Narita 《Canadian Metallurgical Quarterly》1998,72(12):1325-1329
A 78-year-old female was admitted with complaints of malaise and fatigue in the legs. The patient was diagnosed as severe aplastic anemia and treatment was started with metenolone and steroid pulse therapy. Administration of antibiotics and granulocyte-colony stimulating factor which led to a resolution of the high fever. About four months after admission, the patient developed vomiting and abdominal pain with a spiking fever. The next day after suddenly losing consciousness, she died. B. cereus was isolated from blood cultures. Autopsy specimens of the liver, cardiac muscle and lung showed changes due to B. cereus. This pathogen is widely distributed in nature. We should not overlook B. cereus as a contamination, but rather should consider it a potential pathogen in immunocompromised hosts, when it is isolated from blood cultures. 相似文献
59.
H Tada N Aihara T Ohe C Yutani S Hamada H Miyanuma M Takamiya S Kamakura 《Canadian Metallurgical Quarterly》1998,81(4):519-522
In all experimental mammals tested (rats, dogs, primates), intramuscular injections of the oil-soluble antimalarial artemisinin derivatives artemether and arteether have produced an unusual pattern of selective damage to brain stem centers predominantly involved in auditory processing and vestibular reflexes. Artesunate, the most widely used of these compounds, is a water soluble hemisuccinate derivative given parenterally either by intravenous or intramuscular injection. The neurotoxic potential of parenteral artesunate and artemether was compared in a murine model. Adult Swiss albino mice were assigned randomly to 28-day regimens of intramuscular artemether or artesunate in doses ranging from 30 to 100 mg/kg/day. At 30 mg/kg/day, no abnormalities were detected with either drug. At 50 mg/kg/day, abnormalities were observed in six of 12 artemether recipients and two of 12 artesunate recipients. These were reversible in all but one (artemether) mouse. At 100 mg/kg/day, eight of 36 artemether recipients, two of 36 artesunate recipients, and one of 18 control mice died. All but four surviving mice in the artemether group (86%) showed obvious and usually irreversible abnormalities of balance and equilibrium, whereas only four artesunate recipients (11%) exhibited abnormalities, and these were reversible in each case (P < 0.001). At this dose the relative risk (95% confidence interval) for death or disability was 5.3 (2.6-11.2) for artemether recipients. Intramuscular artemether is significantly more neurotoxic than intramuscular artesunate in this murine model. 相似文献
60.
H Nakamura T Oda K Hamada T Hirano N Shimizu H Utiyama 《Canadian Metallurgical Quarterly》1998,273(25):15345-15351
During the exposure of human myelocytic leukemia HL-60 cells to phorbol diester, nonadherent cells die by apoptosis, but adherent cells survive and growth-arrest at G1 phase of the cell cycle. Here we have shown that the adherent cells rapidly died by apoptosis after forced detachment (anoikis), indicating that phorbol diester induced apoptosis by default. Dimethylsphingosine induced apoptosis in the adherent cells, and sphingosine-1-phosphate rescued the detached cells from apoptosis. Sphingosine kinase activity in adherent cells was higher than that in nonadherent cells and was decreased by forced detachment. It is likely that the phorbol diester-induced apoptosis and the adhesion-mediated survival are modulated by sphingosine and sphingosine-1-phosphate, respectively. The adherent cells were reverted and reproliferated when allowed to spontaneously detach from plastic surfaces by removal of phorbol diester. This result suggests that after removal of phorbol diester, the commitment signal of apoptosis by default is lost faster than the survival signal by adherence. 相似文献