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991.
Ruiko Ogata Shiori Mori Shingo Kishi Rika Sasaki Naoya Iwata Hitoshi Ohmori Takamitsu Sasaki Yukiko Nishiguchi Chie Nakashima Kei Goto Isao Kawahara Rina Fujiwara-Tani Hiroki Kuniyasu 《International journal of molecular sciences》2022,23(1)
Cancer dormancy is a state characterized by the quiescence of disseminated cancer cells, and tumor recurrence occurs when such cells re-proliferate after a long incubation period. These cancer cells tend to be treatment resistant and one of the barriers to successful therapeutic intervention. We have previously reported that long-term treatment of cancer cells with linoleic acid (LA) induces a dormancy-like phenotype. However, the mechanism underpinning this effect has not yet been clarified. Here, we investigate the mechanism of LA-induced quiescence in cancer cells. We first confirmed that long-term treatment of the mouse colorectal cancer cell line CT26 with LA induced quiescence. When these cells were inoculated subcutaneously into a syngeneic mouse and fed with an LA diet, the inoculated cancer cells maintained the quiescent state and exhibited markers of dormancy. LA-treated CT26 cells showed reduced oxidative phosphorylation, glycolysis, and energy production as well as reduced expression of the regulatory factors Pgc1α and MycC. MicroRNA expression profiling revealed that LA induced an upregulation in miR-494. The expression of Pgc1α and MycC were both induced by an miR-494 mimic, and the LA-induced decrease in gene expression was abrogated by an miR-494 inhibitor. The expression of miR-494 was enhanced by the mitochondrial oxidative stress produced by LA. In a syngeneic mouse subcutaneous tumor model, growth suppression by an LA diet and growth delay by LA pretreatment + LA diet were found to have similar effects as administration of an miR-494 mimic. In contrast, the effects of LA were abrogated by an miR-494 inhibitor. Analysis of human colorectal cancer tissue revealed that miR-494 was present at low levels in non-metastatic cases and cases with simultaneous liver metastases but was expressed at high levels in cases with delayed liver metastases, which also exhibited reduced expression of PGC1α and MYCC. These results suggest that miR-494 is involved in cancer dormancy induced by high levels of LA intake and that this microRNA may be valuable in targeting dormant cancer cells. 相似文献
992.
993.
Hiroki Kitamura Toshihiro Omori Takuji Ishikawa 《Journal of the Royal Society Interface》2021,18(183)
Bacterial biofilms, which can be found wherever there is water and a substrate, can cause chronic infections and clogging of industrial flow systems. Despite intensive investigation of the dynamics and rheological properties of biofilms, the impact of their rheological properties on streamer growth remains unknown. We numerically simulated biofilm growth in a pillar-flow and investigated the effects of rheological properties of a filamentous flow-shaped biofilm, called a ‘streamer’, on its formation by varying the viscoelasticity. The flow-field is assumed to be a Stokes flow and is solved by a boundary element method. A Maxwell model is used for extracellular matrix-mediated streamer growth to express the fluidity of streamer formations. Both high elastic modulus and viscosity are needed for streamer formation, and high viscosity promotes streamer growth at low cell concentrations. Our findings are consistent with experimental observations and can explain the relationship between the cell concentrations and viscosity at which streamers form. 相似文献
994.
Licheng Liu Gabor Samjeske Shin-ichi Nagamatsu Oki Sekizawa Kensaku Nagasawa Shinobu Takao Yoshiaki Imaizumi Takashi Yamamoto Tomoya Uruga Yasuhiro Iwasawa 《Topics in Catalysis》2014,57(6-9):595-606
Carbon-supported Pd-based binary alloy electrocatalysts (Pd–Co and Pd–Ni) with different particle sizes for polymer electrolyte fuel cells were prepared by a NaBH4 reduction method and investigated to examine effects of the size and lattice constant of the Pd alloy nanoparticles on the oxygen reduction reaction (ORR) activity. The particle size and lattice constant were controlled in the wide ranges 4.2–12.1 and 0.3802–0.3948 nm, respectively by heating the catalysts in specific atmospheres. The alloy structures were characterized by X-ray diffraction, transmission electron microscopy and X-ray absorption fine structure. The electrochemical tests of the Pd–Co/C and Pd–Ni/C catalysts were performed by cyclic voltammetry and rotating disk electrode in 0.1 M HClO4. Nearly linear relationship between the lattice constant and nanoparticle size was observed with the Pd–Co and Pd–Ni nanoparticles. The nanoparticle sizes and lattice constants of the Pd–Co/C and Pd–Ni/C electrocatalysts, which influence the Pd d-band center, showed positive and inverse relations with the ORR specific activities, respectively. The mass activities of the Pd–Co/C and Pd–Ni/C electrocatalysts showed an increasing trend with the lattice expansion. 相似文献
995.
Shinichi Kawasaki Mariko Kato Kana Kobori Hiroki Sakamoto Yoshikazu Kondo Toshikazu Takata 《Polymer Engineering and Science》2009,49(12):2374-2383
This study proposes the new concept of reducing the birefringence of poly(ethylene naphthalate) (PEN) by a novel alloy with fluorene‐based polyester (FBP) involving the “cardo” structure in it. The alloys composed of PEN and FBP were prepared by simple melt blending method (process A) and reactive melt blending (process B). The resulting alloys were characterized by DSC, XRD, DMA, tensile testing, and polarized light microscopy. All PEN‐FBP alloys showed transparency and a single glass transition temperature (Tg), indicating that PEN‐FBP alloys were completely compatible. It was also demonstrated that Tg for PEN was shifted to the high‐temperature side by alloying with FBP. A large amount of the orientation‐induced birefringence was induced in drawn PEN sheets; however, in the cases of PEN‐FBP alloys, it was drastically decreased because of alloying with FBP. We could reveal the new concept for “low‐orientation‐induced birefringence material.” POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
996.
Enrique Rocha-Rangel Sebastián Díaz-de-la-Torre Minoru Umemoto Hiroki Miyamoto Heberto Balmori-Ramírez 《Journal of the American Ceramic Society》2005,88(5):1150-1157
Mullite–ZrO2 composites have been fabricated by attrition milling a powder mixture of zircon, alumina, and aluminum metal with MgO or TiO2 as sintering additives, heating at 1100°C to oxidize the aluminum metal, and consolidation by spark plasma sintering (SPS). The influence of the SPS temperature on the formation of mullite, and the density and the mechanical properties of the resulting composites have been studied. For the mullite–zirconia composites without sintering additives, the mullite formation was accomplished at 1540°C. In contrast, for the composites having MgO and TiO2 , the formation temperature dropped to 1460°C. The composites without sintering additives were almost fully dense (99.9% relative density) and retained a larger amount of tetragonal zirconia. Those materials attained the best mechanical properties ( E =214 GPa and K I C =6 MPa·m1/2 ). To highlight the advantages of using the SPS technique, the obtained results have been compared with the characteristics of a mullite–zirconia composite prepared by the conventional reaction-sintering process. 相似文献
997.
Many dangling bonds in hydrogenated amorphous carbon (a-C:H) films are usually generated by bombardments of high-energy ion precursors in typical chemical vapor deposition (CVD). To generate low dangling bonds, a-C:H films should be deposited from low-energy radical species. Surface wave plasma (SWP) generates low-energy and high-density radicals. We prepare a-C:H films using SWP and investigate the relationship between the plasma characteristics and structures of a-C:H films. The microwave of the TM01 mode was introduced through the dielectric window and SWP generate under the dielectric window. An Ar and C2H2 plasma mixture mainly consists of neutral radical species, and the electron temperature is as low as 1 eV. Electron density significantly decreases with increasing distance from the dielectric window. The a-C:H films are prepared from these hydrocarbon and carbon low-energy radicals as main precursors. The sp2 bonded network cluster size in a-C:H films increase with electron density in SWP. This structure change is the influence of the termination structure of clusters changing to CH from CH3 and CH2. 相似文献
998.
Hideo Sawada Hiroki Takashima Ken‐Ichi Iwaki Rika Furukuwa Katsuhisa Takishita 《大分子材料与工程》2007,292(4):403-406
Novel fluoroalkyl end‐capped oligomer/hydroxyapatite nanocomposites have been easily prepared by the reaction of disodium hydrogenphosphate and calcium chloride in the presence of self‐assembled molecular aggregates formed by fluoroalkyl end‐capped oligomers in aqueous media. The fluorinated hydroxyapatite nanocomposites thus obtained were found to exhibit a good dispersibility in a variety of media, and were applied to the surface modification of glass.
999.
Shogo Nobukawa Hiroki Hayashi Hikaru Shimada Ayumi Kiyama Hiroshi Yoshimura Yutaka Tachikawa Masayuki Yamaguchi 《应用聚合物科学杂志》2014,131(15)
Molecular orientation of two aromatic additives in cellulose acetate propionate (CAP) matrix was investigated from orientation birefringence data and an intermolecular orientation correlation represented by nematic interaction (NI) was evaluated. Poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) oligomers with low molecular weight (ca. 400 g mol?1) were used as the additives. The NI strengths of CAP‐PET and CAP‐PEN were determined to be 0.28 ± 0.05 and 0.96 ± 0.15, respectively. In particular, compared with other polymer/polymer and polymer/small additive blends, the NI value in CAP/PEN blend is much stronger and represents the perfect orientation correlation. The strong orientation correlation is possibly due to the rigid naphtalate structure in PEN. Contrary, a relation between birefringence and orientation function for CAP in bulk and blend showed the same trend, suggesting that the orientation behavior of CAP determines the orientation birefringence. As two ester groups in CAP are responsible for birefringence, the alignment of the ester groups is affected by only the main chain orientation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40570. 相似文献
1000.
Enhanced CO2 separation performance for tertiary amine‐silica membranes via thermally induced local liberation of CH3Cl 下载免费PDF全文
Liang Yu Masakoto Kanezashi Hiroki Nagasawa Norihiro Moriyama Toshinori Tsuru Kenji Ito 《American Institute of Chemical Engineers》2018,64(5):1528-1539
A facile method for the fabrication of amine‐silica membranes with enhanced CO2 separation performance was proposed via the thermally induced liberation of small molecules from quaternary ammonium salt. Quaternary ammonium‐silica (QA‐SiO1.5) xerogel powders/films were fabricated via sol‐gel processing and their thermal stability was systematically studied using thermogravimetric mass spectrometer, Fourier transform infrared, energy dispersive spectroscopy, and positron annihilation lifetime spectroscopy analysis. CO2 sorption performances of QA‐SiO1.5 derived xerogel powders were quantitatively compared after assigning their relevant parameters to a dual‐mode sorption model. The gas permeation performances of membranes derived from QA‐SiO1.5 were evaluated in terms of kinetic diameter and temperature dependence of gas permeance, and activation energy (Ep) required for gas permeation. The results indicate that liberation of the CH3Cl molecules from these membranes significantly improved both CO2 permeation and CO2/N2 separation capabilities. Therefore, the present study provides insight that should be useful in the development of high‐performance CO2 separation membranes via the effect of the thermally induced liberation of small molecules. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1528–1539, 2018 相似文献