全文获取类型
收费全文 | 219篇 |
免费 | 32篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 87篇 |
金属工艺 | 2篇 |
机械仪表 | 5篇 |
建筑科学 | 5篇 |
能源动力 | 9篇 |
轻工业 | 20篇 |
水利工程 | 1篇 |
无线电 | 17篇 |
一般工业技术 | 49篇 |
冶金工业 | 5篇 |
原子能技术 | 9篇 |
自动化技术 | 34篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 24篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 15篇 |
2017年 | 14篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 17篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 19篇 |
2009年 | 14篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1994年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有251条查询结果,搜索用时 15 毫秒
71.
Takashi Nakamura Ryota Tsutsumi Chisato Hashiguchi Toshiki Terao Kei Manabe Tomoyasu Hirai Syuji Fujii Yoshinobu Nakamura 《应用聚合物科学杂志》2021,138(44):51297
In the surface treated inorganic particles with silane coupling agent (SCA), chemisorbed and physisorbed molecules are present in the treated layer. Increasing the amount of chemisorption by increasing the molecular weight of SCAs was investigated. Oligomers formed via self-condensation during storage more than 10 days at room temperature for 3-methacryloxypropyltrimethoxysilane-treated silica particles. Monomeric SCA evaporates easily by heating. The oligomers restrict evaporation, and heating increases the chemisorption. The influence of molecular weight of SCA was investigated. In the case of amino group, the amount of chemisorbed was greater for aminoethylaminooctyltrimethoxysilane with high molecular weight than for 3-aminopropyltriethoxysilane. For SCAs with hydrocarbon chains, the amount of chemisorption was lower for both low molecular weight molecules and decyltrimethoxysilane (D) with a high molecular weight. For fluorocarbon chains, the amount of chemisorption was lower for low molecular weight molecules, whereas it increased significantly by heating for high molecular weight type of 1H,1H,2H,2H-heptadecafluorodecyltriethoxysilane (F). Wide-angle X-ray diffraction analysis of F-treated silica particles showed that the fluorocarbon chains formed an ordered structure. There was no such indication for the D-treated system. This ordered structure seems to influence on higher chemisorption for F-treated systems. 相似文献
72.
Ryota Tanaka Ryo Ishihara Kazuyoshi Miyoshi Daisuke Umeno Kyoichi Saito Shiho Asai Shinsuke Yamada Hideyuki Hirota 《Reactive and Functional Polymers》2010,70(12):986-990
A neutral extractant, tri-n-octylphosphine oxide (TOPO), was used to chemically modify a porous sheet, with a final density of 1.0 mmol/g. First, glycidyl methacrylate (GMA) was graft-polymerized onto a porous polyethylene sheet with an average pore diameter, porosity, and thickness of 1.2 μm, 75%, and 2.0 mm, respectively. Second, an octadecane thiol group was introduced into the poly-GMA graft chain. Third, TOPO was deposited on the graft chain via a hydrophobic interaction. Bismuth chloride solution (BiCl3 in 0.15 M HNO3) was forced through the pores of the TOPO-modified porous sheet. The equilibrium binding capacity for bismuth was 0.19 mmol/g. Bismuth ions bound to TOPO were quantitatively eluted with 11 M HNO3. 相似文献
73.
Yusuke Shimoyama Yusuke Ogata Ryota Ishibashi Yoshio Iwai 《Chemical Engineering Research and Design》2010
Supercritical carbon dioxide drying was performed for the preparation of titania aerogels from sol–gel routes. The conditions of supercritical carbon dioxide drying were 313–323 K and 7.8–15.5 MPa. The solvents in titania wet gels obtained from the sol–gel routes were replaced by acetone. The titania aerogels obtained from supercritical carbon dioxide drying form needle-like structures. In supercritical carbon dioxide drying, the extraction rates of acetone from the wet gels were measured by using an on-line Fourier transform infrared spectroscope. It was found that the titania aerogels with lower cohesion were induced from the formations of homogenous phase for carbon dioxide + acetone system and the lower extraction rates of acetone. Furthermore, titania films were prepared by the depositions of the titania aerogels on ITO-coated PET substrates. The needle-like aerogels with lower cohesion derive the titania film with high surface area. 相似文献
74.
In order to evaluate universities from various aspects, we propose a method of utilizing data envelopment analysis (DEA).
The management of universities is complex, and it is necessary to find out their strengths and weaknesses so that they may
become a better educational institute. In this sense, DEA contributes to the evaluation since it can show the efficiency of
universities based on multiple viewpoints. However, when the number of universities evaluated is increased, the results of
an evaluation are similar. Therefore, it is difficult to understand the specific points of each university. We propose a method
for developing evaluations by adapting the decision-making unit (DMU) to certain viewpoints. The utility and effectiveness
of the proposed method are shown by numerical experiments. 相似文献
75.
Tomoyoshi Fukuda Ryota Yamazaki Syuji Fujii Mariko Sasaki 《Journal of Adhesion Science and Technology》2013,27(15):1641-1651
The surface treatment of spherical silica particles using a silane coupling agent with a glycidoxy group was conducted and the effect of the alkoxy group number on the molecular mobility of the silane chain was investigated by 1H pulse nuclear magnetic resonance (NMR). Silanes with di-alkoxy and tri-alkoxy structures were used, and the silica particles were treated with 2-propanol solution and heated at 120?°C for 24?h after solvent evaporation. The surface coverage of the silica surface was in the range from two to three layers. For multilayer coverage, linear chain and network structures were expected to form on the surface by polycondensation reaction using the di- and tri-alkoxy structures, respectively. However, the relaxation times for silane chains with both di- and tri-alkoxy structures measured by pulse NMR were short, which indicates that both silane chains formed rigid network structures. Fourier transform infrared spectroscopic analysis revealed that ring opening of the epoxy group occurred, followed by reaction to form the network structure, even with the di-alkoxy structure. Ring opening of the epoxy group could be reduced by setting the heating temperature at 80?°C. There was a significant difference in flexibility between the silane-layers with di- and tri-alkoxy structures after heating at 80?°C, as reflected by the relaxation time. 相似文献
76.
Yokota Nobuyuki Mineshima Ryota Yamaguchi Hideyuki Hirase Tatsuaki Ishikawa Hisayoshi Azuma Takayuki Hosomi Masaaki Terada Akihiko 《Clean Technologies and Environmental Policy》2019,21(5):1001-1011
Clean Technologies and Environmental Policy - Anaerobic ammonium oxidation (anammox) has been implemented as a cost-effective nitrogen removal process in wastewater treatment. To apply the process... 相似文献
77.
Kayo Tanaka Hiroaki Tanaka Ryota Tachibana Kento Yoshikawa Takuya Kawamura Sho Takakura Hiroki Takeuchi Tomoaki Ikeda 《International journal of molecular sciences》2022,23(3)
Fetal growth restriction (FGR) is a major cause of poor perinatal outcomes. Although several studies have been conducted to improve the prognosis of FGR in infants, no effective intrauterine treatment method has been established. This study aimed to use tadalafil, a phosphodiesterase 5 inhibitor (PDE5) inhibitor, as a novel intrauterine treatment and conducted several basic and clinical studies. The study investigated the effects of tadalafil on placental mTOR signaling. Tadalafil was administered to mice with L-NG-nitroarginine methyl ester (L-NAME)-induced FGR and associated preeclampsia (PE). Placental phosphorylated mTOR (p-mTOR) signaling was assessed by fluorescent immunohistochemical staining and Western blotting. The expression of p-mTOR was significantly decreased in mice with FGR on 13 days post coitum (d.p.c.) but recovered to the same level as that of the control on 17 d.p.c. following tadalafil treatment. The results were similar for 4E-binding protein 1 (4E-BP1) and S6 ribosomal (S6R) protein, which act downstream in the mTOR signaling pathway. We demonstrate that the tadalafil treatment of FGR in mice improved placental mTOR signaling to facilitate fetal growth. Our study provides the key mechanistic detail about the mode of action of tadalafil and thus would be helpful for future clinical studies on FGR. 相似文献
78.
Ryota Katano Tomohiro Endo Akio Yamamoto Kazufumi Tsujimoto 《Journal of Nuclear Science and Technology》2018,55(10):1099-1109
We proposed the penalized regression ‘adaptive smooth-lasso’ for the estimation of sensitivity coefficients of the neutronics parameters. The proposed method utilizes the variation of the microscopic cross-sections and the neutronics parameters obtained by random sampling. The weighted penalty term of the proposed method is more appropriate for the estimation of the sensitivity of neutronics parameters to the microscopic cross-section than that of the conventional methods. In a numerical verification calculation, sensitivity coefficients of keff of an accelerator-driven system are estimated using the proposed method, the conventional penalized regression, and the direct method. Comparison of these results indicates that the proposed method is superior to the conventional penalized linear regression from the viewpoint of reproduction of the reference sensitivity coefficients obtained by the direct method. Through the verification calculations, the proposed method can be a candidate for a practical method to estimate the sensitivity coefficients with low calculation cost. 相似文献
79.
C2-Symmetric 9,9′-spirobifluorene-containing polyesters (PEs) were synthesized by polycondensation of 2,2′-dihydroxy-9,9′-spirobifluorene (1) with bis(acyl chloride)s (2) at 230 °C in diphenylether. The molecular weights of PEs 3a-3f were sufficiently high (Mw 13,400-41,600). PEs displayed high thermal stability. The glass transition temperatures (Tg) estimated by differential scanning calorimetry analysis appeared in a range 177-352 °C depending on the spacer structure, while the 5% decomposition temperatures (Td5) measured by thermogravimetric analysis were over 416 °C both under nitrogen atmosphere and in air. PEs showed good solubility in typical organic solvents such as CHCl3 and THF easily to afford the tough, transparent, and flexible cast films. The transmittance of the polymer films reached over 90% in the wavelength range from ca. 410-900 nm. In addition, PEs exhibited higher refractive index rather than that of commercially available 9,9-diarylfluorene-containing PE, in addition to very low degree of birefringence presumably due to the C2-symmetric structure. 相似文献
80.
Hirokazu Masai Ryota Shirai Takamichi Miyazaki Kazuki Yoshida Takumi Fujiwara Yomei Tokuda Toshinobu Yoko 《Journal of the American Ceramic Society》2013,96(11):3576-3583
Transparent (Sr0.5Ba0.5)Nb2O6 (SBN50) nanocrystallite‐precipitated phosphate glass‐ceramics were prepared by a conventional glass‐ceramic process. x(SrO–BaO–2Nb2O5) ? (100–4x)P2O5 (xSBNP) glasses with a refractive index of 1.9–2.0 exhibited high water resistance owing to the presence of Q0 and Q1 phosphate units. Both bulk and surface crystallization of the SBN50 phase were observed in 20SBNP and 21SBNP glass‐ceramics. Although the nominal content of SBN50 crystals in the 21SBNP glass was larger than that in the 20SBNP glass, the latter exhibited better crystallinity of SBN50 and a higher number density of precipitated SBN nanocrystallites. By tuning the two‐step heat‐treatment and the chemical composition, transparent SBN50‐precipitated glass‐ceramics were successfully obtained. Given that no remarkable increase of the relative dielectric constants was observed after crystallization of the SBN50 nanocrystallites, it is postulated that the relative dielectric constant of the bulk is mainly governed by the amorphous phosphate region, and that the contribution of precipitation of the SBN50 nanocrystallites to the dielectric constant is not very significant in this system. 相似文献