全文获取类型
收费全文 | 1064篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 39篇 |
化学工业 | 290篇 |
金属工艺 | 19篇 |
机械仪表 | 30篇 |
建筑科学 | 11篇 |
能源动力 | 46篇 |
轻工业 | 57篇 |
水利工程 | 1篇 |
无线电 | 100篇 |
一般工业技术 | 204篇 |
冶金工业 | 228篇 |
原子能技术 | 20篇 |
自动化技术 | 32篇 |
出版年
2021年 | 16篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 34篇 |
2012年 | 21篇 |
2011年 | 41篇 |
2010年 | 34篇 |
2009年 | 32篇 |
2008年 | 24篇 |
2007年 | 39篇 |
2006年 | 35篇 |
2005年 | 32篇 |
2004年 | 37篇 |
2003年 | 42篇 |
2002年 | 27篇 |
2001年 | 21篇 |
2000年 | 22篇 |
1999年 | 35篇 |
1998年 | 88篇 |
1997年 | 70篇 |
1996年 | 58篇 |
1995年 | 25篇 |
1994年 | 28篇 |
1993年 | 29篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 20篇 |
1989年 | 15篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 16篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1972年 | 12篇 |
排序方式: 共有1077条查询结果,搜索用时 156 毫秒
31.
Hoshiaki Iijima Osamu Taguchi Ken-Ichi Hirano 《Metallurgical and Materials Transactions A》1977,8(6):991-995
Interdiffusion coefficient
in cobalt-manganese alloys has been determined by Matano's method in the temperature range between 1133 and 1423 K on (pure
Co)-(Co-30.28 at. pct Mn alloy) and (pure Co)-(Co-51.76 at. pct Mn alloy) couples. This, ∼D, has been found to increase with the increase of manganese content. However, the activation energy (∼Q) and frequency factor (
0) show a maximum at about 10 at. pct Mn. The concentration dependence of
and
has been discussed taking into account the thermodynamic properties of the alloy. The difference in
between the ferro- and paramagnetic phases in Co-5 at. pct Mn alloy has been found to be 24 kJ/mol, which is larger, than
that for the diffusion of Mn54 in this alloy. Further it has been found that the Kirkendall marker moves toward manganese-rich side, showing that manganese
atoms diffuse faster than cobalt atoms. From the marker shift, the intrinsic diffusion coefficients,D
Co andD
Mn, at 33 at. pct Mn have been determined as follows:D
Co=0.22×10−4 exp(−263 kJ mol−1/RT) m2/s, andD
Mn=0.98×10−4 exp(−229 kJ mol−1/RT) m2/s. 相似文献
32.
Koichiro Hirano Masafumi Fukuda Mikio Takano Yoshio Yamazaki Toshiya Muto Sakae Araki Nobuhiro Terunuma Masao Kuriki Mitsuo Akemoto Hitoshi Hayano Junji Urakawa 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2006,560(2):233-239
A multi-bunch photo-cathode RF gun system has been developed as an electron source for the production of intense quasi-monochromatic X-rays based on inverse Compton scattering. The desired multi-bunch beam is 100 bunches/pulse with a total charge of 500 nC and a bunch spacing of 2.8 ns. We modified the gun cavity of a ‘BNL-type IV’ RF gun to allow a CsTe cathode plug in the end plate. The system uses a four-dipole chicane beam line to allow the injection of laser light normal to the cathode surface. We compensate the gun cavity beam loading caused by the high-intensity multi-bunch electron beam by injecting the laser pulse before RF power has filled the cavity. We have achieved a total intensity of 220 nC in 100 bunches with a bunch-to-bunch energy spread under 1.3% (peak-to-peak). This paper concentrates on experiments to generate the high-intensity multi-bunch beam with compensation of the bunch-to-bunch energy spread due to heavy beam loading. 相似文献
33.
For magnetic field analysis by edge elements of the magnetic components, the method considering inhomogeneous current distribution within the conductor windings is investigated. To consider the inhomogeneous current distribution within the windings, we utilized the magnetic vector potential represented by edge elements and the current conservation equation represented by nodal elements in the region of the windings. In the first application, the eddy-current model, which has the conventional wire winding, was analyzed. For correct analysis using our method, it is required that all turns of the wire winding be divided into meshes. However, if the region of the wire winding does not exceed the winding window of the magnetic core, even the combination of our method and the solidly modeled wire winding enables us to correctly analyze the transformer and the inductor with conventional wire winding. In the second application, a flat transformer with conductor winding, such as a copper foil or sheet, was analyzed. The magnetic flux densities within the flat core and the inductance calculated by our method were in good agreement with the experiments. Thus, we confirmed the effectiveness of our method considering inhomogeneous current distribution within the conductor windings. 相似文献
34.
Youichi Ogo Kenji Nomura Hiromichi Ohta Masahiro Hirano Hideo Hosono 《Thin solid films》2006,496(1):64-69
A reactive solid-phase epitaxy (R-SPE) method combines deposition of a thick amorphous or polycrystalline layer with a desired chemical composition and post-deposition solid-phase epitaxial growth. The solid-phase epitaxial growth is invoked by thermal annealing with an assistance of a sacrificial layer working as an epitaxial template. Thereby it enables us to grow high-quality epitaxial films of complex oxides whose epitaxial films are not grown by conventional high-temperature growth techniques. It was reported that 2-nm-thick ZnO layers worked as template for growing InGaO3(ZnO)m (m = integer) epitaxial films. The present study extended the R-SPE technique to growth of various complex oxides with chemical compositions of RAO3(MO)m and to use of various epitaxial template layers. We found that mono oxide epitaxial layers such as In2O3 and Ga2O3 work as template layers as well. Alternatively, a ZnO epitaxial layer is also applicable to ZnO-free compounds. The films obtained were grown heteroepitaxially on YSZ(111) and single-crystalline when the fabrication conditions are optimized. 相似文献
35.
The radical polymerization of N‐isopropylacrylamide was carried out in toluene at low temperatures in the presence of silyl alcohols, such as triethylsilanol. Poly(N‐isopropylacrylamide) with a racemo dyad content of 75% was obtained at ? 80 °C with a 4:1 triethylsilanol to monomer ratio loading. NMR analysis suggests that the mechanism for syndiotactic induction, in the presence of silyl alcohols, may be similar to that observed with alkyl alcohols. In this case, a 1:2 complex formation, via hydrogen bonding interactions, leads to the induction of syndiotactic specificity. Copyright © 2012 Society of Chemical Industry 相似文献
36.
Mingtao Li Li Yang Shaohua Fang Siming Dong Shin‐ichi Hirano Kazuhiro Tachibana 《Polymer International》2012,61(2):259-264
Polymerized ionic liquids (PILs) having guanidinium cations with different counter‐anions, such as PF6? and N(CF3SO2)2? (TFSI?), were synthesized by copolymerization of a guanidinium ionic liquid monomer with methyl acrylate followed by an anion exchange reaction. Furthermore, incorporating a guanidinium ionic liquid, LiTFSI salt and nano‐size SiO2, a quaternary gel polymer electrolyte based on one of the PILs as the polymer host was prepared. The quaternary gel polymer electrolyte was chemically stable even at a higher temperature of 80 °C in contact with the lithium anode. In particular, the electrolyte exhibited high lithium ion conductivity, wide electrochemical stability window and good lithium stripping/plating performance. Li/LiFePO4 batteries with the quaternary gel polymer electrolyte at 80 °C had capacities of 140 and 130 mA h g?1 respectively at 0.1 and 0.2 C current rates. Copyright © 2011 Society of Chemical Industry 相似文献
37.
38.
Keiko Takano Maki Mihashi Tsuneo Hirano 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(2):283-299
Abstract Mechanism of C60 formation from naphthalenes was studied by quantum chemical calculations. a patch up process of T-shape dimerization of naphthalenes followed by the intramolecular ring fusion, all through radical reactions, was proposed for a possible mechanism for the C60 formation from naphthalenes. the reaction barrier was found to be less than 60-70 kcal/mol for each reaction step in this mechanism. 相似文献
39.
Hideyuki Inui Toshimasa Itoh Keiko Yamamoto Shin-Ichi Ikushiro Toshiyuki Sakaki 《International journal of molecular sciences》2014,15(8):14044-14057
Polychlorinated dibenzo-p-dioxins (PCDDs) and coplanar polychlorinated biphenyls (PCBs) contribute to dioxin toxicity in humans and wildlife after bioaccumulation through the food chain from the environment. The authors examined human and rat cytochrome P450 (CYP)-dependent metabolism of PCDDs and PCBs. A number of human CYP isoforms belonging to the CYP1 and CYP2 families showed remarkable activities toward low-chlorinated PCDDs. In particular, human CYP1A1, CYP1A2, and CYP1B1 showed high activities toward monoCDDs, diCDDs, and triCDDs but no detectable activity toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD). Large amino acids located at putative substrate-recognition sites and the F-G loop in rat CYP1A1 contributed to the successful metabolism of 2,3,7,8-tetraCDD. Rat, but not human, CYP1A1 metabolized 3,3'',4,4'',5-pentachlorobiphenyl (CB126) to two hydroxylated metabolites. These metabolites are probably less toxic than is CB126, due to their higher solubility. Homology models of human and rat CYP1A1s and CB126 docking studies indicated that two amino acid differences in the CB126-binding cavity were important for CB126 metabolism. In this review, the importance of CYPs in the metabolism of dioxins and PCBs in mammals and the species-based differences between humans and rats are described. In addition, the authors reveal the molecular mechanism behind the binding modes of dioxins and PCBs in the heme pocket of CYPs. 相似文献
40.
Notch effect on the tensile properties of the Ni3Al foils has been investigated as a function of notch geometry and foil’s thickness. Tensile tests along the rolling direction (RD) and the transverse direction (TD) showed that notch weakening occurred with introduce of a notch. Plastic deformation was observed locally at notch root and the effective stress concentration factor (ke) was much lower than the theoretical stress concentration factor (Kt). Contrary to the anisotropy in fracture stress along the RD and the TD, ke fell on the same curve. Crack initiation mechanism was different between two tensile directions, that is, cracks initiated along the shear band in the RD tension, while cracks initiated homogenously on the slip planes in the TD tension. 相似文献