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排序方式: 共有830条查询结果,搜索用时 31 毫秒
101.
The spatial distribution of Zn2+ during galvanic corrosion of a model Zn/steel couple in 0.01 M NaCl was investigated using a scanning zinc disk electrode. The couple had a coplanar arrangement of a steel substrate with an electroplated zinc layer at the center. During galvanic corrosion, the marked changes in the Zn2+ concentration were confined to a thin solution layer ca. 1.0 mm thick above the couple surface. In this thin solution layer above the zinc layer, a higher concentration region of Zn2+ in the range of 5-18 mM extended around the zinc layer in the solution during galvanic corrosion. Conversely, above the steel surface distant from the zinc layer, the surface concentration of Zn2+ was almost zero during galvanic corrosion. On this surface, the precipitation of zinc corrosion products due to the hydrolysis reaction of Zn2+ was observed. The distribution of the Zn2+ concentration supported that Zn2+ acted as a buffer that suppressed the increased pH due to the cathodic reaction on the steel surface near the zinc layer and almost no corrosion products formed there. The spatial distribution of Zn2+ is discussed in relation to the distributions of potential and pH and the surface morphology of the galvanic couple. 相似文献
102.
Samia Tabassum Eiji Yamasue Hideyuki Okumura Keiichi N. Ishihara 《Journal of Materials Science: Materials in Electronics》2014,25(11):4883-4888
Al-doped ZnO (AZO) thin film, which possess the advantages of low cost, low sheet resistance and high transmittance, are one of the most promising candidates to replace indium tin oxide films as the transparent electrode. However, oxidation causes a substantial increase in the sheet resistance of AZO film after exposing in ambient and especially, damp heat environment. In this work, we compare structural, optical, electrical properties and environmental stability between films prepared by two different methods: sol–gel and rf sputtering. Experimental results indicate that the properties of film can be affected by different deposition method. From the X-ray diffraction analysis, all films have hexagonal wurtzite crystal structure with different preferable orientation in two different methods. Optical transmittance spectra of the AZO films exhibited transparency higher than about 80 % within the visible wavelength region and the optical band gap (Eg) of these films was increased in sputtered film, probably due to the increase of carrier concentration. The better environmental stability was found in AZO film prepared by sputtering method. Improved surface morphology and enhancement of crystal orientation (110) was considered for this improvement. 相似文献
103.
Liquid Crystals: Liquid‐Crystalline Electrolytes for Lithium‐Ion Batteries: Ordered Assemblies of a Mesogen‐Containing Carbonate and a Lithium Salt (Adv. Funct. Mater. 8/2015) 下载免费PDF全文
104.
Hiromi Nakano Motohiro Yamada Masahiro Fukumoto Eiji Yamaguchi 《Journal of Thermal Spray Technology》2011,20(3):407-411
Cold spraying has been developed as a high-quality coating technique. In this article, copper is deposited on an AlN substrate
coated by the sputtering of titanium and copper at a low pressure of less than 1.0 MPa, making this approach suitable for
a wide range of engineering applications. In order to understand the adhesion mechanism at the atomic scale, the interfacial
regions are carefully observed in thin foil samples from the cross sections of the specimens with a HREM. We find a unique
wavy boundary between the sputtered titanium and the sputtered copper. It is assumed that the shear-instability phenomenon
occurs due to the cold-spraying process and influences the adhesive strength. Furthermore, the cold-sprayed copper particles
are connected directly without any oxidation layer due to the appearance of new metallic surfaces during the impact process.
The TEM data clearly reveal the phenomena and mechanisms related to the impact of powder sprayed on the substrate. 相似文献
105.
Shizuo Saitoh Hirofumi Daiguji Eiji Hihara 《International Journal of Heat and Mass Transfer》2007,50(25-26):5215-5225
A Chen-type correlation for flow boiling heat transfer of R-134a in horizontal tubes was modified taking into account the effect of tube diameter. The effect of tube diameter on flow boiling heat transfer coefficient was characterized by the Weber number in gas phase. Results showed that this correlation could be applied to a wide range of tube diameters (0.5–11-mm-ID). In addition, the dryout point and the heat transfer characteristics after the dryout point were also investigated based on the annular flow model. The proposed experimental expressions to predict both the dryout quality and the post-dryout heat transfer coefficient could also be applied to a wide range of tube diameter (0.5–11-mm-ID). 相似文献
106.
Shizuo Saitoh Chaobin DangYoshitaka Nakamura Eiji Hihara 《International Journal of Refrigeration》2011,34(8):1846-1853
The flow boiling heat transfer coefficient of the low-GWP (global warming potential) refrigerant HFO-1234yf inside a smooth small-diameter horizontal tube (inner diameter: 2 mm) was experimentally investigated. The local heat transfer coefficient was measured at heat fluxes of 6-24 kW m−2, mass fluxes of 100-400 kg m−2 s−1, an evaporating temperature of 288.15 K, and an inlet vapor quality of 0-0.25. The results show that the effect of heat flux on the heat transfer was large at low vapor quality, while the effect of mass flux was large at high vapor quality. The heat transfer coefficient of HFO-1234yf was almost the same as that of R-134a. The heat transfer coefficients calculated based on correlations with Saitoh et al. agreed well with the measured values compared to other correlations. The measured pressure drop agreed well with that predicted by the Lockhart-Martinelli correlation. 相似文献
107.
Luciana R. Pires KassabMauricio Eiji Camilo Ali H. Reshak K.J. Plucinski 《Materials Letters》2011,65(10):1445-1447
We have observed substantial influence of the illumination by 3.5 μs CO2 laser on the piezooptical coefficients of 59 PbO - 41 GeO2 (in wt.%) glasses prepared with Tm2O3, Er2O3, Yb2O3 using the following concentrations (in wt.%): B-Tm2O3 (0.5)/Yb2O3 (1.0)/Er2O3(0.5); C-Tm2O3(0.5)/Yb2O3(1.0)/Er2O3 O(1.0); D-Tm2O3 (0.5)/Yb2O3 (1.0)/Er 2O3 (2.0). We have found that the maximal changes were observed for B samples that contain the lowest concentration of Er2O3. The maximal changes are observed around 360 nm near the fundamental absorption edge. There exists some correlation between the maximal intensities of the photoluminescence and the maximal piezooptical changes. The CO2 lasers cause preliminary photothermal changes. The existence of the maxima may be caused by a competition between the phonon and anharmonic phonon subsystems, which are very sensitive to the temperature. 相似文献
108.
Takuya Matsumoto Mohammad Hafiz Uddin Sang Hyun An Kazuto Arakawa Eiji Taguchi Atsushi Nakahira Masayuki Okazaki 《Materials Chemistry and Physics》2011
Hydroxyapatite materials are potentially useful for biomedical application, especially as vehicles for functional molecules. Structural control of bulk apatite materials, such as in the fabrication of hollow microspheres or porous structures, has been studied for this purpose. However, control of the internal structure of the source apatite crystal itself is still a challenge. Here, we show that small organic molecules incorporated in apatite crystals act as porogens which control the porous structure of apatite single crystal. The presence of amino acid under apatite synthesis conditions leads to firm bindings and encapsulation of the amino acid in apatite single crystals. Amino acid elimination by heating or electron beam irradiation enhances the pore formation in apatite single crystal. Moreover, incorporation of an acidic amino acid in apatite induces peapod like nanotubes in apatite single crystals. This study suggests the potential of using small organics for nano-structural control of apatite single crystals which would be valuable for enhancing drug loadings or modulating material digestion in vivo. 相似文献
109.
We have proposed an illumination-collection-type scanning near-field Raman spectroscopy (SNRS) with a completely gold metal-inside-coated (MIC) pyramidal probe without an optical aperture in order to detect the Raman spectra of fine Si devices for local stress measurements. The gold MIC pyramidal probe has been studied to act as a plasmon resonance near-field optical probe with high power using a finite differential time domain (FDTD) simulation and the prototyped SNRS. In the simulation, the propagated optical power can be made available for SNRS. In the experiments, it is clear that the prototyped SNRS enhanced the Si Raman peak signal by plasmon resonance and could measure the Si Raman peak shift by line scanning the Si gate region and the Si active layer. Furthermore, compressive and tensile stresses localized around the Si gate were demonstrated by the Si Raman peak shift with a resolution of about 10 nm. It is clarified that the proposed SNRS has the possibility of detecting the Raman spectra of a local area. 相似文献
110.
Minoru Takeyama Jerzy Wojtowicz Kazimierz Butelski Eiji Watanabe 《Automation in Construction》2003,12(6):689-695
Computer dependent design space is illustrated with the recent international competition project for Kowloon Arts Center. The spatial condition of design resulted from the deployment of Euclidian geometry and use of the nonrational, complex surfaces. Another aspect of computer dependent space was rooted in the contemporary work situation where architects located on the three different continents collaborated in distributed mode over the internet. The resulting project confirms the creative potential of the above aspects of the digital space in contemporary design. 相似文献