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61.
Eileen O'Rourke 《Landscape Research》2005,30(4):483-500
Issues relating to community participation in landscape management, as well as the manipulation of the community for political ends, are addressed. It is argued that the current fashionable participatory model of development and policy formulation requires closer scrutiny and may be unrealistic in certain contexts. A case-study approach is adopted, whereby the role of the community in attempts to construct a visitor interpretative centre at the foot of Mullaghmore Mountain, within the Burren National Park, Ireland, is analysed. The complexity of the term community is exposed, and important questions about who speaks for the community are raised. It is concluded that local development, including ecosystem and landscape management, is best approached neither from a 'top-down' nor a 'bottom-up' developmental model. It is suggested that insights from adaptive co-management models, which promote a multi-level management approach, whereby local knowledge and experience are incorporated within enabling local and extra-local institutional structures, may provide a viable alternative. Finally, it is argued that human-environmental interaction in a specific place, including the management of common pool resources, needs to be situated within the historical, ecological and cultural narrative of its human ecology. 相似文献
62.
Large-grained (100- to 200-μm), yttria-doped, polycrystalline t '-zirconia ceramics were fabricated by heat-treating presintered samples at temperatures 2100°C. Polarized light microscopy revealed the ferroelastic domain structure in the t ' samples. XRD showed that no monoclinic phase was detected on as-polished, ground and fracture surfaces, or on surfaces while under a tensile stress as high as 400 MPa. By contrast, relative changes occurred in the tetragonal peak intensities, which were attributed to ferroelasatic domain switching. The higher toughness of 3-mol%-Y2 O3 -doped t ' samples (7.7 MPa · m1/2 ) compared to that of 8 mol% Y2 O3 cubic samples (2.4 MPa · m1/2 ) was explained in part by ferroelastic domain switching. 相似文献
63.
Cocoa Butter Substitute (CBS) Produced from Palm Mid-fraction/Palm Kernel Oil/Palm Stearin for Confectionery Fillings
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![点击此处可从《Journal of the American Oil Chemists](/ch/ext_images/free.gif)
Nirupam Biswas Yuen Lin Cheow Chin Ping Tan Sivaruby Kanagaratnam Lee Fong Siow 《Journal of the American Oil Chemists' Society》2017,94(2):235-245
This study investigated the physicochemical properties of ternary mixtures of palm mid-fraction (PMF):refined bleached deodorized palm kernel oil (RBDPKO):refined bleached deodorized palm stearin (RBDPS) for cocoa butter substitute (CBS). Fatty acid constituents, triacylglycerol constituents, solid fat contents (SFCs), melting behavior, polymorphism and crystal morphology were determined using gas chromatography (GC), high-performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), pulsed nuclear magnetic resonance (p-NMR), X-ray diffraction (XRD) and polarized light microscopy (PLM), respectively. Eight blends of various ratios of ternary mixtures were investigated based on the previously studied binary fat mixtures. The composition of palmitic (P) and oleic (O), POP, and crystal morphology (size and shape) of the PMF/RBDPKO/RBDPS [14.9/59.6/25.5 (%w/w)] mixture were comparable to cocoa butter (CB), while its melting profile (18.5 and 37 °C), SFC at 20 °C and polymorphism were different from CB. The iso-solid diagrams of the mixture displayed a monotectic effect at 20–25 °C. Therefore, the 14.9/59.6/25.5 PMF/RBDPKO/RBDPS mixture could be used as a CBS in confectionery fillings because of the crystal morphology and monotectic behaviors comparable to those of CB. 相似文献
64.
We report a study of the fluorescence properties of the conjugated polymer poly [2-methoxy-5-(2′-ethyl hexyloxy)-p-phenylene vinylene] (MEH-PPV) and polyethylene oxide (PEO) nanofibers. MEH-PPV/PEO nanofibers with different compositions have been fabricated by the electrospinning technique. The fluorescence spectra of the nanofibers show that the emission shoulder at ∼630 nm blue-shifts ∼45 nm, whereas the main emission peak around 590 nm blue-shifts ∼15 nm with decreasing concentration of MEH-PPV in the nanofiber. In addition, confocal microscopic studies of a single MEH-PPV/PEO electrospun nanofiber indicate that the fluorescence spectra of the nanofiber do not show any polarization dependence. The results are discussed in terms of the aggregation of MEH-PPV in an inert matrix. 相似文献
65.
Ruifen Chen Yonggang Shangguan Chunhui Zhang Feng Chen Eileen Harkin-Jones 《Polymer》2011,52(13):2956-2963
The phase structure evolution of high impact polypropylene copolymer (IPC) during molten-state annealing and its influence on crystallization behaviour were studied. An entirely different architecture of the IPC melt was observed after being annealed, and this architecture resulted in variations of the crystallization behaviour. In addition, it was found that the core-shell structure of the dispersed phase was completely destroyed and the sizes of the dispersed domains increased sharply after being annealed at 200 °C for 200 min. Through examination of the coarseness of the phase morphology using phase contrast microscopy (PCM), it was found that a co-continuous structure and an abnormal ‘sea-island’ structure generally appeared with an increase in annealing time. The original matrix PP component appeared as a dispersed phase, whereas the copolymer components formed a continuous ‘sea-island’ structure. This change is ascribed to the large tension induced by solidification at the phase interface and the great content difference between the components. When the temperature was reduced the structure reverted to its original form. With increasing annealing time, the spherulite profiles became more defined and the spherulite birefringence changed from vague to clear. Overall crystallization rates and nucleation densities decreased, but the spherulite radial growth rates remained almost constant, indicating that molten-state annealing mainly affects the nucleation ability of IPC, due to a coarsened microstructure and decreased interface area. 相似文献
66.
67.
A low-voltage 40-GHz complementary VCO with 15% frequency tuning range in SOI CMOS technology 总被引:1,自引:0,他引:1
Neric Fong Jonghae Kim Plouchart J.-O. Zamdmer N. Duixian Liu Wagner L. Plett C. Tarr G. 《Solid-State Circuits, IEEE Journal of》2004,39(5):841-846
The design of a low-voltage 40-GHz complementary voltage-controlled oscillator (VCO) with 15% frequency tuning range fabricated in 0.13-/spl mu/m partially depleted silicon-on-insulator (SOI) CMOS technology is reported. Technological advantages of SOI over bulk CMOS are demonstrated, and the accumulation MOS (AMOS) varactor limitations on frequency tuning range are addressed. At 1.5-V supply, the VCO core and each output buffer consumes 11.25 mW and 3 mW of power, respectively. The measured phase noise at 40-GHz is -109.73 dBc/Hz at 4-MHz offset from the carrier, and the output power is -8 dBm. VCO performance using high resistivity substrate (/spl sim/300-/spl Omega//spl middot/cm) has the same frequency tuning range but 2 dB better phase noise compared with using low resistivity substrate (10 /spl Omega//spl middot/cm). The VCO occupies a chip area of only 100 /spl mu/m by 100 /spl mu/m (excluding pads). 相似文献
68.
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70.
Fang‐Ming Hsu Chen‐Han Chien Ching‐Fong Shu Chin‐Hung Lai Cheng‐Chih Hsieh Kang‐Wei Wang Pi‐Tai Chou 《Advanced functional materials》2009,19(17):2834-2843
Highly efficient blue electrophosphorescent organic light‐emitting diodes incorporating a bipolar host, 2,7‐bis(diphenylphosphoryl)‐9‐[4‐(N,N‐diphenylamino)phenyl]‐9‐phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis[(4,6‐difluoro‐phenyl)pyridinato‐N,C2´]picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron‐donating (p‐type) triphenylamine group and an electron‐accepting (n‐type) 2,7‐bis(diphenyl‐phosphoryl)fluorene segment linked through the sp3‐hybridized C9 position of the fluorene unit. The lack of conjugation between these p‐ and n‐type groups endows POAPF with a triplet energy gap (ET) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue‐emitting guest. In addition, the built‐in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF‐based device doped with 7 wt% FIrpic exhibits a very low turn‐on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W?1). Even at the practical brightnesses of 100 and 1000 cd m?2, the efficiencies remain high (20.2%/33.8 lm W?1 and 18.8%/24.3 lm W?1, respectively), making POAPF a promising material for use in low‐power‐consumption devices for next‐generation flat‐panel displays and light sources. 相似文献