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排序方式: 共有225条查询结果,搜索用时 15 毫秒
41.
Z Chen W Lei B Chen Y Wang X Liao HH Tan J Zou SP Ringer C Jagadish 《Nanoscale research letters》2012,7(1):486
ABSTRACT: InAs/GaAs(001) quantum dots grown by droplet epitaxy were investigated using electron microscopy. Misfit dislocations in relaxed InAs/GaAs(001) islands were found to be located approximately 2 nm above the crystalline sample surface, which provides an impression that the misfit dislocations did not form at the island/substrate interface. However, detailed microscopy data analysis indicates that the observation is in fact an artefact caused by the surface oxidation of the material that resulted in substrate surface moving down about 2 nm. As such, caution is needed in explaining the observed interfacial structure. 相似文献
42.
Zn(2)SnO(4) nanoparticles (NPs) with a narrow size distribution were synthesized by a simple hydrothermal route by controlling the crystallization process. The average size of NPs was 8 nm, and this was attributed to the formation of a hydroxy carbonate compound as an intermediate phase, which was demonstrated by the structural and elemental analyses. The fine size and visible-transparency of the synthesized NPs enabled the fabrication of transparent films for efficient photoelectrochemical devices. In particular, we demonstrated dye-sensitized solar cells (DSSCs) employing these transparent Zn(2)SnO(4) photoelectrodes with a high energy conversion efficiency of 4.7%, which is mainly due to an improvement of light harvesting property. 相似文献
43.
Aniruddha Ray Xueding Wang Yong-Eun Koo Lee Hoe Jin Hah Gwangseong Kim Thomas Chen Daniel A. Orringer Oren Sagher Xiaojun Liu Raoul Kopelman 《Nano Research》2011,4(11):1163-1173
Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been
made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery. We describe a novel method
to delineate brain tumors, using a highly sensitive photoacoustic imaging technique that is enhanced by tumor-targeting blue
nanoparticles serving as a contrast agent. Experiments on phantoms and on rat brains, ex vivo, demonstrate the high sensitivity of photoacoustic imaging in delineating tumors containing contrast agent at a concentration
much lower than needed for visualization by the naked eye. The limit of detection of the system for the nanoparticles is about
0.77 μg/mL in water (equivalent to 0.84 μmol/L Coomassie Blue dye). The present exploratory study suggests that photoacoustic
imaging, when used with strongly optical absorbing contrast agents, could facilitate cancer surgery intraoperatively by revealing
the distribution and extent of the tumor.
相似文献
44.
We report on the optical trapping characteristics of InP nanowires with dimensions of 30 (±6) nm in diameter and 2-15 μm in length. We describe a method for calibrating the absolute position of individual nanowires relative to the trapping center using synchronous high-speed position sensing and acousto-optic beam switching. Through brownian dynamics we investigate effects of the laser power and polarization on trap stability, as well as length dependence and the effect of simultaneous trapping multiple nanowires. 相似文献
45.
Summary
A wide-angle X-ray diffraction method for measuring poly(trimethylene terephthalate) (PTT) crystal orientation function was
described. It was based on Wilchinsky's treatment of uniaxial orientation. Although PTT has a low symmetry triclinic cell
only one equatorial reflection is needed for the measurement because the unit cell β-angle happened to be 90°, and there is
a strong 010 reflection. The choice of unit cell parameters from the conflicting literature data and the reduction of Wilchinsky's equation
into a simple form allowing the measurement of only one reflection were presented. The discrepancies between literature wide-angle
X-ray and electron diffraction unit cell volumes and crystal densities were also discussed.
Received: 19 January 2001 /Revised version: 23 March 2001/ Accepted: 23 March 2001 相似文献
46.
Antioxidant activities of aqueous extracts of selected plants 总被引:1,自引:0,他引:1
The antioxidant properties of 25 edible tropical plants, expressed as Trolox equivalent antioxidant capacity (TEAC), were studied using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical) scavenging and reducing ferric ion antioxidant potential (FRAP) assays. Their cupric ion chelating activities (CCA) and total polyphenol contents (TPC) were also determined. A strong correlation between TEAC values obtained for the DPPH assay (TEACDPPH) and those for the FRAP assay (TEACFRAP) implied that compounds in the extracts were capable of scavenging the DPPH free radical and reducing ferric ions. A satisfactory correlation of TPC with TEACDPPH and TEACFRAP suggested that polyphenols in the extracts were partly responsible for the antioxidant activities while its correlation with CCA was poor, indicating that polyphenols might not be the main cupric ion chelators. Principal component analysis (PCA) indicated that TEACDPPH, TEACFRAP and TPC contributed to the total variation in the antioxidant activities of the plants. 相似文献
47.
48.
An anionic carrier-mediated separation of L-valine from the dilute aqueous solution was studied with a liquid membrane, constituted
by a solution of D2EHPA (Di-2-Ethyl Hexyl Phosphoric Acid) in 1-decanol and supported by a hydrophobic microporous membrane.
The equilibrium and transport rate data are reported in terms of distribution coefficients and mass transfer coefficients
under the varying conditions of feed phase pH and carrier concentration. The experimental results obtained are analyzed to
confirm the mechanism of the complex formation between carrier and L-valine and to describe the transport rate of L-valine
through the supported liquid membrane by an appropriate theoretical model. The selectivity and the stability of the supported
liquid membrane under study were also evaluated to ensure its potential application as a commercial down-stream process. 相似文献
49.
50.
Hoe I. Ling Huabei Liu Victor N. Kaliakin Dov Leshchinsky 《Canadian Metallurgical Quarterly》2004,130(8):911-920
An advanced generalized plasticity soil model and bounding surface geosynthetic model, in conjunction with a dynamic finite element procedure, are used to analyze the behavior of geosynthetic-reinforced soil retaining walls. The construction behavior of a full-scale wall is first analyzed followed by a series of five shaking table tests conducted in a centrifuge. The parameters for the sandy backfill soils are calibrated through the results of monotonic and cyclic triaxial tests. The wall facing deformations, strains in the geogrid reinforcement layers, lateral earth pressures acting at the facing blocks, and vertical stresses at the foundation are presented. In the centrifugal shaking table tests, the response of the walls subject to 20 cycles of sinusoidal wave having a frequency of 2 Hz and of acceleration amplitude of 0.2g are compared with the results of analysis. The acceleration in the backfill, strain in the geogrid layers, and facing deformation are computed and compared to the test results. The results of analysis for both static and dynamic tests compared reasonably well with the experimental results. 相似文献