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排序方式: 共有158条查询结果,搜索用时 21 毫秒
1.
2.
Jean-Charles Créput Abderrafiaâ Koukam 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2008,12(11):1125-1141
The paper presents an extension of the self- organizing map (SOM) by embedding it into an evolutionary algorithm to solve
the Vehicle Routing Problem (VRP). We call it the memetic SOM. The approach is based on the standard SOM algorithm used as
a main operator in a population based search. This operator is combined with other derived operators specifically dedicated
for greedy insertion moves, a fitness evaluation and a selection operator. The main operators have a similar structure based
on the closest point findings and local moves performed in the plane. They can be interpreted as performing parallels and
massive insertions, simulating the behavior of agents which interact continuously, having localized and limited abilities.
This self-organizing process is intended to allow adaptation to noisy data as well as to confer robustness according to demand
fluctuation. Selection is intended to guide the population based search toward useful solution compromises. We show that the
approach performs better, with respect to solution quality and/or computation time, than other neural network applications
to the VRP presented in the literature. As well, it substantially reduces the gap to classical Operations Research heuristics,
specifically on the large VRP instances with time duration constraint. 相似文献
3.
Duhamel Cécilie Caballero Jacqueline Couvant Thierry Crépin Jérôme Gaslain Fabrice Guerre Catherine Le Hong-Thaï Wehbi Mickaël 《Oxidation of Metals》2017,88(3-4):447-457
Oxidation of Metals - The present work focuses on the intergranular oxidation of Alloy 600 and its weld material Alloy 82 after exposure in simulated primary water at 340–360 °C... 相似文献
4.
A new liquid chromatographic separation method was developed for the speciation of the four main arsenic compounds present in water. Arsenite (As(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate (As(V)) were separated on a recently introduced stationary phase: porous graphitic carbon (PGC). The separation was first obtained under formic acid gradient conditions, but an adsorption phenomenon of As(V) on PGC was observed. To overcome this problem, As(V) was backflushed, and an efficient separation of the four solutes was achieved within 10 min. Extremely low detection limits (ranging from 10 to 70 ng x L(-1)) were obtained by coupling LC with an ICPMS. The method was successfully applied to different spiked mineral waters and a naturally arsenic-containing freshwater. 相似文献
5.
Moya KL Salès N Hässig R Créminon C Grassi J Di Giamberardino L 《Microscopy research and technique》2000,50(1):58-65
We examined the localization of PrP(c) in normal brain using free-floating section immunohistochemistry and monclonal antibody 3F4. In the mature hamster and baboon brain, PrP(c) is localized to the neuropil with a synaptic distribution and the PrP(c) immunoreactivity is denser in regions known for ongoing plasticity. Cell bodies and major fiber tracts have little or no PrP(c) immunoreactivity. At the electron microscopic level, PrP(c) immunoreactivity decorates synaptic profiles, both pre- and postsynaptically. Results obtained with two additional antibodies, 3B5 and Pri-304, showed similar patterns of PrP(c) bands on Western blots, although Pri-304 was less sensitive. On sections through the adult hamster hippocampus, 3B5 and Pri-304 both stained the synaptic neuropil while cell bodies in the pyramidal and dentate granule cell layers were not immunoreactive. Pri-304 differentiated between synaptic layers in the hippocampus and closely resembled the pattern of staining obtained with 3F4. Preliminary results of developing brain showed that PrP(c) is initially localized along fiber tracts in the neonate brain. These results show that PrP(c) has a synaptic distribution in the adult brain and suggest that there are important changes in its distribution during brain development. These results also characterize two additional reagents for studies of PrP(c) localization. 相似文献
6.
7.
A Ducastaing JL Azanza JM Robin J Raymond P Créac'h 《Canadian Metallurgical Quarterly》1976,58(7):771-782
Horse spleen cathepsin D (3.4.23.5.) was purified from crude extract by sodium chloride and ethanol precipitation, column chromatography fractionation on DEAE cellulose and CM Sephadex, re-chromatography on DEAE cellulose and gel filtration. The enzyme has been purified about 3.000 folds with a yield of 30 per cent. The purified enzyme seems to be homogeneous on Sephadex G100, one protein band is apparent on disc electrophoresis. Determined by dansylation the N-terminal amino acid is glycine. A molecular weight of 42,500 +/- 3,000 was obtained with Sephadex G100 gel filtration and light scattering measurements. Amino acid analysis and chemical determinations were performed: cathepsin D is a glycoprotein (2 or 3 osamine residues) including 344 amino acids and 4 disulfide bonds. Spectrophotometric data show that E1cm/1 mg/ml = 1.01 at lambda = 280 nm. ORD measurements indicate about 20 per cent of helicoidal content in the molecule. 相似文献
8.
Investigated kinematic reasoning, the equation of the dimensions of time, space, and velocity. 282 students, aged 8–17 yrs, made judgments about a spatial representation of duration (the mark made by a vibrator on moving tape) and about the velocity of the tape. Results indicate 2 types of errors: (a) errors concerning the inverse relationship between velocity and space (VE errors) and (b) errors regarding the differentiation of duration relative to kinematic frame (T errors). VE type errors were mostly observed at 8–9 yrs of age, while T errors were observed between 10 and 17 yrs of age. An important result was an observed "return" to the T type error (after a time lapse of 1 yr) with Ss producing correct response patterns. Errors are analyzed within the context of a theoretical model of kinematic reasoning. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Lethmate R Ratiney H Wajer FT Crémillieux Y van Ormondt D Graveron-Demilly D 《Magma (New York, N.Y.)》2003,16(1):21-28
A method—PA-keyhole—for 2D/3D dynamic magnetic resonance imaging with radial scanning is proposed. PA-keyhole exploits the
inherent strong oversampling in the center of k-space, which contains crucial temporal information regarding contrast evolution. The method is based on: (1) a rearrangement
of the temporal order of 2D/3D isotropic distributions of trajectories during the scan into subdistributions according to the desired time resolution, (2) a new post-acquisition keyhole approach based on the replacement of the central disk/sphere in k-space using data solely from a subdistribution, and (3) reconstruction of 2D/3D dynamic (time-resolved) images using 2D/3D-gridding
with Pipe's approach to the sampling density compensation and 2D/3D-IFFT. The scan time is not increased with respect to a
conventional 2D/3D radial scan of the same spatial resolution; in addition, one benefits from the dynamic information. The abilities of
PA-keyhole and the sliding window techniques to restore simulated dynamic contrast changes are compared. Results are shown
both for 2D and 3D dynamic imaging using experimental data. An application to in-vivo ventilation of rat lungs using hyperpolarized
helium is demonstrated.
Electronic Publication 相似文献
10.
Taous-Meriem Laleg-Kirati Emmanuelle Crépeau Michel Sorine 《Mathematics of Control, Signals, and Systems (MCSS)》2013,25(1):37-61
This study introduces a new signal analysis method, based on a semi-classical approach. The main idea in this method is to interpret a pulse-shaped signal as a potential of a Schrödinger operator and then to use the discrete spectrum of this operator for the analysis of the signal. We present some numerical examples and the first results obtained with this method on the analysis of arterial blood pressure waveforms. 相似文献