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71.
We report a comparative study of triplex tandem mass spectrometry (MS/MS) based assays of lysosomal enzymes in dried blood spots for the early detection of Pompe, Fabry, and Hurler diseases in newborns. Four methods have been evaluated that differed in sample handling and the equipment used. A newly developed method uses assay quenching with acetonitrile to precipitate blood proteins followed by analysis on an LC-electrospray/MS/MS system capable of multiple consecutive sample injections on two parallel chromatographic columns. This method requires 1.5 min per a triplex analysis of enzyme products and internal standards, which matches the throughput of the previously reported flow injection method. LC separation reduces matrix effects and allows for more facile sample workup. The new LC-based method showed figures of merit that were superior to those of the currently used method based on liquid-liquid extraction into ethyl acetate and flow injection into the mass spectrometer. The other methods we investigated for comprehensive comparison involved liquid-liquid extraction into ethyl acetate followed by LC-ESI-MS/MS and acetonitrile quenching followed by direct flow injection. Both methods using acetonitrile quenching were found to be robust and provide good quality data while requiring fewer liquid transfer steps and less disposable material and labor than did the extraction methods. The individual merits of the new methods are discussed to present an evaluated alternative approach to high-throughput analysis in newborn screening laboratories. 相似文献
72.
Anna Knaislová Jiří Linhart Pavel Novák Filip Průša Jaromír Kopeček František Laufek 《粉末冶金学》2019,62(1):54-60
This work is devoted to the preparation of alloys based on intermetallic compounds in the Ti–Al–Si system by powder metallurgy using mechanical alloying and the spark plasma sintering (SPS) method. The aim was to describe the formation of intermetallic phases during mechanical alloying of TiAl15Si15 (wt-%) alloy and to consolidate the powder prepared by optimised conditions. Phase composition, microstructure and hardness of compacted alloy were determined. Four hours of mechanical alloying is sufficient time for preparation of pure elements free material composed only of intermetallic phases. After consolidation, the TiAl15Si15 alloy has a homogeneous structure composed of silicide (Ti5Si3) in aluminide (TiAl) matrix. The hardness of the material reaches 865?±?42 HV 5. 相似文献
73.
Alkali metals contained in amalgams react with polytetrafluorethylene at room temperature. An electrochemical mechanism of the reaction was suggested. A theoretical relation (dl/dt = Kl?1) was derived and verified by experiment for the rate of penetration of the reaction into the depth of polytetrafluorethylene. The system alkali metal —polytetrafluorethylene forms a typical corrosion galvanic cell with a solid electrolyte. The electrolyte exhibits selective ionic conductivity for Li+. 相似文献
74.
It was found that the product of the reduction of the cyanide complex of hexavalent osmium, OsO2(OH)2(CN)2?2 is the Os(OH)4(CN)3?4 complex and the product of the reduction of the OsO2(CN)2?4 complex is the Os(OH)2(CN)2?2 complex. Further reduction of the Os(OH)4(CN)3?4 complex of trivalent osmium is complicated by a follow-up chemical reaction and the stable reduction product is a complex of divalent osmium, Os(OH)2(CN)4?4 which forms a reversible redox system with the Os(OH)2(CN)3?2 complex with a formal redox protential (1 M KOH, 0.1 M KCN) of ?760 mV/sce. The Os(OH)4(CN)3?2 and Os(OH)2(CN)4?4 complexes are stable only in solutions with at least a ten-fold excess of OH? ions over the concentration of CNt- ions. At greater cyanide concentrations, the chemical reactioins, Os(OH)4(CN)3?2 → Os(OH)2(CN)3?4 and Os(OH)2(CN)4?4 → Os(CN)4?6, occur. The reaction rate for the latter reaction was found to be ?4 = 1.87 × 10t-4 l mol?1 s?1 in solutions with pH = 11.8. The characteristics of the individual forms of the cyanide complexes of osmium are also discussed. 相似文献
75.
Highly porous particles furnish, due to their porosity, smaller Coulter diameters and Coulter volumes than the real particle size and envelope volume, respectively. Finding a relation between these variables (eqn. 4) makes the determination of the latter easier. In addition to the readily obtainable Coulter and porosity data, only one empirical constant for each material class has to be determined. 相似文献
76.
S. M. Tuominen G. W. Franti D. A. Koss 《Metallurgical and Materials Transactions A》1977,8(3):457-463
The phase transformations occurring in a quenched and aged β-phase (bcc) Ti-40 at. pct V+1 at. pct Si alloy have been investigated using transmission electron microscopy. Upon aging at 570°C, the most probable precipitation sequence is the following: bcc super-saturated solid solution»bcc zones»(Ti, V)xSiy (hexagonal)»(Ti, V)3Si (tetragonal). The bcc precipitates may be considered Si-rich GP zones which are homogeneously nucleated and coherent with the matrix. The (Ti, V)xSiy particles are a rod-shaped transition phase aligned along the <100> matrix directions. The precipitation reaction causes two peaks in the dependence of the yield stress or hardness upon aging time. The particle diameter and interparticle spacings of the hexagonal silicides indicate that these precipitates are responsible for the second hardness peak. The bcc zones evidently cause the first hardness peak at short aging times at 570°C. 相似文献
77.
František Mojžíš Jaromír Kukal Jan Švihlík 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2016,20(2):621-636
Detection and localization of astronomical objects are two of the most fundamental topics in astronomical science where localization uses detection results. Object localization is based on modeling of point spread function and estimation of its parameters. Commonly used models as Gauss or Moffat in objects localization provide good approximation of analyzed objects but cannot be sufficient in the case of exact applications such as object energy estimation. Thus the use of sophisticated models is upon the place. One of the key roles plays also the way of the objective function estimation. The least square method is often used, but it expects data with normal distribution, thus there is a question of a maximum likelihood method application. Another important factor of presented problem is choice of the right optimization method. Classical methods for objective function minimization usually require a good initial estimate for all parameters and differentiation of the objective function with respect to model parameters. The results indicated that stochastic methods such as simulated annealing or harmony search achieved better results than the classical optimization methods. 相似文献
78.
Tomasz Jurdziński Friedrich Otto František Mráz Martin Plátek 《Theory of Computing Systems》2008,42(4):488-518
The
-automaton is the weakest form of the nondeterministic version of the restarting automaton that was introduced by Jančar et al. to model the so-called analysis by reduction. Here it is shown that the class ℒ(R) of languages that are accepted by
-automata is incomparable under set inclusion to the class
of Church-Rosser languages and to the class
of growing context-sensitive languages. In fact this already holds for the class
of languages that are accepted by 2-monotone
-automata. In addition, we prove that already the latter class contains
-complete languages, showing that already the 2-monotone
-automaton has a surprisingly large expressive power.
The results of this paper have been announced at DLT 2004 in Auckland, New Zealand.
This work was mainly carried out while T. Jurdziński was visiting the University of Kassel, supported by a grant from the
Deutsche Forschungsgemeinschaft (DFG).
F. Mráz and M. Plátek were partially supported by the Grant Agency of the Czech Republic under Grant-No. 201/04/2102 and by
the program ‘Information Society’ under project 1ET100300517. F. Mráz was also supported by the Grant Agency of Charles University
in Prague under Grant-No. 358/2006/A-INF/MFF. 相似文献
79.
Synapses are stable adhesive domains between two neighbouring cells of the multicellular organisms which serve for cell–cell communication as well as for information processing and storing. The synaptic concept was developed over more than 100 years specifically for neuronal cell–cell communication. In the last ten years, this concept was adapted to embrace other cell–cell communication phenomena. Here, we focus on the recently emerged phagocytic synapse and propose new endosymbiotic synapses and “intracellular organellar synapses”. All these synapses of eukaryotic cells are in a good position to explain the high capacity of eukaryotic cells for integration of diverse signalling inputs into coherent cellular behaviour. 相似文献
80.
Two forms of cyanide complexes of hexavalent osmium were found in alkaline KCN solutions. The initially formed complex, OsO2(OH)2(CN)2?2, is stable only in solutions with at least a ten-fold excess of OH? ions over CN? ions. At higher cyanide concentrations it is converted into the OsO2(CN)2?4 complex. Both these complexes are reduced to tervalent osmium. A more detailed study of complex OsO2(OH)2(CN)2?2 has shown that it is reduced electrochemically according to the scheme of a consecutive electrochemical reaction.OsO2(OH)2(CN)2?2 + 2e(k1,α1) → Os(IV) + e(k2,α2) → Os(OH)4(CN)3?2The values α1 = 0.65 and α2 = 0.40 and the potential dependences of constants k1 and k2 were determined. 相似文献