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81.
The nonspecific preparation that follows a warning stimulus (WS) to speed responding to an impending imperative stimulus (IS) is generally viewed as a strategic, intentional process. An alternative view holds that WS acts as a conditioned stimulus that unintentionally elicits a tendency to respond at the moment of IS presentation as a result of a process of trace conditioning. These views were contrasted as explanatory frameworks for classical effects on reaction time of the duration and intertrial variability of the foreperiod, the interval between WS and IS. It is shown that the conditioning view accounts for the available data at least as well as the strategic view. In addition, the results of 3 experiments provide support for the conditioning view by showing that unintentional contributions to nonspecific preparation can be dissociated from intentional contributions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
82.
Jose García-Torres Elvira Gómez Elisa Vallés 《Journal of Applied Electrochemistry》2009,39(2):233-240
Cobalt electrodeposits were prepared from an electrolytic bath containing cobalt perchlorate. The effect of different species,
organic (thiourea and sodium gluconate) and inorganic (boric acid), on the crystallographic structure, morphology, magnetic
properties and electrochemical behaviour of cobalt electrodeposits was investigated. Amorphous cobalt, hcp cobalt and a non-usual
primitive cubic cobalt phase were observed depending on the bath composition. Depending on the structure, different morphologies
and magnetic properties were found. Coercivity values of the cobalt coatings ranged from around 15 Oe for amorphous, nodular
deposits to 380 Oe for cobalt coatings showing acicular morphology and hcp structure with a (002) preferred orientation. Knowledge
of the influence of the species on the properties of cobalt makes it possible to obtain tailored cobalt films. 相似文献
83.
Zihong Liu Tommy E. Cousins John J. Lesko Elisa D. Sotelino 《Canadian Metallurgical Quarterly》2008,12(6):660-668
No appropriate provisions from either AASHTO Standard (2002) or AASHTO LRFD (2004) bridge design specifications are available for the design of fiber-reinforced polymer (FRP)-deck-on-steel-superstructure bridges. In this research, a parametric study using the finite-element method (FEM) is conducted to examine two design issues concerning the design of FRP-deck-on-steel-superstructure bridges, namely deck relative deflection and load distribution factor (LDF). Results show that the strip method specified in AASHTO LRFD specification as an approximate method of analysis, can also be applied to FRP decks as a practical method. However, different strip width equations have to be determined by either FEM or experimental methods for different types of FRP decks. In this study, one such equation has been derived for the Strongwell deck. In addition, both FEM results and experimental measurements show that the AASHTO LDF equations for glued laminated timber decks on steel stringers provide good estimations of LDF for FRP-deck-on-steel-superstructure bridges. Finally, it is found that the lever rule can be used as an appropriately conservative design method to predict the LDF of FRP-deck-on-steel-superstructure bridges. 相似文献
84.
Isabel C.F.R. Ferreira Lillian Barros Maria Elisa Soares Maria Lourdes Bastos José Alberto Pereira 《Food chemistry》2007,103(1):188-195
Olive trees (Olea europaea L. Cv. Cobrançosa) from the northeast of Portugal were sprayed with three different copper formulations [bordeaux mixture (copper sulphate + calcium hydroxide − 20% Cu), copper hydroxide (40% Cu) and copper oxychloride (50% Cu)] to control olive fungal diseases. The residues of copper in olive leaves, harvested at different times, were evaluated by atomic absorption spectrometry. At all the collection times, treated olive leaves had significantly higher copper contents, compared to the control. The different copper amounts in pesticide formulations lowered the leaves contents in total phenols and hence their antioxidant properties. Olive leaves sprayed with copper oxychloride possessed the highest copper levels and the lowest content in phenols, which influenced its antioxidant activity (higher EC50 values for reducing power, scavenging effect on DPPH radicals and inhibition of erythrocyte hemolysis). Leaves without copper residues proved to be a good natural source of antioxidants, giving values comparable to the reference compounds. 相似文献
85.
Elisa Tripoli Maurizio La GuardiaSanto Giammanco Danila Di MajoMarco Giammanco 《Food chemistry》2007,104(2):466-479
Epidemiological studies have shown an inverse relationship between dietary flavonoid intakes and cardiovascular diseases. Citrus fruits are the main winter fruits consumed in the Mediterranean diet, so they are the main source of dietary flavonoids. The possible beneficial effects are due, not only to the high amounts of vitamins and minerals, but also to the antioxidant properties of their flavonoids. Dietary flavonoids may help to supplement the body antioxidant defences against free radicals. These compounds’ possible beneficial effects are due to their antioxidant activity, which is related to the development of atherosclerosis and cancer, and to anti-inflammatory and antimicrobial activity. The present review summarizes the existing bibliography on biological and pharmacological studies of Citrus flavonoids, both in vitro and in vivo. 相似文献
86.
Elisa Gavari Starkie 《Journal of Engineering Mathematics》1989,23(1):91-94
Programme of meetings — 1989 NATO international scientific exchange programmeEngineering, materials and systems sciences 相似文献
87.
Elisa García‐Tabars John A. Carlin Tyler J. Grassman Diego Martín Ignacio Rey‐Stolle Steven A. Ringel 《Progress in Photovoltaics: Research and Applications》2016,24(5):634-644
The evolution of Si bulk minority carrier lifetime during the heteroepitaxial growth of III–V on Si multijunction solar cell structures via metal‐organic chemical vapor deposition (MOCVD) has been analyzed. In particular, the impact on Si lifetime resulting from the four distinct phases within the overall MOCVD‐based III–V/Si growth process were studied: (1) the Si homoepitaxial emitter/cap layer; (2) GaP heteroepitaxial nucleation; (3) bulk GaP film growth; and (4) thick GaAsyP1‐y compositionally graded metamorphic buffer growth. During Phase 1 (Si homoepitaxy), an approximately two order of magnitude reduction in the Si minority carrier lifetime was observed, from about 450 to ≤1 µs. However, following the GaP nucleation (Phase 2) and thicker film (Phase 3) growths, the lifetime was found to increase by about an order of magnitude. The thick GaAsyP1‐y graded buffer was then found to provide further recovery back to around the initial starting value. The most likely general mechanism behind the observed lifetime evolution is as follows: lifetime degradation during Si homoepitaxy because of the formation of thermally induced defects within the Si bulk, with subsequent lifetime recovery due to passivation by fast‐diffusing atomic hydrogen coming from precursor pyrolysis, especially the group‐V hydrides (PH3, AsH3), during the III–V growth. These results indicate that the MOCVD growth methodology used to create these target III–V/Si solar cell structures has a substantial and dynamic impact on the minority carrier lifetime within the Si substrate. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
88.
Marcos Rodriguez Pascual Daniela Trambitas Elisa Saez Calvo Herman Kramer Geert-jan Witkamp 《Chemical Engineering Research and Design》2010
A crystallizer was built and a procedure developed to accurately measure the eutectic solubility lines where ice and salt coexist in equilibrium with the solution, for potential application of Eutectic Freeze Crystallization. The eutectic solubility lines of the ternary system NaHCO3–Na2CO3–H2O were determined experimentally and calculated with the extended UNIQUAC model. The extended UNIQUAC model describes the experimental data quite well. Anhydrous NaHCO3 and Na2CO3·10H2O were the only two types of crystals present in equilibrium with ice crystals in the ternary system. At the quadruple point NaHCO3 and Na2CO3·10H2O are in equilibrium with a solution of about 4.34 wt% of Na2CO3 and 4.77 wt% of NaHCO3 at −3.32 °C. The anhydrous NaHCO3 crystals were needle shaped with lengths between 5 and 10 μm, that were agglomerated into particles of about 100–300 μm, while the Na2CO3·10H2O crystals were hexagonally shaped with sizes between 100 and 500 μm. 相似文献
89.
Marina Serantoni Elisa Mercadelli Anna Luisa Costa Magda Blosi Laura Esposito Alessandra Sanson 《Ceramics International》2010,36(1):103-106
Sub-micrometer powder (100–150 nm diameter) of Yb-doped yttrium oxide was obtained, for the first time, by microwave-assisted polyol (diethylene glycol, DEG) method. This method is based on fast and homogeneous increase of temperature, due to the microwave heating, and on addition of the hydrolysing agent (water) at high temperature. This promotes a fast nucleation followed by a controlled growth of nuclei. Different procedures were used to process the as-synthesized powders. In some cases washing by ultrapure water was used to dissolve nitrate and DEG by-products, this treatment allowed the use of a lower calcination temperature (150–200 °C less) to obtain the crystalline phase. Analysis of the calcined powder showed different levels of structures: from nanocrystal (10–15 nm), to primary particles (100–150 nm), to micrometer soft aggregates (2–4 μm). The microwave-assisted polyol method resulted an easy way to dope yttria with the desired amount of Yb3+. This work was carried out in order to prepare particles to be used as rare-earth doped Y2O3 and YAG polycrystalline transparent ceramic for laser source applications. 相似文献
90.