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961.
Plasma impedance monitoring (PIM) based on electrical measurements is successfully used as an alternative to determine real time detection endpoint during plasma etching of structured bulk materials. In this paper we present the results with this technique for the endpoint detection during the etching of various materials.The endpoint conditions are tested in the sixth harmonic components of the electrical plasma parameters with an RF sensor. The endpoint is determined when an electrical parameter transition is observed. This transition corresponds to the change of the total reactor impedance, and allows the etching of the doped layer to stop on the bulk substrate.Using a Smith chart we determine the best harmonics/electrical monitoring couple parameters for processes on various materials. Resistivity measurements are used before and after etching in order to confirm the usefulness of the PIM method.In this paper, we also demonstrate how to monitor a real time control of non-uniformity during the reactive ion etching (RIE) process in the case of gallium arsenide etching. 相似文献
962.
A new contact mechanics model is presented and experimentally examined at the nanoscale. The current work addresses the well-established field of contact mechanics, but at the nanoscale where interaction stresses seem to be effective. The new model combines the classic Hertz theory with the new interaction stress concept to provide the stress field in contact bodies with adhesion. Hence, it benefits from the simplicity of non-adhesive models, while offering the same applicability as more complicated models. In order to examine the model, a set of atomic force microscopy experiments were performed on substrates made from single-walled carbon nanotube buckypaper. The stress field in the substrate was obtained by superposition of the Hertzian stress field and the interaction stress field, and then compared to other contact models. Finally, the effect of indentation depth on the stress field was studied for the interaction model as well as for the Hertz, Derjaguin-Muller-Toporov, and Johnson-Kendall-Roberts models. Thus, the amount of error introduced by using the Hertz theory to model contacts with adhesion was found for different indentation depths. It was observed that in the absence of interaction stress data, the Hertz theory predictions led to smaller errors compared to other contact-with-adhesion models. 相似文献
963.
Pascal Coursol Nubia Cardona Valencia Phillip Mackey Stacy Bell Boyd Davis 《JOM Journal of the Minerals, Metals and Materials Society》2012,64(11):1305-1313
In the quest to achieve the highest metal recovery during the smelting of copper concentrates, this study has evaluated the minimum level of soluble copper in iron-silicate slags. The experimental work was performed under slag-cleaning conditions for different levels of Fe in the matte and for a range of Fe/SiO2 ratios in the slag. All experiments were carried out under conditions where three phases were present (copper?Cmatte?Cslag), which is the condition typically prevailing in many slag-cleaning electric furnaces. The %Fe in the electric furnace matte was varied between 0.5?wt.% and 11?wt.%, and two different Fe/SiO2 ratios in the slag were used (targeted values were 1.4 and 1.6). All experiments were performed at 1200°C. From thermodynamic considerations, from industrial experience, and from the results obtained in this study, the minimum soluble copper content in the electric furnace slag is expected to be near 0.55?wt.% Cu. This level does not account for a portion of the copper present as mechanically entrained matte/metal droplets. Taking this into account, the current authors believe an overall copper level in discard slag between 0.7?wt.% and 0.8?wt.% can be obtained with optimal operating conditions. For these conditions, the copper losses in the slag are roughly 75% as dissolved copper and 25% as entrained matte and copper. Such conditions include operating the electric furnace at metallic copper saturation, maintaining the %Fe in the electric furnace matte between 6?wt.% and 9?wt.%, not exceeding a slag temperature of 1250°C, and controlling the Fe/SiO2 ratio in the smelting furnace slag at ??1.5. In addition, magnetite reduction needs to be performed efficiently during the slag-cleaning cycle so as to maintain a total magnetite content of ??7?wt.% in the discard slag. The authors further consider that under exceptionally well-controlled conditions, a copper content in electric furnace discard slag between 0.55?wt.% and 0.7?wt.% can be obtained, by minimizing entrained matte and copper solubility in the discard slag. 相似文献
964.
Gbabode G Dumont N Quist F Schweicher G Moser A Viville P Lazzaroni R Geerts YH 《Advanced materials (Deerfield Beach, Fla.)》2012,24(5):658-662
A new phase of a known discotic liquid crystal is observed at the interface with a rigid substrate. The structure of the substrate-induced phase has been characterized by atomic force microscopy, specular X-ray diffraction, and small-angle and wide-angle grazing incidence X-ray diffraction. The substrate-induced phase, which has a thickness of ~30 nm and a tetragonal symmetry, differs notably from the bulk phase. The occurrence of such phase casts a new light on alignment of discotic liquid crystals. 相似文献
965.
Berd M Puech P Righi A Benfdila A Monthioux M 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(13):2045-2052
The selective excitation of fullerenes encapsulated in single-walled carbon nanotubes (SWCNTs) is carried out by irradiating them using a UV laser, the wavelength of which corresponds exactly to their maximum of absorption. Under such conditions, fullerenes strongly absorb the laser energy, open, and break, while the containing SWCNT merely acts as both a nanoreactor and a mold which is only weakly heated by the laser. The containing tube confines the fullerene fragments, promotes their reconstruction into an inner tube, and protects them from air oxidation. This leads to the overall formation of double-walled carbon nanotubes (DWCNTs). The transformation is found to strongly depend on the laser irradiance and dose. This proves that the related mechanism is a multiphoton photolysis, different from the previous heat-induced transformation attempts found in the literature, whether the heat is produced by means of a thermostat, infrared laser, or nonresonant UV laser. The actual peapod-to-DWCNT transformation is monitored by Raman spectroscopy and high-resolution transmission electron microscopy. 相似文献
966.
Jordi Nin Anne Laurent Pascal Poncelet 《Journal of Intelligent Information Systems》2010,35(3):447-463
Gradual rules allow users to be provided with rules describing the ordering correlations among attributes. Such a rule is
for instance given by the higher the salary and the lower the number of cars, the higher the number of tourist travels. Previously intensively used in fuzzy command systems, these rules were manually provided to the system. More recently, they
have received attention from the data mining community and methods have been defined to automatically extract and maintain
gradual rules from numerical databases. However, no method has been shown to be able to handle data streams, as no method
is scalable enough to manage the high rate which stream data arrive at. In this paper, we thus propose an original approach
to mine data streams for gradual rules. Our method is based on B-Trees and OWA (Ordered Weighted Aggregation) operator in
order to speed up the process. B-Trees are used to store already-known gradual rules in order to maintain the knowledge over
time, while OWA operators provide a fast way to discard non relevant data. 相似文献
967.
Sylvie Fourdrin Maryline Rochery Lon Gengembre Pascal Rumeau Maryline Lewandowski Manuela Ferreira Serge Bourbigot 《应用聚合物科学杂志》2006,102(5):4092-4100
The purpose of this study is to better understand the mechanisms governing the phenomena of fiber/matrix adhesion by controlling the fiber surface properties. This adhesion is evaluated by studying the micromechanical and thermodynamical behavior of the fiber/matrix interface. The complexity of the interactions at the interface requires a global approach that takes into account the chemistry, morphology, and mechanics. The thermodynamical affinity between the binder and fibers is evaluated by the wetting behavior, whereas the mechanical resistance of the fiber/matrix interface is characterized with the pull‐out test. Three distinct approaches are used to classify the different systems according to the nature of the binder and the fiber surface. It is found that there is better adhesion when the spin finish is removed from the fibers, revealing the surface roughness on which the latex can mechanically anchor. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 4092–4100, 2006 相似文献
968.
Peter G. Stroot Pascal E. Saikaly Daniel B. Oerther 《Canadian Metallurgical Quarterly》2005,131(12):1698-1705
Results of mathematical modeling and whole cell 16S ribosomal RNA-targeted fluorescence in situ hybridizations challenge the widely held perception that microbial populations in “steady-state” activated sludge systems share a common net growth rate that is proportional to the inverse of the mean cell residence time. Our results are significant because they encourage bioprocess engineers to appreciate the differences in growth physiology among individual microbial populations in complex mixed microbial communities such as suspended growth activated sludge bioreactor systems. 相似文献
969.
Pascal Salome Charles Leroux Philippe Crevel Jean Pierre Chante 《Microelectronics Reliability》1999,39(11):1579
This work focuses on the interconnect heating during fast ESD transients. A simplified thermal RC network is used to study the behavior of interconnects and to predict their failures, which can be an open circuit or a latent failure due to the decrease of the electromigration lifetime. The RC model is validated by both experiments and finite difference simulations. We observe that the melting of the interconnect system can be considered as instantaneous. Simulations in both solid and liquid phase of the metal are in good agreement with experiments. HBM and MM transients are investigated and a relationship to correlate these ESD stresses with the TLP measurements is studied in depth. We show that a square pulse of 80 ns may be used to predict an HBM stress and a 45 ns pulse is proposed for MM. 相似文献
970.
Guerreiro Maria J. S.; Murphy Dana R.; Van Gerven Pascal W. M. 《Canadian Metallurgical Quarterly》2010,136(6):975
Selective attention requires the ability to focus on relevant information and to ignore irrelevant information. The ability to inhibit irrelevant information has been proposed to be the main source of age-related cognitive change (e.g., Hasher & Zacks, 1988). Although age-related distraction by irrelevant information has been extensively demonstrated in the visual modality, studies involving auditory and cross-modal paradigms have revealed a mixed pattern of results. A comparative evaluation of these paradigms according to sensory modality suggests a twofold trend: Age-related distraction is more likely (a) in unimodal than in cross-modal paradigms and (b) when irrelevant information is presented in the visual modality, rather than in the auditory modality. This distinct pattern of age-related changes in selective attention may be linked to the reliance of the visual and auditory modalities on different filtering mechanisms. Distractors presented through the auditory modality can be filtered at both central and peripheral neurocognitive levels. In contrast, distractors presented through the visual modality are primarily suppressed at more central levels of processing, which may be more vulnerable to aging. We propose the hypothesis that age-related distractibility is modality dependent, a notion that might need to be incorporated in current theories of cognitive aging. Ultimately, this might lead to a more accurate account for the mixed pattern of impaired and preserved selective attention found in advancing age. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献