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261.
Seong Ok Han Mehdi Karevan Md A. Bhuiyan Jung Ho Park Kyriaki Kalaitzidou 《Journal of Materials Science》2012,47(8):3535-3543
The focus of this study is to explore synergy between nanomaterials such as exfoliated graphite nanoplatelets (xGnP) and micro-size
reinforcements such as kenaf natural fibers, in poly(lactic acid) based composites. The nano-biocomposites are made by melt-mixing
followed by injection molding. Prior to melt-mixing the kenaf fibers were coated with the xGnP using sonication. The reinforcement
content used in the study was up to 5 wt% and up to 40 wt% for xGnP and kenaf fibers, respectively. The flexural strength
and modulus and the viscoelastic properties such as storage modulus were determined. It was found that addition of 5 wt% xGnP
did not increase the viscosity of the polymer melt, enhanced the flexural modulus by 25–30% at any fiber loading used but
did not increase the strength, indicating insufficient load transfer at the polymer-xGnP or xGnP-kenaf interface. Finally,
addition of xGnP had a positive effect on the heat distortion temperature but only at higher fiber loadings. 相似文献
262.
Afshar Bazyar Ebrahim Teimoury Mehdi N. Fesharaki 《The International Journal of Advanced Manufacturing Technology》2013,69(1-4):351-360
The purpose of this paper is to investigate the link among risk, governance, and performance. In order to achieve this objective, the paper examines the impact of relational risk on governance decision options (trust, bilateral control, and unilateral control) and performance (design time). Survey research was conducted to collect data from 221 new product development (NPD) relationships and structural equation modeling was conducted to test the hypotheses. The results suggest that relational risk influences trust and bilateral control negatively and unilateral control positively. Results also indicated that trust and bilateral control are positively related to shortened design time while unilateral control and shortened design time are negatively related. We also found that there are threshold effects for modes of governance decision as they influence shortened design time. This study enhances the understanding of NPD relationships by examining the key mechanisms through which governance decision modes are influenced and how they influence NPD performance. In summary, this study shows how relational risk perception through affecting governance decision modes influence shortened design time. 相似文献
263.
Arturo Gomez Ortega Luis Corona Galvan Mehdi Salem Kamel Moussaoui Stephane Segonds Sébastien Rouquette 《Science & Technology of Welding & Joining》2013,18(6):538-547
ABSTRACT4043 aluminium deposits were elaborated using a 3D print device equipped with a Cold Metal Transfer welding source. Two sets of process parameters leading to different average powers were compared in order to establish the relations between the powers and energies produced and the geometrical characteristics of the deposits. The effects of the travel speed and layer superposition on the transfer mechanisms as well as on the geometrical characteristics of the deposits were discussed for both sets of parameters. Finally, the formed microstructures were analysed and the porosity defects were quantified and discussed with regard to the heat input characteristics and the solidification conditions. 相似文献
264.
Kave Moloudi Hadi Samadian Mehdi Jaymand Ehsan Khodamoradi Mojtaba HoseiniGhahfarokhi Farshid Fathi 《IET nanobiotechnology / IET》2020,14(5):428
The main focus of the current study is the fabrication of a multifunctional nanohybrid based on graphene oxide (GO)/iron oxide/gold nanoparticles (NPs) as the combinatorial cancer treatment agent. Gold and iron oxide NPs formed on the GONPs via the in situ synthesis approach. The characterisations showed that gold and iron oxide NPs formed onto the GO. Cell toxicity assessment revealed that the fabricated nanohybrid exhibited negligible toxicity against MCF‐7 cells in low doses (<50 ppm). Temperature measurement showed a time and dose‐dependent heat elevation under the interaction of the nanohybrid with the radio frequency (RF) wave. The highest temperature was recorded using 200 ppm concentration nanohybrid during 40 min exposure. The combinatorial treatments demonstrated that the maximum cell death (average of 53%) was induced with the combination of the nanohybrid with RF waves and radiotherapy (RT). The mechanistic study using the flow cytometry technique illustrated that early apoptosis was the main underlying cell death. Moreover, the dose enhancement factor of 1.63 and 2.63 were obtained from RT and RF, respectively. To sum up, the authors’ findings indicated that the prepared nanohybrid could be considered as multifunctional and combinatorial cancer therapy agents.Inspec keywords: radiation therapy, toxicology, gold, biomedical materials, nanofabrication, nanoparticles, iron compounds, cancer, nanomedicine, cellular biophysics, tumours, graphene compounds, biothermicsOther keywords: graphene oxide nanohybrid, combinatorial cancer treatment agent, cell toxicity assessment, MCF‐7 cells, dose‐dependent heat elevation, multifunctional cancer therapy agents, thermoradiotherapy agent, graphene oxide‐iron oxide‐gold nanoparticles, temperature measurement, radiofrequency wave, flow cytometry, time 40.0 min, CO‐FeO‐Au 相似文献
265.
Kok Kee Yang M. R. Mahmoudian Mehdi Ebadi Hun Lee Koay Wan Jeffrey Basirun 《Metallurgical and Materials Transactions B》2011,42(6):1274-1279
Voltammetry and chronoamperometry for the electrodeposition of tin from Tin(II) methane sulfonate mixed with ionic liquid
and methane sulfonate acid at room temperature was studied. Cyclic voltammetry shows redox waves of Tin(II), which proves
that the electrodeposition of tin from Tin(II) methane sulfonate is a diffusion-controlled process. The diffusion coefficient
of Tin(II) ions in the solvent mixture showed good agreement from both voltammetry and chronoamperometry results. The diffusion
coefficient of Tin(II) in the mixture was much smaller than in aqueous solution, and it depends on the anion of the ionic
liquid. 相似文献
266.
Mehdi Ebadi Wan J. Basirun Yatimah Alias Mohammad R. Mahmoudian 《Metallurgical and Materials Transactions A》2011,42(8):2402-2410
The codeposition of Ni-Co-Fe-Zn alloys from a mixture of 1-ethyl-3-methylimidazolium chloride (EMIC)/ethylene glycol (EG)
was studied using potentiostatic electrodeposition in the potential range of –1.10 and –1.30 V vs saturated calomel electrode (SCE), using a permanent parallel magnetic field (PPMF) of 9 T. The uniform magnetic field was
aligned parallel to the cathode surface. It was found that both normal and anomalous codeposition occurred. Films with different
elemental percentage and deposit morphology were obtained from a mixture of EMIC/EG solution at the applied potentials (–1.10
and –1.30 V) in the absence and presence of a PPMF. The influence of magnetic field on the nucleation and growth process is
studied with respect to the magneto-hydrodynamic effect (MHD) and applied potentials. 相似文献
267.
Hamed Samarghandi Pouria Taabayan Mehdi Behroozi 《The International Journal of Advanced Manufacturing Technology》2013,67(9-12):2701-2715
Dynamic facility layout problem deals with the problem of arranging and rearranging the layout plan of a system throughout several periods. In each period, the material handling costs are different from the past period due to the change in the market demand and product mix. In this paper, the uncertainty that exists in transportation values’ forecast is modeled by fuzzy theory. In this paper, departments have unequal areas. This means that in each period, departments can be placed only in certain places due to different spacing requirements. In addition, closeness rating matrix is considered in order to model the goodness of different layout plans with regard to qualitative factors according to decision maker. Accordingly, fuzzy dynamic facility layout problem with unequal areas and closeness rating matrix is considered that aims to minimize the uncertain material handling costs as well as the shifting costs, and maximize closeness rating with regard to space requirements of unequal area departments. A number of fuzzy algorithms are developed in order to deal with the problem. A number of ranking criteria from the literature are implemented in order to compare the performance of the developed algorithms. 相似文献
268.
S. Mojtaba Taghizadeh Hamid Mirzadeh Mehdi Barikani Maryam Yousefi 《International Journal of Adhesion and Adhesives》2009,29(3):302-308
In this study, miscibility and tack of blends of poly (vinylpyrrolidone) (PVP)/acrylic pressure-sensitive adhesive (PSA) were evaluated. For this purpose, appropriate amounts of PVP (2–30% w/w) were added to an acrylic PSA to obtain visually homogeneous solution. The resulting solution was evenly applied on a polyethylene terephthalate (PET) film with final specific thicknesses of 10, 40, and 70 μm by using a film applicator and miscibility as well as tack values were evaluated. With the addition of 2% (w/w) PVP the tack value decreased and increased in 5% (w/w) PVP and then continuously decreased up to 30%(w/w). It was found that the tack value was related to miscibility as well as to viscosity and the free functional group such as hydroxyl group of the blend. By the morphological analysis performed through scanning electron microscopy (SEM) and also by the study of thermal analysis using the differential scanning calorimetry (DSC) behavior of blends, it was found that the two distinct phases constituted after adding 5% (w/w) of PVP. This resulted in the acrylic PSA forming the continuous phase, and by increasing the concentration of PVP a dispersed phase was developed. The dispersed phase has a higher viscosity than the continuous phase and therefore cannot wet the adherent and hence result in lowering the tack values. 相似文献
269.
Mehdi Ghazanfari Adel Alaeddini Seyed Taghi Akhavan Niaki Mir‐Bahador Aryanezhad 《Quality and Reliability Engineering International》2008,24(7):765-778
Control charts are the most popular statistical process control tools used to monitor process changes. When a control chart indicates an out‐of‐control signal it means that the process has changed. However, control chart signals do not indicate the real time of process changes, which is essential for identifying and removing assignable causes and ultimately improving the process. Identifying the real time of the change is known as the change‐point estimation problem. Most of the traditional methods of estimating the process change point are developed based on the assumption that the process follows a normal distribution with known parameters, which is seldom true. In this paper, we propose clustering techniques to estimate Shewhart control chart change points. The proposed approach does not depend on the true values of the parameters and even the distribution of the process variables. Accordingly, it is applicable to both phase‐I and phase‐II of normal and non‐normal processes. At the end, we discuss the performance of the proposed method in comparison with the traditional procedures through extensive simulation studies. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
270.
K Scheffzek MR Ahmadian L Wiesmüller W Kabsch P Stege F Schmitz A Wittinghofer 《Canadian Metallurgical Quarterly》1998,17(15):4313-4327
Neurofibromin is the product of the NF1 gene, whose alteration is responsible for the pathogenesis of neurofibromatosis type 1 (NF1), one of the most frequent genetic disorders in man. It acts as a GTPase activating protein (GAP) on Ras; based on homology to p120GAP, a segment spanning 250-400 aa and termed GAP-related domain (NF1GRD; 25-40 kDa) has been shown to be responsible for GAP activity and represents the only functionally defined segment of neurofibromin. Missense mutations found in NF1 patients map to NF1GRD, underscoring its importance for pathogenesis. X-ray crystallographic analysis of a proteolytically treated catalytic fragment of NF1GRD comprising residues 1198-1530 (NF1-333) of human neurofibromin reveals NF1GRD as a helical protein that resembles the corresponding fragment derived from p120GAP (GAP-334). A central domain (NF1c) containing all residues conserved among RasGAPs is coupled to an extra domain (NF1ex), which despite very limited sequence homology is surprisingly similar to the corresponding part of GAP-334. Numerous point mutations found in NF1 patients or derived from genetic screening protocols can be analysed on the basis of the three-dimensional structural model, which also allows identification of the site where structural changes in a differentially spliced isoform are to be expected. Based on the structure of the complex between Ras and GAP-334 described earlier, a model of the NF1GRD-Ras complex is proposed which is used to discuss the strikingly different properties of the Ras-p120GAP and Ras-neurofibromin interactions. 相似文献