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21.
Soodabeh Khalili Behnam Khoshandam Mohsen Jahanshahi 《Korean Journal of Chemical Engineering》2016,33(10):2943-2952
Adsorption of pure carbon dioxide and methane was examined on activated carbon prepared from pine cone by chemical activation with H3PO4 to determine the potential for the separation of CO2 from CH4. The prepared adsorbent was characterized by N2 adsorption-desorption, elemental analysis, FTIR, SEM and TEM. The equilibrium adsorption of CO2 and CH4 on AC was determined at 298, 308 and 318 K and pressure range of 1–16 bar. The experimental data of both gases were analyzed using Langmuir and Freundlich models. For CO2, the Langmuir isotherm presented a perfect fit, whereas the isotherm of CH4 was well described by Freundlich model. The selectivity of CO2 over CH4 by AC (CO2: CH4=50: 50, 298K, 5 bar), predicted by ideal adsorbed solution theory (IAST) model, was achieved at 1.68. These data demonstrated that pine cone-based AC prepared in this study can be successfully used in separation of CO2 from CH4. 相似文献
22.
Mohammadreza Kalaee Shahin Akhlaghi Ali Nouri Saeedeh Mazinani Mehrzad Mortezaei Mehdi Afshari Dariush Mostafanezhad Ahmad Allahbakhsh Hamidreza Aliasgari Dehaghi Ali Amirsadri Donya Pakdaman Gohari 《Progress in Organic Coatings》2011,71(2):173-180
Today's strict environmental laws pose significant challenges for coating's formulators to look for eco-friendly products. Powder coatings, particularly polyester/epoxy blends have demonstrated their ability as alternatives to traditional solvent-borne coatings. Recently, the use of nanoparticles such as nano-CaCO3 (nCaCO3) has been suggested as a beneficial strategy towards powder coating application with improved properties. Here, we study the effect of nCaCO3 on morphology, cure behavior, adhesion and hardness of polyester/epoxy systems. The nanoparticles shape, size and dispersion state were investigated through X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. Furthermore, isothermal cure characterization of the neat and filled systems was performed using a torque rheometer. The most important finding based on the rheological studies was the catalytic effect of nCaCO3 on cure reaction of polyester/epoxy, leading to the shorter curing time. Moreover, the kinetic analyses of rheograms revealed a marked decrease in the activation energy of the cure process upon raising nCaCO3 content. Interestingly, pull-off adhesion and hardness tests showed that the hardness and adhesion strength were dramatically increased by the addition of nCaCO3 into the polyester/epoxy system compared to pure blend resin. Therefore, considering the strong competition in powder coating market, the use of nCaCO3 as a commercial and inexpensive nanofiller is necessary not only to reduce the dwell time which has benefits in terms of the energy consumption and economics, but also to improve the performance of final polyester/epoxy coating. 相似文献
23.
Ashkan Heidarkhan Tehrani Ali Zadhoush Saeed Karbasi Saied Nouri Khorasani 《应用聚合物科学杂志》2010,118(5):2682-2689
We sought to determine the impact of electrospinning parameters on a trustworthy criterion that could evidently improve the maximum applicability of fibrous scaffolds for tissue regeneration. We used an image analysis technique to elucidate the web permeability index (WPI) by modeling the formation of electrospun scaffolds. Poly(3‐hydroxybutyrate) (P3HB) scaffolds were fabricated according to predetermined conditions of levels in a Taguchi orthogonal design. The material parameters were the polymer concentration, conductivity, and volatility of the solution. The processing parameters were the applied voltage and nozzle‐to‐collector distance. With a law to monitor the WPI values when the polymer concentration or the applied voltage was increased, the pore interconnectivity was decreased. The quality of the jet instability altered the pore numbers, areas, and other structural characteristics, all of which determined the scaffold porosity and aperture interconnectivity. An initial drastic increase was observed in the WPI values because of the chain entanglement phenomenon above a 6 wt % P3HB content. Although the solution mixture significantly (p < 0.05) changed the scaffold architectural characteristics as a function of the solution viscosity and surface tension, it had a minor impact on the WPI values. The solution mixture gained the third place of significance, and the distance was approved as the least important factor. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
24.
M. Saeed Abaee Soodabeh Forghani Mohammad M. Mojtahedi Klaus Harms 《Journal of Sulfur Chemistry》2016,37(6):683-691
A facile procedure is developed for one-pot synthesis of a new group of dicyanoanilines. Tetrahydro-4H-thiopyran-4-one, 1, undergoes a pseudo four-component reaction with various aldehydes bearing different groups and two equivalents of malononitrile in aqueous media in the presence of triethylamine (Et3N). As a result, novel thiopyran-fused dicyanoanilines 4 are formed efficiently in the reaction mixtures in 90–97% yield within 9–12?h mixing at 40°C. Due to the polarity of the medium, products precipitate in the mixture spontaneously allowing for easy purification by recrystallization avoiding cumbersome chromatographic separations. Characterization of the products was performed by spectroscopic methods and, in one case, was further supported by X-ray crystallographic experiments. 相似文献
25.
The sample complexity of a reinforcement-learning algorithm is highly coupled to how proficiently it explores, which in turn
depends critically on the effective size of its state space. This paper proposes a new exploration mechanism for model-based
algorithms in continuous state spaces that automatically discovers the relevant dimensions of the environment. We show that
this information can be used to dramatically decrease the sample complexity of the algorithm over conventional exploration
techniques. This improvement is achieved by maintaining a low-dimensional representation of the transition function. Empirical
evaluations in several environments, including simulation benchmarks and a real robotics domain, suggest that the new method
outperforms state-of-the-art algorithms and that the behavior is robust and stable. 相似文献
26.
Rong-Ting Huang Dumrong Kasemset N. Nouri C. Colvard D. Ackley 《Journal of Electronic Materials》1989,18(5):603-609
A unique multi-wafer OMVPE reactor with capability to produce atomic-layer abrupt-ness is demonstrated. Uniform GaAs and AlGaAs epitaxial layers were grown on four two-inch wafers or one three- or four-inch wafer. Thickness variation across a three-inch wafer was less than ±2%, while the variation of Al solid composition was less than ±1%. Multiple AlGaAs/GaAs quantum wells ranging in size from 10Å to 140Å were grown with heterointerface roughness less than one monolayer. The electrical properties of HEMT device were studied. Variations of sheet carrier concentration and electron mobility were ±6% and ±5% respectively across a three-inch wafer. The carrier con-centration profile, mobility spectrum and device characteristics of DH-HEMT are also presented. These results indicate that this OMVPE reactor can grow good device struc-tures for microwave and millimeter-wave power device applications. 相似文献
27.
Dr. Teshome Aboye Yuting Kuang Prof. Dr. Nouri Neamati Prof. Dr. Julio A. Camarero 《Chembiochem : a European journal of chemical biology》2015,16(5):827-833
We report here the first rapid parallel production of bioactive folded cyclotides by using Fmoc‐based solid‐phase peptide synthesis in combination with a “tea‐bag” approach. Using this approach, we efficiently synthesized 15 analogues of the CXCR4 antagonist cyclotide MCo‐CVX‐5c. Cyclotides were synthesized in a single‐pot, cyclization/folding reaction in the presence of reduced glutathione. Natively folded cyclotides were quickly purified from the cyclization/folding crude mixture by activated thiol Sepharose‐based chromatography. The different folded cyclotide analogues were then tested for their ability to inhibit the CXCR4 receptor in a cell‐based assay. The results indicated that this approach can be used for the efficient chemical synthesis of libraries of cyclotides with improved biological properties that can be easily interfaced with solution or cell‐based assays for rapid screening. 相似文献
28.
M. Izadinia M. Shamanian H. Mohammadi H. Keyvanlou A. R. Nouri 《Transactions of the Indian Institute of Metals》2012,65(5):497-502
In the present work, using a new approach, Fe?CAl intermetallics were formed on the surface of a low-carbon steel (ST52) in order to study its effects on the oxidation, hardness and abrasive behavior. The samples were welded with gas tungsten arc welding technique using an aluminum?Ciron powder (stoichiometry ratio of 1:1) as filer. The microstructural evolutions of coated samples were then characterized using scanning electron microscopy and X-ray diffraction techniques. Besides, hardness and abrasion tests were carried out to study the abrasive behavior of coated layer. The resistance to hot oxidation of coated samples were evaluated by heating to 500, 600 and 700?°C and holding for 2?h. The results show that Fe3Al and aluminum?Ciron carbide (FeAlC0.65) were formed on surface of samples. The formation of these phases resulted in increase in the hardness and oxidation resistance, while no improvement on the wear resistance was observed. 相似文献
29.
Keltouma Nouri Mohamed Feham Saliha Dali 《Journal of Infrared, Millimeter and Terahertz Waves》2005,26(12):1727-1739
The integral equations technique based on a three dimensional finite element method is applied as a quick and accurate analysis tool for the design of microwave passband filters. A three resonator H-plane bandpass filters with the various shapes of cavities and the irises are analyzed with this method in a single step and for only one mode, take into account all the electromagnetic effects. Consequently, it consumes less memory and CPU time.We propose also to study the same filters filled by homogeneous high dielectric material (ετ = 9.6) for Both resonator and coupling section.All these numerical results have been validated through a comparison with the results available in the scientific literature. 相似文献
30.
Aiming for the simultaneous realization of constant gain, accurate input and output impedance matching and minimum noise figure (NF) over a wide frequency range, the circuit topology and detailed design of wide broadband low noise amplifier (LNA) are presented in this paper. A novel 2.5–3.1 GHz wide-band LNA with unique characteristics has been presented. Its design and layout are done by TSMC 0.18 \(\upmu \hbox {m}\) technology. Common gate stage has been used to improve input matching. In order to enhance output matching and reduce the noise as well, a buffer stage is utilized. Mid-stages which tend to improve the gain and reverse isolation are exploited. The proposed LNA achieves a power gain of 15.9 dB, a NF of 3.5 dB with an input return loss less than \(-\) 11.6, output return loss of \(-\) 19.2 to \(-\) 19 and reverse isolation of \(-\) 38 dB. The LNA consumes 54.6 mW under a supply voltage of 2 V while having some acceptable characteristics. 相似文献