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861.
Driving after drinking (DAD) is a serious public health concern found to be more common among college students than those of other age groups or same-aged non-college peers. The current study examined potential predictors of DAD among a dual-site sample of 3753 (65% female, 58% Caucasian) college students. Results showed that 19.1% of respondents had driven after 3 or more drinks and 8.6% had driven after 5 or more drinks in the past 3 months. A logistic regression model showed that male status, fraternity or sorority affiliation, family history of alcohol abuse, medium or heavy drinking (as compared to light drinking), more approving self-attitudes toward DAD, and alcohol expectancies for sexual enhancement and risk/aggression were independently associated with driving after drinking over and above covariates. These results extend the current understanding of this high risk drinking behavior in collegiate populations and provide implications for preventive strategies. Findings indicate that in addition to targeting at-risk subgroups, valuable directions for DAD-related interventions may include focusing on lowering both self-approval of DAD and alcohol-related expectancies, particularly those associated with risk/aggression and sexuality. 相似文献
862.
Shevchenko Y Francis TJ Blair DA Walsh R DeRosa MC Albert J 《Analytical chemistry》2011,83(18):7027-7034
Surface plasmon resonance (SPR) biosensors prepared using optical fibers can be used as a cost-effective and relatively simple-to-implement alternative to well established biosensor platforms for monitoring biomolecular interactions in situ or possibly in vivo. The fiber biosensor presented in this study utilizes an in-fiber tilted Bragg grating to excite the SPR on the surface of the sensor over a large range of external medium refractive indices, with minimal cross-sensitivity to temperature and without compromising the structural integrity of the fiber. The label-free biorecognition scheme used demonstrates that the sensor relies on the functionalization of the gold-coated fiber with aptamers, synthetic DNA sequences that bind with high specificity to a given target. In addition to monitoring the functionalization of the fiber by the aptamers in real-time, the results also show how the fiber biosensor can detect the presence of the aptamer's target, in various concentrations of thrombin in buffer and serum solutions. The findings also show how the SPR biosensor can be used to evaluate the dissociation constant (K(d)), as the binding constant agrees with values already reported in the literature. 相似文献
863.
Mohamed M. Ibrahim Amine Mezni Mohammed Alsawat Tushar Kumeria Arwa Alrooqi Abdallah A. Shaltout Sameh I. Ahmed Rabah Boukherroub Mohammed A. Amin Tariq Altalhi 《国际能源研究杂志》2020,44(8):6725-6744
A newly synthesized zinc(II) complex, namely tert-butyl N-(2 mercaptoethyl)carbamatozinc(II) complex [Zn(Boc-S)2] (Boc = tert-butyl N-[2-mercaptoethyl]carbamate), has been used as an organozinc precursor for the production of crystalline ZnO and ZnO/TiO2 nanoparticles. The synthesized complex and the obtained nanomaterials were fully characterized using various spectroscopic and surface analysis techniques. Their surface morphology, chemical purity and stoichiometry have been investigated by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) as well as X-ray fluorescence. The synthesized Zn(II) molecular complex, ZnO and ZnO/TiO2 nanomaterials have been tested in alkaline aqueous solution (1.0 MNaOH) for the hydrogen evolution reaction (HER) using various electrochemical techniques. The results revealed high HER catalytic performance of ZnO and ZnO/TiO2 cathode materials, with the latter exhibiting higher catalytic activity recording an exchange current density (jo) of 0.3 mA cm−2. This current value, which approaches that of Pt wire (0.5 mA cm−2), cross-sectional area ~0.008 cm2, is about 11 and 100 times greater than those measured for ZnO alone (0.028 mA cm−2) and TiO2 alone (0.0032 mA cm−2), respectively. Moderate catalytic activity was recorded for the complex catalyst, namely GC-Zn(Boc-S)2 with jo value of (0.01 mA cm−2). Tafel slope values of 130 and 122 mV dec−1 were calculated for ZnO and ZnO/TiO2, respectively. Such Tafel slope values, which are close to that of the Pt wire (120 mV dec−1), referred to a Volmer-controlled HER kinetics. Other important electrochemical parameters describing the kinetics of the HER, such as roughness factor (Rf) and turnover frequency (TOF) were also estimated and discussed. The high numerical values of the various HER kinetic parameters recorded for the ZnO/TiO2 catalyst, in addition to its high stability and durability (stable for up to 10 000 continuous cathodic polarization cycles), besides maintaining its morphology and chemical composition after stability test (confirmed from SEM/EDX and XRD examinations), located it in a privileged position among the most efficient HER electrocatalysts reported in the literature. 相似文献
864.
865.
The present study reports the use of locally available fish (Labeo rohita) scales for Pb(II) removal from aqueous solutions under different experimental conditions. Maximum Pb(II) adsorption (196.8 mg g(-1)) occurred at pH 3.5. Pb(II) sorption was found to be pH, dose, initial metal concentration, contact time and shaking speed dependent while particle size and temperature independent. Experimental data of Pb(II) biosorption onto fish scales fitted well to Freundlich isotherm model in comparison to the model of Langmuir. The fast adsorption process in first 30 min followed by subsequent slow adsorption rate was suitably described by pseudo-second order model. In addition, this study was designed to evaluate the effect of physical and chemical pretreatments on surface properties of fish scales by the application of Fourier Transform Infrared (FTIR) Spectroscopic analysis. Physical pretreatments resulted in partial degradation of some functional groups. Alkaline pretreatments of fish scales did not have any significant influence on the nature of functional groups responsible for Pb(II) uptake, while acidic pretreatments resulted in degeneration of the most of functional groups on biosorbent cell wall. FTIR analysis confirmed the involvement of amino, carboxylic, phosphate and carbonyl groups in Pb(II) biosorption by fish scales. 相似文献
866.
Michael Sheyka Ihab El-Kady Tariq Khraishi Mahmoud M. Reda Taha 《International Journal of Mechanics and Materials in Design》2008,4(4):407-418
Photonic crystals (PCs) are synthetic materials that are used to control light propagation. PCs have a frequency bandgap where
light is forbidden to propagate. This bandgap is strongly tied to the microstructure of the photonic crystal. Three-dimensional
tungsten photonic crystal in a Lincoln-log microstructure has been suggested as a strong alternative filter in photovoltaic
cells with significantly high power efficiency. PCs have also been suggested as sensors for submicron damage. Therefore, mechanical
characterization of three-dimensional photonic crystals becomes of interest. Here we report on mechanical characterization
of tungsten PC using means of micro-indentation. We also present a three-dimensional finite element simulation of the structural
response of a Tungsten photonic crystal under micro-indentation load. Stresses developed in the PC can be used to quantify
the level of damage in the crystal. We compare our simulation results with the experimental observations of a Vickers and
Knoop micro-indentation experiments of tungsten PC. The FE models were proven able to simulate the mechanical response of
the PC with a good accuracy. The calibrated FE models can be further used to realize the mechanical behavior of PC under different
thermal and mechanical stresses when used as filters in photovoltaic cells or to simulate the effect of damage in PC sensors. 相似文献
867.
868.
Microbial communities involved in methane production from hydrocarbons in oil sands tailings 总被引:1,自引:0,他引:1
T Siddique T Penner J Klassen C Nesbø JM Foght 《Environmental science & technology》2012,46(17):9802-9810
Microbial metabolism of residual hydrocarbons, primarily short-chain n-alkanes and certain monoaromatic hydrocarbons, in oil sands tailings ponds produces large volumes of CH(4) in situ. We characterized the microbial communities involved in methanogenic biodegradation of whole naphtha (a bitumen extraction solvent) and its short-chain n-alkane (C(6)-C(10)) and BTEX (benzene, toluene, ethylbenzene, and xylenes) components using primary enrichment cultures derived from oil sands tailings. Clone libraries of bacterial 16S rRNA genes amplified from these enrichments showed increased proportions of two orders of Bacteria: Clostridiales and Syntrophobacterales, with Desulfotomaculum and Syntrophus/Smithella as the closest named relatives, respectively. In parallel archaeal clone libraries, sequences affiliated with cultivated acetoclastic methanogens (Methanosaetaceae) were enriched in cultures amended with n-alkanes, whereas hydrogenotrophic methanogens (Methanomicrobiales) were enriched with BTEX. Naphtha-amended cultures harbored a blend of these two archaeal communities. The results imply syntrophic oxidation of hydrocarbons in oil sands tailings, with the activities of different carbon flow pathways to CH(4) being influenced by the primary hydrocarbon substrate. These results have implications for predicting greenhouse gas emissions from oil sands tailings repositories. 相似文献
869.
Naveed Ejaz Tayyab Bin Tariq Sung Wook Baik 《Journal of Visual Communication and Image Representation》2012,23(7):1031-1040
Video summarization is a method to reduce redundancy and generate succinct representation of the video data. One of the mechanisms to generate video summaries is to extract key frames which represent the most important content of the video. In this paper, a new technique for key frame extraction is presented. The scheme uses an aggregation mechanism to combine the visual features extracted from the correlation of RGB color channels, color histogram, and moments of inertia to extract key frames from the video. An adaptive formula is then used to combine the results of the current iteration with those from the previous. The use of the adaptive formula generates a smooth output function and also reduces redundancy. The results are compared to some of the other techniques based on objective criteria. The experimental results show that the proposed technique generates summaries that are closer to the summaries created by humans. 相似文献
870.
Mohammad Abdel Kareem Jaradat Mohamed Al-Fandi Mohammad Tariq Nasir 《Mechatronics》2012,22(4):468-480
This paper presents a new strategy for automating three-dimensional miniaturized manipulators using a visual feedback. This automation scheme can be used to handle the challenges associated with manipulation of minute soft components such as biological entities. The developed vision control system combines a depth and planar motion control using a single camera and an auto focus algorithm. This visual process was conducted by applying image segmentation and probe recognition along with depth alignment. To demonstrate the feasibility, reliability and robustness of this newly proposed strategy, extensive computer simulations were performed on images of a Zyvex® nanomanipulator obtained using a Scanning Electron Microscope (SEM). Also, a prototype manipulator with a visual feedback and an automatic controller was constructed and tested using soft elements. The results showed good accuracy and robustness of the end-effector recognition, positioning and aligning without occlusion difficulties. 相似文献