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991.
Recently, wireless multimedia sensor networks (WMSNs) have emerged as one of the most important technologies, driven by the development of powerful multimedia device such as CMOS. WMSNs require several factors such as resource constraints, specific QoS, high bandwidth and so on. In this paper, we propose a hierarchical heterogeneous network model based routing protocol for WMSNs. In our proposal, proposed network model is classified into monitoring class, delivery class and aggregation class. Also we define two kinds of the routing path in order to ensure bandwidth and QoS. In simulation results, we illustrate the performance of our proposal.  相似文献   
992.
Terahertz time-domain spectroscopy accesses the frequency range between 100 GHz and 5 THz by using the coherent generation and detection based on femtosecond laser sources. On the way to obtain fingerprint absorption spectra of molecular solids, terahertz waveguides have proven to be a valuable tool to extend the results to narrow and high resolution linewidths of crystalline solids. We will discuss the development, properties and applications of terahertz waveguide geometries for spectroscopic applications, in particular high-resolution measurements using parallel-plate waveguides.  相似文献   
993.
For a high speed duobinary transmitter clock frequency defines the transmission limit. A conventional duobinary transmitter needs a clock frequency equal to the data rate. In this work we propose a duobinary transmitter that uses a clock frequency half of the output data rate and hence achieves double the transmission rate for a given clock frequency as compared to a conventional duobinary transmitter. In the proposed transmitter the duobinary precoder is integrated into the last stage of a tree structured serializer to combine two NRZ data streams at half the transmission data rate. Two modes for the precoder have been incorporated into the design. The first mode is applicable for data transmission over copper whereas the second mode is suitable for wavelength division multiplexed optical transmission. A DLL based clock multiplier unit is employed to produce the high frequency clock with 50% duty cycle needed for the precoding operation. It incorporates a clock generation logic with integrated duty cycle control. A charge pump with dynamic current matching and a high resolution PFD are employed to reduce static phase error in locking and hence achieves improved jitter performance. A new delay cell along with automatic mode selection is proposed. To cover a wide range of data rate, the DLL is designed for a wide locking range and maintains almost 50% duty cycle. The design is implemented in 1.8-V, 0.18 μm Digital CMOS technology with an f T of 27 GHz. Simulations shows that, the duobinary transmitter circuit works up-to 10 Gb/s and consumes 60 mW of power.  相似文献   
994.
The night-vision image fusion plays a critical role in detecting targets and obstructions in low light or total darkness, which has great importance for pedestrian recognition, vehicle navigation, surveillance and monitoring applications. The central idea is to fuse low-light visible and infrared imagery into a single output. In this paper, we describe a new fusion framework for spatially registered visual and infrared images. The proposed framework utilizes the properties of fractal dimension and phase congruency in the non-subsampled contourlet transform (NSCT) domain. The proposed framework applies multiscale NSCT on visual and IR images to get low- and high-frequency bands. The varied frequency bands of the transformed images are then fused while exploiting their characteristics. Finally, the inverse NSCT is performed to get the fused image. The performance of the proposed framework is validated by extensive experiments on different scene imaginary, where the definite advantages are demonstrated subjectively and objectively.  相似文献   
995.
Only minimum amounts of carbon can be incorporated into silver, gold, and copper in a thermodynamically stable form. Here, the structure of stable silver carbon alloys is described, which are produced by thermoelectrically charging molten silver with carbon ions. Transmission electron microscopy and Raman scattering are combined to establish that large amount of carbon is accommodated in the form of epitaxial graphene‐like sheets. The carbon bonds covalently to the silver matrix as predicted from density functional theory (DFT) calculations with bond energies in the range 1.1–2.2 eV per atom or vacancy. Graphitic‐like sheets embedded in the crystal lattice of silver form 3D epitaxial structures with the host metal with a strain of ≈13% compared to equilibrium graphene. The carbon nanostructures persist upon remelting and resolidification. A DFT‐based analysis of the phonon density of states confirms the presence of intense vibration modes related to the Ag? C bonds observed in the Raman spectra of the alloy. The solid silver–high carbon alloy, termed “Ag‐covetic,” displays room temperature electrical conductivity of 5.62 × 107 S m?1 even for carbon concentrations of up to ≈6 wt% (36 at%). This process of incorporation of carbon presents a new paradigm for electrocharging assisted bulk processing.  相似文献   
996.
Zusammenfassung Die Nichtstärke-Polysaccharide (NSP) der Kakaobohne wurden nach ihrer Löslichkeit in Wasser und Natronlauge steigender Konzentration fraktioniert. Die Fraktionen wurden durch das Muster der Zuckerbausteine nach Hydrolyse bzw. Methanolyse charakterisiert und gelchromatographisch aufgetrennt. Im Verlauf der Kakaoverarbeitung waren nennenswerte Veränderungen nur beim Alkalisieren des Kakaopulvers zu beobachten. Die Meßwerte für die wasserlöslichen Kakao-NSP können bei der Analyse der Dickungsmittel in Kakaoerzeugnissen berücksichtigt werden.
Non-starch polysaccharides of cocoa
The non-starch polysaccharides (NSP) of the cocoa bean were fractionated according to their solubility in water and in solutions of increasing alkalinity. In these fractions, the monosaccharide patterns after hydrolysis or methanolysis and the molecular mass distributions were determined. During cocoa processing, distinct changes in the NSP composition were observed only for the solubilisation of cocoa powder by alkaline treatment. The results obtained for the water-soluble cocoa NSP may be considered as blank values for the analysis of thickeners and gums in cocoa products.
  相似文献   
997.
Glutenin was prepared from gluten of the wheat variety Rektor by extraction of gliadin with aqueous ethanol. It was cleaved successively into soluble peptides by the enzymes trypsin and thermolysin. Separation of the peptide mixtures was performed by gel permeation chromatography (GPC) on Sephadex G25 and reversed phase high performance liquid chromatography (RP-HPLC) on ODS-Hypersil. Cystine peptides were detected by differential chromatography of the samples prior to and after reduction. After isolation by multi-step RP-HPLC, the cystine peptides were reduced. The resulting cysteine peptides were alkylated with 4-vinylpyridine, separated by RP-HPLC and sequenced by means of the Edman degradation. The isolated cystine peptides represented a considerable portion of the total cysteine in glutenin: four out of seven cysteine residues of HMW subunits, and eight out of nine cysteine residues of LMW subunits are documented by at least one cystine peptide. Most of the peptides corresponded to known sequences of gluten protein components. From the structures of some tryptic peptides, inter- and intramolecular disulphide bonds for HMW subunits of glutenin have been proven. Cystine peptides from the thermolytic digest have been assigned to LMW subunits of glutenin and toγ-gliadins. Other peptides have been closely related to partial sequences of these protein components. The results have allowed several conclusions about the arrangement of intra- and intermolecular disulphide bridges in gluten proteins.  相似文献   
998.
A rapid X-ray spectrometric (XRS) method has been developed for the determination of the total glucosinolate content of oilseed rape and other Brassica oilseeds. The method is based on analysis for fully oxidised sulphur (S6+), which includes half the sulphur (S) in the glucosinolate molecule, and the S in sulphate. Results are highly correlated with glucosinolate content determined by glucose release, a standard method widely used in Australia. The relationship is total glucosinolates = (23·97 S6+ -9·43) r2 = 0·987, where the glucosinolate content is expressed as μmol g?1 and the S6+ content in mg g?1. The relationship is applicable to seed of any glucosinolate content and to meal, and is unaffected by changes in protein sulphur content. The correlation of glucosinolates with S6+ is shown to be closer than the correlation with total S. The latter correlation forms the basis of the existing XRS method, used within the European Community in recent years. The advantages of S6+ derive from the linearity of the regression and the elimination of errors caused by variation in protein content. The method should be valuable to the Australian oilseed industry because it allows the rapid screening of breeding lines to ensure low glucosinolate content and the assessment of deliveries for crushing and of meal.  相似文献   
999.
AUTO-SMASH: A self-calibrating technique for SMASH imaging   总被引:9,自引:0,他引:9  
Recently a new fast magnetic resonance imaging strategy, SMASH, has been described, which is based on partially parallel imaging with radiofrequency coil arrays. In this paper, an internal sensitivity calibration technique for the SMASH imaging method using self-calibration signals is described. Coil sensitivity information required for SMASH imaging is obtained during the actual scan using correlations between undersampled SMASH signal data and additionally sampled calibration signals with appropriate offsets ink-space. The advantages of this sensitivity reference method are that no extra coil array sensitivity maps have to be acquired and that it provides coil sensitivity information in areas of highly non-uniform spin-density. This auto-calibrating approach can be easily implemented with only a small sacrifice of the overall time savings afforded by SMASH imaging. The results obtained from phantom imaging experiments and from cardiac studies in nine volunteers indicate that the self-calibrating approach is an effective method to increase the potential and the flexibility of rapid imaging with SMASH.  相似文献   
1000.
Fenk  Josef  Sehrig  Peter 《Wireless Networks》1998,4(1):87-97
Circuit solutions of various types of gain controlled IF amplifiers with digital and analog gain control are described. Advantages and disadvantages of the different solutions are shown. Requirements for lowpower, lowvoltage, low noise, high gain and linearity at high IFfrequencies from the system point of view are worked out. Solutions will be presented to optain optimum performance by technology and circuit design technique for digital wireless telephone systems used for GSM and PCN systems.  相似文献   
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