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931.
Nanomedicine is gaining ground worldwide in therapy and diagnostics. Novel nanoscopic imaging probes serve as imaging tools for studying dynamic biological processes in vitro and in vivo. To allow detectability in the physiological environment, the nanostructure‐based probes need to be either inherently detectable by biomedical imaging techniques, or serve as carriers for existing imaging agents. In this study, the potential of mesoporous silica nanoparticles carrying commercially available fluorochromes as self‐regenerating cell labels for long‐term cellular tracking is investigated. The particle surface is organically modified for enhanced cellular uptake, the fluorescence intensity of labeled cells is followed over time both in vitro and in vivo. The particles are not exocytosed and particles which escaped cells due to cell injury or death are degraded and no labeling of nontargeted cell populations are observed. The labeling efficiency is significantly improved as compared to that of quantum dots of similar emission wavelength. Labeled human breast cancer cells are xenotransplanted in nude mice, and the fluorescent cells can be detected in vivo for a period of 1 month. Moreover, ex vivo analysis reveals fluorescently labeled metastatic colonies in lymph node and rib, highlighting the capability of the developed probes for tracking of metastasis.  相似文献   
932.
In this paper we present an extension to the co-design approach based on LOTOS presented in Fourth International Workshop on Hardware-Software Co-Design, 1996. In this new version we add a prototyping stage to our design flow, that allows to validate the design at the implementation level. We present the complete approach, stressing the prototyping stage after partitioning. An example of an Ethernet bridge serves us to illustrate our approach and present some results.  相似文献   
933.
This mixed‐methods study presents a comparative analysis of the use and perceived usefulness of Facebook and Twitter, among Swedish citizens and crisis communication professionals, as crisis communication tools and information sources. The use and perceived usefulness of Facebook and Twitter are not congruent and consistent between the two different groups, according to the overall study. Communication professionals, for example, report higher levels of perceived usefulness regarding Facebook's potential as a crisis communication tool than do the citizens. Taken together, the results show that researchers (within social media and crisis communication) and crisis managers both need to deal with the fact that social media is not a homogenous phenomenon with a single coherent role in crisis management and communication research and practice.  相似文献   
934.
Artificial neural networks are sophisticated modelling and prediction tools capable of extracting complex, non-linear relationships between predictor (input) and predicted (output) variables. This study explores this capacity by modelling non-linearities in the hardiness-modulated burnout process with a neural network. Specifically, two multi-layer feed-forward artificial neural networks are concatenated in an attempt to model the composite non-linear burnout process. Sensitivity analysis, a Monte Carlo–based global simulation technique, is then utilised to examine the first-order effects of the predictor variables on the burnout sub-dimensions and consequences. Results show that (1) this concatenated artificial neural network approach is feasible to model the burnout process, (2) sensitivity analysis is a prolific method to study the relative importance of predictor variables and (3) the relationships among variables involved in the development of burnout and its consequences are to different degrees non-linear.  相似文献   
935.
Optical networks are moving from opaque and translucent architectures towards all-optical (transparent) architectures. In translucent architectures a small amount of regeneration (e.g. optical–electronic–optical conversion) is available in the network. The incorporation of the physical impairments in the routing and wavelength assignment (RWA) problem in transparent optical networks has recently received some attention from the research communities. This work compiles a comprehensive survey of the proposed algorithms that address this issue. The physical layer impairments and related classification in optical networks are initially presented followed by physical layer impairments (PLI) constrained and aware RWA algorithms. Algorithmic approach, current PLI-RWA proposals, impact of wavelength conversion on these algorithms, protection and resilience considerations, and proposed extensions to control planes are covered in this work. Further research topics are presented in this study.  相似文献   
936.
Reflectance data in the green, red and near-infrared wavelength region were acquired by the SPOT high resolution visible and geometric imaging instruments for an agricultural area in Denmark (56°N, 9°E) for the purpose of estimating leaf chlorophyll content (Cab) and green leaf area index (LAI). SPOT reflectance observations were atmospherically corrected using aerosol data from MODIS and profiles of air temperature, humidity and ozone from the Atmospheric Infrared Sounder (AIRS), and used as input for the inversion of a canopy reflectance model. Computationally efficient inversion schemes were developed for the retrieval of soil and land cover-specific parameters which were used to build multiple species and site dependent formulations relating the two biophysical properties of interest to vegetation indices or single spectral band reflectances. Subsequently, the family of model generated relationships, each a function of soil background and canopy characteristics, was employed for a fast pixel-wise mapping of Cab and LAI.The biophysical parameter retrieval scheme is completely automated and image-based and solves for the soil background reflectance signal, leaf mesophyll structure, specific dry matter content, Markov clumping characteristics, Cab and LAI without utilizing calibration measurements.Despite the high vulnerability of near-infrared reflectances (ρnir) to variations in background properties, an efficient correction for background influences and a strong sensitivity of ρnir to LAI, caused LAI-ρnir relationships to be very useful and preferable over LAI-NDVI relationships for LAI prediction when LAI > 2. Reflectances in the green waveband (ρgreen) were chosen for producing maps of Cab.The application of LAI-NDVI, LAI-ρnir and Cab-ρgreen relationships provided reliable quantitative estimates of Cab and LAI for agricultural crops characterized by contrasting architectures and leaf biochemical constituents with overall root mean square deviations between estimates and in-situ measurements of 0.74 for LAI and 5.0 μg cm− 2 for Cab.The results of this study illustrate the non-uniqueness of spectral reflectance relationships and the potential of physically-based inverse and forward canopy reflectance modeling techniques for a reasonably fast and accurate retrieval of key biophysical parameters at regional scales.  相似文献   
937.
The electrochemical performance of porous silicon (pSi) stabilized via thermal decomposition of acetylene gas is investigated for the first time. In this study, pSi undergoes two thermal treatments at either 525 or 800 °C, which result in hydrogen‐terminated thermally hydrocarbonized pSi (THCpSi) and hydroxyl‐terminated thermally carbonized pSi (TCpSi), respectively, the latter upon dipping in hydrofluoric acid to activate the surface termination. Electrochemical characterization, using cyclic voltammetry, chronocoulometry, and electrochemical impedance spectroscopy in the presence of several redox pairs, [Fe(CN)6]3/4?, [Ru(NH3)6]2/3+, and hydroquinone/quinone, is used to demonstrate the versatility and high stability to degradation of carbon‐stabilized pSi nanostructures and their excellent electrochemical performance. Added to the large surface area, adjustable pore morphology and tailorable surface chemistry of THCpSi and TCpSi, these nanostructures demonstrate fast electron‐transfer kinetics, providing key advantages over conventional carbon electrodes. The versatile surface chemistry of THCpSi and TCpSi offer various possibilities to introduce multiple functional groups depending on the nature of the bioreceptor to be immobilized. For proof of principle, the use of a THCpSi‐based immunosensor to detect MS2 bacteriophage is demonstrated by means of electrochemical impedance spectroscopy, showing a detection limit of 4.9 pfu mL?1. Carbon‐stabilized pSi structures represent a new class of nanostructured electrodes for biosensing applications.  相似文献   
938.
The ability to selectively remove sections from 3D‐printed structures with high resolution remains a current challenge in 3D laser lithography. A novel photoresist is introduced to enable the additive fabrication of 3D microstructures at one wavelength and subsequent spatially controlled cleavage of the printed resist at another wavelength. The photoresist is composed of a difunctional acrylate cross‐linker containing a photolabile o‐nitrobenzyl ether moiety. 3D microstructures are written by photoinduced radical polymerization of acrylates using Ivocerin as photoinitiator upon exposure to 900 nm laser light. Subsequent scanning using a laser at 700 nm wavelength allows for the selective removal of the resist by photocleaving the o‐nitrobenzyl group. Both steps rely on two‐photon absorption. The fabricated and erased features are imaged using scanning electron microscopy (SEM) and laser scanning microscopy (LSM). In addition, a single wire bond is successfully eliminated from an array, proving the possibility of complete or partial removal of structures on demand.  相似文献   
939.
940.
The tangible interaction approach has in recent years become a promising alternative to multitouch tabletops for very young children. Children learning with tangible user interfaces can benefit from the same pedagogical values as learning with materials in physical play. The NIKVision tabletop and games have been designed to provide leisure and fun while reinforcing physical manipulation and co-located gaming for young children (3- to 6-year-olds). Interaction is provided in NIKVision by the handling of conventional toys and computer augmentation on a table surface. First of all, the paper sets out the results of a summative evaluation carried out in nurseries and schools summarising the performance of the tabletop in terms of usability, user experience and physical and co-located gaming. Secondly, the paper presents an evaluation carried out in a special education school with children with cognitive disabilities, in an attempt to widen the range of possible beneficiaries of tangible interfaces. The challenge in this case is to ensure children’s comprehension of the game and to adequately combine feedback on the application with teacher interventions. In fact, the initial results reinforce the idea of not trying to substitute but rather to assist teachers and emphasise the possibilities offered by the tabletop as a tool to promote student autonomy.  相似文献   
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