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排序方式: 共有956条查询结果,搜索用时 125 毫秒
891.
MPLS Recovery Mechanisms for IP-over-WDM Networks 总被引:2,自引:0,他引:2
Colle Didier Van Heuven Pim Develder Chris Van den Berghe Steven Lievens Ilse Pickavet Mario Demeester Piet 《Photonic Network Communications》2001,3(1-2):23-40
Due to the fast increase of Internet traffic and the enormous bandwidth potential of all-optical transport networks based on wavelength division multiplexing, an IP-over-WDM network scenario is likely to be widespread in future communication networks. At the same time, IP networks are becoming more and more mission-critical. Hence, it is of paramount importance for IP-over-WDM networks to be able to recover quickly from frequently occurring network failures. This paper explains how multi-protocol label switching (both electrical and optical) recovery mechanisms can be important to reach that goal. Moreover, a novel MPLS recovery mechanism called fast topology-driven constrained-based rerouting is presented. Different MPLS recovery mechanisms are compared to each other. Special attention hereby goes to the additional capacity that is required to recover from frequently occurring failures. 相似文献
892.
Ctia Ornelas Jaime Ruiz Lionel Salmon Didier Astruc 《Advanced Synthesis \u0026amp; Catalysis》2008,350(6):837-845
Water‐soluble 1,2,3‐triazolyl dendrimers were synthesized by “click chemistry” and used to stabilize palladium nanoparticles (PdNPs). These new “click” dendrimer‐stabilized nanoparticles (DSN) are highly stable to air and moisture and are catalytically active for olefin hydrogenation and Suzuki coupling reaction, in aqueous media, under ambient conditions using a low amount of palladium (0.01 mol% Pd). Kinetic studies show high catalytic efficiency and high stability for the new “click” DSN in both reactions. The complexation of potassium tetrachloropalladate (K2PdCl4) to the triazole ligands present in the dendritic structures was monitored by UV/vis and, after reduction, the nanoparticles were characterized by transmission electron microscopy (TEM). 相似文献
893.
Christophe Proust Didier JamoisEtienne Studer 《International Journal of Hydrogen Energy》2011,36(3):2367-2373
Within the scope of the French national project DRIVE and European project HyPER, high pressure jet flames of hydrogen were produced and instrumented.The experimental technique and measurement strategy are presented. Many aspects are original developments like the direct measurement of the mass flow rate by weighing continuously the hydrogen container, the image processing to extract the flame geometry, the heat flux measurement device, the thermocouples arrangement…Flames were observed from 900 bar down to 1 bar with orifices ranging from 1 to 3 mm. An original set of data is now available about the main flame characteristics and about some thermodynamic aspects of hydrogen releases under high pressure.A brief comparison of some available models is presented. 相似文献
894.
Emotion recognition ability has been identified as a central component of emotional competence. We describe the development of an instrument that objectively measures this ability on the basis of actor portrayals of dynamic expressions of 10 emotions (2 variants each for 5 emotion families), operationalized as recognition accuracy in 4 presentation modes combining the visual and auditory sense modalities (audio/video, audio only, video only, still picture). Data from a large validation study, including construct validation using related tests (Profile of Nonverbal Sensitivity; Rosenthal, Hall, DiMatteo, Rogers, & Archer, 1979; Japanese and Caucasian Facial Expressions of Emotion; Biehl et al., 1997; Diagnostic Analysis of Nonverbal Accuracy; Nowicki & Duke, 1994; Emotion Recognition Index; Scherer & Scherer, 2008), are reported. The results show the utility of a test designed to measure both coarse and fine-grained emotion differentiation and modality-specific skills. Factor analysis of the data suggests 2 separate abilities, visual and auditory recognition, which seem to be largely independent of personality dispositions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
895.
896.
Linguraru MG Ayache N Bardinet E Ballester MA Galanaud D Haïk S Faucheux B Hauw JJ Cozzone P Dormont D Brandel JP 《IEEE transactions on medical imaging》2006,25(8):1052-1067
We present a method for the analysis of basal ganglia (including the thalamus) for accurate detection of human spongiform encephalopathy in multisequence magnetic resonance imaging (MRI) of the brain. One common feature of most forms of prion protein diseases is the appearance of hyperintensities in the deep grey matter area of the brain in T2-weighted magnetic resonance (MR) images. We employ T1, T2, and Flair-T2 MR sequences for the detection of intensity deviations in the internal nuclei. First, the MR data are registered to a probabilistic atlas and normalized in intensity. Then smoothing is applied with edge enhancement. The segmentation of hyperintensities is performed using a model of the human visual system. For more accurate results, a priori anatomical data from a segmented atlas are employed to refine the registration and remove false positives. The results are robust over the patient data and in accordance with the clinical ground truth. Our method further allows the quantification of intensity distributions in basal ganglia. The caudate nuclei are highlighted as main areas of diagnosis of sporadic Creutzfeldt-Jakob Disease (sCJD), in agreement with the histological data. The algorithm permitted the classification of the intensities of abnormal signals in sCJD patient FLAIR images with a higher hypersignal in caudate nuclei (10/10) and putamen (6/10) than in thalami. Defining normalized MRI measures of the intensity relations between the internal grey nuclei of patients, we robustly differentiate sCJD and variant CJD (vCJD) patients, in an attempt to create an automatic classification tool of human spongiform encephalopathies. 相似文献
897.
Kroubi M Daulouede S Karembe H Jallouli Y Howsam M Mossalayi D Vincendeau P Betbeder D 《Nanotechnology》2010,21(50):505102
There is a real need to develop new therapeutic strategies for African trypanosomiasis infections. In our study, we developed a new drug delivery system of diminazene (DMZ), a trypanocidal drug registered for veterinary use. This drug candidate presents a limited efficacy, a poor affinity for brain tissue and instability. The development of colloidal formulations based on a porous cationic nanoparticle with an oily core ((70)DGNP(+)), has potentially two advantages: stabilization of the drug and potential targeting of the parasite. We analyzed two processes of drug loading: in process (DMZ was added during the preparation of (70)DGNP(+) at 80?°C) and post-loading (DMZ was mixed with a (70)DGNP(+) solution at room temperature). Poor stability of the drug was observed using the in process technique. When using the post-loading technique over 80% drug entrapment efficiency was obtained at a ratio of DMZ:phospholipids (wt:wt) < 5%. Moreover, DMZ loaded into (70)DGNP(+) was found to be protected against oxidation and was stable for at least six months at 4?°C. Finally, in vitro tests on T.b. brucei showed an increased efficacy of DMZ loaded in (70)DGNP(+). 相似文献
898.
Performance Evaluation of Multi-Layer Traffic Engineering Enabled IP-over-ION Networks 总被引:3,自引:0,他引:3
Qiang?Yan Didier?ColleEmail author Sophie?De?Maesschalck Bart?Puype Ilse?Lievens Mario?Pickavet Piet?Demeester 《Photonic Network Communications》2005,9(3):255-280
Recently, network operators started implementing traffic engineering (TE) techniques in their network. These TE techniques typically involve a single layer (for example, the IP/multi-protocol label switching (MPLS) layer). Although single-layer TE (STE) can improve the network performance (e.g., throughput, quality of service (QoS)), this improvement is bounded by the available capacity in that network layer. The evolution towards intelligent optical networks (IONs) allows further increasing the improvements achievable by the TE techniques, by involving more than one layer in the TE actions. Multi-layer TE (MTE) occupies network resources in a smart way and optimizes the QoS since it dynamically reconfigures the logical topology in the upper layer by properly updating the optical connections in the underlying optical layer. However, the performance of the network is impacted by the configuration scheme adopted by MTE. Therefore, in this paper, we focus on analyzing the influence of the MTE configuration scheme on the MTE behavior, and evaluate the network performance by studying simulation results obtained from a realistic IP-over-ION network. 相似文献
899.
900.
We present what we believe to be a new digital holographic imaging method that is able to determine simultaneously the distributions of intensity, phase, and polarization state at the surface of a specimen on the basis of a single image acquisition. Two reference waves with orthogonal polarization states interfere with the object wave to create a hologram that is recorded on a CCD camera. Two wave fronts, one for each perpendicular polarization state, are numerically reconstructed in intensity and phase. Combining the intensity and the phase distributions of these two wave fronts permits the determination of all the components of the Jones vector of the object-wave front. We show that this method can be used to image and measure the distribution of the polarization state at the surface of a specimen, and the obtained results indicate that precise quantitative measurements of the polarization state can be achieved. An application of the method to image the birefringence of a stressed polymethyl methacrylate sample is presented. 相似文献