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711.
What Is Second Screening? Exploring Motivations of Second Screen Use and Its Effect on Online Political Participation 下载免费PDF全文
Homero Gil de Zúñiga Victor Garcia‐Perdomo Shannon C. McGregor 《The Journal of communication》2015,65(5):793-815
This study focuses on second screening for news, a hybrid media process that combines watching news on television and a second, web‐connected screen (i.e., smart‐phone, laptop). Based on U.S.‐national, 2‐wave panel data, the paper (a) examines people's motivations to engage in second screen use, and then (b) advances the relationship between second screening and online political behaviors. Discussing and pursuing further information are both central motivations for second screen use. Furthermore, results suggest second screening for news is a significant predictor of online political participation and a key link between TV news and political engagement as this relationship is fully mediated. The study advances theoretically and empirically ways in which an informed public opinion may partake of a more engaged democracy. 相似文献
712.
Suranji Rathnayaka Benjamin Shannon Pathmanathan Rajeev Jayantha Kodikara 《Water Resources Management》2016,30(2):471-485
Ageing water infrastructure is one of the major problems faced by water utilities around the world at present, and urgent solutions are required in order to maintain the integrity of the water supply network. In order to use pipe failure prediction models, accurate information about loads acting on these pipes is important. Water pressure (steady-state and transient) is one of the key loads that needs to be estimated accurately in order to improve the predictability of pipe failures. This paper reports the results of a pressure monitoring program, which was conducted to measure pressure fluctuations during events of pressure transients in three selected network sections in Australia. Pressure measurements were conducted in network sections which were considered as susceptible to pressure transients. Potential sources of pressure transients were identified, and high speed data loggers were installed in selected locations of each network to measure and monitor pressure transients. Pressure transients that were generated during normal operation were measured for a period of one month in each selected section. Further, some of the pressure transients were manually made to simulate the different pressures due to pump start-ups within the network. Pressure fluctuations that could potentially lead to pipe failures were measured at many locations during the monitoring program (several selected failures were reported in this article). Therefore, the effect of pressure transients must not be ignored in pipe failure prediction. 相似文献
713.
Ozone levels in passenger cabins of commercial aircraft on North American and transoceanic routes 总被引:2,自引:0,他引:2
Bhangar S Cowlin SC Singer BC Sextro RG Nazaroff WW 《Environmental science & technology》2008,42(11):3938-3943
Ozone levels in airplane cabins, and factors that influence them, were studied on northern hemisphere commercial passenger flights on domestic U.S., transatlantic, and transpacific routes. Real-time data from 76 flights were collected in 2006--2007 with a battery-powered UV photometric monitor. Sample mean ozone level, peak-hour ozone level, and flight-integrated ozone exposures were highly variable across domestic segments (N = 68), with ranges of < 1.5 to 146 parts per billion by volume (ppbv), 3--275 ppbv, and < 1.5 to 488 ppbv-hour, respectively. On planes equipped with ozone catalysts, the mean peak-hour ozone level (4.7 ppbv, N = 22)was substantially lower than on planes not equipped with catalysts (47 ppbv, N = 46). Peak-hour ozone levels on eight transoceanic flight segments, all on planes equipped with ozone catalysts, were in the range < 1.5 to 58 ppbv. Seasonal variation on domestic routes without converters is reasonably modeled by a sinusoidal curve that predicts peak-hour levels to be approximately 70 ppbv higher in Feb--March than in Aug--Sept The temporal trend is broadly consistent with expectations, given the seasonal cycle in tropopause height. Episodically elevated (>100 ppbv) ozone levels on domestic flights were associated with winter-spring storms that are linked to enhanced exchange between the lower stratosphere and the upper troposphere. 相似文献
714.
Spatio-temporal reconstruction of bilateral auditory steady-state responses using MEG beamformers 总被引:1,自引:0,他引:1
Popescu M Popescu EA Chan T Blunt SD Lewine JD 《IEEE transactions on bio-medical engineering》2008,55(3):1092-1102
A rapidly growing number of neuromagnetic studies focus on the analysis of auditory steady-state responses (ASSR) in relation to a diverse array of factors including age, selective attention, and presence of psychopathology. The objectives of these studies require accurate spatio-temporal estimation of the underlying neural generators, a challenging task due to the relatively low signal strength and high correlation between bilateral auditory cortical sources. This paper evaluates the performance of two beamforming schemes that can potentially overcome such difficulties: 1) the linearly constrained minimum variance beamformer with partial sensor coverage (LCMV-PSC), and 2) the multiple constrained minimum-variance beamformer with coherent source region suppression (MCMV-CSRS). Simulation experiments are conducted to assess the impact of source parameters on the reconstruction accuracy. The results indicate that the LCMV-PSC method is prone to localization errors that essentially occur along medio-lateral directions, increase with source depth, and are associated to amplitude and phase distortions of the estimated time courses of activity. Comparatively, the MCMV-CSRS method exhibits precise localization and minimal amplitude and phase distortion for a broad range of relative interferer's positions within the suppression region. The results from the numerical experiments are validated on real magnetoencephalographic (MEG) data collected from a 40-Hz ASSR paradigm. 相似文献
715.
Monte Carlo methods are often applied to the calculation of the apparent emissivities of blackbody cavities. However, for cavities with complex as well as some commonly encountered geometries, the emission Monte Carlo method experiences problems of convergence. The emission and absorption Monte Carlo methods are compared on the basis of ease of implementation and convergence speed when applied to blackbody sources. A new method to determine solution convergence compatible with both methods is developed, and the convergence speeds of the two methods are compared through the application of both methods to a right-circular cylinder cavity. It is shown that the absorption method converges faster and is easier to implement than the emission method when applied to most blackbody and lower emissivity cavities. 相似文献
716.
To test the relationship between characteristic mode of cognitive reactivity to conflict-arousing stimuli in a laboratory situation as compared with life in general, Ss (adult male hospitalized psychiatric patients between 21 and 45) were placed in one of 3 categories, which reflected characteristic modes of dealing with conflictual ideas and feelings (externalizers, internalizers, acting-outers). Ss were then presented with visual stimuli (words and pictures) geared to heighten conflict arousal; capacity for recognition was measured by the level of illumination required for identification of the stimulus. The results indicated that externalizers and acter-outer demonstrated lower thresholds of recognition for conflictarousing (sexual, aggressive, dependent) stimuli than for neutral ones, and internalizers revealed higher thresholds. No relationship was found between specific conflict area or psychiatric diagnosis and perceptual mode. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
717.
Cai X Lei QP Lamb DH Shannon A Jacoby J Kruk J Kensinger RD Ryall R Zablackis E Cash P 《Analytical chemistry》2004,76(24):7387-7390
Hydrogen peroxide has been used to cleave the native Neisseria meningiditis polysaccharide (PS) from mega-Dalton molecular weight to a smaller size (approximately 20 kDa) depolymerized polysaccharide. The polysaccharide was examined after partial peroxide depolymerization to verify the presence of the carboxyl group at position 1 and the intactness of the internal sialic acid repeating units. The reducing end group of meningococcal polysaccharide type C was also examined after derivatization by L-tyrosine hydrazide. Partial peroxide depolymerization did not result in loss of the position 1 carboxyl group at the reducing end of the polysaccharide. In addition, no loss of structural integrity was noted for the internal sialic repeat units. 相似文献
718.
The acute phase response to inflammation is mediated in part by the endogenous production of pro-inflammatory cytokines. Interleukin 6 (IL-6) and members of its superfamily, including ciliary neurotrophic factor (CNTF) and leukaemia inhibitory factor (LIF) have been implicated as primary mediators of the hepatic acute phase response. In the present report, mice suffering a turpentine-induced myositis were passively immunized with antibodies against either IL-6, CNTF or LIF. Passive immunization against IL-6 attenuated the anorexia and completely prevented the hypoalbuminaemia, and increases in the serum concentration of the acute phase reactants, amyloid P, amyloid A and seromucoid. In contrast, passive immunization against either CNTF or LIF failed to modulate the anorexia, weight loss or hepatic acute phase protein responses. The findings suggest that IL-6, but not other members of its superfamily, is primarily responsible for the hepatic acute phase response, and contributes to the anorexia, associated with turpentine-induced myositis. 相似文献
719.
The use of opioids for chronic pain of non-malignant origin remains controversial. However, problems anticipated from experience with animal experiments and pain-free abusers seldom cause difficulties when opioids are used appropriately to treat pain. With sensible guidelines, and in the context of a multidisciplinary pain clinic, opioids may provide the only hope of relief to many sufferers of chronic pain. 相似文献
720.
Francine BermanGregory E. Shannon 《Information Sciences》1993,70(3):241-269
An edge grammar is a formal mechanism for representing families of related graphs (binary trees, hypercubes, meshes, etc.). Given an edge grammar, larger graphs in the family are derived from simple basis graphs using edge rewriting rules. A drawback to many graph grammars is that they cannot represent some important, highly regular graph families such as the family of shuffle-exchange graphs. Edge grammars, however, exist for all “computable” graph families, and simple edge grammars exist for most regular graph families. In this paper, we define and illustrate edge grammars and analyze them in the context of formal language theory. Our results include hierarchy and decidability properties. Because this work originally was motivated by a need to represent graph families found in parallel computation, the application of edge grammars in this context is also discussed. 相似文献