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241.
242.
We consider optimized collaborative transmit diversity schemes for the situation when the source and the relay know the magnitudes of all channel gains in the system. We demonstrate how one can optimally allocate not only transmit power but also the time and bandwidth used by the different nodes. Numerical examples illustrate the possible performance gain over nonadaptive collaboration. 相似文献
243.
Alty S.R. Jakobsson A. Larsson E.G. 《IEEE transactions on circuits and systems. I, Regular papers》2005,52(3):516-521
In this paper, we present a computationally efficient sliding window time updating of the Capon and amplitude and phase estimation (APES) matched filterbank spectral estimators based on the time-variant displacement structure of the data covariance matrix. The presented algorithm forms a natural extension of the most computationally efficient algorithm to date, and offers a significant computational gain as compared to the computational complexity associated with the batch re-evaluation of the spectral estimates for each time-update. Furthermore, through simulations, the algorithm is found to be numerically superior to the time-updated spectral estimate formed from directly updating the data covariance matrix. 相似文献
244.
245.
Per-Lennart Larsson 《Tribology Letters》2014,54(1):89-97
In the present study, quantitative relations for the determination of surface residual stresses, using sharp indentation testing, are presented. The relations are based on previous results for equi-biaxial residual fields but further developed to apply also for a general situation. The present analysis relies on theoretical methods, but the results are validated using previous experimental and numerical findings. Cone indentation of classical Mises elastoplastic material behavior is assumed throughout the investigation for clarity but not out of necessity. Further development for a complete characterization of a general residual stress field is discussed in some detail. 相似文献
246.
Batteries, in particular lithium‐ion (Li‐ion) batteries, are seen as an alternative to fossil fuels in the automotive sector. Li‐ion batteries, however, have some safety issues including possible emissions of toxic fluorine‐containing compounds during fire and other abuse situations. This paper demonstrates the possibilities to use the Fourier transform infrared technique to assess some of the most important compounds, including hydrogen fluoride and the far less often measured POF3 and PF5. The study is conducted in the cone calorimeter with different solvents used in Li‐ion batteries. The measurements show that, in addition to hydrogen fluoride, with a known high toxicity, POF3 is emitted and can be quantified using Fourier transform infrared. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
247.
For the risk for spontaneous combustion in storage of biomass pellets to be assessed, it is important to know how prone the fuel is to self‐heating. There are traditional methods that are used to determine self‐heating characteristics of fuels, eg, basket heating tests. The results from basket heating tests indirectly give the reactivity from a series of tests at high temperatures. This paper presents a sensitive screening test procedure for biomass pellets using isothermal calorimetry for direct measurement of the heat production rate at typical bulk storage temperatures. This method can be used to directly compare the reactivity of different batches of biomass pellets. The results could be used, eg, by storage security managers to gain better knowledge of their fuels propensity for self‐heating and thereby for safer storage. A large number of tests have been performed to develop the test procedure presented. Different parameters, such as temperature, type of the test sample (powder/crushed or pellets), mass of test sample, and preheating time, have been varied. Furthermore, gas concentrations in the sample ampoule have been measured before and after some tests to study the oxygen consumption and the formation of CO and CO2. Three different types of pellets with different characteristics were tested to assess the variation in behaviour. Based on these tests, a screening test procedure is presented with a test temperature of 60°C, a sample size of 4 g, a 15‐minute preheating period at the test temperature, and 24‐hour test duration. 相似文献
248.
H. Choi S. Byrne T. Sigsgaard P. S. Thorne L. Larsson A. Sebastian C.‐G. Bornehag 《Indoor air》2014,24(2):158-170
Qualitative reporting of home indoor moisture problems predicts respiratory diseases. However, causal agents underlying such qualitative markers remain unknown. In the homes of 198 multiple allergic case children and 202 controls in Sweden, we cultivated culturable fungi by directly plating dust, and quantified (1‐3, 1‐6)‐β‐d ‐glucan and ergosterol in dust samples from the child's bedroom. We examined the relationship between these fungal agents and degree of parent or inspector‐reported home indoor dampness, and microbiological laboratory's mold index. We also compared the concentrations of these agents between multiple allergic cases and healthy controls, as well as IgE‐sensitization among cases. The concentrations of culturable fungal agents were comparable between houses with parent and inspector‐reported mold issues and those without. There were no differences in concentrations of the individual or the total summed culturable fungi, (1‐3, 1‐6)‐β‐d ‐glucan, and ergosterol between the controls and the multiple allergic case children, or individual diagnosis of asthma, rhinitis, or eczema. Culturable fungi, (1‐3, 1‐6)‐β‐d ‐glucan, and ergosterol in dust were not associated with qualitative markers of indoor dampness or mold or indoor humidity. Furthermore, these agents in dust samples were not associated with any health outcomes in the children. 相似文献
249.
Rodríguez-Manzo G.; Pellicer F.; Larsson K.; Fernández-Guasti A. 《Canadian Metallurgical Quarterly》2000,114(3):553
The aim of the present study was to establish whether electrical and/or drug stimulation of the medial preoptic area/anterior hypothalamus (mPOA/AH) surmounts the sexual behavior inhibition that results from copulation to exhaustion. Thus, intermittent electrical stimulation of the mPOA/AH (alone or combined with the systemic injection of yohimbine or apomorphine, at doses that were subthreshold for reversing sexual exhaustion) or intrapreoptic treatments to block GABAergic transmission were applied to sexually satiated rats. The results suggest that the mPOA/AH is not responsible for male sexual behavior inhibition or for the pharmacologically induced sexual behavior expression in satiated rats. Data are discussed in terms of the roles ascribed to the mPOA/AH, both in the control of sexual behavior expression and in the regulation of the postejaculatory interval. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
250.
Jonas M. Bengtsson Yitbarek Wolde-Hawariat Hamida Khbaish Merid Negash Bekele Jembere Emiru Seyoum Bill S. Hansson Mattias C. Larsson Ylva Hillbur 《Journal of chemical ecology》2009,35(9):1063-1076
The sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), is a key pest on sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Ethiopia. At present there is a lack of efficient control methods. Trapping shows promise for reduction
of the pest population, but would benefit from the development of attractive lures. To find attractants that could be used
for control of P. interrupta, either by mass trapping or by monitoring as part of integrated pest management, we screened headspace collections of sorghum
and the highly attractive weed Abutilon figarianum Webb (Malvaceae) for antennal activity using gas chromatograph-coupled electroantennographic detection (GC-EAD). Compounds
active in GC-EAD were identified by combined gas chromatography and mass spectrometry (GC-MS). Field trapping suggested that
attraction is governed by a few influential compounds, rather than specific odor blends. Synthetic sorghum and abutilon odor
blends were attractive, but neither blend outperformed the previously tested attractants eugenol and methyl salicylate, of
which the latter also was part of the abutilon blend. The strong influence of single compounds led us to search for novel
attractive compounds, and to investigate the role of individual olfactory receptor neurons (ORNs) in the perception of kairomones.
We screened the response characteristics of ORNs to 82 putative kairomones in single sensillum recordings (SSR), and found
a number of key ligand candidates for specific classes of ORNs. Out of these key ligand candidates, six previously untested
compounds were selected for field trapping trials: anethole, benzaldehyde, racemic 2,3-butanediol, isoamyl alcohol, methyl
benzoate and methyl octanoate. The compounds were selected on the basis that they activated different classes of ORNs, thus
allowing us to test potential kairomones that activate large non-overlapping populations of the peripheral olfactory system,
while avoiding redundant multiple activations of the same ORN type. Field trapping results revealed that racemic 2,3-butanediol
is a powerful novel attractant for P. interrupta. 相似文献