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91.
Compact Models of Spreading Resistances for Electrical/Thermal Design of Devices and ICs 总被引:1,自引:0,他引:1
Karmalkar S. Mohan P.V. Nair H.P. Yeluri R. 《Electron Devices, IEEE Transactions on》2007,54(7):1734-1743
Building upon our recent work (IEEE Electron Device Lett., vol. 26, pp. 909-912, Dec, 2005), we present simple and continuous closed-form models for several rectangular and circular spreading resistance geometries encountered in electrical/thermal design of devices and integrated circuits. The resistance geometries considered involve current/heat flow between parallel contacts of rectangular or circular shape and concentric or eccentric nature, between a horizontal and a vertical stripe, and between a horizontal circular contact and a surrounding vertical cylindrical contact. The modeling procedure involves normalization of the spreading resistance with respect to its value under 1D flow conditions, followed by a curve-fit of the variation of this normalized resistance with contact area in terms of physical parameters. The resistance models may also be used to estimate the reciprocal of capacitance of similar insulator-electrode geometries, by replacing the resistivity by the reciprocal of the insulator permittivity. 相似文献
92.
A. Krishnamoorthy Sajeev S. Nair Viswanath C. Narayanan 《International journal of systems science》2013,44(10):1800-1816
This paper considers an (s,S) production inventory system with positive service time, with time for producing each item following Erlang distribution. Customers arrive according to a Poisson process. A customer who arrives when there is no inventory in the system is considered lost. On the other hand, a customer who finds a busy server with at least one inventory in the system joins a queue of infinite capacity. When the inventory level falls to s, production process is switched on, and it is switched off when the inventory level reaches back to S. Service time to each customer also follows an Erlang distribution. The service of a customer may be interrupted, where the time for such a phenomenon follows an exponential distribution, whenever it occurs. An interrupted service, after repair, resumes from where it was stopped. The correction/repair time follows an exponential distribution. We assume that the service of a single customer may encounter any number of interruptions and that the customer being served waits there until his service is completed. Moreover, at a time the server is subject to at most one interruption. We also assume that no inventory is lost due to a service interruption. Like the service process, the production process also is subject to interruptions, where the duration to an interruption follows an exponential distribution. However, in contrast to the service interruption, in the case of interruption to production process, we assume that the item being processed is lost because of interruption. That is, the production process, on being interrupted, restarts from the beginning, after repair. The repair time of an interrupted production process follows exponential distribution. Few of the last service phases are assumed to be protected in the sense that the service will not be interrupted while being in these phases. The same is assumed for the production process also.The model is analysed as a level-independent quasi-birth–death process. We apply a novel method to obtain an explicit expression for the necessary and sufficient condition for the stability of the system under study. This method works even if we assume general phase-type distributions for the production as well as the service processes, and hence can be used to characterise the stability of inventory systems where the assumption of disallowing the customers to join the system, when there is a shortage of inventory has been made. Under stability, we apply matrix analytic methods to compute the system state distribution. In consequence to that, several system performance measures have been derived, and their dependence on the system parameters has been studied numerically. 相似文献
93.
K. Balachandran 《International journal of control》2013,86(3):486-491
In this paper sufficient conditions for the complete controllability of a stochastic semilinear integrodifferential system in finite dimensional spaces are established using the resolvent matrix and the Banach fixed point theorem. An example is provided to illustrate the result. 相似文献
94.
Pramod P. Nair 《International journal of remote sensing》2013,34(17):4933-4941
An algorithm for supervised classification of multisensor images is proposed. The mixture of experts (ME) architecture with dynamic weight allocation is used for multiclass classification. Here the classification is treated as a maximum likelihood problem and the synaptic weights of the expert network and gating network are updated by a stochastic multigradient approach. Data from an optical sensor with four bands and a synthetic aperture radar (SAR) image of the same scene has been fused and classified. The algorithm is compared to some other advanced training algorithms in the literature for the same image data. 相似文献
95.
We apply Linear Error Correction (LEC) code to a novel encoding scheme to assure two fundamental requirements for transmission channels and storage units: security and dependability. Our design has the capacity to adapt itself to different applications and their various characteristics such as availability, error rate, and vulnerabilities. Based on simple logic operations, our scheme affords fast encryption, scalability (dual or more column erasures), and flexibility (LEC encoder employed as a front end to any conventional compression scheme). Performance results are very promising: Experiments on dual erasures outperform conventional compression algorithms including Arithmetic Coding, Huffman, and LZ77. 相似文献
96.
ABSTRACT Two new symmetrical diamides, namely straight-chain alkyl substituted neutral tetra-butyl-malonamide(TBMA) and sterlcally hindered branched-chain alkyl substituted tetra-isobutyl malonamide(TIBMA) were synthesised, characterised and used for the extraction of U(VI) and Pu(IV) from nitric acid media into n-dodecane. Both the cations were found to be extracted as their disolvates. Interestingly TBMA extracted more efficiently than TIBMA but afforded poor selectivity for Pu/U separation. The thermodynamic parameters involved in the extraction, determined by the temperature variation method, indicated the reactions in all cases to be enthalpy favoured. Entropy was found to be counteracting the extraction of U(VI) and favouring the extraction of Pu(IV). The recovery of diamides from the loaded actinides could be easily accomplished by using dilute oxalic acid or dilute U(IV) as the strippant for Pu(IV) and using dilute Na2C03 as that for U(VI). 相似文献
97.
Cheruvathoor Poulose Aby Kalarical Janardhanan Sreeram Balachandran Unni Nair Thirumalachari Ramasami 《Coloration Technology》2007,123(6):374-378
The colour of inorganic colorants is based on metal ions such as cadmium, lead, chromium or cobalt, the majority of which are unfortunately potentially toxic. Thus, there is in a need to introduce alternative metal or metal oxides, which would be environmentally friendly and economically viable as a replacement for potentially toxic inorganic colorants. Rare earth-based colorants offer an additional opportunity for the development of optically pure colours. In this study, a replacement for potentially toxic colorants has been sought through the use of a rare earth metal ion, cerium. Appropriate doping of cerium oxides with molybdenum and iron gives an orange–red colorant. The conditions ideal for optimal colour have been standardised and the resultant colorant characterised through powder X-ray diffraction techniques, particle size measurement, etc. The colorants exhibit good hiding power and tinting strength. 相似文献
98.
Anitha Nair Shubha Sathyendranath Trevor Platt Jesus Morales Venetia Stuart Marie-Hélène Forget Emmanuel Devred Heather Bouman 《Remote sensing of environment》2008,112(8):3366-3375
The principal goal in early missions of satellite-borne visible spectral radiometry (ocean colour) was to create synoptic fields of phytoplankton biomass indexed as concentration of chlorophyll-a. In the context of climate change, a major application of the results has been in the modelling of primary production and the ocean carbon cycle. It is now recognised that a partition of the marine autotrophic pool into a suite of phytoplankton functional types, each type having a characteristic role in the biogeochemical cycle of the ocean, would increase our understanding of the role of phytoplankton in the global carbon cycle. At the same time, new methods have been emerging that use visible spectral radiometry to map some of the phytoplankton functional types. Here, we assess the state of the art, and suggest paths for future work. 相似文献
99.
K.H. Sabeena Farvin S. Hari Senthil KumarR. Anandan Suseela MathewT.V. Sankar P.G. Viswanathan Nair 《Food chemistry》2007,105(4):1390-1395
We have investigated the preventive effects of squalene against isoprenaline-induced myocardial infarction in male albino rats. Supplementation with squalene significantly prevented the isoprenaline-induced adverse changes in the levels of protein and glycoprotein components in plasma and heart tissue of experimental groups of rats. It exerted an antioxidant effect by inhibiting the isoprenaline-induced lipid peroxidation and by maintaining the level of non-enzymatic free radical-scavenger, reduced glutathione at near normalcy. Histopathological observations also confirmed the possible cardioprotective action of squalene by maintaining the normal architecture of the heart tissue. The results of the present investigation demonstrate that supplementation with squalene offers cardioprotection in experimental rats by its antioxidant and membrane- stabilizing properties. 相似文献
100.
In this paper we present how a normal pressure nozzle can be adapted into a successful electrostatic assisted atomiser for one particular industrial application. The “Reverse Modelling” technique for the design of the nozzle head, induction electrode and counter 'wetting' electrode using finite element method is of universal value and can be used widely in induction charging electrostatic spraying applications where wetting is a problem. Experimental results showed that under the same operating condition, an optimised geometry and position of electrodes can give a spray current an order of magnitude higher than the previous design without any wetting problem. An optimum combination of an induction and a counter electrode geometry and positions will ensure a non-wetting induction nozzle assembly with very high charging efficiency. 相似文献