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21.
Ten samples of mineral-matter residue were obtained by the radio-frequency low-temperature ashing of subbituminous and bituminous coals. The low-temperature ash samples were then heated progressively from 400 °C to 1400 °C at 100 °C intervals. Mineral phases present at each temperature interval were determined by X-ray diffraction analyses. The minerals originally present in the coals (quartz, kaolinite, illite, pyrite, calcite, gypsum, dolomite, and sphalerite) were all altered to higher temperature phases. Several of these phases, including kaolinite, metakaolinite, mullite, anhydrite, and anorthite, were found only in limited temperature ranges. Therefore the temperature of formation of the ashes in which they occur may be determined. Mineralogical differences were observed between coal samples from the Rocky Mountain Province, the Illinois Basin, and the Appalachians; and as a result of these mineralogical differences, different high-temperature phases resulted as the samples were heated. However, regional generalizations cannot be made until a greater number of samples have been studied.  相似文献   
22.
The AOAC indirect, AOAC direct and EEC direct available P2O5 methods are compared by two different collaborative studies on DAP and GTSP. The collaborative studies found the AOAC direct and EEC direct available P2O5 methods to be lower than the AOAC indirect P2O5 method when the citrate insoluble P2O5 was greater than 0.3% P2O5. Results found in the Association of Florida Phosphate Chemist Check Sample Program confirmed the lower analysis.Until 1950 the primary method of analysis for available P2O5 was the AOAC indirect method. A faster method for available P2O5 was developed and adopted in the 50's by the AOAC. Diammonium phosphate from phosphate rock was not manufactured until 1959. The current fertilizer of today was not evaluated by the AOAC direct available P2O5 method because the fertilizer had not been manufactured.The current practice to use the empirical method for determining available P2O5 for plants was evaluated in the 30's, but it is still being applied to fertilizer materials of today. Several agronomic studies with current fertilizers have shown the so-called citrate insoluble P2O5 to be available to plants, which implies a new agronomic study should be evaluated for today's fertilizer to determine its availability.Based on the high cost of P2O5 production, available P2O5 methods must be equal when applied to the same fertilizer. Manufacturers of P2O5 in fertilizers cannot tolerate a 1.0% P2O5 difference between different available P2O5 methods. No one manufacturer or buyer should have an advantage over another because of the analytical method used to determine the available P2O5. If the so-called citrate insoluble P2O5 can be proved as available P2O5, the manufacturer should be able to sell that product as total available P2O5. If every regulatory agency developed their own available P2O5 method, the result would be confusion in determining the available P2O5 and inequities in the marketing of the product. The AOAC should establish methods that are equal in value for available P2O5.Quick, unofficial available P2O5 methods used to determine large volumes of fertilizer samples can be used by regulatory agencies to speed up the analyses. When deficient fertilizer samples are found by the unofficial method, the official methods should be used to determine true availability. The quick methods of questionable accuracy should be used for screening only. Regulatory agencies should operate in a posture of being fair to the consumer and manufacturer.  相似文献   
23.
Multimedia Tools and Applications - Detection and clustering of commercial advertisements plays an important role in multimedia indexing also in the creation of personalized user content. In...  相似文献   
24.
Grain coarsening tests were carried out on Al-4.5 pct Cu and Al-4.5 pct Si alloys. The effects of three variables, melt composition, pour temperature, and mold temperature, were determined. It was found that the macrostructure generally coarsened with increased pour and mold temperatures. Coarsening was extreme in the unrefined alloys but was retarded by the active grain refiners like titanium and columbium. The effect of boron was spectacular in suppressing coarsening tendencies. The results of the investigation support the carbide theory of nucleation as opposed to the peritectic theory.  相似文献   
25.
Quality criteria used in the computer-aided design and analysis of casting processes typically relate geometric, thermal, or solidification parameters to structural features such as centerline shrinkage and microporosity. Quality criteria for the prediction of porosity in castings have been used successfully in steel, but the application of criteria functions to nonferrous alloys has been less successful. Recent work suggests that the dominating mechanism that determines the amount and distribution of porosity in castings is strongly dependent on the solidification mode of the alloy and the solidification conditions. Accordingly, casting processes and alloy types are divided into four groups, and a different set of criteria functions are obtained for each group.  相似文献   
26.
We have developed an IT governance disclosure framework to examine how firms communicate their IT governance activities. Using this framework for a sample of 200 commercial banking firms, our empirical assessment indicates that differences in the level of disclosure are systematically related to differences in institutional settings. We also find that firms with relatively good corporate governance practices consider IT performance measurement matters to be highly important when informing and communicating with shareholders.  相似文献   
27.

Wireless sensor networks (WSN) is considered as one of the exploring technology for its deployment of the massive number of dedicated sensor nodes which sense the environment and collect the data. The collected data are sent to the sink node through the intermediate nodes. Since the sensors node data are exposed to the internet, there is a possibility of vulnerability in the WSN. The common attack that affects most of the sensor nodes is the Distributed Denial of Services (DDoS) attack. This paper aims to identify the DDoS (Flooding) attack quickly and to recover the data of sensor nodes using the fuzzy logic mechanism. Fuzzy based DDoS attack Detection and Recovery mechanism (FBDR) uses type 1 fuzzy logic to detect the occurrence of DDoS attack in a node. Similarly fuzzy- type 2 is used for the recovery of data from the DDoS attack. Both the type 1 fuzzy-based rule and type 2 fuzzy-based rule perform well in terms of identifying the DDoS attack and recover the data under attack. It also helps to reduce the energy consumption of each node and improves the lifetime of the network. The proposed FBDR scheme is also compared with other related existing schemes. The proposed method saves energy usage by up to 20% compared with the related schemes. The experimental results represent that the FBDR method works better than other similar schemes.

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28.
29.
Beta brass single crystal, bicrystal and tricrystal stress strain behavior were determined for a series of isoaxial specimens in which the bicrystals and tricrystals were incompatible in shear along the grain boundary. Volume fractions of grain boundary deformation were also determined to ascertain the effect of increased constraint on grain boundary strengthening. It was found that bicrystal flow stress was considerably higher than single crystal flow stress and that tricrystal strain hardening was only slightly larger than that of the bicrystal. For the tricrystals the grain boundary deformation zone is larger than that of corresponding bicrystals because of both configurational and constraint effects. This larger zone indicates that secondary stresses extend further from the boundary in tricrystals than in bicrystals. It was concluded that despite increased constraint, , the average grain boundary stress for the tricrystals, is smaller than that for corresponding bicrystals and that because of the increased extent of the secondary stress,σ b i, the stress in the center component away from the grain boundary, is higher than that of the single crystal at corresponding strains. The relationship of these observations to corresponding stresses in polycrystalline material is examined. where Taek Dong Lee was formerly a Graduate Student. This paper is based on a thesis to be submitted by Taek Dong Lee in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Polytechnic Institute of New York.  相似文献   
30.
In this paper we discuss a real-life case study to optimize the logistics network for the collection of containers from end-of-life vehicle dismantlers in the Netherlands. Advanced planning concepts, such as dynamic assignment of dismantlers to logistic service providers, are analyzed using a simulation model. Based on this model, we periodically solve a vehicle routing problem to gain insight into the long-term performance of the system. The vehicle routing problem considered is a multi-depot pickup and delivery problem with alternative delivery locations. A special characteristic of the problem is the limited vehicle capacity of two containers. We solve this problem with a heuristic based on route generation and set partitioning.  相似文献   
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