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61.
S. Das R. Roy A.B. Chattopadhyay 《International Journal of Machine Tools and Manufacture》1996,36(7):789-797
Recent trends, being towards mostly unmanned automated machining systems and consistent system operations, need reliable on-line monitoring processes. A proper on-line cutting tool condition monitoring system is essential for deciding when to change the tool. Many methods have been attempted in this connection.Recently, artificial neural networks have been tried for this purpose because of its inherent simplicity and reasonably quick data-processing capability. The present work uses the back propagation algorithm for training the neural network of 5-3-1 structure. The technique shows close matching of estimation of average flank wear and directly measured wear value. Thus the system developed demonstrates the possibility of successful tool wear monitoring on-line. 相似文献
62.
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64.
Polyaniline doped with nonoxidizing Bronsted acids is recognized as a conducting material, as its electrical conductivity changes with percentage of doping. In the present work, different percentages of doped polyaniline were blended with polyacrylamide and their electrical conductivities as well as the positron annihilation lifetimes were measured. Analysis of data yielded three lifetime components. It was observed that the value of the short lifetime component remained constant for doping concentration, whereas that of the intermediate component τ2 decreased. The relative intensity pertaining to τ2, however, increased with the increase in doped PANI concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 930–933, 2003 相似文献
65.
Asoke C. D. Chaklader Sankar Das Gupta Edmond C. Y. Lin Boris Gutowski 《Journal of the American Ceramic Society》1992,75(8):2283-2285
Al2 O3 and SiC composite materials have been produced from mixtures of aluminosilicates (both natural minerals and synthetic) and carbon as precursor materials. These composites are produced by heating a mixture of kaolinite (or synthetic aluminosilicates) and carbon in stoichiometric proportion above 1550°C, so that only Al2 O3 and SiC remain as the major phases. A similar process has also been used for synthesizing other composite powders having mixtures of Al2 O3 , SiC, TiC, and ZrO2 in different proportions (all compounds together or selective mixtures of some of them), as desired. The microstructure of hot-pressed dense compacts, produced from these powders, revealed that the SiC phase is distributed very homogeneously, even occasionally within Al2 O3 grains on a nanosize scale. The homogeneous distribution of SiC particles within the system produced high fracture toughness of the hot-pressed material (KIC ∼ 7.0 MPa · m1/2 ) and having Vicker's hardness values greater than 2000 kgf/mm2 . 相似文献
66.
In this paper we reviewed some of our work on the photo induced coloration of Poly(p-phenylene sulfide) (PPS) and compared it to recent results obtained from the thermal treatment of resins that varied in molecular weight and ionic content. The results from this study suggest that coloration of amorphous PPS films after UV irradiation is caused by products different from those that cause coloration in semicrystalline PPS after thermoxidation. In addition, we found that polymer end group chemistry and resin molecular weights play important roles in the thermoxidative coloration of PPS, but only nominally influence the photooxidative coloration of the resin. PPS coloration may arise from the accumulation of specific, colored products (e.g., phenyl-phenyl moieties) and the possible presence of intermolecular aggregates. The mechanism and extent by which these structures occur in UV irradiated or heated PPS are likely dependent upon the polymer morphology of the samples tested. 相似文献
67.
This paper presents CMP-VR (Chip-Multiprocessor with Victim Retention), an approach to improve cache performance by reducing the number of off-chip memory accesses. The objective of this approach is to retain the chosen victim cache blocks on the chip for the longest possible time. It may be possible that some sets of the CMPs last level cache (LLC) are heavily used, while certain others are not. In CMP-VR, some number of ways from every set are used as reserved storage. It allows a victim block from a heavily used set to be stored into the reserve space of another set. In this way the load of heavily used sets are distributed among the underused sets. This logically increases the associativity of the heavily used sets without increasing the actual associativity and size of the cache. Experimental evaluation using full-system simulation shows that CMP-VR has less off-chip miss-rate as compared to baseline Tiled CMP. Results are presented for different cache sizes and associativity for CMP-VR and baseline configuration. The best improvements obtained are 45.5% and 14% in terms of miss rate and cycles per instruction (CPI) respectively for a 4 MB, 4-way set associative LLC. Reduction in CPI and miss rate together guarantees performance improvement. 相似文献
68.
The preparation of dibasic acid-containing soy phospholipid was made by transesterification reaction with alkyl ester of diabasic acid with both lipase and alkoxide as a catalyst. The extent of incorporation of a dibasic acid varied with the molecular size of the dibasic acid. The extent of incorporation in soy phospholipids was 4–13% in the case of adipic acid and 9–20% in the case of sebacic acid. The surface-active properties of these modified soy phospholipids were examined and were found to be different from those of the original (unmodified) soy phospholipid. The interfacial properties such as critical micelle concentration (CMC), γCMC, surface excess concentration Γmax, and minimum area per molecule (Å), and thermodynamic parameters such as standard free energy of micellization, were found to depend on the hydrophobic part of the dibasic acids. 相似文献
69.
Swapan Kumar Mandal Rabindra Nath Datta Prasanta Kumar Das Dipak Kumar Basu 《应用聚合物科学杂志》1988,35(4):987-994
The reaction between bis(diisopropyl) thiophosphoryl disulfide (DIPDIS) and silica has been investigated. The study reveals that DIPDIS can be used as a coupling agent for silica. The chemical bond between the silanol groups of silica and DIPDIS has been established through the isolation and characterization of isopropyl alcohol that is eliminated from the reaction. The chemical nature of the bond is also supported by the IR analysis of the reaction products of silica and DIPDIS obtained both in the presence and absence of rubber. From the exploratory studies it is indicated that DIPDIS can also react with NR even during mixing of ingredients. When used with 2-mercaptobenzothiazole (MBT) or N-oxydiethylene-2-benzothiazole sulfenamide (OBTS) in the presence of silica, DIPDIS exhibits notable activation of cure and enhances the torque, modulus, tensile strength, and the scorch safety. 相似文献
70.
The activities of guinea pig lung mitochondrial and microsomal glycerophosphate acyltransferase differed in sensitivity to
polymyxin B1. At an antibiotic concentration of 1 mg/ml, the mitochondrial enzyme activity was stimulated twofold, but the microsomal
enzyme activity was completely inhibited. Furthermore, the mitochondrial enzyme activity was stimulated by polymyxin B1 without the addition of exogenous acyl-CoA. Additional experiments ruled out the possibility of polymyxin B1 acting as a substrate for the mitochondrial acyltransferase. These results suggest either that the polymyxin B1 sensitivity of mitochondrial and microsomal glycerophosphate acyltransferase is different or that their accessibility to
substrates is different because the two isoenzymes are located differently in the different phospholipid microenvironment
of the membranes. 相似文献