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981.
A. I. Ul'yanov É. F. Merzlyakov R. G. Faizullin 《Powder Metallurgy and Metal Ceramics》1995,33(1-2):61-63
Density and carbon content are studied for their effect on strength (hardness) and magnetic (coercive force, saturation magnetization) properties of powder steels ZhGr1 and ZhGr1D3. It is shown that the hardness of articles made of these steels may be determined indirectly by measuring two magnetic characteristics.Physicotechnical Institute, Russian Academy of Sciences, Izhevsk. Translated from Poroshkovaya Metallurgiya, Nos. 1–2, pp. 67–69, January–February, 1994. 相似文献
982.
F. Riffard H. Buscail E. Caudron R. Cueff C. Issartel S. Perrier 《Corrosion Science》2003,45(12):2867-2880
The present results reveal the interest of sol–gel coating technique to improve 304 steel high temperature oxidation resistance. An yttrium sol–gel coating appears to enhance the oxidation resistance during isothermal oxidation test, to decrease widely the oxide weight gain and to reduce the initial transient oxidation stage generally observed in the case of blank steels. Moreover, the experimental results confirm that yttrium sol–gel coating also plays a significant role on the cyclic oxidation behaviour of the 304 steel. In fact, the yttrium addition promotes remarkably the prolongation of the period during which the oxide scale still remains adherent to the substrate. 相似文献
983.
984.
985.
Y. C. Wu Darning Feng W. F. Koch 《Journal of research of the National Institute of Standards and Technology》1991,96(6):757-762
Ionic interactions in the two systems NaCl-HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid) and NaCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic acid) have been studied in terms of their mutual influence on the respective activity coefficients of each component. Activity coefficients for each component of the two systems and for corresponding buffers are calculated from emf measurements of solutions containing NaCl, the aminosulfonic acid, and its conjugate base in a NalSE/solution/AgCl-Ag cell at 5, 15, 25, and 37 °C. 相似文献
986.
Formulations containing 4 parts cornstrach, 5 parts poly(ethylene-co-acrylic) (EAA), 1 part urea, and 1.6 parts of either water or aqueous ammonia were extruded at either 110–120°C or 150–160°C; and the resulting extrudates were then extrusion-blown into films. Complex formation between EAA and starch was measured by either X-ray diffraction or by solvent extraction of uncomplexed EAA. Although the processing temperature had only a minor effect on the amount of EAA complexed by starch, use of aqueous ammonia rather than water in these formulations increased the amount of complexed EAA by about a factor of 2. In films prepared with aqueous ammonia, the polysaccharide phase was present as submicron-sized domains. When ammonia was omitted from these formulations, the polysaccharide phase was less uniform in size and contained particles that were over an order of magnitude larger than those observed with ammonia. 相似文献
987.
Yang Wang Mansour N. Salem A. Brennan K.F. Ruden P.P. 《Quantum Electronics, IEEE Journal of》1992,28(2):507-513
The authors present a theoretical analysis of a possible avalanching photodetector (APD)-based on II-VI compound semiconductors. Each unit cell is composed of a HgTe layer, or a similar semimetal, sandwiched between two layers of CdTe and HgCdTe or similar semiconducting materials. The barrier layers are graded so that the leading barrier height is just high enough to eliminate the thermionic emission dark current out of the well. The use of a semimetal within the well has a distinct advantage over a semiconductor, which is that the ionization process is essentially an interband mechanism since the confined carriers within the well lie within the overlapping conduction and valence bands. As a result, the concentration of target carriers is virtually inexhaustible as in a conventional interband device 相似文献
988.
A multi-technique approach, incorporating nuclear magnetic resonance (NMR), elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis and surface area determination, has been used to investigate the formation of chars by oxidized cellulose. It was found that oxidation of the cellulose tends to increase the surface area of the resulting char. NMR, elemental analysis and DSC show how cellulose oxidation tends to increase aromaticity and cross-linking. This, in turn, decreases diffusion rates of volatiles out of the oxidized cellulose during pyrolysis, giving denser carbons and higher BET surface areas. 相似文献
989.
Dell'Acqua F. Fisher R. 《IEEE transactions on pattern analysis and machine intelligence》2002,24(4):569-575
Analysis and reconstruction of range images usually focuses on complex objects completely contained in the field of view; little attention has been devoted so far to the reconstruction of simply shaped wide areas like parts of a wall hidden behind furniture pieces in an indoor range image. The work presented in the paper is aimed at such reconstruction. First of all, the range image is partitioned based on depth discontinuities and fold edges. Next, the planes best fitting each of the regions constituting the partition of the image are determined. A third step locates potentially contiguous surfaces, while a final step reconstructs the hidden regions. The paper presents results for reconstruction of the shape of planar surfaces behind arbitrary occluding surfaces. The system proved to be effective and the reconstructed surfaces appear to be reasonable. Some examples of results are presented from the Bornholm church range images 相似文献
990.
Balasa F. Catthoor F. Hugo De Man 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1995,3(2):157-172
Memory cost is responsible for a large amount of the chip and/or board area of customized video and image processing system realizations. In this paper, we present a novel technique-founded on data-flow analysis which allows one to address the problem of background memory size evaluation for a given nonprocedural algorithm specification, operating on multidimensional signals with affine indexes. Most of the target applications are characterized by a huge number of signals, so a new polyhedral data-flow model operating on groups of scalar signals is proposed. These groups are obtained by a novel analytical partitioning technique, allowing to select a desired granularity, depending on the application complexity. The method incorporates a way to tradeoff memory size with computational and controller complexity 相似文献