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61.
A new miniature bandpass filter, comprising three-conductor short-circuited spurline resonators of approximately a quarter-wavelength long, with a very wide bandwidth approaching multioctaves is reported for the first time. The chain matrix of the filter resonator is derived. The new filter has been developed using microstrip line with less than 1 dB insertion loss over a passband from 2 to 8 GHz. Reasonably good agreement between the measured and calculated results is observed 相似文献
62.
To synthesize diamond films by microwave plasma enhanced chemical vapor deposition (MPECVD), the methane concentration (CH4/H2)plays a crucial role. It is well-known that there always exists a critical methane concentration (≤0.6%) only below which
a good quality diamond film can be obtained. In this study, however, the phenomena of diamond synthesis resulting from high
carbon concentration conditions were observed. The molten metals, e.g., Ag, Cu, were used as the deposition substrates on
which crystalline diamonds can be achieved from a methane content of CH4/H2≥6% or even from solid carbon sources. These results suggest that there may exist a low methane content boundary layer (<0.6%)
in the proximity of molten metal surface on which suitable species, CH, CH+, Hα and Hβ are composed for the diamond nucleation and growth similar to the condition as in the conventional low methane contents.
The molten metal inclines to dissolve other forms of carbonaceous materials other than diamond, and thus keeps a much higher
steady supply of carbon atoms that enhances the quality as well as the growth rate of the forming diamonds.
Received: 23 June 2001 / Accepted: 23 July 2001 相似文献
63.
64.
65.
Hayden J.D. Taft R.C. Kenkare P. Mazure C. Gunderson C. Nguyen B.-Y. Woo M. Lage C. Roman B.J. Radhakrishna S. Subrahmanyan R. Sitaram A.R. Pelley P. Lin J.-H. Kemp K. Kirsch H. 《Electron Devices, IEEE Transactions on》1994,41(12):2318-2325
An advanced, high-performance, quadruple well, quadruple polysilicon BiCMOS technology has been developed for fast 16 Mb SRAM's. A split word-line bitcell architecture, using four levels of polysilicon and two self-aligned contacts, achieves a cell area of 8.61 μm2 with conventional I-line lithography and 7.32 μm2 with I-line plus phase-shift or with deep UV lithography. The process features PELOX isolation to provide a 1.0 μm active pitch, MOSFET transistors designed for a 0.80 μm gate poly pitch, a double polysilicon bipolar transistor with aggressively scaled parasitics, and a thin-film polysilicon transistor to enhance bitcell stability. A quadruple-well structure improves soft error rate (SER) and allows simultaneous optimization of MOSFET and bipolar performance 相似文献
66.
Parasitic bipolar gain in fully depleted n-channel SOI MOSFET's 总被引:3,自引:0,他引:3
Ver Ploeg E.P. Nguyen C.T. Wong S.S. Plummer J.D. 《Electron Devices, IEEE Transactions on》1994,41(6):970-977
Fully depleted SOI MOSFET's include an inherent parasitic lateral bipolar structure with a floating base. We present here the first complete physically based explanation of the bipolar gain mechanism, and its dependence on bias and technological parameters. A simple, one-dimensional physical model, with no fitting parameters, is constructed, and is shown to agree well with simulations and measurements performed on a new type of SOI MOSFET structure. It is shown that parameters which affect the gain, such as SOI layer thickness, body doping concentration and gate and drain voltages, do so primarily by affecting the concentration of holes in the body region. Thus, current gain falls dramatically with increasing drain voltage due to the associated impact ionization driven increase in the hole concentration. Gummel plots of this parasitic bipolar indicate an apparent ideality factor of 0.5 for the hole current, due to the body hole concentration's dependence on drain voltage 相似文献
67.
Sanghera J.S. Nguyen V.Q. Pureza P.C. Kung F.H. Miklos R. Aggarwal I.D. 《Lightwave Technology, Journal of》1994,12(5):737-741
Improved purification and processing techniques have been utilized to fabricate Ge30As10Se30Te30 glass fibers with a minimum loss of O.11 dB/m at 6.6 μm. This is the lowest loss reported for any telluride glass fiber in the infrared region. Furthermore, the fibers exhibit less than 1 dB/m loss between 5.25 and 9.5 μm 相似文献
68.
Digital filter bank design quadratic-constrained formulation 总被引:5,自引:0,他引:5
Formulate the filter bank design problem as an quadratic-constrained least-squares minimization problem. The solution of the minimization problem converges very quickly since the cost function as well as the constraints are quadratic functions with respect to the unknown parameters. The formulations of the perfect-reconstruction cosine-modulated filter bank, of the near-perfect-reconstruction pseudo-QMF bank, and of the two-channel biorthogonal linear-phase filter bank are derived using the proposed approach. Compared with other design methods, the proposed technique yields PR filter banks with much higher stopband attenuation. The proposed technique can also be extended to design multidimensional filter banks 相似文献
69.
70.
Several types of ink are used in web offset printing. However, heatset inks predominate in general commercial work. In these inks, the vehicle consists of resin dissolved in a solvent, and drying takes place mainly by evaporation. In heatset web offset printing, the printed web is passed through dryers, which raise the temperature of the web enough to cause evaporation of the solvent. leaving only the resin to bind the pigment into a film and to the paper.
Since the solvents used in the heatset inks vary in boiling range from approximately 232° C to 316° C, and the solvent selected depends on the printing conditions, it is necessary to determine the vapor pressure values of heatset inks versus web temperatures for drying calculations. The isoteniscope method is limited to only the vapor pressure measurement of liquids. It cannot be used for materials such as heatset inks. To overcome this difficulty, an apparatus was designed and con- structed by TEC Systems for directly measuring the vapor pressure versus temperature of heatset inks from approximately 21°C to 316°C. In this paper, TEC's apparatus, test procedure developed, and typical test results for pure solvents and heatset inks will be described. 相似文献
Since the solvents used in the heatset inks vary in boiling range from approximately 232° C to 316° C, and the solvent selected depends on the printing conditions, it is necessary to determine the vapor pressure values of heatset inks versus web temperatures for drying calculations. The isoteniscope method is limited to only the vapor pressure measurement of liquids. It cannot be used for materials such as heatset inks. To overcome this difficulty, an apparatus was designed and con- structed by TEC Systems for directly measuring the vapor pressure versus temperature of heatset inks from approximately 21°C to 316°C. In this paper, TEC's apparatus, test procedure developed, and typical test results for pure solvents and heatset inks will be described. 相似文献