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961.
The number of adders and critical paths in a multiplier block of a multiple constant multiplication based implementation of a finite impulse response (FIR) filter can be minimized through common subexpression elimination (CSE) techniques. A two‐bit common subexpression (CS) can be located recursively in a non‐canonic sign digit (CSD) representation of the filter coefficients. An efficient algorithm is presented in this paper to improve the elimination of a CS from the multiplier block of an FIR filter so that it can be realized with fewer adders and low logical depth as compared to the existing CSE methods in the literature. Vinod and others claimed the highest reduction in the number of logical operators (LOs) without increasing the logic depth (LD) requirement. Using the design examples given by Vinod and others, we compare the average reduction in LOs and LDs achieved by our algorithm. Our algorithm shows average LO improvements of 30.8%, 5.5%, and 22.5% with a comparative LD requirement over that of Vinod and others for three design examples. Improvement increases as the filter order increases, and for the highest filter order and lowest coefficient width, the LO improvements are 70.3%, 75.3%, and 72.2% for the three design examples. 相似文献
962.
Md. Z. R. Khan M. M. S. Hassan T. Rahman A. K. M. Ahsan 《International Journal of Electronics》2013,100(4):215-229
A new and compact formula for the base transit time, τ b , of a modern high speed npn bipolar transistor with exponential base doping profile is derived considering doping dependence of mobility, bandgap narrowing effect, high injection effect and carrier velocity saturation at the base edge of the collector–base junction. The collector current density, J c , and minority carrier stored charge, Q b , in the base are separately expressed as a function of the injected electron density n o in the base in order to find an empirical expression for τ b . The modelling of J c , Q b and τ b is essential for the design of high-speed bipolar transistor. The expressions are applicable for arbitrary injection before the onset of the Kirk effect and they are simple and straight forward to give insight into device operation. The base transit time calculated analytically is compared with simulation results in order to demonstrate the validity of the assumptions made in deriving the expression. The closed form expressions for collector current density and base transit time offer a physical insight into device operation and are a useful tool in device design and optimization. 相似文献
963.
Devika Kannan Ahmad Jafarian Hassan Alibabaei Khamene Laya Olfat 《The International Journal of Advanced Manufacturing Technology》2013,68(1-4):849-862
A budget is a detailed and comprehensive plan estimated to use a company’s resources over a specific period, and a primary purpose of budget allocation is to drive all activities towards organizational goals. But it seems, often, there is no logical and coherent relationship between overall objectives and action plans. This paper has drawn a consistent relationship between an organization's strategic plans to operational budgeting in a competitive environment. According to the step-by-step model proposed in this article, a strategic plan’s importance considers the main competitors of the market as an external environment factor and a balanced scorecard factors as an internal environment. Both are calculated by an artificial neuro-fuzzy inference systems approach to outshine competing companies. Then, sub-progress must be hierarchically determined in specific plans. In passing, a fuzzy quality function deployment method translates a strategic plan’s weight to detailed task importance (as the smallest component of an operational program) at the mercy of four houses of a quality matrix. An operational budget is allocated to programs for propagating strategic plans in a competitive environment. Finally, a case study in an automobile industry is presented and discussed to illustrate the application of the developed pattern. 相似文献
964.
Salah Hamed Ramadan Ali Hassan Hassan Mohamed Mohamed Kamal Bedewy 《International Journal of Precision Engineering and Manufacturing》2009,10(5):19-25
This paper aims at exploiting the accurate precise measurements of CMM machine in exploring and investigating the wear happening
between contacting solid surfaces. For instance, excessive wear, if detected by the CMM measurements, in a cylinder bore of
an internal combustion engine can dramatically affect its performance quality, sealing function, scheme of lubrication, and
eventually its service life span. In such case, the finger print would be the original design GD&T tolerances. Widely spread
availability of CMM machines at a reasonable cost may make the applicability of this novel technique of wear detection feasible.
In this work, precise and accurate measurements of deviations in roundness, straightness, and concentricity in a cylinder
bore of an air cooled Automotive Diesel Engine dismantled for an overhaul using a CMM machine have been executed and analyzed
to validate this technique. Thus, the results have been presented, discussed, analyzed and interpreted in order to evaluate
the status of the engine during operation. Locations of remarkable deviations representing aggressive wear happenings in the
cylinder bore are detected and investigated. The measurements, within the limits of uncertainty attributes, could reflect
the performance quality of the engine, the suitability of the applied scheduled maintenance plan, and may also point at possible
adverse operating conditions contributed to this wear. In the light of the findings, recommendations may thus be drawn and
offered to the engine designer to improve his design. For instance, surface treatments and coatings could be preferably changed,
or an innovative constructional modification may be suggested to homogenize the wear occurrence in the cylinder bore during
operation. This may extend the operating life span of the cylinder and in turn reduces the maintenance expenses. This novel
technique for the wear development recalling proved to be successful and reliable tool to diagnose the root causes of the
wear aggression occurrence. 相似文献
965.
Fleet management models and algorithms for an oil-tanker routing and scheduling problem 总被引:1,自引:0,他引:1
This paper explores models and algorithms for routing and scheduling ships in a maritime transportation system. The principal thrust of this research effort is focused on the Kuwait Petroleum Corporation (KPC) Problem. This problem is of great economic significance to the State of Kuwait, whose economy has been traditionally dominated to a large extent by the oil sector, and any enhancement in the existing ad-hoc scheduling procedure has the potential for significant savings. A mixed-integer programming model for the KPC problem is constructed in this paper. The resulting mathematical formulation is rather complex to solve due to the integrality conditions and the overwhelming size of the problem for a typical demand contract scenario. Consequently, an alternate aggregate model that retains the principal features of the KPC problem is formulated. The latter model is computationally far more tractable than the initial model, and a specialized rolling horizon heuristic is developed no solve it. The proposed heuristic procedure enables us to derive solutions for practical sized problems that could not be handled by directly solving even the aggregate model. The initial formulation is solved using CPLEX-4.0-MIP capabilities for a number of relatively small-sized test cases, whereas for larger problem instances, the aggregate formulation is solved using CPLEX-4.0-MIP in concert with the developed rolling horizon heuristic, and related results are reported. An ad-hoc routing procedure that is intended to simulate the current KPC scheduling practice is also described and implemented. The results demonstrate that the proposed approach substantially improves upon the results obtained using the current scheduling practice at KPC. 相似文献
966.
This paper proposes a novel method for solving the Non-convex Economic Dispatch (NED) problems, by the Fuzzy Adaptive Modified Particle Swarm Optimization (FAMPSO). Practical ED problems have non-smooth cost functions with equality and inequality constraints when generator valve-point loading effects are taken into account. Modern heuristic optimization techniques have been given much attention by many researchers due to their ability to find an almost global optimal solution for ED problems. PSO is one of modern heuristic algorithms, in which particles change place to get close to the best position and find the global minimum point. However, the classic PSO may converge to a local optimum solution and the performance of the PSO highly depends on the internal parameters. To overcome these drawbacks, in this paper, a new mutation is proposed to improve the global searching capability and prevent the convergence to local minima. Also, a fuzzy system is used to tune its parameters such as inertia weight and learning factors. 相似文献
967.
968.
Ali M. Hassan Osama A. G. Wahba A. M. Naser A. Mohy Eldin 《Journal of Coatings Technology and Research》2016,13(3):517-525
Metal complex pigments have been widely used for various applications such as pigments in coatings. This work presents the use of microwave technique (Green chemistry) for the synthesis of new copper(II), nickel(II), iron(III), and chromium(III) Schiff base complexes derived from metal salts and Schiff base ligand. Also, the microwave technique was used in the synthesis of Schiff base ligand which is derived from selected amine, namely methoxy-tolidine, and selected aldehyde, namely 2-hydroxynaphthaldehyde. The prepared ligand and metal complex pigments were characterized by elemental analysis, NMR, spectral UV–Vis, infrared, and thermal gravimetric analysis. The physical and mechanical properties and corrosion resistance of dry paint films were also examined. The obtained results revealed that the prepared metal complex pigments showed excellent mechanical and corrosion resistance. 相似文献
969.
The effect of alginate and chitosan concentrations on some properties of chitosan‐coated alginate beads and survivability of encapsulated Lactobacillus rhamnosus in simulated gastrointestinal conditions and during heat processing 下载免费PDF全文
970.
This study analyses the effects of the radiation exchange inside a horticultural greenhouse, under winter climatic conditions, according to the number of squared heating tubes used. These ones, hot and isothermal, are equidistant inside the greenhouse volume. The governing differential equations are discretized using a finite volume method and the coupling pressure–velocity problem is carried out by the SIMPLER algorithm. The algebraic systems obtained are solved by a conjugate gradient method. Results are reported in terms of isotherms, streamlines and average Nusselt number for Rayleigh number of 103–106. The contour lines show that the radiative effects are noted near the solid surfaces, and become increasingly important when the Rayleigh number increases. As a result, the rise in the value of Rayleigh number leads to an increase of the overall heat transfer within the greenhouse. 相似文献