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91.
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We report for the first time a bidirectional optical backplane bus for a high performance system containing nine multi-chip module (MCM) boards, operating at 632.8 and 1300 nm. The backplane bus reported here employs arrays of multiplexed polymer-based waveguide holograms in conjunction with a waveguiding plate, within which 16 substrate guided waves for 72 (8×9) cascaded fanouts, are generated. Data transfer of 1.2 Gbt/s at 1.3-μm wavelength is demonstrated for a single bus line with 72 cascaded fanouts. Packaging-related issues such as transceiver size and misalignment are embarked upon to provide a reliable system with a wide bandwidth coverage. Theoretical treatment to minimize intensity fluctuations among the nine modules in both directions is further presented and an optimum design rule is provided. The backplane bus demonstrated, is for general-purpose and therefore compatible with such IEEE standardized buses as VMEbus, Futurebus and FASTBUS, and can function as a backplane bus in existing computing environments 相似文献
94.
In this paper we present some issues encountered in the implementation of a kernel for a multiprocessor system using a high level language called CCNPASCAL. We present the nature of the problem concerning each issue, the solutions we adopted and possible better alternatives which we could not adopt for various reasons. 相似文献
95.
96.
V. Natarajan N. R. Taskar I. B. Bhat S. K. Ghandhi 《Journal of Electronic Materials》1988,17(6):479-483
The organometallic vapor phase epitaxy of HgCdTe onto (100)2°-(110) GaAs substrates is described in this paper. A buffer layer
of CdTe has been grown prior to the growth of HgCdTe, to take up the large lattice mismatch with the GaAs. Considerations
for the thickness of this buffer layer are outlined, and it is shown by quantitative Secondary Ion Mass Spectroscopy that
there is negligible diffusion of gallium from the GaAs substrate for the growth conditions described. Hall effect measurements
give mobilities comparable to those reported for bulk grown crystals. An extrinsicn-type carrier concentration of 2 × 1016/cm3 is obtained, and is mainly due to residual impurities in the starting chemicals. The alloy composition has been determined
at 298 K by Fourier transform infrared transmission (FTIR) spectrometry; this is found to be extremely uniform over a 15 ×
7 mm area, as evidenced by an overlapping of FTIR plots taken over this area. HgCdTe layers have been grown on buffer layers
varying in thickness from 0.1 to 1.9μm. It is found that a buffer thickness of about 1.9μm or larger is required to obtain high quality HgCdTe, both in terms of the electrical characteristics (mobility and carrier
concentration) and the infrared transmission curves (peak transmission). 相似文献
97.
Finite elements and computer codes are being used extensively for the calculation of deflections, terminal reactions and stresses in piping and pressure vessels. In these practices, pipelines are usually idealised by straight or curved beams. In contrast to this, the theory for pipe bend is based on differential equations of shell theory and by using the flexibility factor concept, it is possible to introduce the effect of bends into a pipe system. It can be said that inaccuracies in bend flexibility factors and stress intensification factors can lead to erroneous results when the straight lengths to which they are attached to are short. Thin walled piping elbow's wall thickness are likely to vary as a result of manufacturing processes. With the increasing use of thin-wall pipe at high stresses the effect of the internal pressure becomes significant. In the present paper stresses in a piping elbow due to internal pressure are studied in the presence of thickness variation.A finite element scheme with a doubly curved shell element which can account for variation in thickness has been utilized in the present paper. The effect of wall thickness variation in a 90° bend taking into account the end constraint due to tangent pipe to which they are attached to on the stress distribution has been studied for varying pipe factors.In order to study how the stress intensification factor will differ with different arc lengths, bends of various included angles having non-uniform wall thickness have been analyzed.The material of the piping system is assumed to behave elastically.Numerical results show that the non-uniform thickness of the bend wall does not affect maximum stress factor even in the case of bends with pipe factors of the order 0.05. For 90° bends as pipe factor increases from 0.05 the maximum stress factor increases and then decreases as pipe factor approaches 0.15. For other included angle bends the stress factor varies linearly with a maximum value at low pipe factor. The maximum stress factor is found to vary linearly with bend angle for all pipe factors and thinning factor of the pipe wall. 相似文献
98.
The present investigation is aimed toward the development of knowledge-based aids for the design of mechanical systems. We have developed and implemented the knowledgebased aid system, which includes MEET and DPMED. The basic approach of MEET follows along the lines ofDesign=Refinement+ Constraint Propagation. This approach has been proven successful in the circuit design domain. Our attempts to utilize MEET have convinced us that we need to extend this methodology to solve mechanical design problems. The DPMED methodology has been applied to design gear-pairs, v-belts, bearings, and shafts. Rules for selecting materials, critical design criteria, and so on are incorporated as part of the rule-system. In order for DPMED to select the design parameter values within the feasible design space, design criteria need to be investigated. Based on these criteria and input/output specifications, DPMED attempts to perform parameter selections. DPMED uses a general hill-climbing algorithm to guide the search. 相似文献
99.
Ramamurthy Natarajan 《Fuel》1979,58(11):815-818
Combustion of Bunker C fuel drops has been studied by high-speed cinematography using both suspended and falling drop techniques. Suspended drops burned disruptively, the liquid phase shattering and the gas phase displaying ‘explosive’ behaviour. Falling drops of pre-heated fuel burned smoothly, whereas non-preheated fuel drops burned in stages, with frequent extinction and re-ignition, accompanied by fluctuating combustion in the gas phase, suggesting rapid and irregular evolution of volatiles. 相似文献
100.
S Natarajan ND Theise SN Thung L Antonio F Paronetto P Hytiroglou 《Canadian Metallurgical Quarterly》1997,21(3):312-318
The deaths of 10 heroin body packers are reported and contrasted to those of cocaine body packers. Only one was a woman, and all were traveling to or from Colombia. Drug packets deteriorated in the gastrointestinal tract and caused the deaths of eight victims. Accomplices removed drug packets from two of these smugglers after death occurred. One died of peritonitis stemming from a small-bowel obstruction caused by the drug packets, and one died from the recreational use of heroin (nasally ingested). The heroin recovered was < or = 881 g, and the drug purity of the contraband in three cases was between 65% and 73%. Blood concentrations of morphine were < 1.0 mg/L in four victims; no morphine was detected in the smuggler who died of peritonitis. However, two victims had blood morphine concentrations of 4.4 mg/L and 6.7 mg/L, respectively, and three had morphine concentrations of 35.8, 39.4, and 52.6 mg/L, respectively. Fatal heroin body packing differs from cocaine body packing in that individuals may have extremely high drug levels in their blood and their accomplices appear to be more likely to abandon them in a remote location after attempting to remove the drug packets after death has occurred. 相似文献