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161.
A concatenated coded modulation scheme is presented for error control in data communications. The scheme is achieved by concatenating a Reed-Solomon outer code and a bandwidth efficient block inner code for M-ary phase-shift keying (PSK) modulation. Error performance of the scheme is analyzed for an additive white Gaussian noise (AWGN) channel. It is shown that extremely high reliability can be attained by using a simple M-ary PSK modulation inner-code and a relatively powerful Reed-Solomon outer code. Furthermore, if an inner code of high effective rate is used, the bandwidth expansion required by the scheme due to coding will be greatly reduced. The scheme is particularly effective for high-speed satellite communications for large file transfer where high reliability is required. A simple method is also presented for constructing block codes for M-ary PSK modulation. Soome short M-ary PSK codes with good minimum squared Euclidean distance are constructed. These codes have trellis structure and hence can be decoded with a soft-decision Viterbi decoding algorithm. Furthermore, some of these codes are phase invariant under multiples of 45° rotation  相似文献   
162.
Previous research has shown that a stereotype favorable to physically attractive individuals seems to exist. The present study examined how this "what is beautiful is good" stereotype influences observers' attributions of responsibility to target persons. Ss were 72 male and 72 female high school students. A significant interaction was found between physical attractiveness and the outcome of the event. Physically attractive women were seen as more responsible for a good outcome than unattractive women, while unattractive females were seen as more responsible for a bad outcome than attractive females. Results are interpreted within a framework of balance theory. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
163.
The states in the surface and the bulk phases of Na ion-sensitive polymeric membranes based on a synthetic carrier were investigated using SEM, IR, 13C-NMR, and GC. The 13C-NMR study revealed that conformation change of the carrier took place when the carrier was incorporated into the membrane phase. From SEM, IR, and 13C-NMR experiments with a deteriorated membrane, the conformation change of the carrier was proposed as one of the deterioration factors other than the decrease in the diffusion coefficient of the carrier in the membrane phase.  相似文献   
164.
Phosphatidylinositol 3-kinase (PI 3-kinase) is stimulated by association with a variety of tyrosine kinase receptors and intracellular tyrosine-phosphorylated substrates. We isolated a cDNA that encodes a 50-kDa regulatory subunit of PI 3-kinase with an expression cloning method using 32P-labeled insulin receptor substrate-1 (IRS-1). This 50-kDa protein contains two SH2 domains and an inter-SH2 domain of p85alpha, but the SH3 and bcr homology domains of p85alpha were replaced by a unique 6-amino acid sequence. Thus, this protein appears to be generated by alternative splicing of the p85alpha gene product. We suggest that this protein be called p50alpha. Northern blotting using a specific DNA probe corresponding to p50alpha revealed 6.0- and 2.8-kb bands in hepatic, brain, and renal tissues. The expression of p50alpha protein and its associated PI 3-kinase were detected in lysates prepared from the liver, brain, and muscle using a specific antibody against p50alpha. Taken together, these observations indicate that the p85alpha gene actually generates three protein products of 85, 55, and 50 kDa. The distributions of the three proteins (p85alpha, p55alpha, and p50alpha), in various rat tissues and also in various brain compartments, were found to be different. Interestingly, p50alpha forms a heterodimer with p110 that can as well as cannot be labeled with wortmannin, whereas p85alpha and p55alpha associate only with p110 that can be wortmannin-labeled. Furthermore, p50alpha exhibits a markedly higher capacity for activation of associated PI 3-kinase via insulin stimulation and has a higher affinity for tyrosine-phosphorylated IRS-1 than the other isoforms. Considering the high level of p50alpha expression in the liver and its marked responsiveness to insulin, p50alpha appears to play an important role in the activation of hepatic PI 3-kinase. Each of the three alpha isoforms has a different function and may have specific roles in various tissues.  相似文献   
165.
166.
The cI repressor of bacteriophage lambda is better-fitted to the proximal interactions in which it naturally takes part than to the long-distance cooperative interactions on DNA for which it has become representative. The first observation in support of this statement is the ambiguity of an untypical DNAase I footprint which has become a diagnostic for DNA circularisation (and thus for the capacity of the protein to control expression at a distance). However, it was also observed without effective DNA looping when lac repressor binds to nearly contiguous sites. Additionally, the surface of interaction between the two dimers seems to be more important than the one commonly admitted (via some contacts between the flexible arms), the biological function of the repressor is lost when the sites are separated and loops have not been observed for large separation of the sites. In fact, naturally distant interactions can conform to shorter distances, as an intrinsic property of DNA looping. On the contrary, interactions which are naturally optimised for contiguity are generally constrained to proximity. Alternative protein-protein contacts are generally responsible for this situation (cf. CRP versus NRI in Escherichia coli).  相似文献   
167.
A new concept for an overvoltage self-protected thyristor was theoretically analyzed and the thyristor manufactured. Its breakover operation is basically a combination of punchthrough and avalanche phenomena. Temperature dependence of the original structure in this thyristor is 5% from 20 to 125°C. A second device which has a function to predict breakover voltage was also produced. The difference in temperature dependence of breakover voltage for both devices was investigated by an analytical model. Structures offering improved characteristics were proposed. The breakover voltage decrease of the developed structures at high temperature could be made equal to that of the original structure by a slight modification of the breakover region  相似文献   
168.
The effects on chemical and physical properties of PET (poly(ethylene terephthalate)) film surfaces as a result of microstructuring induced by KrF-laser (248 nm) radiation were investigated. On irradiation, the properties of film surfaces changed in proportion to radiation flux intensity. Close to threshold values, bulbous swellings appeared on the surface, which showed hydrophilic properties. At the threshold and above, regular rippling was seen, and the surface showed hydrophobic properties. Excimer laser irradiation induced chemical modification of the surface, decrease in the O/C ratio, dissociation of ester binding and amorphism as observed by X-ray-induced photoelectron spectroscopic and Fourier-transform infrared analysis.  相似文献   
169.
Hydrogen radical process for photoresist removal by use of hot W catalyst has been investigated for a possible application to advanced Cu/low-k dielectric interconnects in LSI. It is found that etching rates of resists depend critically on sample temperature (Ts) and are higher than 1 μm/min at the optimized condition. H radical irradiation effects on porous methylsilsesquioxane (p-MSQ) have been studied from measurements of k value and capacitance of the advanced interconnect test sample. No radical process is observed to induce the increase in k value of p-MSQ films. These results suggest that the hydrogen radical process for resist removal with W catalyst is promising for production of advanced interconnects.  相似文献   
170.
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