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71.
The antifols, inhibitors of the dihydrofolate reductase (DHFR), such as pyrimethamine and proguanil, have been used against Plasmodium falciparum in the areas where chloroquine resistance is widespread. This use has selected resistant strains in Southeast Asia and South America. The resistance is correlated with point mutations in precise positions of the DHFR gene. A reliable semi-nested PCR diagnosis test was established and used to determine the genotypic features of 29 isolates of P. falciparum originating from Africa. The results obtained by the PCR technique were compared with those of the in vitro drug sensitivity test. Some isolates were found to be polyclonal. Among the mutations tested, only mutations on codon 108 which generate an asparagine induce a decrease in sensitivity to pyrimethamine and cycloguanil, whereas mutation on codon 59 strengthens resistance to both antifols. No mutation on codon 16 or codon 164 was found.  相似文献   
72.
A circuit useful as a lock detector in microwave phase-locked loop (PLL) systems has been developed. This circuit avoids the quadrature phase detector or coherent amplitude detector commonly used as a lock indicator in PLLS, thereby reducing the microwave circuitry and components. It is based on the properties of the phase-error signal coming from the phase detector; a frequency-voltage conversion is performed on it in a low-frequency (secondary) PLL, the input to which is the output of the phase detector in the main (microwave) PLL. The secondary voltage-controlled oscillator (VCO) control signal gives, after a comparison, a logic level related to the lock condition in the main (microwave) PLL. This circuit has been used with success in microwave phase-locked oscillators (PLOs) in which the phase detection was made at 290 MHz, 2.55 GHz, 27 GHz and 29.7 GHz  相似文献   
73.
Text Summarization models facilitate biomedical clinicians and researchers in acquiring informative data from enormous domain-specific literature within less time and effort. Evaluating and selecting the most informative sentences from biomedical articles is always challenging. This study aims to develop a dual-mode biomedical text summarization model to achieve enhanced coverage and information. The research also includes checking the fitment of appropriate graph ranking techniques for improved performance of the summarization model. The input biomedical text is mapped as a graph where meaningful sentences are evaluated as the central node and the critical associations between them. The proposed framework utilizes the top k similarity technique in a combination of UMLS and a sampled probability-based clustering method which aids in unearthing relevant meanings of the biomedical domain-specific word vectors and finding the best possible associations between crucial sentences. The quality of the framework is assessed via different parameters like information retention, coverage, readability, cohesion, and ROUGE scores in clustering and non-clustering modes. The significant benefits of the suggested technique are capturing crucial biomedical information with increased coverage and reasonable memory consumption. The configurable settings of combined parameters reduce execution time, enhance memory utilization, and extract relevant information outperforming other biomedical baseline models. An improvement of 17% is achieved when the proposed model is checked against similar biomedical text summarizers.  相似文献   
74.
Various crystallization parameters were studied during the fabrication of Bi3.15Nd0.85Ti3O12 (BNdT) thin films on Pt/Ti/SiO2/Si (100) by metal organic solution decomposition method. The effect of crystallization processes, crystallization ambients on the properties of BNdT thin films such as orientation, ferroelectric properties were examined. By adopting different fabrication processes, it is possible to get both highly c-axis oriented as well as randomly oriented thin films. Highly c-axis oriented BNdT thin film showed a large remnant polarization (2Pr) of 70 μC/cm2 at an applied voltage of 10 V and exhibited a fatigue free behavior unto 2 × 109 switching cycles. The improved ferroelectric properties of BNdT thin films suggest their suitability for high density ferroelectric random access memory applications.  相似文献   
75.
Nanotube-assisted protein deactivation   总被引:1,自引:0,他引:1  
Conjugating proteins onto carbon nanotubes has numerous applications in biosensing, imaging and cellular delivery. However, remotely controlling the activity of proteins in these conjugates has never been demonstrated. Here we show that upon near-infrared irradiation, carbon nanotubes mediate the selective deactivation of proteins in situ by photochemical effects. We designed nanotube-peptide conjugates to selectively destroy the anthrax toxin, and also optically transparent coatings that can self-clean following either visible or near-infrared irradiation. Nanotube-assisted protein deactivation may be broadly applicable to the selective destruction of pathogens and cells, and will have applications ranging from antifouling coatings to functional proteomics.  相似文献   
76.
LCNO (Li0.35Cr0.10Ni0.55O) sample was prepared by modified sol–gel method and annealed at different temperatures (400, 800 and 1000 °C) in order to have variation in the size of grains and grain boundaries. The crystallinity and phase purity have been studied by employing the X-ray diffraction (XRD) technique. All the samples are crystallize to cubic symmetry with \(Fm\overline 3 m\) space group and, XRD patterns could be analysed by employing the Rietveld method. The microstructural and elemental analysis of the sample has been carried out by using the field emission scanning electron microscopy (FESEM). The grain size increases with the increase in annealing temperature which leads to increase the dielectric constant with the grain size. Interestingly, the enhancement of dielectric constant with the increase in grain size could be explained by the Barrier Layer Capacitances (BLCs) model. The frequency dispersion of dielectric constant could be explained by the Maxwell Wagner relaxation model. Furthermore, it is also observed that the activation energy obtained from dielectric relaxation analysis is comparable with the activation energy obtained by impedance analysis (Cole–Cole). In addition, the correlation between microstructure (grains and grain boundaries) with electrical transport properties of LCNO has been reported.  相似文献   
77.
78.
The end-of-life electric cables from both domestic and industrial sources offer an attractive resource of copper metal. In addition, copper wastes generated during fabrication of copper components remains another valuable source of recyclable copper. This work reports a simple, cost-effective and eco-friendly direct electrolytic refining using waste electrical copper wire scrap and copper plate rejects for producing the value added high purity copper powder. Suitable anode support system was applied in which compressed wire scrap or copper plate rejects were held to make anode for electrolytic cell. Electrolysis parameters like current density, acid concentration and copper ion concentration were varied to arrive at optimum condition. Results showed the energy consumption of 1.44 kW h/kg at 89% current efficiency for producing the copper powder, that consisted of >80% of–325 mesh size particles, from waste copper wire anodes. However, slightly lower energy consumption of 1.32 kW h/kg at 91% current efficiency was observed during production of copper powder from copper fabrication rejects. The copper powder thus produced was characterised by chemical analysis, XRD and optical microscope to examine the purity and morphology etc. and found suitable for powder metallurgical applications. Present investigations have established the potential utilisation of copper waste wire scrap and copper plate rejects for the production of value added high purity copper powder.  相似文献   
79.
In manufacturing industries, the facility layout design is a very important task, as it is concerned with the overall manufacturing cost and profit of the industry. The facility layout problem (FLP) is solved by arranging the departments or facilities of known dimensions on the available floor space. The objective of this article is to implement the firefly algorithm (FA) for solving unequal-area, fixed-shape FLPs and optimizing the costs of total material handling and transportation between the facilities. The FA is a nature-inspired algorithm and can be used for combinatorial optimization problems. Benchmark problems from the previous literature are solved using the FA. To check its effectiveness, it is implemented to solve large-sized FLPs. Computational results obtained using the FA show that the algorithm is less time consuming and the total layout costs for FLPs are better than the best results achieved so far.  相似文献   
80.
HycycleS was a cooperation of nine European partners and further non-European partners and aimed at the qualification and enhancement of materials and components for key steps of solar and nuclear powered thermochemical cycles for hydrogen generation from water. The focus of HycycleS was the decomposition of sulphuric acid (H2SO4) which is the central step of the sulphur-based family of those processes. Emphasis was put on materials and components for H2SO4 evaporation, decomposition, and sulphur dioxide separation. The suitability of materials and components was demonstrated by decomposing H2SO4 and separating its decomposition products in scalable prototypes.  相似文献   
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