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911.
Immunocytochemically detectable MT and p53 have been found more commonly in comedo DCIS of the breast with high-grade cytology. The aim of this study is to confirm these findings and to investigate the relationship between MT and p53 in a single large series of cases of DCIS of the breast. To this end, 127 cases of DCIS were classified histologically according to architecture, cytonuclear differentiation (grade), presence and extent of intraduct necrosis, and using the Van Nuys system. Sections were immunostained for p53 and MT (E9) using established techniques, and the extent and intensity of staining were assessed semi-quantitively. The results confirmed that there was generally more MT and p53 positivity in poorly differentiated (grade 3) DCIS with extensive necrosis and that MT expression was greater in grade 2 lesions than p53 expression. However, overall there was no statistically significant correlation between p53 and MT staining. The results indicate that MT and p53 overexpression may arise from independent mechanisms in early breast neoplasia.  相似文献   
912.
This paper proposes a method for determining the coordination of the rate of change of frequency (ROCOF) and under/overfrequency relays for distributed generation protection considering islanding detection and frequency-tripping requirements. The method is based on the concept of application region, which defines a region in the trigger time versus active power imbalance space where frequency-based relays can be adjusted to satisfy the anti-islanding and frequency-tripping requirements simultaneously. This method can be used to optimally determine the instantaneous and time-delay settings of different frequency-based relays in a unified manner. The application region can be also employed to evaluate how much an existing frequency-based protection scheme violates one of the above-mentioned requirements. In addition, it can be used to set different combinations of frequency-based relays in order to make the distributed generator frequency-based protection system as efficient as possible, since it respects the region that satisfies both requirements.  相似文献   
913.
A commercial activated carbon (AC) was used as a catalyst support either in its original form or after two different oxidation treatments, namely air oxidation and HNO3 oxidation, aiming at the enhancement of its textural and surface chemical characteristics. These properties were determined by N2 adsorption and temperature programmed desorption (TPD), respectively. Monometallic Pt and bimetallic Pt–Sn catalysts were prepared on the AC supports. Impregnation was used in the preparation of the monometallic samples. For the bimetallic samples, coimpregnation and a sequential impregnation procedure, in which the Sn precursor is introduced prior to Pt, were used. The Pt load was kept fixed as 1 wt.% for all monometallic and bimetallic samples. Two different Sn loads, 0.25 and 0.50 wt.%, were used for the bimetallic samples in order to investigate the effects of Sn load on the catalytic properties. The catalyst samples were characterized by H2 adsorption, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and structure insensitive benzene hydrogenation. The activities of all samples were measured in CO oxidation. The results indicate the strong effects of the surface chemistry of the AC supports, the Pt:Sn ratio, the preparation procedure and the reduction procedure, on the CO oxidation activities of the catalysts.  相似文献   
914.
Charcot-Marie-Tooth (CMT) disease is the commonest inherited peripheral neuropathy. The clinical study of 45 patients with CMT is presented. They were derived from Antonio Pedro Hospital of Universidade Federal Fluminense in Niteroi, RJ, Brazil. Such patients could be divided by the motor conduction velocity in two types: a demyelinating form or type I (11 cases) and an axonal form or type II (34 cases). The disease was inherited as an autosomal dominant trait in 23 patients and as an autosomal recessive trait in 7 cases. In 15 patients the disorder was sporadic. The age of onset was in most of our cases before the 20 years. All of them had distal weakness in lower limbs. 38.2% had also distal weakness in upper limbs. 80% had distal wasting of the lower limbs and 50% had distal wasting of upper limbs. The tendon reflexes were absent in 64% in lower limbs and in 28% in upper limbs. The sensitive impairment in the distal regions of the extremities was mild in most patients. We found enlargement of peripheral nerves in 7 patients of type I. Pes cavus was present in 21 cases and scoliosis in 7. We found postural tremor of hands in 6 patients. In 9 cases there were rare features as mental retardation, trigeminal nevralgia, optic atrophy, deafness and calf enlargement. In most of our cases the clinical course was very slow progressive. A greater severity was seen in our sporadic cases.  相似文献   
915.
916.
    
Chitosan (Ch) and N‐carboxymethylchitosan (N‐CMCh) films were prepared by the casting method at concentrations of 1% and 2% of polymer, with or without plasticizer: polyethylene glycol (PEG‐400) and glycerol (G), at 15% (w/w). The influence of composition on mechanical properties, water vapour transmission rate (WVTR), water saturation, and aqueous dissolution of the films was analysed. The thermal stability of the mixture (polymer:plasticizer, 1:1) was evaluated by thermogravimetric analysis (TGA). In general, all the properties were affected by the plasticizers. The plasticized films showed lower strength and a higher percentage of elongation (%E), in the following order: G > PEG‐400 > unplasticized film. The total WVTR increased with Ch concentration, with a different WVTR profile for Ch and N‐CMCh. While the PEG‐400 addition did not significantly modify the WVTR profile of films, the glycerol enhanced the transport of water vapour through both polymers. The plasticizer addition increased the time of water film saturation, in the following order: G > PEG‐400 > unplasticized film; this was more pronounced in the N‐CMCh films, probably due to the formation of hydrogen bonds. The solubility of the films was also affected by their composition. Copyright © 2006 Society of Chemical Industry  相似文献   
917.
918.
Genetic programming for knowledge discovery in chest-pain diagnosis   总被引:10,自引:0,他引:10  
Explores a promising data mining approach. Despite the small number of examples available in the authors' application domain (taking into account the large number of attributes), the results of their experiments can be considered very promising. The discovered rules had good performance concerning predictive accuracy, considering both the rule set as a whole and each individual rule. Furthermore, what is more important from a data mining viewpoint, the system discovered some comprehensible rules. It is interesting to note that the system achieved very consistent results by working from “tabula rasa,” without any background knowledge, and with a small number of examples. The authors emphasize that their system is still in an experiment in the research stage of development. Therefore, the results presented here should not be used alone for real-world diagnoses without consulting a physician. Future research includes a careful selection of attributes in a preprocessing step, so as to reduce the number of attributes (and the corresponding search space) given to the GP. Attribute selection is a very active research area in data mining. Given the results obtained so far, GP has been demonstrated to be a really useful data mining tool, but future work should also include the application of the GP system proposed here to other data sets, to further validate the results reported in this article  相似文献   
919.
The aim of this study was to investigate the rate of contamination, species identification and antimicrobial resistance of thermophilic Campylobacter spp. in pig carcasses during the slaughter process in a slaughterhouse in Brazil. Two hundred and fifty-nine samples were collected at 7 different stages of the slaughter process for Campylobacter determination by both qualitative and quantitative methods. Typical colonies were subjected to API Campy, real-time polymerase chain reaction (PCR) and antimicrobial resistance testing. Campylobacter was found in 18.9% of the carcasses and 3.5% of the samples. Dehairing was the slaughter stage with the highest Campylobacter contamination (55.6%). All Campylobacter strains were confirmed by real-time PCR and showed multi-drug resistance to cephalothin, nalidixic acid, norfloxacin, tetracycline and trimethoprim. None of the strains were resistant to amoxicillin/clavulanic acid, ampicillin and chloramphenicol. Despite the low occurrence of Campylobacter spp. in pig samples, the antimicrobial resistance of Campylobacter strains represents a considerable risk for the consumption of pork meat and confirms the need for continuous monitoring of Campylobacter in the pig production chain.  相似文献   
920.
We report on the strong temperature-dependent thermal expansion, α(D), in CdS quantum dots (QDs) embedded in a glass template. We have performed a systematic study by using the temperature-dependent first-order Raman spectra, in CdS bulk and in dot samples, in order to assess the size dependence of α(D), and where the role of the compressive strain provoked by the glass host matrix on the dot response is discussed. We report the Grüneisen mode parameters and the anharmonic coupling constants for small CdS dots with mean radius R?~?2.0?nm. We found that γ parameters change, with respect to the bulk CdS, in a range between 20 and 50%, while the anharmonicity contribution from two-phonon decay channel becomes the most important process to the temperature-shift properties.  相似文献   
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