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排序方式: 共有102条查询结果,搜索用时 566 毫秒
51.
This paper investigates the use of fuzzy logic for fault detection and diagnosis in a pulsewidth modulation voltage source inverter (PWM-VSI) induction motor drive. The proposed fuzzy technique requires the measurement of the output inverter currents to detect intermittent loss of firing pulses in the inverter power switches. For diagnosis purposes, a localization domain made with seven patterns is built with the stator Concordia current vector. One is dedicated to the healthy domain and the six others to each inverter power switch. The fuzzy bases of the proposed technique are extracted from the current analysis of the fault modes in the PWM-VSI. Experimental results on a 1.5-kW induction motor drive are presented to demonstrate the effectiveness of the proposed fuzzy approach.  相似文献   
52.
Journal of Materials Science: Materials in Electronics - Nature provides a wide range of dielectric biopolymers that can be used in electronic devices. In this work, organic field-effect...  相似文献   
53.
Despite sequence similarity to SARS-CoV-1, SARS-CoV-2 has demonstrated greater widespread virulence and unique challenges to researchers aiming to study its pathogenicity in humans. The interaction of the viral receptor binding domain (RBD) with its main host cell receptor, angiotensin-converting enzyme 2 (ACE2), has emerged as a critical focal point for the development of anti-viral therapeutics and vaccines. In this study, we selectively identify and characterize the impact of mutating certain amino acid residues in the RBD of SARS-CoV-2 and in ACE2, by utilizing our recently developed NanoBiT technology-based biosensor as well as pseudotyped-virus infectivity assays. Specifically, we examine the mutational effects on RBD-ACE2 binding ability, efficacy of competitive inhibitors, as well as neutralizing antibody activity. We also look at the implications the mutations may have on virus transmissibility, host susceptibility, and the virus transmission path to humans. These critical determinants of virus–host interactions may provide more effective targets for ongoing vaccines, drug development, and potentially pave the way for determining the genetic variation underlying disease severity.  相似文献   
54.
The design of reverse logistics and remanufacturing processes and the recovery of end-of-life products have been well-studied in the literature. Quality, reliability, maintenance and warranty for recovered products and the remanufacturing activities that extend their life are integral issues in reverse logistics. This paper reviews recent and relevant literature on these issues in closed-loop supply chains, with a focus on remanufactured or second-hand products. The published literature is first classified into domain areas of research and practice. The wide array of mathematical tools and techniques used in the literature are then identified and mapped. Finally, the findings are summarised and the main research gaps are highlighted.  相似文献   
55.
Enterprise businesses are more than ever challenged by competitors that frequently refine and tailor their offers to clients. In this context, enterprise information systems (EIS) are especially important because: (1) they remain one of the last levers to increase the performance and competitiveness of the enterprise, (2) we operate in a business world where the product itself has reached a limit of performance and quality due to uniform capacity of industrial tools in a globalized economy and (3) the EIS can increase the product value thanks to additional digital services (built on data associated to the product) in order to meet and fit better client’s needs. However, the use of EISs reaches a limit in collaborative environments because enterprises management methods diverge and EISs are mainly inflexible resource packages that are not built with an interoperability objective. Consequently, we need to make EISs interoperable in order to achieve the needed gains competitiveness and performance. This paper contribution can be summarized as follows: (1) it relates existing work and it examines barriers that, at the moment, are preventing further improvements due to current methodological and technological limits, and (2) it proposes a conceptual framework and five challenges that model based approaches must overcome to achieve interoperability between EIS in the near and long term.  相似文献   
56.
To determine the origin and nature of mucinlike material in fine-needle aspiration (FNA) smears of the breast in noncancerous breast lesions, we studied breast FNA smears from four patients. All smears contained epithelial cells floating in a mucinlike background, which raised suspicion for mucinous (colloid) carcinoma. Mucicarmine stain was performed on one smear from each case. Subsequent tissue biopsy specimens were studied using mucicarmine, periodic acid-Schiff with and without diastase, and alcian blue stains at pH 2.7 and 0.9 on selected tissue sections. Correlation of the cytologic and histologic findings of each lesion was performed. The mucinlike background in all four FNA smears stained strongly with mucicarmine. Corresponding biopsy specimens revealed pseudoangiomatous hyperplasia in the first case, fibroadenoma and atypical ductal hyperplasia in the second, benign phyllodes tumor in the third, and fibroadenoma in the fourth. Each lesion in cases 1 to 3 was associated closely with fibrocystic changes. In case 4, cystic changes were located within the fibroadenoma. On tissue sections of all four cases, the cyst contents and 10% to 50% of normal lobule and duct contents stained with mucicarmine, indicating that the cyst contents were the most probable source of mucin in the FNA smears. The presence of pools of mucicarmine-positive material in FNA smears of the breast is not an exclusive feature of mucinous carcinoma; mucicarmine-positive mucin can arise from benign cystic changes as well as from normal lobules and ducts.  相似文献   
57.
This study shows markedly different isotype distributions of antibodies to asexual blood stages of Plasmodium falciparum and to merozoite surface protein 1 in clinically immune Senegalese adults depending on the study site. The relationships between immunoglobulin M (IgM) and IgG and between IgG3 and IgG1 antibodies differed in settings where transmission is perennial compared to settings where it is seasonal. This suggests a role for antibody class and/or subclass production and utilization in the regulation of protective immunity to such antigens.  相似文献   
58.
59.
OBJECTIVE: To measure the frequency and associated factors of cervicovaginal HIV shedding and to determine the impact of sexually transmitted disease (STD) treatment on HIV shedding. DESIGN: Cross-sectional study with 1-week follow-up. SETTING: Confidential clinic for female sex workers in Abidjan, C?te d'Ivoire. PARTICIPANTS: A total of 1201 female sex workers. INTERVENTIONS: STD treatment based on clinical signs. MAIN OUTCOME MEASURES: HIV serostatus; cervicovaginal HIV shedding at enrollment and at 1-week follow-up; STD status at enrollment and at 1-week follow-up. RESULTS: Cervicovaginal shedding of HIV-1 in HIV-1-seropositive women was more frequent (96 out of 404, 24%) than shedding of HIV-2 in HIV-2-seropositive women [one out of 21, 5%; odds ratio (OR), 6.2; 95% confidence interval (CI), 1.0-261]. Among 609 HIV-1-seropositive or dually seroreactive women, HIV-1 shedding was significantly more frequent in immunosuppressed women [adjusted OR (AOR), 6.3; 95% CI, 3.4-11.9; and AOR, 2.9; 95% CI, 1.6-5.0 for CD4 < 14% and CD4 14-28%, respectively, versus CD4 > 28%], and in women with Neisseria gonorrhoeae (AOR, 1.9; 95% CI, 1.2-3.0), those with Chlamydia trachomatis (AOR, 2.5; 95% CI, 1.1-5.8), and with a cervical or vaginal ulcer (AOR, 3.9; 95% CI, 2.1-7.4). HIV-1 shedding decreased from 42 to 21% (P < 0.005) in women whose STD were cured. CONCLUSIONS: These data help to explain the difference in transmissibility between HIV-1 and HIV-2 and the increased infectiousness of HIV in the presence of immunosuppression and STD. In addition, they lend biological plausibility to arguments for making STD control an integral part of HIV prevention strategies in Africa.  相似文献   
60.
This paper describes a comparative study allowing the selection of the most appropriate electric-propulsion system for a parallel hybrid electric vehicle (HEV). This paper is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the four main electric-propulsion systems, namely the dc motor, the induction motor (IM), the permanent magnet synchronous motor, and the switched reluctance motor. The main conclusion drawn by the proposed comparative study is that it is the cage IM that better fulfills the major requirements of the HEV electric propulsion  相似文献   
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