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41.
MEMS传感器除了传统应用如喷墨打印头、投影仪、麦克风、汽车等领域,它还广泛应用在手机、平板电脑等移动终端上,可为设备添加更多智能化功能。据IHS iSuppli公司的MEMS市场调查显示,2011年最大的十家MEMS厂商的合计营业收入为47亿美元,比2010年的42亿美元增长12%。德州仪器继续稳居全球最大的MEMS器件制造商地位,在激烈竞争中保住了冠军位置,惠普仍然屈居第二。十大MEMS厂商中其他几家按降序排列依次是博世、意法半导体、佳能、松下、电装、楼氏、ADI和爱普生。飞思卡尔半导体原来也位于十大厂商行列,但2011年排名第十一,跌出了前十之列。  相似文献   
42.
在iPhoneg和iPad的推动下,智能手机和平板电脑中的触控屏应用急剧增长,从而导致触摸控制器出货量在未来短短五年将增长近两倍。  相似文献   
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BACKGROUND AND PURPOSE: We investigated the frequency of cerebral microembolism detected by transcranial Doppler ultrasonography in patients with clinical evidence of retinal ischemia, including transient monocular blindness, central and branch retinal artery infarction, and ischemic oculopathy, and assessed its correlation with carotid artery stenosis. METHODS: Records of 331 consecutive patients examined during a 47-month period at the Neurovascular Laboratory were reviewed. Of the original 453 intracranial arteries, 186 middle cerebral arteries (MCAs) satisfied qualifying criteria that excluded patients with cardiac embolic sources. Forty-five MCAs ipsilateral to the symptomatic eye constituted the study group. The control group consisted of 141 asymptomatic MCAs. Microembolus detection studies were performed on transcranial Doppler instruments equipped with special software, and the degree of carotid artery stenosis was measured by cerebral or MR angiography or by color duplex studies. RESULTS: Microembolism was detected in 40.0% of study MCAs and 9.2% of controls (P < 0.001). In the study group, microembolic signals were detected in 61.9% of MCAs tested within a week of symptom onset and 20.8% of those tested afterward (P < 0.001). Severe (> or = 70%) carotid stenosis or occlusion was more frequent in the study group (P < 0.001). Microembolic signals were detected in 25.3% and 11.2%, respectively, of MCAs distal to carotid arteries with 70% to 100% and 0% to 69% stenosis (P = 0.013). CONCLUSIONS: In patients without cardiac embolic sources, cerebral microembolism is frequently present on the side of retinal ischemia, particularly during the week after onset of symptoms. It is often associated with severe stenosis or occlusion of the ipsilateral carotid artery.  相似文献   
45.
Sensory studies of four fingers were performed on 72 patients with early (distal motor latency <4.2 ms) carpal tunnel syndrome (CTS) and on 43 control subjects. Results demonstrate that sensory studies of digit 4 yields the highest sensitivity (88%) for diagnosis of early CTS. The sensitivity of digit 1, digit 2, and digit 3 was 61%, 22%, and 50%, respectively.  相似文献   
46.
The rate of breakdown of food in mastication depends on the ratio of two mechanical properties of the food--the toughness and modulus of elasticity (Agrawal et al., 1997)--a result which can be predicted by an analysis of the energetics of fracture. The work input to produce food fragmentation is provided by the masticatory muscles, the activity levels of which depend on sensory feedback from the mouth. Here, we test the hypothesis that the activity of a representative of this musculature is modulated by the above combination of food properties. The surface electrical activity (EMG) of the anterior temporalis muscles of ten human subjects was recorded while subjects chewed standardized volumes of 15 food types. The integrated EMG in these muscles was highly significantly related to the square root of the ratio of the above two food properties. Significant correlations were found between this food property index and integrated EMG, both when data for all chews and all subjects were lumped together (r = -0.86; p < 0.0001) and when correlation coefficients between the index and EMG were plotted for each chew made by each subject. Except for two subjects in the first chew, these coefficients reached and maintained highly significant levels throughout the masticatory sequence. Thus, a clear relationship between the electrical activity of a jaw-closing muscle and the mechanical properties of food has been found for the first time.  相似文献   
47.
OBJECTIVE: Hospitalization for cardiac disease is associated with an increased risk for depression, which itself confers a poorer prognosis. Few prospective studies have examined the determinants of depression after hospitalization in cardiac patients, and even fewer have examined depression within the weeks after hospital discharge. The present study assessed the prospective relations among perceptions of social support and trait hostility in predicting symptoms of depressive symptoms at 1 month after hospitalization for a diagnostic angiography in 506 coronary artery disease (CAD) patients. METHOD: A series of structural equation models 1) estimated the predictive relations of social support, hostility, and depressive symptoms while in the hospital to symptoms of depression 1 month after hospitalization, and 2) compared these relations across gender, predicted risk classification, and age. RESULTS: Social support assessed during hospitalization was independently negatively associated with depressive symptoms 1 month after hospitalization, after controlling for baseline symptoms of depression, gender, disease severity, and age. Hostility was an indirect predictor of postdischarge depressive symptomology by way of its negative relation with social support. This pattern of relations did not differ across gender, predicted risk classification, and age. CONCLUSIONS: Our findings suggest that a patient's perceived social support during hospitalization is a determinant of depressive symptoms 1 month later. The relation of social support and hostility to subsequent depressive symptoms was similar across a variety of populations.  相似文献   
48.
The epithelium of the digestive system mucosa consists of a highly dynamic cell population. The conditions under which mitotic activity in the gastrointestinal epithelium is regulated is as yet poorly understood. Nevertheless, it is assumed that some biogenic amines might be involved. Having demonstrated that dopaminergic cells occur in the stomach of gerbils (Meriones unguiculatus), in the present study we examined the influence of dopamine antagonist haloperidol on the proliferation of epithelial cells in the mucosa of the stomach. Proliferating cells were detected immunocytochemically and quantified after in-vivo labeling with 5-bromo-2'-desoxyuridine in both haloperidol- and saline-treated animals. The results show that acute doses of haloperidol significantly increases the proliferation rate in the pyloric mucosa, suggesting that dopamine plays a probable modulatory role in the regulation of mitotic activity. These findings are discussed with regard to the role of paraneurons in regulating epithelial mitosis.  相似文献   
49.
OBJECTIVE: The hemodynamic, respiratory, and metabolic responses to exercise were studied in IDDM patients and control subjects to detect diabetic cardiomyopathy. RESEARCH DESIGN AND METHODS: Eight subjects aged 25-40 years with diabetes of at least 10 years' duration were compared with eight control subjects aged 21-46 years. All subjects underwent a progressive incremental bicycle exercise test with measurement of gas exchange, blood glucose, lactate, fat metabolite, and catecholamine levels and two steady-state exercise tests with measurement of cardiac output by a CO2 rebreathing method. A new first-pass radionuclide method was used to measure cardiac ejection fractions (EFs) at rest, peak exercise, and steady-state exercise. RESULTS: The peak achieved oxygen consumption was similar in the diabetic and control subjects (29.9 [25.1-34.6] and 31.4 [26.9-35.9] ml.min-1.kg-1, respectively; mean [95% CI]). There were no significant differences in heart rate, double product, ventilation, respiratory exchange ratio, or ventilatory equivalents for oxygen and CO2 during the incremental test. Glucose levels were higher in the diabetic subjects, but there were no significant differences in levels of lactate, catecholamines, free fatty acids, glycerol, or beta-hydroxybutyrate. Left ventricular EF fell from rest to peak exercise within the diabetic group (66.0% [59.6-72.4] at rest; 53.6% [45.6-61.6] at peak; P < 0.05) but this did not differ significantly from the control group (58.7% [52.3-65.1] at rest; 60.3% [48.9-71.7] at peak). Right ventricular EFs were similar in each group, and there was no reduction in peak filling rate to suggest diastolic dysfunction. The cardiac output responses to exercise were also similar in the two groups. CONCLUSIONS: There is no evidence of impairment of the exercise response in subjects with long-standing diabetes, and the apparent fall in left ventricular EF at peak exercise could be related to hemodynamic adaptation.  相似文献   
50.
The serological response to MMR vaccine was evaluated in 109 9-month-old infants having no history of measles vaccination, and in 98 15-month-old children who had received monocomponent measles immunisation at 9 months. The combined vaccine contained Schwarz, Urabe Am9, and Wistar RA 27/3 live attenuated virus strains. Preimmunisation antibody levels were extremely low for the 9-month-old children, indicating that maternally-transmitted antibodies do not persist at this age. In the case of mumps, preimmunisation antibody levels were significantly higher in the 15-month-old than in the 9-month-old group. A difference between groups in terms of postimmunisation antibody titres was observed only for rubella, with titres being significantly higher in the older group. Seroconversion rates were high in both groups and no serious events attributable to vaccination were observed. The MMR vaccine can thus be administered to children as young as 9 months of age. Evidence for the efficacy of a two-dose schedule, i.e. at 9 and 15 months, is presented.  相似文献   
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