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61.
An experiment investigating the effect of communication training and three group composition variables was performed with Patriot air defense teams for two different types of aircraft identification tasks. It was predicted that communication training would significantly enhance communication quantity and quality and, in turn, team performance for both tasks. Although the training did sometimes improve team communication processes, it did not improve team performance. The variable that had the biggest positive effect on communication quality and team performance was the number of hours a team had worked together. This effect was only found, however, for the type of task for which Patriot teams routinely train. It did not transfer to the less frequent and more cognitively stressing task where there is conflicting information about unknown aircraft, as in the USS Vincennes tragedy  相似文献   
62.
There has been minimal experimentation testing the effectiveness of icons (or interface features in general) on distributed team decision making. To overcome this deficiency, an experiment tested the effectiveness of a "send" icon to remind team members to send information to their teammates, and a "receive" icon to tell them when they had received information, for a simulated, military task. As predicted, the "send" icon was effective in maintaining information flow, particularly when time pressure was high and simulated teammates sent less information, because it reduced memory burden and supported proactive behavior. The "receive" icon was only effective in supporting decision accuracy when time pressure was low. As time pressure increased, participants' with the "receive" icon increasingly used a strategy of making decisions before reading the most important information, completely counter to expectations. These results illustrate the subtle, sometimes surprising way task characteristics (e.g., time pressure) can affect participants' strategies and, thereby, ify the positive effect of displays on performance. The experiment also examined other task characteristics and working memory capacity, and showed how the lens model equation (LME) helped explain all effects on decision accuracy.  相似文献   
63.
    
Abstract We draw on leading theories about the structural causes of racial inequality in the US to investigate inter‐metropolitan differences in white and black per capita income. The analysis, which is based on a sample of 112 metropolitan areas and uses 1990 census data, examines the influence of spatial, economic, and demographic factors on black‐white income inequality. Our results show severe income inequality between blacks and whites in most metropolitan areas, with black per capita income being 55% of white per capita income, on average. We find that racial educational inequality and unemployment differences were the strongest predictors of racially based income inequality. We also find that metropolitan areas that are highly ranked on a business and financial dominance hierarchy have the most interracial income inequality. However, when a metropolitan area has a high level of manufacturing employment vis‐a‐vis low service employment it has less income inequality. We discuss the implications of these and other findings for theories about, and public policy regarding, urban inequality.  相似文献   
64.
65.
Hypoplasia of the optic nerve in association with porencephaly   总被引:4,自引:0,他引:4  
Two cases of hypoplasia of the optic nerve associated with porencephaly are described. The clinicopathological correlation of the double ring sign is presented and the possible mechanism of optic nerve hypoplasia being a secondary degeneration is discussed.  相似文献   
66.
A 48-year-old man presented to the emergency department complaining of fever, chills, myalgias, and diffuse abdominal discomfort of four days' duration. A nonpruritic rash had developed on his left palm, arms, legs, and buttocks on the fourth day. He had not had respiratory symptoms, nausea, vomiting, or diarrhea.  相似文献   
67.
We investigated the effect of inhibition of a polyol pathway on the glucose-induced increase in transforming growth factor-beta (TGF-beta) production and activity of protein kinase C (PKC) in cultured human mesangial cells (MCs). The exposure of MCs to 33 mmol/l glucose resulted in an increase in TGFbeta production, measured by ELISA, compared with 5 mmol/l glucose. The glucose-induced increase in TGF-beta was prevented by concomitant incubation with epalrestat, an aldose reductase inhibitor (ARI), in a dose-dependent manner at a concentration of more than 10(-6) mol/l. Moreover, the glucose-induced enhancement of PKC activity in the membrane fraction of MCs was also abolished by epalrestat. The addition of epalrestat to MCs cultured with 5 mmol/l glucose showed no demonstrable effects on TGF-beta production and PKC activity. These results provide direct evidence for linkages between derangements in polyol pathway and glucose-induced overproduction of TGF-beta and enhancement of PKC activity in MCs. Accordingly, the effect of an ARI on these metabolic abnormalities in MCs may justify its clinical application for treatment of diabetic nephropathy.  相似文献   
68.
Episodic ataxia type-1 is a rare human neurological syndrome which occurs during childhood and persists through the whole life of affected patients. Several heterozygous point mutations have been found in the coding sequence of the voltage-gated potassium channel gene hKv1.1 of different affected families. V408A and E325D mutations are located in the cytoplasmic putative pore region of hKv1.1 channels and profoundly alter their gating properties. V408A channels showed increased kinetic rates of activation, deactivation and C-type inactivation. Expression of E325D channels in Xenopus oocytes led to an approximately 13-fold current amplitude reduction and to a 52.4 mV positive shift in the voltage dependence of activation. Moreover, the E325D mutation altered the kinetics of activation, deactivation, C-type inactivation and channel open probability. Heteromeric channels composed of two wild-type and two mutated subunits, linked as dimers, showed gating properties intermediate between channels formed from four normal or four mutated subunits. The results demonstrate that the highly conserved residues Val408 and Glu325 play a pivotal role in several gating processes of a human potassium channel, and suggest a pathogenetic mechanism by which the impairment of the delayed-rectifier function of affected neurons is related to the type and number of mutated subunits which make up the hKv1.1 channels.  相似文献   
69.
Tests of interpersonal theories of depression have established that elevated depression levels among peers portend increases in individuals' own depressive symptoms, a phenomenon known as depression socialization. Susceptibility to this socialization effect may be enhanced during the transition to adolescence as the strength of peer influence rises dramatically. Socialization of depressive symptoms among members of child and adolescent friendship groups was examined over a 1-year period among 648 youth in grades six through eight. Sociometric methods were utilized to identify friendship groups and ascertain the prospective effect of group-level depressive symptoms on youths' own depressive symptoms. Hierarchical linear modeling results revealed a significant socialization effect and indicated that this effect was most potent for (a) girls and (b) individuals on the periphery of friendship groups. Future studies would benefit from incorporating child and adolescent peer groups as a developmentally salient context for interpersonal models of depression. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
70.
BACKGROUND: Thrombolytic therapy improves survival after myocardial infarction through reperfusion of the infarct-related artery. Thrombin generated during thrombolytic administration may reduce the efficacy of thrombolysis. A direct thrombin inhibitor may improve early patency rates. METHODS AND RESULTS: Four hundred twelve patients presenting within 12 hours with ST-segment elevation were given aspirin and streptokinase and randomized in a double-blind manner to receive up to 60 hours of either heparin (5000 U bolus followed by 1000 to 1200 U/h), low-dose hirulog (0.125 mg/kg bolus followed by 0.25 mg x kg(-1) x h(-1) for 12 hours then 0.125 mg x kg(-1) x h(-1)), or high-dose hirulog (0.25 mg/kg bolus followed by 0.5 mg x kg(-1) x h(-1) for 12 hours then 0.25 mg x kg(-1) x h(-1)). The primary outcome was Thrombolysis In Myocardial Infarction trial (TIMI) grade 3 flow of the infarct-related artery at 90 to 120 minutes. TIMI 3 flow was 35% (95% CI, 28% to 44%) with heparin, 46% (95% CI, 38% to 55%) with low-dose hirulog, and 48% (95% CI, 40% to 57%) with high-dose hirulog (heparin versus hirulog, P=.023; heparin versus high-dose hirulog, P=.03). At 48 hours, reocclusion had occurred in 7% of heparin, 5% of low-dose hirulog, and 1% of high-dose hirulog patients (P=NS). By 35 days, death, cardiogenic shock, or reinfarction had occurred in 25 heparin (17.9%), 19 low-dose hirulog (14%), and 17 high-dose hirulog patients (12.5%) (P=NS). Two strokes occurred with heparin, none with low-dose hirulog, and two with high-dose hirulog. Major bleeding (40% from the groin site) occurred in 28% of heparin, 14% of low-dose hirulog, and 19% of high-dose hirulog patients (heparin versus low-dose hirulog, P<.01). CONCLUSIONS: Hirulog was more effective than heparin in producing early patency in patients treated with aspirin and streptokinase without increasing the risk of major bleeding. Direct thrombin inhibition may improve clinical outcome.  相似文献   
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