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31.
Volume data these days is usually massive in terms of its topology, multiple fields, or temporal component. With the gap between compute and memory performance widening, the memory subsystem becomes the primary bottleneck for scientific volume visualization. Simple, structured, regular representations are often infeasible because the buses and interconnects involved need to accommodate the data required for interactive rendering. In this state-of-the-art report, we review works focusing on large-scale volume rendering beyond those typical structured and regular grid representations. We focus primarily on hierarchical and adaptive mesh refinement representations, unstructured meshes, and compressed representations that gained recent popularity. We review works that approach this kind of data using strategies such as out-of-core rendering, massive parallelism, and other strategies to cope with the sheer size of the ever-increasing volume of data produced by today's supercomputers and acquisition devices. We emphasize the data management side of large-scale volume rendering systems and also include a review of tools that support the various volume data types discussed.  相似文献   
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Salehi  M.  Wald  G.  Schmitz  T. L.  Haas  R.  Ovtcharova  J. 《Forschung im Ingenieurwesen》2020,84(2):129-139
Forschung im Ingenieurwesen - In diesem Artikel wird die probabilistische Modellierung und Vorhersage für die Standzeit und Zuverlässigkeit eines Fräswerkzeugs mittels der...  相似文献   
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OBJECTIVE: To determine the relation between blood folic acid and serum vitamin B12 in neural tube defect pregnancies using data from the MRC Vitamin Study and a literature review of all studies. DESIGN: Stored blood samples collected as part of a randomised trial of vitamin supplementation in the prevention of neural tube defects were retrieved from affected pregnancies (cases) and unaffected pregnancies (controls). Four controls were matched with each case by centre, maternal age and duration of storage of the blood sample. The samples had been collected from women at entry to the trial, immediately before the women became pregnant, and at around 12 weeks of pregnancy. Our results were combined with those already published from other studies to obtain an overall assessment of blood folic acid and vitamin B12 in relation to neural tube defects. SETTING: Blood samples were collected as part of the MRC Vitamin Study. The collaborating centres were in the United Kingdom, Hungary, Israel, Australia, Canada and Russia. PARTICIPANTS: Twenty-seven women with neural tube defect pregnancies and 108 matched controls with unaffected pregnancies. RESULTS: Serum and red cell folic acid and serum vitamin B12 levels were lower in the cases than in controls at each of the three occasions when blood samples were collected, but no comparison was significant (P > 0.05). A systematic review of all studies from the literature showed that on average, during the 1st trimester of pregnancy, serum folic acid was 0.6 ng/ml lower in neural tube defect pregnancies (P < 0.01), red cell folic acid was 77 ng/ml lower (P < 0.001) and serum vitamin B12 was 38 ng/l lower (P < 0.001). A logistic regression showed no association between serum B12 and neural tube defects after allowing for serum folic acid. CONCLUSION: our results are consistent with other evidence that folic acid and vitamin B12 levels are lower in women with neural tube defect pregnancies and consistent with evidence from randomised trials which showed that folic acid is protective.  相似文献   
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The historical background of ethical issues in health care, leading to the establishment of standards by governing authorities, is traced. The types of standards and their scopes are examined. The ways in which the clinical engineer is involved with standards are discussed.  相似文献   
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BACKGROUND: Pertussis is a highly contagious bacterial infection caused by Bordetella pertussis. Before routine vaccination against pertussis was available, most persons were infected during childhood. After widespread vaccination, however, the incidence of pertussis in the United States dropped by more than 95 percent, though localized outbreaks continue to occur. METHODS: A multidisciplinary team developed a set of review articles as part of continuing medical education modules in the Teaching Immunization in Medical Education (TIME) Project. The team developed the materials using expert judgment and selected materials from the literature and the Centers for Disease Control and Prevention (CDC). The first step was the creation of specific learning objectives that used the spectrum of Bloom's taxonomy, when possible. After the materials were developed, they were pilot-tested and revised. Subsequently they underwent summative evaluation by field-testing the materials with 24 other primary care physicians. Then the materials were reviewed by the CDC and national vaccine experts and revised based on their comments. RESULTS AND CONCLUSIONS: The efficacy of whole-cell pertussis vaccine is about 70 to 90 percent, though local adverse events are common. Since 1990 several purified, acellular pertussis vaccines have been developed that have one quarter to one half of the common adverse events associated with whole-cell vaccine and have similar efficacy rates. The incidence of pertussis can be further reduced by increasing age-appropriate vaccination rates.  相似文献   
37.
We present an assessment of the methods used to construct maps for a new solar radiation atlas for Europe. For this atlas, station data and satellite-derived data are used in an interpolation/merging process to derive maps of the long-term monthly global radiation that cover an area ranging from 30° W to 70° E and from 25° to 75° N. Our focus is on the discussion of the accuracy of the method applied: a co-kriging technique. Special emphasis is put on a discussion as to whether the use of satellite-derived radiation maps with a low spatial resolution brings benefits.  相似文献   
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CONTEXT: The common cold is one of the most frequently occurring illnesses and is responsible for substantial morbidity and economic loss. Biochemical evidence suggests that zinc may be an effective treatment, and zinc gluconate glycine (ZGG) lozenges have been shown to reduce the duration of cold symptoms in adults. OBJECTIVE: To determine the efficacy of ZGG treatment of colds in children and adolescents. DESIGN: A randomized, double-masked, placebo-controlled study. SETTING: Two suburban school districts in Cleveland, Ohio. PATIENTS: A total of 249 students in grades 1 through 12 were enrolled within the first 24 hours of experiencing at least 2 of 9 symptoms of the common cold. INTERVENTION: Zinc lozenges, 10 mg, orally dissolved, 5 times a day (in grades 1-6) or 6 times a day (in grades 7-12). MAIN OUTCOME MEASURES: Time to resolution of cold symptoms based on subjective daily symptom scores for cough, headache, hoarseness, muscle ache, nasal congestion, nasal drainage, scratchy throat, sore throat, and sneezing. RESULTS: Time to resolution of all cold symptoms did not differ significantly between students receiving zinc (n = 124) and those receiving placebo (n = 125) (median, 9 days; 95% confidence interval [CI], 8-9 days; median, 9 days, 95% CI, 7-10 days, respectively; P=.71). There were no significant differences in the time to resolution of any of the 9 symptoms studied. Compared with controls, more students in the zinc group reported adverse effects (88.6% vs 79.8%; P=.06); bad taste (60.2% vs 37.9%; P=.001); nausea (29.3% vs 16.1%; P=.01); mouth, tongue, or throat discomfort (36.6% vs 24.2%; P=.03); and diarrhea (10.6% vs 4.0%; P=.05). CONCLUSIONS: In this community-based, randomized controlled trial, ZGG lozenges were not effective in treating cold symptoms in children and adolescents. Further studies with virologic testing are needed to clarify what role, if any, zinc may play in treating cold symptoms.  相似文献   
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Bis(1H-pyrazol-1-yl)- and bis(1H-imidazol-1-yl)pyrimidines were synthesized and evaluated for cytoprotective effects. Among them, 4,6-bis(1H-pyrazol-1-yl)pyrimidine (3) showed a potent inhibitory effect on the HCl.ethanol-, ethanol-, and water immersion stress-induced gastric lesions in rats, and a very low acute toxicity. One of the major factors responsible for the cytoprotective effects of 3 is the increase in the bicarbonate secretion. This compound appears to be a promising cytoprotective drug for the treatment of gastric mucosal ulcers.  相似文献   
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