全文获取类型
收费全文 | 2394篇 |
免费 | 1篇 |
专业分类
综合类 | 1篇 |
化学工业 | 6篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
能源动力 | 1篇 |
轻工业 | 15篇 |
石油天然气 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 12篇 |
冶金工业 | 2322篇 |
原子能技术 | 1篇 |
自动化技术 | 13篇 |
出版年
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 12篇 |
2004年 | 4篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 86篇 |
1998年 | 783篇 |
1997年 | 392篇 |
1996年 | 245篇 |
1995年 | 148篇 |
1994年 | 115篇 |
1993年 | 144篇 |
1992年 | 23篇 |
1991年 | 26篇 |
1990年 | 33篇 |
1989年 | 24篇 |
1988年 | 29篇 |
1987年 | 42篇 |
1986年 | 20篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 28篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 30篇 |
1976年 | 100篇 |
1975年 | 5篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1958年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2395条查询结果,搜索用时 15 毫秒
911.
CL Morcos LD Platt DE Carlson KD Gregory NH Greene LM Korst 《Canadian Metallurgical Quarterly》1998,92(2):232-236
A 48-year-old asymptomatic male hepatitis B virus carrier presented with a 2-day history of fever, chills, right upper quadrant abdominal pain, and jaundice. Shock was detected on admission. Emergency abdominal computed tomography (CT) scanning without contrast enhancement showed the features of acute pancreatitis. Hemobilia, edematous pancreatitis, cholestasis and cholecystitis were found on exploratory laparotomy. Neither stone nor active bleeding were detected on intraoperative choledochoscopic examination. Postoperative T-tube cholangiography one month later revealed non-opacification of the left intrahepatic duct. The patient's abdominal pain and hemobilia recurred. Celiac angiography and CT scanning with contrast showed two hepatocellular carcinomas (HCC) in the left lobe of the liver. This is the first case report in the English literature of HCC presenting as jaundice, hemobilia, and acute pancreatitis. 相似文献
912.
913.
CL Brummel IN Lee Y Zhou SJ Benkovic N Winograd 《Canadian Metallurgical Quarterly》1994,264(5157):399-402
The molecular weights of femtomole quantities of small peptides attached to polystyrene beads have been determined with imaging time-of-flight secondary ion mass spectrometry. The analysis is made possible by the selective clipping of the bond linking the peptide to a bead with trifluoroacetic acid vapor before the secondary ion mass spectrometry assay. The approach can be applied to large numbers of 30- to 60-micrometer polystyrene beads for the direct characterization of massive combinatorial libraries. 相似文献
914.
915.
BACKGROUND: Selection methods vary greatly in ease and cost-effectiveness. The effects of selection factors associated with subjects' recruitment into studies can introduce bias and seriously limit the generalizability of results. METHODS: For an epidemiologic study, we recruited an age-stratified random sample of 1,422 community-dwelling individuals aged 65+ years from the voter registration lists in a rural area of southwestern Pennsylvania. The first 1,366 of these were accrued through intensive recruitment efforts; the last 56 of them responded to a single mailing. To increase sample size for future risk factor analyses, we also recruited by direct advertisement a sample of 259 volunteers from the same area. The three groups were compared on selected baseline characteristics and subsequent mortality. RESULTS: The two subgroups of the random sample were not significantly different on any of the variables we examined. Compared to the random sample, in cross-sectional analyses, volunteers were significantly more likely to be women, more educated, and less likely to have used several health and human services. Volunteers also had higher cognitive test scores and Instrumental Activities of Daily Living (IADL) ability. Over 6-8 years (10,861 person-years) of follow-up, volunteers had significantly lower mortality rates than randomly selected subjects. CONCLUSIONS: Health-related studies with populations composed partly or entirely of volunteers should take potential volunteer bias into account when analyzing and interpreting data. 相似文献
916.
917.
AR Brown CM Cobb CL Dunlap JN Manch-Citron 《Canadian Metallurgical Quarterly》1997,18(7):724-6, 728-32, 734
Papillary lesions of the oral cavity are extremely common, and inflammatory palatal hyperplasia is well known to dental practitioners. Advanced sophistication in viral laboratory technologies makes it apparent that various forms of the human papilloma virus are often causative. However, this is not true for inflammatory palatal hyperplasia. This article describes a patient with anatomically well-demarcated, multiple squamous cell papillomas of the palate that could not be classified as inflammatory palatal hyperplasia, nor could a viral etiology be ascertained, despite exhaustive laboratory studies. The lesion recurred despite numerous surgical ablation attempts. Eradication was achieved only after applying free soft-tissue grafts over the areas of excision. The differential diagnosis of papillary lesions with an emphasis on viral etiology, laboratory studies associated with their identification, and a hypothesis that explains why grafting was the only successful means of treatment are also discussed. 相似文献
918.
JD Manord CL Garrard M Yoselevitz DA Devund WC Sternbergh JC Bowen SR Money 《Canadian Metallurgical Quarterly》1997,149(9):334-337
A case of endovascular treatment of abdominal aortic aneurysm is discussed along with a review of the literature. This recently introduced Food and Drug Administration Phase II treatment modality may have a significant impact on the approach to the treatment of aneurysmal disease. This discussion details the treatment of one typical patient and reviews the current status of endovascular therapy as it applies to infrarenal abdominal aortic aneurysms. 相似文献
919.
920.
BACKGROUND: At therapeutic dosage, cetirizine and ebastine induce significant inhibition of skin reactivity to histamine. The consistency of their efficacy, that is, efficacy with the least interindividual variability among subjects, has not been carefully assessed, however. OBJECTIVE: To compare the consistency and efficacy of these antihistamines on skin reactivity. METHODS: Twenty-four healthy volunteers participated in a randomized double-blind crossover study. The areas of wheals and flares induced by increasing (0, 5, 10, 50, 100, 200, and 300 mg/mL) histamine concentrations, administered by prick tests, were measured before and four hours after intake of 10 mg of each antihistamine, allowing concentration-response curves to be established. The threshold histamine concentrations inducing wheal areas of 3 mm2 (positivity) were calculated by interpolation. The coefficient of variation (SD/mean %) was used to evaluate the consistency of the response. RESULTS: Pretreatment concentration-response curves were similar, and threshold concentrations identical (0.29 mg/mL and 0.34 mg/mL for cetirizine and ebastine, respectively). For both, curves were lower after treatment than before. After cetirizine, the threshold concentration was significantly higher (217 mg/mL) than after ebastine (0.82 mg/mL) (P < .001), and total inhibition of the wheal reaction was observed in 21 of 24 patients at the lowest histamine concentration and in 17 of 24 at the highest. Ebastine never totally inhibited reaction, even to 5 mg/mL of histamine. Over the entire concentration-response curve, the coefficient of variation for the wheal reaction was 6.3% for cetirizine and 72.6% for ebastine, and, for flares, 11.0% and 83.7%, respectively. Hence, variability was much lower after cetirizine. CONCLUSION: Our study shows clearly that the efficacy of a single therapeutic dosage of cetirizine is consistently good for suppression of cutaneous reactivity to histamine in healthy volunteers. The need for ebastine to metabolize into the active carebastine might explain its lesser consistency. 相似文献