全文获取类型
收费全文 | 566篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 1篇 |
综合类 | 5篇 |
化学工业 | 8篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 1篇 |
轻工业 | 5篇 |
无线电 | 3篇 |
一般工业技术 | 2篇 |
冶金工业 | 535篇 |
原子能技术 | 1篇 |
自动化技术 | 4篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 18篇 |
1998年 | 156篇 |
1997年 | 84篇 |
1996年 | 67篇 |
1995年 | 45篇 |
1994年 | 20篇 |
1993年 | 24篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 28篇 |
1976年 | 46篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有569条查询结果,搜索用时 16 毫秒
471.
Screening for breast cancer can result in early detection of malignancies and lives saved. Many employers now offer periodic screening as an employee health benefit, and some have established screening programs in the workplace. This study was performed to identify the employer costs of breast cancer screening in the workplace, referrals for suspicious findings, and initial treatment of malignant disease. Additionally, the costs for these same services, had they been obtained outside of a workplace screening program, were estimated. Data on program components and associated costs for an established employer based breast cancer screening program were obtained. These costs were compared to those among a hypothetical cohort of women not enrolled in the workplace screening program. From 1989 through 1995, 1,416 women participated in the program. Nearly 2,500 screening mammograms and approximately 2,773 clinical breast examinations were performed, resulting in 292 referrals to physicians outside of the program for additional diagnostic procedures and treatment as needed. These referrals resulted in the detection of 12 malignancies: 8 Stage I; 3 Stage II; and 1 Stage III. Mammographic and clinical breast examination screening cost $249,041; referrals resulting in benign disease or no detectable disease cost $185,002; and referrals resulting in malignant disease, followed by initial treatment, cost $148,530. Therefore, the total cost was $582,573. Approximately 47% of the cost of referrals and initial treatment were due to employee lost productivity. Total cost in the hypothetical cohort was $1,067,948 under the assumptions that all women received screening outside of the workplace, and that the same number of malignancies were detected at the same stage as in the workplace program. These findings indicate referrals resulting in detection of benign disease or no disease accounted for a substantial proportion of the total cost of the program. In addition, employee lost productivity accounted for almost 50% of the cost of all referrals and initial treatment. Workplace screening is a relatively efficient approach for early detection of breast cancer when compared to off site screening or no screening. The efficiency could be improved with a reduction in the number and cost of unnecessary referrals. 相似文献
472.
A Raid B Oliver A Abdelrahman RI Sha''afi JJ Hajjar 《Canadian Metallurgical Quarterly》1993,202(4):435-439
Antibodies to hepatitis C virus (HCV) were measured in 1,580 Ethiopian subjects representing urban and rural populations. Sera found positive by a repeated second generation enzyme immunoassay (EIA) were subjected to three additional confirmatory tests. The overall confirmed seroprevalence was 2.0%. Less than 1% were confirmed to be seropositive in rural communities, with 1.4% positive among blood donors, 1.6% positive among patients with dermatologic disorders, 3.6% among leprosy patients, and 6.0% among patients attending a University Hospital clinic for neurologic disorders. The patients in the groups with leprosy and neurologic disorders have most likely been in ill health for many years and have sought relief by traditional healers or treatment at poorly equipped clinics. This group of patients demonstrated a high prevalence of antibodies to HCV. In Ethiopia, especially in small clinics, there is a shortage of syringes and needles and they have to be reused many times often with inadequate sterilization. Therefore, these syringes and needles may be contaminated, thus being a risk factor for HCV and HIV infection. 相似文献
473.
K Riesbeck A Dorling G Kemball-Cook JH McVey M Jones EG Tuddenham RI Lechler 《Canadian Metallurgical Quarterly》1997,78(6):1488-1494
Tissue factor pathway inhibitor (TFPI) is one of the main regulators of the tissue factor (TF) pathway of coagulation. To tether human TFPI to the cell surface, full length or truncated TFPI lacking the third Kunitz domain were fused with domains three and four and the carboxy-terminal sequence of human CD4. Constructs were transfected into a mouse fibroblast cell line and individual clones were checked for expression using monoclonal antibodies directed against the first two TFPI Kunitz domains and against CD4. Specific human FXa binding was detected by flow cytometry using an anti-FX polyclonal antibody, and inhibition of FXa proteolytic activity was verified by chromogenic substrate assay using S-2765. In addition, TFPI-CD4-expressing cells, preincubated with FXa, specifically bound human TF-FVIIa complexes as revealed with an anti-human TF polyclonal antibody. No functional difference was observed between full length or truncated TFPI-CD4. These results demonstrate that functionally intact TFPI can be tethered to the cell surface. Genetic manipulation of, for example, endothelial cells leading to the stable expression of TFPI may inhibit the development of coronary artery heart disease following cardiac allotransplantation, and may inhibit thrombosis in the context of xenotransplantation. 相似文献
474.
475.
476.
DL Roerig RI Wang MM Mueller DL Lewand SM Adams 《Canadian Metallurgical Quarterly》1976,22(11):1915-1918
Radioimmunoassay was compared to thin-layer and gas--liquid chromatographic methods for detection of methadone in the urine of patients undergoing methadone maintenance therapy as treatment of heroin abuse. With urine samples known to contain methadone, 84% were positive by thin-layer chromatography as compared to 99% positives by the other two methods. This difference is attributed to the difference in sensitivity of the three methods. All three methods gave consistently positive results with urine samples from patients receiving 25 mg of methadone per day or more. With smaller daily doses the percentage of positive results obtained with thin-layer chromatography decreased. Analysis of urine samples not containing methadone showed no incidence of cross reaction of other drugs with the methadone radioimmunoassay. The methadone radioimmunoassay appears to be both sensitive and reliable; however, certain other factors limit its use as a primary screening method. 相似文献
477.
The authors used several indices to assess the relationship between marijuana and hostility as both inner affect and verbal behavior in a small-group setting. Marijuana subjects reported a small but statistically significant decrease in hostile feelings after the introduction of a frustration stimulus. They also showed significantly less verbal hostility than placebo subjects both before and after introduction of a frustration stimulus. The authors note that research findings on marijuana and hostility are not consistent and suggest a multidetermined relationship based on dose, environment, nature of the frustration stimulus, and intraindividual factors. 相似文献
478.
SR Daniels JI Hudson RI Horwitz 《Canadian Metallurgical Quarterly》1995,48(12):1413-27; discussion 1429-40
This article examines the methodology of the epidemiological studies of the association between L-tryptophan and eosinophilia-myalgia syndrome (EMS) and evaluates the validity of the conclusions from these studies. In the initial case-control studies of L-tryptophantryptophan and EMS there were a variety of methodological problems, including different sources and different exclusion criteria for cases and controls, which could have resulted in selection bias, as well as problems with information bias and confounding. The studies of manufacturer and brand also had similar potential for bias. The L-tryptophan-EMS association is based on two small studies that had important methodological inadequacies. Subsequent studies of brand of L-tryptophan also contained errors in design, which may have produced biased results and call the conclusions into question. The cause of eosinophilia-myalgia syndrome remains unknown. 相似文献
479.
CB Gutiérrez JI Rodríguez Barbosa RI Tascón L Costa P Riera EF Rodríguez Ferri 《Canadian Metallurgical Quarterly》1995,137(3):62-64
Seventy-one isolates of Actinobacillus pleuropneumoniae isolated from the lungs of pigs in outbreaks of pleuropneumonia in Spain were serotyped by indirect haemagglutination. Serotype 4 (42.2 per cent), serotype 7 (22.5 per cent) and serotype 2 (12.8 per cent) were predominant, whereas serotypes 1, 3, 6, 8, 9, 12 and untypable isolates were present only in small numbers. Serotypes 1, 2, 4 and 7 originated mainly from cases of acute pleuropneumonia, whereas serotypes 3, 6, 8, 9 and 12 were associated with chronically infected herds. The susceptibility of the isolates to 20 antimicrobial agents was determined by agar disc diffusion. Most were susceptible to cefuroxime, cefaclor, cefazolin, kanamycin, tobramycin, gentamicin, oxolinic acid, ciprofloxacin, enoxacin, thiamphenicol, colistin and trimethoprim/sulphamethoxazole. Marked resistance was found with amoxicillin, ticarcillin, oxytetracycline, doxycycline and metronidazole. Rifampicin, fosfomycin and tiamulin were the agents most effective against the isolates tested. 相似文献
480.
SM Genensky HE Petersen RW Clewett RI Yoshimura 《Canadian Metallurgical Quarterly》1978,55(9):615-626
This paper describes the various parts of a new interactive classroom television system (ICTS) that is being used by partially sighted elementary school children. This ICTS permits children to view one of seven separately controlled TV screens and thereby be in continuous visual communication with their teacher, classmates, and classroom. Comments are made on the advantages of educating partially sighted children separately from normally sighted children. 相似文献