全文获取类型
收费全文 | 729篇 |
免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 3篇 |
化学工业 | 2篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
能源动力 | 2篇 |
轻工业 | 1篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 4篇 |
冶金工业 | 710篇 |
自动化技术 | 2篇 |
出版年
2018年 | 1篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1999年 | 25篇 |
1998年 | 240篇 |
1997年 | 124篇 |
1996年 | 71篇 |
1995年 | 48篇 |
1994年 | 42篇 |
1993年 | 48篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 10篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 17篇 |
1976年 | 36篇 |
1975年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有730条查询结果,搜索用时 15 毫秒
721.
722.
BACKGROUND: To assess relationship between psychosocial factors and self-rated functioning in rheumatoid arthritis (RA). METHODS: In 66 RA patients (mean age +/- SD = 50.8 +/- 12.6 years, women 49 (74%), illness duration mean +/- SD = 13.4 +/- 10.5 years) aspects of developmental psychosocial stress thought to influence human behavior were assessed in an in depth interview using structured biographical history. Furthermore evaluation included Trait anxiety, global functional status according to the ACR criteria, radiological staging of illness and patients' self-ratings of functioning obtained by the Health Assessment Questionnaire (HAQ). Bivariate correlations were performed using psychosocial and somatic factors and self-rated functional status. RESULTS: Scores of developmental psychosocial stress significantly correlated with interviewers scoring of nurture (r = -0.722, p < 0.001) indicating good internal consistency of interview data. Significant correlations were found between patients' scoring of functional status (HAQ) and (i) ACR criteria (r = 0.490, p < 0.0001) and (ii) score of Trait anxiety (r = 0.367, p < 0.003). There was no significant correlation between developmental psychosocial stress and HAQ score. CONCLUSION: Developmental psychosocial stress does not significantly contribute as to how RA patients perceive their functional ability. In a proportion of RA patients self-rated functional status may depend on the patients disposition (e.g. neuroticism) probably promoting impaired illness behavior (e.g. regressive tendencies) which should be considered in assessing treatment procedures. 相似文献
723.
M Prinz-Zaiss AN Yeap V Moguilevski L Trigg BP McGrath 《Canadian Metallurgical Quarterly》1995,22(6-7):472-474
1. Two groups of age- and sex-matched subjects, eight healthy controls and 10 patients, suffering from recurrent vasodepressor syncope, participated in a study to examine autonomic function and sequential changes in power distribution of heart rate (HR) variability during graded head-up tilt. 2. The following autonomic function tests were performed: valsalva ratio, HR responses to deep breathing and posture, BP responses to sustained handgrip and postural change. Each subject was tilted at 15 degrees, 30 degrees, 45 degrees, 60 degrees and 80 degrees head-up, each for 15 min, or until symptoms occurred. The eight control subjects completed the tilt study without any symptoms, while all 10 patients developed presyncope and/or syncope at various tilt angles. 3. Resting blood pressure (BP) was lower in the patient group, while resting HR, autonomic function tests and resting HR variability components were similar in the two groups. 4. The control group showed a progressive increase in low frequency power component (LF) from supine to end tilt (delta LF 20.06 +/- 14.50%) and a progressive fall in high frequency (HF) component (delta HF - 24.62 +/- 10.64%). In contrast, in the patient group, LF fell during tilt in the presyncope period (delta LF - 10.57 +/- 12.93%, P < 0.01 vs control group). HF and HF:LF ratio responses did not differ significantly in the two groups. 5. At end tilt, the increase in plasma noradrenaline was significantly greater in the control group than in the patient group (delta NA 0.83 +/- 0.27 vs 0.28 +/- 0.14 pmol/mL, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
724.
Because lung cancer is a major health care problem in Canada, it would be useful to identify the direct health care costs of diagnosing and treating this disease and to create an analytic framework within which diagnostic and therapeutic options can be assessed. This paper describes a method of modelling the costs of care for lung cancer. The perspective of the costing model is that of the government as payer in a universal health care system. Clinical algorithms were developed to describe the management of non-small cell (NSCLC) and small cell (SCLC) lung cancer. Patients were allocated to the treatment algorithms in the model, based on a knowledge of the stage distribution of cases within provincial cancer registries and an estimate of the use of therapeutic modalities, according to lung cancer experts. A microsimulation model (POHEM) developed at Statistics Canada was used to integrate data on risk factors, disease onset and progression, health care resource utilization and direct medical care costs. The model incorporates survival data on patients, according to cell type and stage, based on published studies. Relapse and terminal care costs were assigned during the year of death, in order to determine the cost of continuing care and the cumulative cost of lung cancer management over time. Patients surviving five years were assumed to be cured. The model estimates that the total five year cost to provide care to the 15,624 cases of lung cancer diagnosed in Canada in 1988 was in excess of $328 million. Over 82% of this total was spent in the first year for diagnostic tests, therapy (surgery, chemotherapy, radiation therapy, or combinations of these), hospitalization and follow-up costs. The average five year cost per case was $21,000, and ranged from a high of $29,860 for limited disease SCLC, to a low of $16,500 for Stage IV NSCLC. The actual cost of providing care, including the management of complications, is unknown and our estimates should be regarded as an idealized estimate of the cost of lung cancer management. However, the POHEM model has a level of sophistication which, we believe, reasonably reflects the cost per case and total costs of treating lung cancer by stage and therapeutic modality in Canada. 相似文献
725.
726.
727.
JM Gold TA Blaxton BP Hermann C Randolph P Fedio TE Goldberg WH Theodore DR Weinberger 《Canadian Metallurgical Quarterly》1995,17(1):59-65
The relation between use of sunscreens, different host factors and malignant melanoma was investigated in a population-based, matched case-control study of malignant melanoma in the South Swedish Health Care Region, which has the highest risk for melanoma in Sweden, between 1 July 1988 and 30 June 1990. In total, 400 melanoma patients and 640 healthy controls aged 15-75 years answered a comprehensive questionnaire regarding different epidemiologic variables, including questions on use of sunscreens and different constitutional factors. The use of sunscreens was not found to protect against developing malignant melanoma. Instead, an unexpected relation between the use of sunscreens and the risk of developing malignant melanoma was seen (odds ratio (OR) 1.8 for almost always vs never using sunscreens). A tentative dose-response relation was found. Virtually the same ORs were seen in both sexes. Furthermore, persons younger than 50 years had a higher OR than persons older than 50 years. When different melanoma presentation sites were considered, lesions of the trunk were associated with sunscreen use in females (adjusted OR = 3.7 for almost always vs never using sunscreens), while lesions of the extremity or head and neck were associated with sunscreen use in males (adjusted OR = 3.2 for almost always vs never using sunscreens). Raised naevi on the left arm and freckling were shown to be the major constitutional risk factors (OR = 3.9 for more than three naevi vs none and OR = 1.4, respectively). The results were essentially unaltered in a histopathologically re-examined material. Further investigations are needed in order to form a basis for melanoma prevention. 相似文献
728.
This study tested whether symptoms of pain and edema associated with change during the premenstrual phase of the monthly menstrual cycle exhibit a seasonal pattern. Menstruating chronic myofascial face pain cases (N = 99) and acquaintance controls (N = 100) were questioned about their premenstrual symptoms during the prior month in each of 10 consecutive months. Unlike myofascial face pain and psychological distress, premenstrual symptoms of general discomfort and edema did not show an exacerbation in the dark months for either cases or controls. The positive results for distress and facial pain and the negative results for the premenstrual symptoms occurred whether or not respondents met an algorithmic diagnosis of DSM-IV premenstrual dysphoric syndrome. 相似文献
729.
730.