全文获取类型
收费全文 | 502篇 |
免费 | 27篇 |
国内免费 | 22篇 |
专业分类
儿科学 | 35篇 |
妇产科学 | 3篇 |
基础医学 | 53篇 |
口腔科学 | 15篇 |
临床医学 | 66篇 |
内科学 | 91篇 |
皮肤病学 | 1篇 |
神经病学 | 9篇 |
特种医学 | 169篇 |
外科学 | 18篇 |
综合类 | 11篇 |
预防医学 | 33篇 |
眼科学 | 4篇 |
药学 | 29篇 |
肿瘤学 | 14篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 16篇 |
2012年 | 8篇 |
2011年 | 15篇 |
2010年 | 15篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 18篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1998年 | 30篇 |
1997年 | 27篇 |
1996年 | 39篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 26篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 13篇 |
1989年 | 22篇 |
1988年 | 24篇 |
1987年 | 25篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 20篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 9篇 |
1976年 | 18篇 |
1975年 | 7篇 |
排序方式: 共有551条查询结果,搜索用时 15 毫秒
11.
12.
13.
J. Peplies A. Fraterman R. Scott P. Russo K. Bammann 《European journal of epidemiology》2010,25(9):607-617
Large scale international multicentre studies require sophisticated quality management for the collection, processing and logistics of biological samples to ensure a maximum degree of standardisation across different environmental conditions and settings. This paper describes a quality management system for the collection of biological samples (QMS-BS) which was applied during IDEFICS, a large European multicentre study. The application was evaluated by several criteria like response rates for the different types of biological samples, measures of sample quality, compliance with the QMS-BS and efficiency of the document and sample control and of the quality assurance system. Response rates varied from 56.6% for venous blood collection to 90.1% for saliva collection. All sample types were associated with problems of sample quality (e.g. haemolysis of blood samples, lack of cooling for urine samples or desiccation of saliva samples). Overall compliance with the QMS-BS was good, with some exceptions mainly related to sample control. In conclusion the QMS-BS is a valuable tool for the management of biological sample collection in epidemiological multicentre studies. 相似文献
14.
David RH Christie Kenneth W Tiver 《Journal of Medical Imaging and Radiation Oncology》1996,40(3):331-333
Five patients who received radiotherapy (RT) for 7 melanotic freckles (MF, also known as Hutchinson's freckles, lentigo maligna) were reviewed 8 to 37 months after their treatment by RT. Local control and a favourable cosmetic result occurred in all patients. Treatment toxicity was minimal. Few reports about the use of RT for MF exist. Many other treatments including observation alone have been associated with high rates of recurrence, and in some cases conversion to invasive melanoma has occurred. RT appears to be a safe and effective treatment for this condition, providing that doses equivalent to 44 Gy in 11 fractions or more are given. 相似文献
15.
Granulomatous disease of the intestinal tract (Crohn's disease) 总被引:1,自引:0,他引:1
16.
Tarsal navicular stress fractures: radiographic evaluation 总被引:3,自引:0,他引:3
Tarsal navicular stress fractures are a potential source of disabling foot pain in physically active individuals. The diagnosis of tarsal navicular stress fracture requires a high index of clinical and radiographic suspicion because the fracture is only rarely evident on routine radiographs or standard tomograms. The radiographic diagnosis of a tarsal navicular stress fracture may require anatomic anteroposterior tomograms or a radionuclide bone scan with plantar views. Radiographic examinations of 23 fractures in 21 patients are evaluated. 相似文献
17.
Butler MW Mullan RH Schaffer KE Crotty TB Luke DA Donnelly SC 《Irish journal of medical science》2003,172(4):204-205
Background Hydatid disease is rare in Ireland and its incidence and prevalence are unknown. Most cases are diagnosed by a combination
of clinical findings, morphological features on imaging and by serological testing.
Aims We describe an Irish case of pulmonary hydatid disease detected at bronchoscopy by bronchoalveolar lavage, and discuss the
diagnosis and treatment of the disorder. 相似文献
18.
OBJECTIVES: The negative health effects of cigarette smoking are nowadays well known. An important prerequisite for the implementation of rewarding health promotion campaigns aiming at reducing the tobacco dependency in the general population is the knowledge about smoking prevalences in different social population groups, and specific information about social factors and determinants influencing smoking behaviour. METHODS: In this regard, the Microcensus is a very valuable data source for Germany. Included in the present analysis are persons aged 18 years and older, which are present in the "Microcensus Public Use File 1995" and had answered the questions about their smoking behaviour (N = 186,424). The dependent study variable is current cigarette smoking. Independent study variables are sociodemographic factors (age, sex, family status), occupational status, unemployment, socio-economic situation and regional-specific variables (size of community, East vs West Germany). RESULTS: All together, 30.5% of the males and 18.0% of the females were current smokers. Significantly higher smoking rates were observed for persons living in metropolitan areas, persons with low educational achievement and low occupational status, for people being divorced, unemployed, and living on social welfare. In a second step, we analysed the cumulative effect of these social factors for current smoking status. In summary, it was found that the cumulation of social determinants explained a great part of the variance in smoking prevalence. Current smoking was four to six times more prevalent in population groups characterised by several unfavourable social conditions compared to more privilege population groups. CONCLUSIONS: Thus, smoking related prevention activities should be evaluated, among others, regarding their potential to reduce the social polarisation of the smoking epidemic. 相似文献
19.
Low birthweight infants aged 4-41 days were given from birth one of three experimental milk formulae varying widely in content of calcium and phosphate. Ca and P in feed, urine, and faeces were measured between carmine markers corresponding to a metabolic period of 48 hours. Calcium enriched in 46Ca to provide a marker for the dietary Ca was added to one feed and 46Ca measured in urine and faeces. True absorption of Ca and endogenous excretion into the bowel could then be inferred. True absorption of Ca was proportional to Ca intake and independent of P intake. Endogenous faecal excretion seemed to be independent of both Ca P intakes, and varied widely between different infants in the range 4-150 mg/day. Urine Ca was low and retention was essentially the difference between true absorption and endogenous faecal excretion. Retention of Ca tended to be much greater on a high Ca intake, but the variability in retention between infants on a given intake was large, paralleling the variability in endogenous faecal excretion. The variability in plasma Ca concentrations in newborn infants may in part be a consequence of wide individual variability in endogenous faecal excretion. The 46Ca marker technique provides a means of investigating the factors determining this variability. 相似文献
20.
DP Southall WA Arrowsmith JR Oakley G McEnery RH Anderson EA Shinebourne 《Archives of disease in childhood》1979,54(10):776-779
Two neonates with arrhythmias and the long QT syndrome are described. The arrhythmias were detected in utero and both infants were apparently well after birth. The first infant, although well, had a bradycardia for the first 9 days of life. A normal heart rate was documented at 10 days but a prolonged QT interval was not appreciated on the ECG. He was discharged from hospital but died suddenly and unexpectedly 3 days later. A post-mortem examination failed to find a cause for his death which therefore fell into the category of the sudden infant death syndrome (SIDS). A retrospective analysis of the perinatal electrocardiogram showed a probable junctional rhythm with 2:1 conduction to the ventricle; the QT interval was prolonged at 0.52 seconds (QTC = 0.63). The second infant had a QT interval of 0.52 seconds (QTC = 0.54) and frequent ventricular premature beats on a 24-hour electrocardiogram. She was treated with propranolol and remains well 2 years later. Sudden infant death has often been described in the siblings of children with the long QT syndrome and one other report described a case of SIDS which was said to have had a prolonged QT interval on the perinatal ECG. This report, however, provides unquestionable evidence, in one case, of an association between the long QT syndrome and SIDS. 相似文献