全文获取类型
收费全文 | 663篇 |
免费 | 32篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 25篇 |
基础医学 | 66篇 |
口腔科学 | 15篇 |
临床医学 | 55篇 |
内科学 | 140篇 |
皮肤病学 | 6篇 |
神经病学 | 91篇 |
特种医学 | 158篇 |
外科学 | 55篇 |
综合类 | 11篇 |
预防医学 | 31篇 |
眼科学 | 2篇 |
药学 | 32篇 |
2篇 | |
中国医学 | 3篇 |
肿瘤学 | 22篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 18篇 |
2013年 | 22篇 |
2012年 | 25篇 |
2011年 | 25篇 |
2010年 | 14篇 |
2009年 | 19篇 |
2008年 | 16篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 15篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 12篇 |
1999年 | 19篇 |
1998年 | 28篇 |
1997年 | 26篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 22篇 |
1993年 | 24篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 32篇 |
1988年 | 17篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 32篇 |
1984年 | 15篇 |
1983年 | 13篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1934年 | 2篇 |
1933年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有715条查询结果,搜索用时 0 毫秒
51.
Early life and later determinants of adult disease: a 50 year follow-up study of the Newcastle Thousand Families cohort 总被引:2,自引:0,他引:2
DW Lamont Dr L Parker MA Cohen M White SMA Bennett NC Unwin AW Craft KGMM Alberti 《Public health》1998,112(2):85-93
The relative contribution of socioeconomic, behavioural and biological factors operating in fetal and infant life, childhood and adulthood to risk for cardiovascular disease, respiratory diseases and non-insulin-dependent diabetes in middle age has become an important research issue. All 1142 babies born in Newcastle upon Tyne in May and June 1947 were recruited into a prospective cohort study of child health (the ‘Thousand Families’ study) and followed in great detail to the age of 15 y, with a brief further follow up at age 22 y. Children from poorer families were at greatest risk of severe respiratory tract infection in infancy. Children from professional and managerial families were on average taller and heavier throughout childhood than those from semi- and unskilled manual social classes. Repeated infections in early childhood greatly increased the risk of developing chronic respiratory disease by age 15 y. This paper outlines a new investigation designed to trace surviving members of this cohort and to chart the relationships between their socioeconomic circumstances, lifestyles, experiences and health from birth through to the present day. Existing data on socioeconomic circumstances and infections in infancy and childhood, infant nutrition, birthweight and physical development to age 22 y will be linked to information gained from a new study. This comprises a postal questionnaire survey of study members' adult health, socioeconomic circumstances and lifestyle, and a hospital based clinical examination including heart and lung function, glucose tolerance, blood lipids and anthropometric measurements at age 49–51 y. Out of a target sample of 979 people for whom sufficient data are available on the first year of life, 866 (88%) have been traced and 649 are still resident in the North of England. Those study members who have been traced are highly representative of the original cohort. The Thousand Families cohort provides a unique opportunity for detailed epidemiological study because of the wealth of data available on infant and childhood socioeconomic and family circumstances, all of which was collected prospectively. In addition, there has been comparatively little loss to follow-up since 1948. 相似文献
52.
Nicky McCreesh Lisa G Johnston Andrew Copas Pam Sonnenberg Janet Seeley Richard J Hayes Simon DW Frost Richard G White 《International journal of health geographics》2011,10(1):1-12
Background
The purpose of the project was to delineate a series of contiguous neighbourhood-based "Data Zones" within the Region of Peel (Ontario) for the purpose of health data analysis and dissemination. Zones were to be built on Census Tracts (N = 205) and obey a series of requirements defined by the Region of Peel. This paper explores a method that combines statistical analysis with ground-truthing, consultation, and the use of a decision tree.Data
Census Tract data for Peel were derived from the 2006 Canadian Census Master file.Methods
Following correlation analysis to reduce the data set, Principal Component Analysis was applied to the data set to reduce the complexity and derive an index. The Getis-Ord Gi*statistic was then applied to look for statistically significant clusters of like Census Tracts. A detailed decision tree for the amalgamation of remaining zones and ground-truthing with Peel staff verified the resulting zones.Results
A total of 15 Data Zones that are similar with respect to socioeconomic and sociodemographic attributes and that met criteria defined by Peel were derived for the region.Conclusion
The approach used in this analysis, which was bolstered by a series of checks and balances throughout the process, gives statistical validity to the defined zones and resulted in a robust series of Data Zones for use by Peel Public Health. We conclude by offering insight into alternative uses of the methodology, and limitations. 相似文献53.
Eighty-eight intravenous cannulae with valved injection sideports were examined bacteriologically after approximately three days (64–80 h) normal clinical use. Three methods of culture of the cannulae were used, which distinguished contamination of the outer and inner surfaces as well as detecting bacteria remaining on the inner cannula surface following a washing procedure of the lumen. Of the cannulae sampled, 40·9 per cent were found to be contaminated on their inner surfaces and no correlation was obtained between use of the sideport and contamination of the cannulae at this site. It was concluded that contamination of a cannula lumen did not necessarily result in bacteraemia. 相似文献
54.
55.
The results of Kr-81m/Tc-99m ventilation-perfusion (VP) lung scintigraphy were correlated with the results of pulmonary angiography for 74 patients suspected of having pulmonary embolism (PE). Among patients having a diagnostic scan, the sensitivity and specificity of scintigraphy were 91% and 94%, respectively. Also, 157 consecutive cases of Kr-81m/Tc-99m VP lung scintigraphy were reviewed, and the frequency of an indeterminate scan was found to be 22%. A similar frequency was found for VP scintigraphy with xenon-133. Of eight patients who had indeterminate scans due to the presence of a single VP mismatch, four were demonstrated to have PE by angiography. Kr-81m is an excellent agent for VP scanning in cases of suspected PE, offering accuracy in diagnosis as well as favorable physical properties. 相似文献
56.
Detailed per-oral small bowel examination vs. enteroclysis. Part II: Radiographic accuracy 总被引:5,自引:0,他引:5
Accuracy of the detailed per-oral small bowel series and enteroclysis was compared in 134 patients known to have (or not have) disease of the small bowel. Overall sensitivity of the per-oral examination was 92% and specificity 94%, compared to 94% and 89%, respectively, for enteroclysis. There was no difference between the two in Crohn disease, adhesions, and metastatic disease; however, enteroclysis was thought to be more effective in delineating peritoneal adhesions in patients with obstruction. The authors conclude that while the per-oral study and enteroclysis are equally valid methods of examining the small bowel, the per-oral study is preferable as a screening examination because it requires less time, has fewer side effects, and involves a lower radiation exposure. 相似文献
57.
Regional myocardial dysfunction: evaluation of patients with prior myocardial infarction with fast CT 总被引:1,自引:0,他引:1
Lipton MJ; Farmer DW; Killebrew EJ; Bouchard A; Dean PB; Ringertz HG; Higgins CB 《Radiology》1985,157(3):735-740
A prototype ultrafast cine computed tomographic (CT) scanner, designed specifically for cardiac imaging, was used to evaluate a preliminary series of patients with prior myocardial infarction (n = 21) and a control group without coronary artery disease (n = 5). Multilevel 50-msec CT scan exposures were obtained during peripheral intravenous bolus injections of contrast medium. A comparison was made between cine-CT scans and standard left ventriculographic images in assessing segmental left ventricular motion. Results indicate that cine CT, performed at sufficiently rapid speeds (20 scans per second) to allow useful analysis of regional ventricular wall motion, can provide adequate image quality. Analysis of 110 segments revealed a good correlation (90.9%) between the two techniques in characterizing normal from abnormal regional wall motion. Cine CT, based on this initial study, demonstrates considerable potential for evaluating not only cardiac chamber dimensions but also segmental wall dynamics. 相似文献
58.
Mercado S; Hunter DW; Castaneda-Zuniga WR; Amplatz K; Young AT; Cardella JF; Lange PH; Hulbert JC; Reddy P 《Radiology》1986,158(1):207-209
Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems. 相似文献
59.
Darcy MD; Cardella JF; Hunter DW; Smith TP; Castaneda-Zuniga WR; Lund G; Amplatz K 《Radiology》1986,161(3):611-614
The Amplatz retrievable vena caval filter was designed in an attempt to decrease complications associated with the placement of Mobin-Uddin or Kimray-Greenfield filters. The design allows percutaneous retrieval, thus expanding application of the filter to situations requiring temporary prophylaxis against pulmonary embolism. Filters have been placed in 16 patients, nine (56%) for prophylactic purposes. All filters were easily inserted percutaneously. Complications occurred in three patients; these included complete thrombosis of the inferior vena cava below the filter, misplacement of one filter into the pericaval retroperitoneal tissue, and development of thrombus cranial to the filter. With the current introduction system, the possibility of filter misplacement has been essentially eliminated. No patient experienced symptoms suggestive of pulmonary embolism after filter insertion. One filter retrieval has been performed, with no complications. 相似文献
60.
An intraluminal culture method was evaluated for central venous catheters and compared to conventional catheter tip cultures and cultures from the insertion site. The colonization-rate of the catheters was 43.7% using conventional tip culture, 34.4% with the intraluminal method and 40.1% at the skin puncture site. Only 37.5% of the catheters showed identical bacteria at the skin puncture site and catheter-tip, compared with 87.5% between intraluminal culture and catheter-tip culture (P less than 0.05). 相似文献