全文获取类型
收费全文 | 2320篇 |
免费 | 200篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 139篇 |
妇产科学 | 128篇 |
基础医学 | 245篇 |
口腔科学 | 47篇 |
临床医学 | 255篇 |
内科学 | 450篇 |
皮肤病学 | 51篇 |
神经病学 | 76篇 |
特种医学 | 171篇 |
外科学 | 185篇 |
综合类 | 156篇 |
预防医学 | 246篇 |
眼科学 | 19篇 |
药学 | 204篇 |
1篇 | |
中国医学 | 75篇 |
肿瘤学 | 65篇 |
出版年
2021年 | 20篇 |
2018年 | 24篇 |
2017年 | 25篇 |
2016年 | 21篇 |
2015年 | 44篇 |
2014年 | 49篇 |
2013年 | 68篇 |
2012年 | 76篇 |
2011年 | 85篇 |
2010年 | 65篇 |
2009年 | 58篇 |
2008年 | 79篇 |
2007年 | 65篇 |
2006年 | 69篇 |
2005年 | 47篇 |
2004年 | 48篇 |
2003年 | 36篇 |
2002年 | 34篇 |
2001年 | 43篇 |
2000年 | 36篇 |
1999年 | 49篇 |
1998年 | 52篇 |
1997年 | 63篇 |
1996年 | 61篇 |
1995年 | 55篇 |
1994年 | 60篇 |
1993年 | 48篇 |
1992年 | 41篇 |
1991年 | 37篇 |
1990年 | 42篇 |
1989年 | 56篇 |
1988年 | 52篇 |
1987年 | 44篇 |
1986年 | 38篇 |
1985年 | 25篇 |
1984年 | 32篇 |
1983年 | 37篇 |
1982年 | 26篇 |
1981年 | 27篇 |
1980年 | 26篇 |
1979年 | 30篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1959年 | 35篇 |
1958年 | 58篇 |
1957年 | 87篇 |
1956年 | 45篇 |
1955年 | 75篇 |
1954年 | 67篇 |
1953年 | 17篇 |
排序方式: 共有2534条查询结果,搜索用时 0 毫秒
1.
2.
Acute respiratory distress during Caesarean section under spinal anaesthesia A probable case of anaphylactoid reaction to Syntocinon 总被引:2,自引:0,他引:2
A case of life-threatening respiratory distress during a Caesarean section under spinal anaesthesia is reported. Possible causes of the event including anaphylactoid reactions and the methods of their diagnosis are discussed. The most likely cause of the episode was felt to be an anaphylactoid reaction to Syntocinon. 相似文献
3.
Abstract: This paper dicusses the use of esophageal dilatation with a Rigiflex TTS balloon. This method was used 45 times on 11 patients affected by anastomotic or a severe grade peptic esophageal stenosis. Fluoroscopic guidance was used in 36 procedures (80%) without effecting the mean duration of the treatment (12 minutes). The results were considered satisfactory when these goals had been achieved: a) dilatation of the stenosis over 15 mm; b) a dysphagia free-time of more than 6 months. A satisfactory result was achieved in 10 patients (90.9%), without deaths and major complications. 5 patients received 1 dilatation and the other 5 needed, 3-3-4-7–11 procedures respectively to obtain a satisfactory result. On these basis we consider that its great efficacy, security and tolerability depend on the following characteristics of the Rigiflex TTS balloon: 1) “radial” dilatation; 2) the possibility of introducing the balloon through the operative channel of the fiberscope; 3) direct visualization of the stenosis during dilatation. The following disadvantages with this method are: the absence of a tactile sensation of dilatation and the elevated cost of the instrument. We conclude that the Rigiflex TTS balloon is an important alternative to guide-wire techniques, especially for the treatment of severe esophageal strictures. 相似文献
4.
妊娠肝内胆汁淤积症患者血清一氧化氮和内皮素的变化及意义 总被引:2,自引:0,他引:2
目的:探讨妊娠肝内胆汁淤积症(ICP)患者外周静脉血清、新生儿脐静脉血清中一氧化氮(NO)、内皮素(ET)、丙二醛(MDA)和超氧化物歧化酶(SOD)含量的变化及在ICP发病中的作用。方法:以ICP组28例为研究组,测定其外周静脉血清及新生儿脐静脉血清中的NO、ET、MDA和SOD,以年龄相近的24例正常孕妇作为对照组。结果:ICP患者的MDA和ET含量较正常晚期妊娠显著增高(P<0.01),ICP患者的NO和SOD含量与对照组相比无显著性差异(P>0.05)。母血清中NO、ET、MDA含量均较新生儿脐静脉血清中的含量高,差异有显著性(P<0.01)。结论:妊娠期体内氧化和抗氧化失衡及ET水平的增高可能与ICP的发生、发展有关。 相似文献
5.
T Hoehn M William A R McPhaden H Stannigel E Mayatepek R M Wadsworth 《The European respiratory journal》2006,27(6):1311-1315
Abnormal growth and development of lymphatic pulmonary structures leads to severe hypoxia in congenital pulmonary lymphangiectasis (CPL). This case study aims to determine the cellular source and topographical distribution of the nitric oxide synthases in CPL. It studies the post mortem tissue of a term newborn with the clinical course and histological findings of CPL and three controls without pulmonary pathology. It was found that endothelial cells of pulmonary arteries and lymphatic structures stained significantly more for endothelial nitric oxide synthase protein in the CPL patient compared to the controls. The authors conclude that synthesis of endothelial nitric oxide synthase is upregulated in vascular and lymphatic endothelial cells in congenital pulmonary lymphangiectasis. 相似文献
6.
Accumulation of factors influencing respiratory illness in members of a national birth cohort and their offspring. 总被引:7,自引:0,他引:7
下载免费PDF全文
![点击此处可从《Journal of epidemiology and community health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
STUDY OBJECTIVE--The aim was to investigate predictors of childhood lower respiratory tract illness in two generations, and predictors of adult lower respiratory disorders in the first generation. DESIGN--Data on respiratory health and environmental factors from a national birth cohort study were examined from birth to 36 years. Data were also collected on the parents of the subjects and on the subjects' first born offspring from birth to eight years. Main outcome measures were: reports of lower respiratory tract illness before 2 years; lower respiratory tract illness of a week or more between age 20 and 36 years; regular phlegm production at 25 and 36 years; reports of wheeze or asthma at age 36 years; peak expiratory flow rate (PEFR) at age 36 years measured by nurses during home visits; and mothers' reports of lower respiratory illness in first born offspring before 2 years. SUBJECTS--Subjects were a sample of 5362 single, legitimate births taken from all those occurring in England, Wales, and Scotland in one week in 1946, and studied regularly from birth to age 43 years. Data on the subjects' parents and on their 1676 first offspring born while they were aged 19-25 years were also collected. MAIN RESULTS--Lower respiratory tract illness before 2 years fell from 25% in the population born in 1946 to 13% in their first born offspring. In those born in 1946, poor home environment, parental bronchitis, and atmospheric pollution were the best predictors of lower respiratory illness before 2 years, and these three factors and childhood lower respiratory illness and later smoking were the best predictors of adult lower respiratory tract problems. Risk factors for lower respiratory illness in the offspring were manual social class, parental and grandparental lower respiratory disease, and parental smoking. CONCLUSIONS--Risks for adult lower respiratory problems accumulated in childhood through illness, poor social circumstances, and atmospheric pollution. Smoking exacerbated early life risks and was an independent risk factor. In the offspring generation, parental smoking was a risk factor for early life chest illness, together with parental illness and low social class. Reduction of prevalence in the offspring generation was probably accounted for by improvement in home circumstances, reduced atmospheric pollution, and lower rates of parental lower respiratory illness, but current rates of smoking seem likely to prevent much further reduction in early life lower respiratory illness, and thus in this aspect of risk for subsequent adult lower respiratory problems. The accumulation of risk in childhood and adolescence for later adult problems implies a long time scale for the reduction of adult lower respiratory disorders. 相似文献
7.
G. M. Price A. A. Paul F. B. Key A. C. Harter T. J. Cole K. C. Day M. E. J. Wadsworth 《Journal of human nutrition and dietetics》1995,8(6):417-428
A diary method using household measures was employed to obtain dietary records in a large national prospective survey and a computer program, DIDO (Diet In Data Out), was designed for direct entry of the diaries. The accuracy of this computerized coding system was examined alongside that of the manual coding used for a similar diary in a previous wave, 7 years earlier, of the same survey. Accuracy was assessed by analysis of the errors in the coded and checked records by stringent re-checking of nominal 2% random subsamples of the diet diaries coded by each method. The mean time to code and check each of the 2086 7-day records in the whole survey using DIDO was 58 minutes (SD 30) compared with reported results of 1–4 hours for manual methods. The mean error rate of computerized coding and checking with DIDO was 2.3% (SD 2.1; range 0–8.9) per diary in the subsample. Correcting these mistakes made insignificant changes to the calculated mean energy and nutrient intakes for the subsample. The percentage of individuals changing to an adjacent third of nutrient distribution after correcting unambiguous errors ranged from none (for alcohol) to 11% (for carbohydrate and calcium intake). The mean error rate on a similar subsample of diaries from the earlier survey which had been coded manually was significantly higher at 5.9% (SD 4.1; range 0–17) per diary. Emphasis is laid on the importance, in coding, of dealing with ambiguities in the subjects' records, since this can affect the accuracy and the precision of the nutrient results obtained. We conclude that the DIDO coding method has the advantages of greater accuracy, speed, consistency and efficient data handling, and affords greater data accessibility for checking, compared with manual systems. 相似文献
8.
Anti-basal ganglia antibodies (ABGA) have been associated with poststreptococcal encephalitis similar to encephalitis lethargica (EL). We report two children with parainfectious encephalitis of similar phenotype and IgG ABGA. However, the associated pathogens in the two cases differed; beta-hemolytic streptococcus and herpes zoster. ABGA may not be specific to poststreptococcal encephalitis, but rather a surrogate marker of an inflammatory mediated movement disorder, which may respond to immunotherapy. 相似文献
9.
10.