全文获取类型
收费全文 | 1661篇 |
免费 | 147篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 100篇 |
妇产科学 | 35篇 |
基础医学 | 187篇 |
口腔科学 | 41篇 |
临床医学 | 224篇 |
内科学 | 340篇 |
皮肤病学 | 29篇 |
神经病学 | 57篇 |
特种医学 | 269篇 |
外科学 | 115篇 |
综合类 | 50篇 |
预防医学 | 175篇 |
眼科学 | 23篇 |
药学 | 150篇 |
中国医学 | 1篇 |
肿瘤学 | 64篇 |
出版年
2021年 | 11篇 |
2019年 | 9篇 |
2018年 | 15篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 25篇 |
2014年 | 19篇 |
2013年 | 47篇 |
2012年 | 37篇 |
2011年 | 45篇 |
2010年 | 38篇 |
2009年 | 52篇 |
2008年 | 48篇 |
2007年 | 86篇 |
2006年 | 54篇 |
2005年 | 47篇 |
2004年 | 40篇 |
2003年 | 30篇 |
2002年 | 34篇 |
2001年 | 36篇 |
2000年 | 37篇 |
1999年 | 43篇 |
1998年 | 69篇 |
1997年 | 77篇 |
1996年 | 84篇 |
1995年 | 72篇 |
1994年 | 47篇 |
1993年 | 62篇 |
1992年 | 34篇 |
1991年 | 37篇 |
1990年 | 41篇 |
1989年 | 67篇 |
1988年 | 47篇 |
1987年 | 50篇 |
1986年 | 25篇 |
1985年 | 33篇 |
1984年 | 31篇 |
1983年 | 44篇 |
1982年 | 32篇 |
1981年 | 21篇 |
1980年 | 30篇 |
1979年 | 26篇 |
1978年 | 19篇 |
1977年 | 20篇 |
1976年 | 12篇 |
1975年 | 14篇 |
1974年 | 8篇 |
1972年 | 9篇 |
1969年 | 8篇 |
1968年 | 6篇 |
排序方式: 共有1874条查询结果,搜索用时 15 毫秒
1.
Leonidas JC; Berdon WE; Valderrama E; Neveling U; Schuval S; Weiss SJ; Hilfer C; Godine L 《Radiology》1996,198(2):377
2.
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
3.
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
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
4.
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
5.
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
6.
7.
8.
9.
Nine normal bone marrow donors aged 7-166 months (median 69 months) received autologous red cells which had been removed from their marrow harvest after collection. The median volume of marrow removed from the donors was 18.6 ml/kg which was equivalent to a median blood volume loss of 23.3%. Three infant donors were transfused with autologous red blood cells intraoperatively. These cells had been salvaged from the initial marrow aliquot and were transfused while bone marrow harvesting continued. No donors required homologous blood transfusion. This technique is useful for marrow donors in the pediatric age group when preharvest autologous blood collection is not feasible or available. 相似文献
10.
Kaufmann SJ; Sharif K; Sharma V; McVerry BA 《Human reproduction (Oxford, England)》1998,13(2):498-499
The patient was diagnosed in childhood as having severe congenital
neutropenia and had recurrent admissions with severe infections. In 1987,
prior to getting married, she was sterilized. She continued to require i.v.
antibiotics when she contracted a severe infection. On one occasion, she
was treated with growth colony stimulating factor (G- CSF). Her increased
neutrophil count was sustained following this treatment. In June 1993, she
wished to start a family and underwent in- vitro fertilization (IVF)
treatment. G-CSF was given prior to oocyte retrieval. She conceived on her
first cycle and an ultrasound scan revealed a singleton pregnancy.
Throughout the course of the pregnancy, her white cell count was monitored
closely and remained at <1.0x10(9)/l. The pregnancy progressed
uneventfully and at 37 weeks gestation she was admitted for G-CSF
injections. At 38 weeks she was delivered of a boy weighing 3350 g, by
elective Caesarean section. His white cell count was normal. This is the
first case of G-CSF being used before conception and during pregnancy in a
patient with congenital neutropenia. It shows that advances in cytokine
therapy and close interdisciplinary liaison can lead to a successful
outcome and help patients, who would otherwise remain childless, to achieve
a family.
相似文献