首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   152447篇
  免费   10438篇
  国内免费   769篇
耳鼻咽喉   1405篇
儿科学   3898篇
妇产科学   2753篇
基础医学   20543篇
口腔科学   3454篇
临床医学   14690篇
内科学   32857篇
皮肤病学   2877篇
神经病学   14783篇
特种医学   6123篇
外国民族医学   6篇
外科学   22995篇
综合类   1902篇
现状与发展   2篇
一般理论   139篇
预防医学   11005篇
眼科学   3188篇
药学   10482篇
  1篇
中国医学   245篇
肿瘤学   10306篇
  2023年   744篇
  2022年   1039篇
  2021年   2828篇
  2020年   1957篇
  2019年   2817篇
  2018年   3428篇
  2017年   2663篇
  2016年   3046篇
  2015年   3512篇
  2014年   5032篇
  2013年   6800篇
  2012年   10520篇
  2011年   11139篇
  2010年   6350篇
  2009年   6043篇
  2008年   10197篇
  2007年   10878篇
  2006年   10348篇
  2005年   10596篇
  2004年   10004篇
  2003年   9488篇
  2002年   8907篇
  2001年   1483篇
  2000年   1113篇
  1999年   1597篇
  1998年   2106篇
  1997年   1645篇
  1996年   1421篇
  1995年   1290篇
  1994年   1140篇
  1993年   1113篇
  1992年   776篇
  1991年   784篇
  1990年   609篇
  1989年   596篇
  1988年   557篇
  1987年   572篇
  1986年   507篇
  1985年   534篇
  1984年   636篇
  1983年   565篇
  1982年   759篇
  1981年   701篇
  1980年   602篇
  1979年   364篇
  1978年   375篇
  1977年   403篇
  1976年   342篇
  1975年   293篇
  1974年   249篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
191.
Intramuscular adrenaline is the treatment of choice for food-related anaphylactic reactions. Although auto-injectable adrenaline devices are routinely prescribed for patients at risk of serious reactions, previous studies have shown that only one-third to one and a half of patients or their carers are able to properly use these devices. The aim of this study was to determine which factors are most strongly associated with the effective use of these devices. A 122 children with food allergies who had previously been prescribed EpiPens and were attending a single specialist pediatric allergy center in the UK. were studied prospectively. A 69% of parents were unable to use the EpiPen, did not have it available, or did not know when it should be administered. A prior practical demonstration was associated with a 4-5 fold greater chance that parents would be able to use the device (p < 0.005). Prior consultation with an allergy specialist rather than a general physician, and parents who independently sought additional information from the national self-help allergy organization were also four to six times more likely to be competent with these devices (p < 0.005). The study clearly shows that for EpiPens to be used safely and effectively it is essential to educate the carer at the time the device is prescribed.  相似文献   
192.
Our molecular understanding of growth hormone-induced signal transduction has improved significantly over the past decades. At the same time, human population genetics and the analysis of genetically engineered animals have led to the discovery of genes that control specific aspects of the overall growth process. Although, currently, growth disorders are still diagnosed and treated on empirical bases, it might soon be possible to stratify patients predominantly by genetic defect, with treatment based on our molecular understanding of the role of the affected gene in the disease.  相似文献   
193.
194.
195.
196.
Global coronary blood flow and metabolism were measured in seven patients on the first postoperative day following coronary revascularization to test the hypothesis that tracheal extubation produces adverse haemodynamic responses akin to those observed during tracheal intubation. Regional coronary flow and metabolic measurements were made in five of the seven patients. Extubation from a continuous positive airway pressure (CPAP) of 5 cm H2O was associated with a statistically significant rise in cardiac index from 3.44 ± 0.23 L · min-1 · m-2 to 3.73 ± 0.15L·min-1 ·m-2 related to an increase in stroke index, without significant changes in heart rate, mean arterial and pulmonary capillary wedge pressure. Consequently the changes in myocardial oxygen consumption (8.52 ± 0.55 to 8.85 ± 0.93 ml · min-1) and coronary blood flow (172 ± 18 to 179 ± 17 ml·min-1) were less prominent than those reported during intubation, where substantial rises in myocardial oxygen consumption and coronary flow occurred. Two patients experienced cardiac lactate production but there were no changes in systemic or coronary haemodynamics, nor were there clinical or electrocardiographic signs of ischaemia. We conclude that extubation does not appear to be associated with adverse systemic or coronary haemodynamic responses in patients following coronary bypass grafting. However, the revascularized myocardium may remain vulnerable to anaerobic metabolism in the immediate postoperative period. Pour savoir si comme ľintubation, ľextubation de la trachée provoque des perturbations hémodynamiques, on a mesuré le métabolisme et la circulation coronarienne globale chez sept patients, au lendemain ďun pontage aorto-coronarien. On a aussi calculé les valeurs régionales de ces mêmes variables pour cinq ďentre eux. Ľindex cardiaque de 3.44 ± 0.23 L · min-1 · m-2 sous pression positive en respiration spontanée (CPAP) de 5 cm. H2O s’est élevé à 3.73 ± 0.15 L · min-1 · m-2 post-extubation avec une augmentation significative du volume ďéjection. La fréquence cardiaque et les pressions artérielles moyennes et capillaires pulmonaires n’ont pas changé. Ainsi ľaugmentation de la consommation ďoxygène du myocarde de 8.52 ± 0.55 à 8.85 ± 0.93 ml · min-1 et celle du flot coronarien de 172 ± 18 à 179 ± 17 ml · min-1 ont été moindres que celles, importantes, déjà observées lors de ľintubation. On a noté chez deux patients une production de lactate par le myocarde, sans changement de ľhémodynamic systémique et coronarienne non plus que de signe clinique ou électrocardiographique ďischémie. Donc, après un pontage coronarien, ľextubation ne semble pas causer ďeffet néfaste sur les circulations systémique et coronarienne, toutefois, le myocarde revascularisé peut demeurer sensible au métabolisme anaérobique.  相似文献   
197.
Exhaled nitric oxide (FENO) is raised in atopy. The mechanism for this is unclear. The aim of this study was to investigate whether the number of AAT repeats in intron 20 of the NOS1 gene, recently associated with variations in FENO in adults with asthma and cystic fibrosis, was associated with the raised FENO in healthy atopic children. Eighty-seven healthy children (44 girls, 42 atopic, age range 6–18 years) underwent measurements of FENO, spirometry, airway responsiveness and skin prick testing. Genotyping was carried out to determine the number of AAT repeats. There was no association between the number of AAT repeats and FENO in either the whole sample of healthy children (n = 87) or in the subsample of healthy atopics (n = 42). However, a greater number of atopic children had two high repeat alleles compared with non-atopic children (33.3% vs. 13.6%, respectively, p = 0.03). This suggests that variations in the NOS1 gene may contribute to atopy without this relationship being reflected by FENO.  相似文献   
198.
199.
Colorectal cancer is one of the best studied of all malignant diseases interms of genetics and/or molecular prognostic factors. These factors, and relationships with prognosis, may have important implications especially in the design of surgical and adjuvant chemo-radiotherapy options. However, the true prognostic significance of all known factors has yet to be realised. We have reviewed the literature with specific focus on the role of molecular markers involved in prognosis and the prediction of response to adjuvant treatment.  相似文献   
200.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号