全文获取类型
收费全文 | 1620篇 |
免费 | 147篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 115篇 |
儿科学 | 55篇 |
妇产科学 | 13篇 |
基础医学 | 245篇 |
口腔科学 | 57篇 |
临床医学 | 108篇 |
内科学 | 343篇 |
皮肤病学 | 24篇 |
神经病学 | 109篇 |
特种医学 | 117篇 |
外科学 | 169篇 |
综合类 | 29篇 |
预防医学 | 163篇 |
眼科学 | 12篇 |
药学 | 123篇 |
中国医学 | 1篇 |
肿瘤学 | 101篇 |
出版年
2023年 | 8篇 |
2022年 | 7篇 |
2021年 | 17篇 |
2020年 | 16篇 |
2019年 | 14篇 |
2018年 | 28篇 |
2017年 | 28篇 |
2016年 | 34篇 |
2015年 | 33篇 |
2014年 | 49篇 |
2013年 | 58篇 |
2012年 | 77篇 |
2011年 | 89篇 |
2010年 | 46篇 |
2009年 | 69篇 |
2008年 | 74篇 |
2007年 | 88篇 |
2006年 | 68篇 |
2005年 | 84篇 |
2004年 | 73篇 |
2003年 | 75篇 |
2002年 | 82篇 |
2001年 | 59篇 |
2000年 | 60篇 |
1999年 | 55篇 |
1998年 | 40篇 |
1997年 | 47篇 |
1996年 | 41篇 |
1995年 | 32篇 |
1994年 | 22篇 |
1993年 | 25篇 |
1992年 | 23篇 |
1991年 | 23篇 |
1990年 | 13篇 |
1989年 | 33篇 |
1988年 | 29篇 |
1987年 | 20篇 |
1986年 | 25篇 |
1985年 | 20篇 |
1984年 | 12篇 |
1983年 | 15篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1978年 | 5篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有1784条查询结果,搜索用时 15 毫秒
1.
2.
The role of growth factors and cytokines in the impaired healing of chronic leg ulcers remains uncertain. The aim of this study was to determine whether changes in the amount and location of cytokines and growth factors may be associated with impaired healing in chronic leg ulcers. Biopsies from leg ulcers of 21 patients and from normal skin of nine healthy volunteers were examined immunohistochemically for selected growth factors and cytokines. Greater staining intensity was found in keratinocytes at the edges of ulcers compared to normal skin, or skin adjacent to the ulcers. Staining at the ulcer edge was more intense in nonhealing ulcers for only vascular endothelial growth factor and platelet-derived growth factor, whereas staining in the adjacent skin was more intense for all factors in the nonhealing phase. For all factors staining was cytoplasmic, suggesting production in these areas. This study shows up-regulation of the production of cytokines and growth factors in keratinocytes of chronic leg ulcers that is greater when the ulcers are nonhealing. 相似文献
3.
4.
Effects of the long acting beta agonist formoterol on asthma control in asthmatic patients using inhaled corticosteroids. The Netherlands and Canadian Formoterol Study Investigators 总被引:3,自引:2,他引:1
下载免费PDF全文
![点击此处可从《Thorax》网站下载免费的PDF全文](/ch/ext_images/free.gif)
T. van der Molen D. S. Postma M. O. Turner B. M. Jong J. L. Malo K. Chapman R. Grossman C. S. de Graaff R. A. Riemersma M. R. Sears 《Thorax》1997,52(6):535-539
BACKGROUND: The long acting beta 2 agonist formoterol has proved to be an effective bronchodilator with a prolonged action of 12-14 hours. However, the precise role of formoterol in the maintenance treatment of asthma is still under debate. A study was performed to investigate the efficacy and safety of treatment with formoterol for six months in subjects with asthma. METHODS: In a multicentre double blind, placebo controlled, parallel group study 239 subjects with mild to moderate asthma were randomly assigned to treatment with either inhaled formoterol 24 micrograms twice daily (n = 125) or placebo (n = 114) during eight months. The study consisted of a four week run in period, a 24 week treatment period, and a four week washout period. All subjects were using regular inhaled corticosteroids (100-3200 micrograms daily) but were still needing at least five inhalations of short acting beta 2 agonist per week for symptom relief. The study was performed in 10 outpatient clinics in Canada, and five outpatient clinics and one coordinating centre for 44 Dutch general practitioners in The Netherlands. Twice daily self-reported peak expiratory flow (PEF) measurements, symptom scores, and rescue beta 2 agonist use during the last 28 treatment days compared with baseline values were used as main outcome measures. Spirometric values were measured at entry, at the start of treatment, after four, 12 and 24 weeks of treatment, and after four weeks washout. RESULTS: One hundred and twenty five subjects received formoterol 24 micrograms twice daily via Turbohaler and 114 received placebo. Baseline FEV1 was 67.1% predicted and mean bronchodilator reversibility was 26%. The mean total asthma symptom score was 3.6 (maximum possible 21). A significant decrease in symptoms in favour of formoterol (difference from placebo -0.64, 95% CI -0.04 to -1.23, p = 0.04) was observed. Compared with placebo, morning PEF increased (difference from placebo 28 l/min, 95% CI 18.3 to 37.7, p = 0.0001) and the use of short acting beta 1 agonists decreased (daytime difference from placebo -1.1 inhalation, 95% CI -1.4 to -0.7, p = 0.0001) in the formoterol group. PEF returned to baseline following discontinuation of formoterol, as did asthma symptom scores. Thirty three patients treated with formoterol and 32 treated with placebo required treatment with prednisolone during the study (58 and 55 courses, respectively). CONCLUSIONS: Adding formoterol 24 micrograms twice daily by Turbohaler to inhaled corticosteroids was effective in improving symptom scores and morning PEF, and decreasing the use of rescue beta 2 agonists. There was no apparent loss of asthma control during 24 weeks of treatment with formoterol.
相似文献
相似文献
5.
6.
7.
8.
9.
Picotamide inhibition of excess in vitro thromboxane B2 release by colorectal mucosa in inflammatory bowel disease. 总被引:1,自引:0,他引:1
Collins CE Benson MJ Burnham WR Rampton DS 《Alimentary pharmacology & therapeutics》1996,10(3):315-320
BACKGROUND: Inflammatory bowel disease is associated with increased mucosal release of eicosanoids. Among these, thromboxane A2 has been proposed as a possible inflammatory mediator; its suppression may be a useful therapeutic option. METHODS: Using a tissue incubation technique, we compared release of immunoreactive thromboxane B2 by colonic biopsies from patients with ulcerative colitis, Crohn's disease and controls, and assessed the inhibitory effect of picotamide, a thromboxane synthesis inhibitor-receptor antagonist, which has been widely used in Italy for management of ischaemic heart and cerebrovascular disease. RESULTS: Increased amounts of thromboxane B2 were released from biopsies from patients with active ulcerative colitis (median 238 pg/20 min/mg wet weight (interquartile range 147- 325), n = 12) and active Crohn's disease (252 (174-450), 6) compared with those from patients with quiescent ulcerative colitis (95 (61- 140), 12) or Crohn's disease (105 (57-201), 13), or controls (136 (64- 206), 8). Incubation with picotamide at concentrations between 100 microM and 1 mM reduced thromboxane B2 release (IC50 890 microM). CONCLUSION: Since increased thromboxane A2 production may have pathogenetic importance, thromboxane synthesis inhibitor-receptor antagonists such as picotamide merit therapeutic trial in the management of inflammatory bowel disease. 相似文献
10.
Relation between respiratory symptoms, pulmonary function and peak flow variability in adults. 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Thorax》网站下载免费的PDF全文](/ch/ext_images/free.gif)
BACKGROUND--A study was carried out to determine whether subjects with respiratory symptoms are more likely to have impaired lung function or increased airway lability, and to quantify these relationships in a population of adults. METHODS--Data were collected from 511 participants (aged 20-70 years) from the Dutch part of the European Community Respiratory Health Survey (ECRHS). The symptoms analysed were: wheeze, dyspnoea > or = grade 3, nocturnal dyspnoea, cough and phlegm, and history of allergy. Lung function was measured by peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1). PEF variability was used as an index for bronchial lability. RESULTS--Both FEV1 and PEF were decreased with increasing numbers of symptoms. Subjects with one symptom had an increased risk of having an FEV1 value of < 70% (OR = 4.2) and this risk increased with an increasing number of symptoms. Subjects with three or more symptoms had an increased risk of having a PEF value of < 70%, a diurnal variation in PEF of > 10% (both OR = 4.4), and an increased risk of high between day variation (OR = 6.6). CONCLUSIONS--Subject-reported symptoms are related to impaired lung function and to increased variability of peak flow. 相似文献