全文获取类型
收费全文 | 8154篇 |
免费 | 715篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 396篇 |
妇产科学 | 247篇 |
基础医学 | 1141篇 |
口腔科学 | 187篇 |
临床医学 | 1261篇 |
内科学 | 1406篇 |
皮肤病学 | 159篇 |
神经病学 | 624篇 |
特种医学 | 197篇 |
外国民族医学 | 1篇 |
外科学 | 875篇 |
综合类 | 157篇 |
一般理论 | 7篇 |
预防医学 | 1071篇 |
眼科学 | 65篇 |
药学 | 421篇 |
中国医学 | 6篇 |
肿瘤学 | 621篇 |
出版年
2021年 | 130篇 |
2020年 | 79篇 |
2019年 | 129篇 |
2018年 | 140篇 |
2017年 | 117篇 |
2016年 | 144篇 |
2015年 | 163篇 |
2014年 | 215篇 |
2013年 | 363篇 |
2012年 | 432篇 |
2011年 | 493篇 |
2010年 | 251篇 |
2009年 | 218篇 |
2008年 | 445篇 |
2007年 | 443篇 |
2006年 | 446篇 |
2005年 | 389篇 |
2004年 | 471篇 |
2003年 | 392篇 |
2002年 | 426篇 |
2001年 | 184篇 |
2000年 | 136篇 |
1999年 | 164篇 |
1998年 | 98篇 |
1997年 | 94篇 |
1996年 | 94篇 |
1995年 | 86篇 |
1994年 | 78篇 |
1993年 | 72篇 |
1992年 | 125篇 |
1991年 | 105篇 |
1990年 | 103篇 |
1989年 | 97篇 |
1988年 | 84篇 |
1987年 | 82篇 |
1986年 | 87篇 |
1985年 | 98篇 |
1984年 | 89篇 |
1983年 | 62篇 |
1982年 | 52篇 |
1981年 | 48篇 |
1980年 | 51篇 |
1979年 | 83篇 |
1978年 | 53篇 |
1974年 | 60篇 |
1973年 | 52篇 |
1972年 | 58篇 |
1971年 | 54篇 |
1969年 | 51篇 |
1968年 | 48篇 |
排序方式: 共有8885条查询结果,搜索用时 218 毫秒
21.
Comparison of sulphur dioxide and metabisulphite airway reactivity in subjects with asthma.
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--In asthmatic subjects bronchoconstriction is induced by inhalation of the common food preservatives sulphur dioxide (SO2) and metabisulphite (MBS). SO2 and MBS challenges share many similarities, but it is not known whether they are equivalent. In this study of subjects with mild clinical asthma equivalence was assessed by comparing SO2 and MBS reactivity by estimating the total dose of SO2 inhaled during SO2 and MBS challenges, and by calculating SO2 uptake during both challenges. In addition, as the MBS solutions inhaled were acidic and hyperosmolar, the effect of these factors on MBS responsiveness was investigated. METHODS--Fifteen subjects were challenged on separate days with doubling (0.5 to 8.0 ppm) concentrations of SO2 gas inhaled during three minute periods of isocapnic hyperventilation and MBS administered in doses ranging from 0.1 to 12.8 mumol using the Wright protocol. On two other days SO2 and MBS challenges were preceded by a challenge with phosphate buffered saline (PBS) solutions of pH and osmolarity similar to MBS solutions. Response was measured as the dose or concentration causing a 20% fall in FEV1 (PD20 or PC20). RESULTS--All subjects reacted to MBS and 14 responded to SO2. Geometric mean histamine PD20 was 1.61 mumol (95% confidence interval 0.72 to 3.60). MBS and SO2 airway responsiveness were not significantly related. Estimates of the mean concentration of SO2 inhaled during SO2 and MBS challenges differed, as did estimates of the mean SO2 uptake during both challenges. MBS and SO2 reactivity were not affected by prior challenge with PBS solutions. CONCLUSIONS--SO2 and MBS challenges are not comparable. MBS reactivity was not affected by the hyperosmolar, acidic nature of its solutions. 相似文献
22.
23.
Emma J. Birks MRCP Magdi H. Yacoub DSc FRS Ani Anyanwu FRCS Rosemary Radley Smith FRCP Nicholas R. Banner FRCP Asghar Khaghani FRCS 《The Journal of heart and lung transplantation》2004,23(12):3688-1344
BACKGROUND: Transplantation for patients with a high pulmonary vascular resistance (PVR) carries an increased risk of mortality and right heart failure following heart transplantation and continues to be a major problem. We evaluated the use of hearts from patients who underwent heart and lung transplantation for primary pulmonary hypertension (PPH) as part of a domino procedure because these hearts have hypertrophied right ventricles used to increased pulmonary pressures, but could have a compromised left ventricle or irreversible damage of the right ventricle. METHODS: We reviewed 12 patients with PVR >4 Wood units who underwent orthotopic heart transplantation between 1989 and 1998 using hearts from donors with PPH as part of a domino procedure. RESULTS: We studied 10 men and 2 women, mean age 42.9 years. Mean PVR was 5.3 (range, 4-9) Wood units. Mean ischemia time was 85.3 minutes, and mean donor age was 32 years. Actuarial survival was 75% at 1 year and 75% at 5 years. In the early post-operative period, 3 patients had temporary arrhythmias, 2 required permanent pacemaker implantation, 1 had atrial fibrillation, and 1 had ventricular tachycardia that required defibrillator implantation. At a mean follow-up of 7.8 years, 2 patients had developed asymptomatic transplant coronary disease (both at 8.5 years after transplantation), 1 moderate and 1 very mild; the rest had none. Mean left ventricular ejection fraction at latest follow-up was 70.1% (range, 63%-78%). Right ventricular function assessed clinically and by echocardiography was adequate in the short and long term. CONCLUSIONS: Our results suggest that heart and lung recipients with PPH can provide useful donor hearts to patients with increased PVR and that these hearts function well in the intermediate and long term. 相似文献
24.
C. Noonan M. Farrell J. Mullaney H. Cassidy M. A. Asghar B. J. Young Marie Hickey-Dwyer A. Patterson W. Power M. Hillery A. Benedict-Smith L. M. T. Collum S. Fitzsimon E. O’Donoghue R. Hitchings G. B. Arden A. O’Mahony A. Murray A. Whyte M. Shehata Hugh O’Donoghue Rosemary Robinson J. Toland P. Eustace 《Irish journal of medical science》1991,160(10):322-324
25.
26.
27.
Free hydrocortisone, hydrocortisone incorporated into microspheres and empty microspheres have been administered orally to rats with carrageenan-induced hindpaw inflammation. Hydrocortisone administered in particles was effective at a lower dose than free steroid in reducing inflammation. Inflammatory exudates were able to release steroid from the microspheres by proteolytic degradation. 相似文献
28.
A mobility protocol for critically ill adults. 总被引:1,自引:0,他引:1
Rosemary A Timmerman 《Dimensions of critical care nursing》2007,26(5):175-9; quiz 180-1
Although the complications of immobility are well-described in the literature, critically ill patients are often subjected to prolonged periods of bed rest. Nurses, by virtue of their expertise in preventing iatrogenic complications, are in an ideal position to prevent the adverse outcomes associated with immobility. This article describes how nurses can use a mobility protocol to increase the activity of critically ill patients in a timely manner that may prevent the infirmity and suffering that is caused by unnecessarily long periods of bed rest. 相似文献
29.
The study reports on a questionnaire study of final-year medical students' self-reported attitudes to dealing with dying patients. All respondents had some direct clinical experience with dying patients, and reported that such encounters were largely unproblematic. Alleviating patient anxiety and counseling relatives were seen as important aspects of the doctor's role, along with diagnosis, and management of symptoms. “High fear” respondents were more likely to report difficulty in discussing the prognosis with the dying and to experience minor psychological problems. 相似文献
30.