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   577篇
  免费   15篇
  国内免费   1篇
耳鼻咽喉   19篇
儿科学   19篇
妇产科学   24篇
基础医学   31篇
口腔科学   20篇
临床医学   60篇
内科学   216篇
皮肤病学   4篇
神经病学   32篇
特种医学   25篇
外科学   89篇
综合类   6篇
预防医学   12篇
眼科学   6篇
药学   15篇
肿瘤学   15篇
  2024年   1篇
  2023年   2篇
  2022年   5篇
  2021年   12篇
  2020年   1篇
  2019年   6篇
  2018年   12篇
  2017年   10篇
  2016年   10篇
  2015年   11篇
  2014年   16篇
  2013年   30篇
  2012年   32篇
  2011年   35篇
  2010年   16篇
  2009年   26篇
  2008年   64篇
  2007年   66篇
  2006年   72篇
  2005年   45篇
  2004年   48篇
  2003年   25篇
  2002年   27篇
  2001年   3篇
  2000年   4篇
  1999年   5篇
  1998年   4篇
  1996年   3篇
  1995年   1篇
  1993年   1篇
排序方式: 共有593条查询结果,搜索用时 31 毫秒
71.
Basal septal hypertrophy (BSH), a cause of left ventricular outflow tract (LVOT) obstruction, is thought to occur by increased ventricular dynamics. The aim of the study was to evaluate the effect of pharmacologic stress on LVOT gradients in a group of hypertensive patients with BSH. Dobutamine stress was used in 24 hypertensive patients (mean age 56 +/-8 years; 11 women) with BSH and 20 normal controls (mean age 54 +/-9 years; 7 women). Ejection fraction and myocardial mass, basal septal dimension, and LVOT diameter were measured with 2-dimensional echocardiography. LVOT velocities and transmitral velocities before and at peak dobutamine infusion were determined by continuous wave Doppler and pulsed Doppler, respectively. There were no differences in mean ejection fraction and myocardial mass between BSH patients (58 +/-3%, 204 +/-24 g) and normals (56 +/-4%, 201 +/-32 g). The basal septum was thicker in patients (1.55 +/-0.2 cm) than in normals (1.03 +/-0.1 cm, p<0.001). Maximum LVOT velocities were similar in BSH (1.2 +/-0.4 m/sec) and normals (1.1 +/-0.2 m/sec) at rest. At peak stress, maximum LVOT velocities were higher in BSH (3.3 +/-0.6 m/sec) than normals (1.7 +/-0.4 m/sec, p<0.001). LV rate-pressure product at peak stress was higher in BSH (23,326 +/-4,388) than normals (17,592 +/-2,409, p<0.001). LV isovolumetric relaxation time was prolonged, and the E/A ratio was decreased in the patients at rest (130 +/-14 msec and 0.72 +/-0.18, respectively, p<0.001). At peak stress, diastolic function did not significantly change in two groups. The correlations between LVOT velocity change by stress and mean LVOT diameter (r=-0.668, p<0.001) and mean BS thickness (r=0.610; p<0.001) were significant in the whole group. High velocities appeared on LVOT at peak pharmacologic stress in the hypertensive patients with BSH compared with control group. This suggests dynamic ventricular ejection by stress may contribute to hypertrophy of the basal segment, which is the closest part of septum to increased afterload.  相似文献   
72.
73.
Background: Adenosine is widely used for the diagnosis and the termination of supraventricular arrhythmias. There are many case reports and few series about the proarrhythmic potential of adenosine. We sought to evaluate the proarrhythmic potential of adenosine used to terminate the supraventricular arrhythmias. Methods: The records of all patients that received adenosine for the termination of supraventricular tachycardia were reviewed retrospectively and those with a continuous electrocardiographic (ECG) recording during adenosine administration were included to the study. Results: Our search identified 52 supraventricular episodes of 46 patients with a continuous ECG recording during adenosine administration. Following adenosine administration, premature ventricular contraction (PVC) or ventricular tachycardia (VT) developed in 22 (47.8%) patients and in 26 (50%) tachycardia episodes. No patient had a sustained VT. Nonsustained VT developed in eight (17.4%) patients. All VT episodes were polymorphic, short, and self‐terminating. When the basal and demographic properties of patients with PVC or VT and those without PVT or VT were compared, there was no significant difference. Conclusions: Adenosine is a quite safe and effective drug for the termination of narrow QRS complex tachycardia but it often induces nonsustained VT or PVC that are clinically insignificant in the absence of other accompanying heart disease.  相似文献   
74.
OBJECTIVE: The purpose of this study was to evaluate the long term effect of clopidogrel-based antiplatelet therapy on neointimal formation. METHODS: This study comprised 78 patients with typical stable angina pectoris or documented myocardial ischaemia, and with only one angiographic lesion in one native coronary artery undergoing successful stent implantation without predilatation with C-reactive protein levels < or =5 mg/l at 72 h after the procedure. All patients received dual antiplatelet therapy with 75 mg/day clopidogrel and 300 mg/day aspirin for four weeks. Clopidogrel was switched to isochronous placebo in half of the patients (n=39) at the end of the fourth week. This allocation was maintained for 20 weeks, and at week 24 of the study, coronary angiography and intravascular ultrasound imaging were performed again in all cases in order to evaluate the changes that had occurred in the in-stent neointimal formation; rates of restenosis were also recorded RESULTS: At the end of the follow-up period, angiographic stenosis diameter and restenosis rates were smaller in the clopidogrel group than in the placebo group (23.3% versus 35.6%, p=0.05 and 5.12% versus 10.25%; p=0.03 respectively); the intravascular ultrasonographic neointimal cross sectional area was also smaller in the clopidogrel group (3.6 +/- 2.7 mm(2) versus 5.2 +/- 2.5 mm(2), p=0.03). CONCLUSIONS: Long-term clopidogrel administration significantly reduced neointimal formation at the stent site as well as reducing major clinical events in patients who did not develop high-risk systemic inflammatory response after percutaneous coronary intervention.  相似文献   
75.
76.
AIM: To compare interferon monotherapy with combination treatment using interferon and lamivudine in children with chronic hepatitis B. METHODS: Data from 65 children who had received either interferon-alpha (5 MU/m2 subcutaneous thrice a week for 6 months; n=35; Group 1) or this dose of interferon-alpha for 6 months with oral lamivudine for one year (4 mg/Kg/day, maximum 100 mg/day; n=30; Group 2) were analyzed retrospectively. Complete response was defined as ALT normalization, HBeAg/anti-HBe seroconversion and HBV DNA clearance. RESULTS: ALT normalization rates were similar in Groups 1 and 2 at the end of interferon treatment (13 [38%] and 16 [52%], respectively), at 12 months (19 [56%] and 18 [58%]) and at 24 months (24 [71%] and 23 [74%]). HBV DNA clearance was more frequently observed at 6 months in Group 2 than in Group 1 (19 [63%] versus 7 [20%]; p=0.01), but not at 12 months (19 [63%] versus 17 [49%]) or at 24 months (20 [67%] versus 21 [60%]). Rate of HBeAg/anti-HBe seroconversion was higher in Group 2 at 12 months (18 [60%] versus 11 [31%]; p< 0.05). Rate of complete response was similar in Groups 1 and 2 at 6 months (5 [14%] and 10 [33%], respectively), 12 months (14 [40%] and 17 [57%]) and 24 months (20 [57%] and 19 [63%]). CONCLUSION: Although lamivudine and interferon combination achieved higher initial rates of HBV DNA loss and HBeAg/anti-HBe seroconversion than interferon alone, the final response rates were similar with the two treatments. The combination treatment is therefore not indicated for chronic hepatitis B in children.  相似文献   
77.

Background  

Treatment of a number of complications that occur after abdominal surgeries may require that Urgent Abdominal Re-explorations (UARs), the life-saving and obligatory operations, are performed. The objectives of this study were to evaluate the reasons for performing UARs, outcomes of relaparotomies (RLs) and factors that affect mortality.  相似文献   
78.
BACKGROUND: Baroreceptor reflexes are regulated by nerve terminals of the glossopharyngeal and vagal nerves. The body of pressure-sensitive neurons of these nerves is located in the petrosal ganglion of both nerves. We examined whether there is a relationship between the neuron numbers of the inferior ganglion of the glossopharyngeal nerve and blood pressure values. METHODS: Petrosal ganglions were examined in 18 male hybrid rabbits divided into three equal groups: Group A normotensive (TA=90-100 mmHg), Group B hypertensive (TA>100 mmHg); and Group C hypotensive (TA<90 mmHg). After examination of blood pressure for one week, all animals were sacrificed, and the petrosal ganglions extracted bilaterally and examined histopathologically using the physical dissector method. RESULTS: The mean (+/-SD) neuronal density was: Group A 8700+/-200, Group B 7800+/-250 and Group C 9800+/-300, respectively. The difference between the groups B and C as compared to A was significant (p<0.01) while the difference between Groups B and C was highly significant (p<0.001). CONCLUSIONS: An inverse relationship was noticed between the neuronal density in the petrosal ganglion and blood pressure values with potential implications in the study of the etiology of hypertension.  相似文献   
79.
Cor triatriatum dexter is a very rare congenital abnormality in which the right atrium is divided into two chambers by a membrane. In this abnormality, there is a high incidence of associated congenital abnormalities, particularly of the right heart. In this case study, a 67-year-old man with Ebstein's anomaly, atrial septal defect, and cor triatriatum dexter is presented and echocardiography is discussed as a noninvasive diagnostic tool.  相似文献   
80.
In this study we aimed to determine the role of piracetam (PIR) in preventing radiation induced cochlear damage after total-cranium irradiation (radiotherapy; RT). Male albino guinea pigs used in the study were randomly divided into three groups. Group 1 (Control group) (n=11) received neither PIR nor irradiation, but received saline solution intraperitoneally (i.p.) and received sham irradiation. Group 2 (RT group) (n=32) was exposed to total cranium irradiation of 33 Gy in 5 fractions of 6.6 Gy/d for five successive days, with a calculated (alpha/beta=3.5) biological effective dose of fractionated irradiation equal to 60 Gy conventional fractionation, then received saline solution for five successive days i.p. Group 3 (PIR+RT group) (n=33) received total cranium irradiation, plus 350 mg/kg per day PIR for five successive days i.p. After the last dose of RT, the guinea pigs were all sacrificed at the 4th, 24th and 96th hours, respectively. Their cochleas were enucleated for histopathologic examination. It was observed that total cranium irradiation (RT group) promoted degeneration in stria vascularis (SV), spiral ganglion cells (SG), outer hair cells (OHC) and inner hair cell (IHC) of cochleas at these times (p<0.05). While in the PIR+RT group, there was no statistically significant difference on radiation-induced cochlear degeneration in SV and OHC at 4th (p>0.05) and IHC at 4th, 24th hours (p>0.05), there was a significant difference on radiation-induced cochlear degeneration in SV and OHC at 24th and 96th hours (p<0.05), IHC at 96th hour (p<0.05) and SG at 4th, 24th and 96th hours (p<0.05). There was no any cochlear degeneration in the control group. Piracetam might reduce radiation-induced cochlear damage in the guinea pig. These results are pioneer to studies that will be performed with PIR for radiation toxicity protection.  相似文献   
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