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   1073篇
  免费   28篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   30篇
妇产科学   20篇
基础医学   57篇
口腔科学   15篇
临床医学   233篇
内科学   290篇
皮肤病学   48篇
神经病学   19篇
特种医学   2篇
外科学   89篇
综合类   9篇
一般理论   57篇
预防医学   46篇
眼科学   18篇
药学   149篇
中国医学   1篇
肿瘤学   19篇
  2016年   11篇
  2015年   8篇
  2013年   23篇
  2012年   10篇
  2010年   21篇
  2009年   36篇
  2008年   8篇
  2006年   12篇
  2003年   8篇
  1999年   18篇
  1998年   36篇
  1997年   50篇
  1996年   54篇
  1995年   45篇
  1994年   37篇
  1993年   39篇
  1992年   34篇
  1991年   34篇
  1990年   35篇
  1989年   24篇
  1988年   30篇
  1987年   24篇
  1986年   22篇
  1985年   23篇
  1984年   26篇
  1983年   22篇
  1982年   16篇
  1981年   14篇
  1980年   30篇
  1979年   24篇
  1978年   15篇
  1977年   15篇
  1976年   15篇
  1975年   8篇
  1972年   10篇
  1971年   12篇
  1970年   11篇
  1967年   9篇
  1966年   16篇
  1965年   7篇
  1964年   8篇
  1963年   14篇
  1962年   11篇
  1961年   7篇
  1959年   15篇
  1958年   11篇
  1957年   13篇
  1956年   8篇
  1954年   11篇
  1948年   7篇
排序方式: 共有1103条查询结果,搜索用时 109 毫秒
41.
42.
Comparing ICD Implantation with and Without Intraoperative Defibrillation Testing. Introduction: The need to perform defibrillation testing (DT) at the time of implantable cardioverter defibrillator (ICD) insertion is controversial. In the absence of randomized trials, some regions now perform more than half of ICD implants without DT. Methods: During the last year of enrolment in the Resynchronization for Ambulatory Heart Failure Trial, a substudy randomized patients to ICD implantation with versus without DT. Results: Among 252 patients screened, 145 were enrolled; 75 randomized to DT and 70 to no DT. Patients were similar in terms of age (65.9 ± 9.3 years vs 67.9 ± 8.9 years); LVEF (24.7 ± 4.6% vs 23.6 ± 4.6%), QRS width (154.8 ± 23.5 vs 155.8 ± 23.6 ms), and history of atrial fibrillation (5% vs 6%). All 68 patients in the DT arm tested according to the protocol achieved a successful DT (≤25 J); 96% without requiring any system modification. No patient experienced perioperative stroke, myocardial infarction, heart failure (HF), intubation or unplanned ICU stay. The length of hospital stay was not prolonged in the DT group: 20.2 ± 26.3 hours versus 21.3 ± 23.0 hours, P = 0.79. One patient in the DT arm had a failed appropriate shock and no patient suffered an arrhythmic death. The composite of HF hospitalization or all‐cause mortality occurred in 10% of patients in the no‐DT arm and 19% of patients in the DT arm (HR = 0.53, 95% CI: 0.21–1.31, P = 0.14). Conclusions: In this randomized trial, perioperative complications, failed appropriate shocks, and arrhythmic death were all uncommon regardless of DT. There was a nonsignificant increase in the risk of death or HF hospitalization with DT. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1313‐1316, December 2012)  相似文献   
43.
The immunohistochemical expression of p53 and c-erbB-2 gene proteins was examined in a series of 130 breast adenocarcinomas. This study intended to investigate whether the frequency of the altered expression of the tumour suppressor gene p53 and the overexpression of the oncogene c-erbB-2 in breast cancer tissue cells correlated with other variables known to affect the biological behaviour of these tumours and the overall survival of the patients (median follow-up time: 6 years). The expression of p53 protein and c-erbB-2 gene product was evaluated immunohistochemically. Expression of p53 protein was detected in 30 (23 per cent) of the neoplasms examined, while 26 (20 per cent) out of the 130 cases demonstrated positive c-erbB-2 immunoreactivity. There was a statistically significant association between p53 protein expression and primary tumour size, lymph node involvement, and oestrogen receptor positivity. The incidence of c-erbB-2 positivity was significantly correlated with high tumour grade, axillary node invasion, large tumour size, and the absence of steroid receptors. p53 immuno-expression was clearly associated with c-erbB-2 protein overexpression. Concomitant p53 and c-erbB-2 positive immunolabelling, which emerged in 14 out of the 130 cases (10·7 per cent), was clearly associated with high grade, large size, positive nodal status, ductal infiltrating (NOS) histological type, and low values of progesterone receptors. Overall survival of patients was not significantly related to the immunoreactivity of either p53 or c-erbB-2 considered separately, whereas there was a clearly significant trend to worse overall prognosis in cancers with double p53/c-erbB-2 positive phenotype. The simultaneous immunodetection of p53/c-erbB-2 appears to have greater negative prognostic relevance than their separate expression.  相似文献   
44.
Background: Ablation of ventricular tachycardia (VT) reduces implantable cardioverter defibrillator shocks. Intracardiac ultrasound (ICE) can visualize and quantify the function of all left ventricular wall segments. We thus hypothesized that ICE could identify scar tissue and provide a guide to facilitate substrate‐guided VT ablation. Methods: Eighteen patients underwent VT ablation with real time ICE mapping from the right atrium and ventricle with online 3D‐image reconstruction of scar segments. The left ventricle was also scar mapped by traditional electroanatomic mapping (CARTO) for comparison. Images from these 2 scar mapping techniques were compared to each other as well as to a preprocedure transthoracic echocardiogram. Results: The average age was 65 ± 12 years and 12 (67%) were male (15 [83%] had ischemic cardiomyopathy). Two patients (12%) had recurrence of their clinical VT (1 remained on an antiarrhythmic medication, the other had a repeat ablation) over a follow‐up of 127 ± 33 days. No periprocedural or long‐term adverse events occurred. A total of 248 wall segments were analyzed. All 3 modalities were concordant in scar identification in 193 (78%) segments. The ICE segments correlated with the electroanatomic map in 213 (86%) segments versus 198 (80%), which correlated with transthoracic echocardiography and electroanatomic mapping (P = 0.046). Specifically, the ICE wall motion scores were closer to the electroanatomic mapping in the basal segments and showed a higher accuracy in ischemic heart disease. Conclusion: These data demonstrate that real time ICE images provide accurate chamber geometries and scar boundaries of the left ventricle. These scar borders were more accurate than transthoracic echocardiography and illustrate the feasibility of ICE for substrate‐based ablation for VT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 678‐684, June 2010)  相似文献   
45.
46.
Suicidal ideation amongst acutely medically ill and continuing care geriatric inpatients has not been examined previously. Data from two pooled depression prevalence studies on acute geriatric wards and one such study on continuing care geriatric wards were re-examined. The Brief Assessment Schedule (BAS) measured depression. It also contains items measuring feelings of life not worth living, suicidal ideation and pessimism. The prevalence of feelings of life not worth living, suicidal ideation and pessimism were 29%, 13% and 50%, respectively, in the acute sample, 33%, 26% and 52%, respectively, in the continuing care sample, and 38%, 29% and 55%, respectively, in the continuing care dementia sub-sample. These three variables were significantly inter-correlated, and they were associated with BAS depression scores and caseness in both the acute and continuing care sample. Feelings of life not worth living, suicidal ideation and pessimism are not uncommon in this population. Findings of this study require replication and implications for further avenues of research are discussed.  相似文献   
47.
48.
BENIGN ORGASMIC CEPHALGIA   总被引:3,自引:0,他引:3  
  相似文献   
49.
50.
Determination of Lymphocyte Turnover by Continuous Infusion of H3 Thymidine   总被引:12,自引:0,他引:12  
The use of an osmotic pump for continuous infusion of H3 thymidine in ratsis described. Estimates of turnover times of cells in the peripheral blood are4 days for granulocytes, 60 days for large lymphocytes and in excess of 100days for small lymphocytes. These turnover times include initial delay in release or maturation after the last mitosis in the marrow or nodes, and anytime spent outside the circulation prior to final disappearance of a given cellfrom the peripheral blood. The data exclude reutilization as an explanationfor the observed longevity of lymphocytes.

Accepted on November 7, 1961  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