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   376篇
  免费   22篇
  国内免费   1篇
耳鼻咽喉   3篇
儿科学   10篇
妇产科学   10篇
基础医学   21篇
口腔科学   5篇
临床医学   13篇
内科学   88篇
皮肤病学   1篇
神经病学   10篇
特种医学   6篇
外科学   163篇
综合类   4篇
预防医学   13篇
眼科学   6篇
药学   15篇
中国医学   2篇
肿瘤学   29篇
  2023年   3篇
  2022年   12篇
  2021年   13篇
  2020年   8篇
  2019年   17篇
  2018年   21篇
  2017年   7篇
  2016年   12篇
  2015年   13篇
  2014年   46篇
  2013年   31篇
  2012年   59篇
  2011年   53篇
  2010年   19篇
  2009年   10篇
  2008年   11篇
  2007年   4篇
  2006年   6篇
  2005年   8篇
  2004年   6篇
  2003年   3篇
  2002年   5篇
  2001年   2篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1990年   4篇
  1989年   3篇
  1987年   1篇
  1985年   1篇
  1984年   4篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1963年   1篇
排序方式: 共有399条查询结果,搜索用时 15 毫秒
91.

Objective

Black men are more prone to harbor prostate cancer. They are more likely to succumb to this tumor than their White counterparts and may benefit from early detection and treatment. In this study, we assess the nationwide and regional disparity in prostate-specific antigen (PSA) screening for prostate cancer between Black men and non-Hispanic Whites (NHWs).

Methods

A total of 247,079 (weighted 55,185,102) men, aged 40 to 99 years, who responded to the 2012 and 2014 behavioral risk factor surveillance system surveys were used for our analysis. End points consisted of self-reported PSA screening and self-reported nonrecommended PSA screening within 12 months of the interview. The latter was defined as screening in men with <10-year life expectancy. Available sociodemographic variables were used to predict these end points. The independent predictors from multivariate models were used to calculate the adjusted prevalence of PSA screening and nonrecommended PSA screening on a nationwide and regional level. These numbers were calculated for Blacks and NHWs separately and were compared between the 2 groups.

Results

Prevalence of PSA screening was 30.7% in NHWs vs. 28.1% in Blacks (P<0.001). On a region-based analysis, New England, Middle Atlantic, South Atlantic, East North Central, East South Central, West South Central, and Mountain showed a significantly higher rate of PSA screening in NHWs as compared to Blacks (all P<0.001). Middle Atlantic had a significantly higher prevalence of nonrecommended screening in NHWs as compared to Blacks, whereas South Atlantic, West South Central, and Pacific had a significantly higher prevalence of nonrecommended screening in Blacks as compared to NHWs (all P<0.001). Overall, 43 states performed screening more frequently to NHWs, whereas only 8 states performed it more frequently to Black men. The nonrecommended screening was performed more frequently to NHWs in 19 states, whereas 24 states performed it more frequently to Black men.

Conclusion

Our study demonstrates that on a regional-level (and state-level), there are significant racial differences in overall and nonrecommended PSA screening across the United States. Further research is necessary to identify the reasons for the differences and help overcoming it.  相似文献   
92.
Growth was assessed in children following 128 separate kidney transplants using a generalized growth curve multivariate analysis. The height standard deviation score was the dependent variable. Time since transplant, prednisone dosage, and creatinine clearance were the independent variables. For the purposes of comparison patients were grouped according to sex, race, age at transplantation, initial allograft function, acute rejection episodes and the use of cyclosporin A. Patient's height standard deviation scores tended to increase negatively after transplantation. However, children who received transplants before their 7th birthday, with initial allograft function greater than 60 ml/min per 1.73 m2, exhibited catch-up growth. Height standard deviation scores positively improved in males but not in females, as prednisone dosage was decreased. Height standard deviation scores became more negative as renal function decreased after transplantation. Changes in renal function produced the greatest effect upon height in black children, children less than 7 years, and males.  相似文献   
93.
94.

Background

Although therapeutic guidelines recommend the use of neoadjuvant chemotherapy before radical cystectomy (RC) in patients who have muscle-invasive bladder cancer (MIBC), this approach remains largely underused. One of the main reasons for this phenomenon might reside in concerns regarding the risk of morbidity and mortality associated with neoadjuvant chemotherapy.

Objective

To compare perioperative outcomes between patients receiving neoadjuvant chemotherapy and those treated with RC alone.

Design, setting, and participants

Relying on the Surveillance Epidemiology and End Results–Medicare-linked database, 3760 patients diagnosed with MIBC between 2000 and 2009 were evaluated.

Intervention

RC alone or RC plus neoadjuvant chemotherapy.

Outcome measurements and statistical analysis

Complications occurred within 30 and 90 d after surgery. Heterologous blood transfusions (HBTs), length of stay (LoS), readmission, and perioperative mortality were compared. To decrease the effect of unmeasured confounders associated with treatment selection, propensity score–matched analyses were performed.

Results and limitations

Overall, 416 (11.1%) of patients received neoadjuvant chemotherapy. Following propensity score matching, 416 (20%) and 1664 (80%) patients treated with RC plus neoadjuvant chemotherapy and RC alone remained, respectively. The 30-d complication, readmission, and mortality rates were 66.0%, 32.2%, and 5.3%, respectively. The 90-d complication, readmission, and mortality rates were 72.5%, 46.6%, and 8.2%, respectively. When patients were stratified according to neoadjuvant chemotherapy status, no significant differences were observed in the rates of complications, HBT, prolonged LoS, readmission, and mortality between the two groups (all p ≥ 0.1). These results were confirmed in multivariate analyses, where the use of neoadjuvant chemotherapy was not associated with higher risk of 30- and 90-d complications, HBT, prolonged LoS, readmission, and mortality (all p ≥ 0.1). Our study is limited by its retrospective nature.

Conclusions

The use of neoadjuvant chemotherapy is not associated with higher perioperative morbidity or mortality. These results should encourage wider use of neoadjuvant chemotherapy when clinically indicated.

Patient summary

Chemotherapy before radical cystectomy in patients with muscle-invasive bladder cancer does not increase the risk of complications or death. The use of chemotherapy should be strongly encouraged, as recommended by clinical guidelines, given its benefits.  相似文献   
95.
96.
BACKGROUND. Based on epicardial mapping, different mechanisms of termination of reentrant ventricular tachycardia by various pharmacological interventions are described. METHODS AND RESULTS. In 40 Langendorff-perfused rabbit hearts, rings of anisotropic left ventricular epicardium were made by a cryoprocedure. Sustained monomorphic ventricular tachycardia based on continuous circus movement of the impulse around the ring was induced by programmed stimulation. Increasing doses of heptanol (n = 10), potassium (n = 10), tetrodotoxin (n = 6), RP62719 (a new class III drug) (n = 4), flecainide (n = 5), and propafenone (n = 5) were administered to terminate ventricular tachycardia. Epicardial mapping (248 points) was used to study the mechanism of termination of ventricular tachycardia. In 28 of 40 hearts, ventricular tachycardia terminated because the drugs produced complete conduction block of the impulse in a segment of the reentrant pathway. In the remaining 12 hearts (heptanol, n = 2; potassium, n = 3; tetrodotoxin, n = 2; RP62719, n = 2; flecainide, n = 1; and propafenone, n = 2), termination of ventricular tachycardia occurred by collision of the circulating impulse with a spontaneous antidromic wave front reflected within the circuit. This phenomenon occurred when the circulating impulse encountered an arc of functional conduction block that did not extend along the whole width of the ring. As a result, the impulse dissociated into a continuing orthodromic circulating wave and a returning antidromic echo-wave caused by microreentry within the ring. CONCLUSIONS. Independent of their mechanisms of action, sodium channel blockers, electrical uncouplers, and class III drugs terminate reentrant ventricular tachycardia either by complete conduction block or by collision of the impulse with an echo-wave.  相似文献   
97.
OBJECTIVE: The aim was to evaluate the interleukin (IL)‐27 levels in Helicobacter pylori (H. pylori)‐infected patients with gastric ulcer (GU) or duodenal ulcer (DU) and to determine its association with H. pylori virulence factor cytotoxin‐associated gene A (CagA). METHODS: In all, 127 H. pylori infected patients (including 96 DU patients, of whom 61 were anti‐CagA+ and 35 were anti‐CagA) and 31 GU patients (of whom 15 were anti‐CagA+ and 16 were anti‐CagA), 60 asymptomatic (AS) carriers (of whom 30 were anti‐CagA+ and 30 were anti‐CagA) and 30 healthy H. pylori‐negative participants (as a control) were enrolled in the study. Serum concentrations of IL‐27 were measured by the enzyme‐linked immunosorbent assay method. RESULTS: The mean levels of IL‐27 in the GU (44.26 ± 7.12 pg/mL) and DU patients (40.84 ± 3.90 pg/mL) was significantly higher than those observed in the AS carriers (22.06 ± 1.90 pg/mL, P < 0.001) and the control group (18.12 ± 1.68 pg/mL, P < 0.001 and P < 0.002, respectively). In the GU, DU and AS groups the levels of IL‐27 in anti‐CagA+ participants were not significantly differ from that in the anti‐CagA participants. CONCLUSIONS: These results showed that the mean concentration of IL‐27 in H. pylori‐infected peptic ulcer (PU) patients was higher than in AS carriers and the healthy control group. The serum concentrations of IL‐27 were not affected by the CagA factor.  相似文献   
98.
Septum Presents the Optimum Site for Maximal Electrical Separation. Cardiac resynchronization therapy (CRT) benefits selected heart failure (HF) patients. The optimal placement of the right ventricle (RV) lead during biventricular pacing has not been assessed. Greater electrical separation (ES) between left ventricle (LV) and RV leads has been associated with better clinical outcomes. The site of maximal electrical separation(MES) in the RV is unknown. Methods: Prospective study of 50 CRT patients. The LV lead was placed in a postero‐lateral branch of the coronary sinus. ES was recorded at 6 sites within the RV during LV pacing at 600 milliseconds cycle length (CL). The median ES was recorded with a roving deflectable catheter at the RV outflow tract (RVOT), high septum, inflow septum, mid‐septum, apical septum and apex. Results: Mean age was 67 ± 7 years, 39 were male (78%). Thirty had ischemic etiology (60%). Mean left ventricular ejection fraction (LVEF) was 25 ± 7%, QRS duration pre and post was 165 ± 26 milliseconds and 138.5 ± 15.6 milliseconds (P < 0.001). Mapping ES showed a difference between 20 and 50 milliseconds distributed across the RV in the majority of patients (40/49). However, 7 subjects demonstrated delay distribution of between 50 and 82 milliseconds. ES was significant greater in the RV mid‐septum (161.2 ± 23.7 milliseconds) compared with RVOT (154.1 ± 20.8 milliseconds) and apex (148.0 ± 25.5 milliseconds; P < 0.001). The site of Maximal ES was most commonly found at the mid‐septum (40 patients, 80%) and only rarely at the RVOT (5, 10%) and apex (5, 10%; P < 0.01). Conclusion: MES was observed most commonly at the RV septum and rarely at the RV apex. Better correction of electrical and mechanical dyssynchrony by CRT may be achieved by placing the RV lead in a site outside of the apex in the majority of patients. Clinical studies exploring RV septal pacing in CRT seem warranted.  相似文献   
99.
Lasers in Medical Science - Herein, we report the influence of administering different protocols of preconditioned diabetic adipose-derived mesenchymal stem cells (ADSs) with photobiomodulation in...  相似文献   
100.
Lasers in Medical Science - The single and associated impressions of photobiomodulation (PBM) and adipose-derived stem cells (ADS) on stereological parameters (SP), and gene expression (GE) of some...  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