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   669篇
  免费   33篇
  国内免费   6篇
耳鼻咽喉   17篇
儿科学   31篇
妇产科学   10篇
基础医学   48篇
口腔科学   17篇
临床医学   41篇
内科学   185篇
皮肤病学   5篇
神经病学   24篇
特种医学   15篇
外科学   144篇
综合类   4篇
预防医学   69篇
眼科学   29篇
药学   44篇
肿瘤学   25篇
  2024年   1篇
  2023年   4篇
  2022年   15篇
  2021年   30篇
  2020年   22篇
  2019年   16篇
  2018年   28篇
  2017年   17篇
  2016年   11篇
  2015年   14篇
  2014年   27篇
  2013年   43篇
  2012年   37篇
  2011年   64篇
  2010年   31篇
  2009年   34篇
  2008年   50篇
  2007年   48篇
  2006年   44篇
  2005年   44篇
  2004年   40篇
  2003年   33篇
  2002年   25篇
  2001年   7篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1996年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1974年   1篇
排序方式: 共有708条查询结果,搜索用时 15 毫秒
61.
62.
63.
BACKGROUND: Prognostic information in peripheral arterial disease (PAD) may provide the basis for optimal management strategies at an early stage. This study aimed to develop a prognostic risk index for long-term mortality in patients with PAD. METHODS: In a single-center observational cohort study, 2642 patients with an ankle-brachial index of 0.90 or lower were randomly divided into derivation (n = 1332) and validation (n = 1310) cohorts. Cox regression analysis with stepwise backward elimination identified predictors of 1-year, 5-year, and 10-year mortality in the derivation cohort. Weighted points were assigned to each predictor. Index discrimination was determined in both the derivation and validation cohorts. RESULTS: During 10 years of follow-up, 42.2% and 40.4% of patients died in the derivation and validation cohorts, respectively. The risk index for 10-year mortality (+ points) included renal dysfunction (+12), heart failure (+7), ST-segment changes (+5), age greater than 65 years (+5), hypercholesterolemia (+5), ankle-brachial index lower than 0.60 (+4), Q-waves (+4), diabetes (+3), cerebrovascular disease (+3), and pulmonary disease (+3). Statins (-6), aspirin (-4), and beta-blockers (-4) were associated with reduced 10-year mortality. Patients were stratified into low (<0 points), low-intermediate (0-5 points), high-intermediate (6-9 points), and high (>9 points) risk categories, according to risk score. Ten-year mortality rates were 22.1%, 32.2%, 45.8%, and 70.4%, respectively (P < .001) and comparable to mortality in the validation cohort. C statistics demonstrated good discrimination in both the derivation (0.72) and validation cohorts (0.73). CONCLUSIONS: A prognostic risk index for long-term mortality stratified patients with PAD into different risk categories. This may be useful for risk stratification, patient counseling, and medical decision making.  相似文献   
64.
AIMS: Statins have been suggested to prevent haematological malignancies. Several epidemiological studies have evaluated this association, while randomized controlled trials (RCTs) on cardiovascular outcomes have provided relevant data as secondary end-points. Our aim was to examine the strength of this association through a detailed meta-analysis of the studies published in peer-reviewed literature. METHODS: A comprehensive search for articles published up to December 2006 was performed, reviews of each study were conducted and data abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the random effects model. RESULTS: Fourteen studies (six RCTs, seven case-control and one cohort study) contributed to the analysis. Studies were grouped on the basis of study design, and two separate meta-analyses were conducted. There was no evidence of an association between statin use and haematological malignancies among either RCTs (RR = 0.92, 95% CI 0.72, 1.16) or the observational studies (RR = 0.83, 95% CI 0.53, 1.29). Similarly, we found no evidence of publication bias. However, high heterogeneity was detected among the observational studies. CONCLUSION: Our meta-analysis findings do not support a potential role of statins in the prevention of haematological malignancies.  相似文献   
65.
The aim of this study was to assess whether cardiac auscultation performed by pediatric trainees and neonatologists can reliably distinguish innocent from pathologic heart murmurs in asymptomatic neonates. From January 2008 to April 2009 the pediatric trainees of our institution were requested to refer all asymptomatic neonates with a murmur and classify the murmurs as ??innocent,?? ??pathologic,?? or ??possibly pathologic.?? Prior to echocardiography, each neonate was evaluated by two experienced neonatologists. The echocardiographic studies of 169 neonates were analyzed. Abnormal cardiac anatomy was found in 55 neonates (32.6%). The overall ability of pediatric trainees in identifying congenital heart disease (CHD) was moderate [area under the curve (AUC)?=?0.855] and significantly lower compared to neonatologists (AUC?=?0.919, p?=?0.007). However, at ??lower?? levels of clinical confidence (i.e., clinical diagnosis of possibly pathologic murmurs), pediatric trainees had good ability in excluding CHD (sensitivity 94.6%; negative likelihood ratio?=?0.09). The ability of cardiac auscultation for diagnosing CHD in asymptomatic neonates is limited and dependent on the physician??s experience and level of clinical confidence. Echocardiography should remain an option for all neonates with a possibly pathologic murmur.  相似文献   
66.
Graefe's Archive for Clinical and Experimental Ophthalmology - To develop a fully automated algorithm for accurate detection of fovea location in atrophic age-related macular degeneration...  相似文献   
67.
BACKGROUND: Radical cystoprostatectomy and radical prostatectomy are the two major operations where prostate is totally and radically removed. Radical cystoprostatectomy is usually performed in patients with invasive bladder cancer. The aim of the study was to examine Total PSA, Free PSA, and Free/Total Ratio elimination kinetics after radical cystoprostatectomy. METHODS: Serum PSA, Free PSA, and Free/Total Ratio were determined preoperatively, at the time of cystoprostatectomy specimen removal and then at 3, 6, 12, 24, 48, 72, and 168 hr, from seven patients with muscle invasive bladder cancer, who underwent radical cystoprostatectomy. Free and Total PSA concentrations were measured with non-competitive immunological procedures. The elimination rates and half-lives of Total, Free PSA and Free/Total Ratio were studied using a nonlinear regression analysis. RESULTS: Surgical manipulations caused about 1.5-fold increase of PSA, 5-fold increase in Free PSA and 3-fold increase in Free/Total Ratio. PSA and Free PSA followed a biphasic elimination pattern of a rapid exponential (a) phase with a half-life of 4.27 and 2.14 hr and a terminal, nonexponential (b) phase with a half-life of 63 and 173.2 hr, respectively. Free/Total PSA Ratio followed, also, a biphasic kinetic pattern of a rapid exponential decline with a half-life of 3.34 and a terminal non-exponential increase with a doubling time of 43 hr. CONCLUSIONS: Comparing PSA kinetics after radical cystoprostatectomy with those of radical prostatectomy, it appears that PSA follows the same elimination pattern in both models. In contrast, Free PSA and Free/Total Ratio elimination kinetics' patterns differ between the two surgical models.  相似文献   
68.
69.
RATIONALE AND HYPOTHESIS: Acute lung injury is a frequent complication of severe sepsis or blood loss and is often associated with an excessive inflammatory response requiring mechanical ventilation. We tested the hypothesis that the types of fluids used during early resuscitation have an important effect on the evolution of lung injury. METHODS: Rats were subjected to either hemorrhage or endotoxemia for 1 hr, followed by resuscitation to a controlled mean blood pressure with Ringer's lactate, 5% albumin, or 25% albumin for 1 hr. After resuscitation, blood cytokine levels were measured. The lung was then excised and ventilated with a tidal volume of 30 mL/kg for 2 hrs. RESULTS: The volume of fluids required was significantly smaller in the albumin-treated groups than in the Ringer's lactate groups. In the hemorrhagic shock model, plasma concentrations of tumor necrosis factor-alpha, interleukin-6, and macrophage inflammatory protein-2 were significantly lower and interleukin-10 was significantly higher in the albumin-treated groups compared with the Ringer's lactate-treated group. The levels of tumor necrosis factor-alpha and macrophage inflammatory protein-2 in bronchoalveolar lavage fluid were lower and interleukin-10 was higher in the albumin-treated groups than in the Ringer's lactate group. The decreased cytokine production was associated with a reduction of hydrogen peroxide formation with albumin resuscitation. The lung wet/dry ratio was lower in the 5% albumin (0.54 +/- 0.01) and 25% albumin (0.55 +/- 0.02) groups than in the Ringer's lactate group (0.62 +/- 0.02; both p <.05). These effects of albumin seen in the hemorrhagic shock model were not observed in the endotoxic shock model. CONCLUSIONS: We conclude that resuscitation with albumin may have utility in reducing ventilator-induced lung injury after hemorrhagic shock, but not after endotoxic shock. These findings suggest that the mechanisms leading to ventilator-induced lung injury after hemorrhage differ from those after endotoxemia.  相似文献   
70.
OBJECTIVES: The objective of this study was to evaluate the association of high plasma levels of either C-reactive protein (CRP), lipoprotein (a) (Lp[a]) or total homocysteine (tHCY) with the long-term prognosis after successful coronary stenting (CS). BACKGROUND: High plasma levels of either CRP, Lp(a) or tHCY may have an impact in coronary artery disease. However, long-term prospective data after coronary stenting (CS) are limited. METHODS: Four-hundred and eighty-three consecutive patients with either stable or unstable coronary syndromes were followed for up to three years after successful CS. The composite of cardiac death, myocardial infarction or rehospitalization for rest unstable angina, whichever occurred first, was the prespecified primary end point. Moreover, the one-year incidence of clinical recurrence of symptoms, in-stent restenosis (ISR) and progression of atherosclerosis to a significant lesion (PTSL) were additionally evaluated. PTSL was defined as an increase by at least 25% in the luminal diameter stenosis of a known nonsignificant lesion (or=70% luminal diameter stenosis). RESULTS: By the end of the follow-up, high plasma levels of either CRP or Lp(a) but not tHCY were independently associated with the primary end point. In particular, CRP >or=0.68 mg/dl (p < 0.001) or Lp(a) >or=25 mg/dl (p = 0.003) conferred a significantly increased risk. By 1 year, a CRP >or=0.68 mg/dl conferred a significantly increased risk for clinical recurrence of symptoms (p < 0.001) or PTSL (p < 0.001). None of the studied biochemical markers was related to ISR. CONCLUSIONS: High plasma levels of either CRP or Lp(a) but not tHCY may be associated with a higher incidence of late adverse events after successful CS. PTSL in vessels not previously intervened upon may play a significant role in the underlying pathophysiology as opposed to ISR.  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