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   2193篇
  免费   100篇
  国内免费   9篇
耳鼻咽喉   23篇
儿科学   81篇
妇产科学   33篇
基础医学   338篇
口腔科学   96篇
临床医学   115篇
内科学   399篇
皮肤病学   30篇
神经病学   246篇
特种医学   111篇
外科学   255篇
综合类   14篇
一般理论   2篇
预防医学   187篇
眼科学   21篇
药学   200篇
中国医学   9篇
肿瘤学   142篇
  2023年   11篇
  2022年   23篇
  2021年   47篇
  2020年   39篇
  2019年   43篇
  2018年   47篇
  2017年   51篇
  2016年   33篇
  2015年   68篇
  2014年   83篇
  2013年   90篇
  2012年   175篇
  2011年   161篇
  2010年   91篇
  2009年   79篇
  2008年   156篇
  2007年   178篇
  2006年   150篇
  2005年   150篇
  2004年   138篇
  2003年   145篇
  2002年   135篇
  2001年   16篇
  2000年   13篇
  1999年   16篇
  1998年   14篇
  1997年   23篇
  1996年   12篇
  1995年   7篇
  1994年   9篇
  1993年   7篇
  1992年   10篇
  1991年   3篇
  1990年   2篇
  1989年   5篇
  1988年   9篇
  1987年   2篇
  1986年   3篇
  1985年   7篇
  1984年   4篇
  1983年   6篇
  1982年   7篇
  1981年   4篇
  1980年   5篇
  1979年   4篇
  1975年   4篇
  1974年   2篇
  1969年   4篇
  1968年   2篇
  1922年   2篇
排序方式: 共有2302条查询结果,搜索用时 31 毫秒
71.

Background  

Glioblastoma remains one of the most devastating human malignancies, and despite therapeutic advances, there are no drugs that significantly improve the patient survival. Altered expression of the Aurora kinases was found in different malignancies, and their inhibition has been studied in cancer therapy. In this study, we analyzed the expression of Aurora A and Aurora B in glioblastoma samples and also analyzed whether the effects of Aurora kinase inhibition were associated with temozolomide or not on cell lines and primary cultures of glioblastoma.  相似文献   
72.

OBJECTIVE:

There are several treatments for obstructive sleep apnea syndrome, such as weight loss, use of an oral appliance and continuous positive airway pressure, that can be used to reduce the signs and symptoms of obstructive sleep apnea syndrome. Few studies have evaluated the effectiveness of a physical training program compared with other treatments. The aim of this study was to assess the effects of physical exercise on subjective and objective sleep parameters, quality of life and mood in obstructive sleep apnea patients and to compare these effects with the effects of continuous positive airway pressure and oral appliance treatments.

METHODS:

Male patients with moderate to severe obstructive sleep apnea and body mass indices less than 30 kg/m2 were randomly assigned to three groups: continuous positive airway pressure (n = 9), oral appliance (n = 9) and physical exercise (n = 7). Polysomnographic recordings, blood samples and daytime sleepiness measurements were obtained prior to and after two months of physical exercise or treatment with continuous positive airway pressure or an oral appliance. Clinicaltrials.gov: NCT01289392

RESULTS:

After treatment with continuous positive airway pressure or an oral appliance, the patients presented with a significant reduction in the apnea-hypopnea index. We did not observe changes in the sleep parameters studied in the physical exercise group. However, this group presented reductions in the following parameters: T leukocytes, very-low-density lipoprotein and triglycerides. Two months of exercise training also had a positive impact on subjective daytime sleepiness.

CONCLUSIONS:

Our results suggest that isolated physical exercise training was able to modify only subjective daytime sleepiness and some blood measures. Continuous positive airway pressure and oral appliances modified the apnea-hypopnea index.  相似文献   
73.
IntroductionInhibition of platelet aggregation appears two hours after the first dose of clopidogrel, becomes significant after the second dose, and progresses to a steady-state value of 55% by day seven. Low response to clopidogrel has been associated with increased risk of stent thrombosis and ischemic events, particularly in the context of stable heart disease treated by percutaneous coronary intervention.ObjectiveTo stratify medium-term prognosis of an acute coronary syndrome (ACS) population by platelet aggregation.MethodsWe performed a prospective longitudinal study of 70 patients admitted for an ACS between May and August 2009. Platelet function was assessed by ADP-induced platelet aggregation using a commercially available kit (Multiplate® analyzer) at discharge. The primary endpoint was a combined outcome of mortality, non-fatal myocardial infarction, or unstable angina, with a median follow-up of 136.0 (79.0–188.0) days.ResultsThe median value of platelet aggregation was 16.0 U (11.0–22.5 U) with a maximum of 41.0 U and a minimum of 4.0 U (normal value according to the manufacturer: 53–122 U). After ROC curve analysis with respect to the combined endpoint (AUC 0.72), we concluded that a value of 18.5 U conferred a sensitivity of 75.0% and a specificity of 68% to that result. We therefore created two groups based on that level: group A – platelet aggregation <18.5 U, n = 44; and group B – platelet aggregation ≥18.5 U, n = 26. The groups were similar with respect to demographic data (age 60.5 [49.0–65.0] vs. 62.0 [49.0–65.0] years, p = 0.21), previous cardiovascular history, and admission diagnosis. There were no associations between left ventricular ejection fraction, GRACE risk score, or length of hospital stay and platelet aggregation. The groups were also similar with respect to antiplatelet, anticoagulant, proton pump inhibitor (63.6 vs. 46.2%, p = 0.15) and statin therapy. The variability in platelets and hemoglobin was also similar between groups. Combined event-free survival was higher in group A (96.0 vs. 76.7%, log-rank p < 0.01). Platelet aggregation higher than 18.5 U was an independent predictor of the combined event (HR 6.75, 95% CI 1.38–32.90, p = 0.02).ConclusionIn our ACS population platelet aggregation at discharge was a predictor of medium-term prognosis.  相似文献   
74.
75.
IntroductionSeveral presentations of neurologic complications caused by JC virus (JCV) in human immunodeficiency virus (HIV)-infected patients have been described and need to be distinguished from the “classic” form of progressive multifocal leukoencephalopathy (PML). The objectives of this study were: 1) to describe the spectrum and frequency of presentations of JCV-associated central nervous system (CNS) diseases; 2) identify factors associated with in-hospital mortality of patients with JCV-associated CNS disease; and 3) to estimate the overall mortality of this population.Material and methodsThis was a retrospective study of HIV-infected patients admitted consecutively for JCV-associated CNS diseases in a referral teaching center in Sao Paulo, Brazil, from 2002 to 2007. All patients with laboratory confirmed JCV-associated CNS diseases were included using the following criteria: compatible clinical and radiological features associated with the presence of JCV DNA in the cerebrospinal fluid. JCV-associated CNS diseases were classified as follows: 1) classic PML; 2) inflammatory PML; and 3) JC virus granule cell neuronopathy (GCN).ResultsWe included 47 cases. JCV-associated CNS diseases were classified as follows: 1) classic PML: 42 (89%); 2) inflammatory PML: three (6%); and 3) JC virus GCN: four (9%). Nosocomial pneumonia (p = 0.003), previous diagnosis of HIV infection (p = 0.03), and imaging showing cerebellar and/or brainstem involvement (p = 0.02) were associated with in-hospital mortality. Overall mortality during hospitalization was 34%.ConclusionsNovel presentations of JCV-associated CNS diseases were observed in our setting; nosocomial pneumonia, previous diagnosis of HIV infection, and cerebellar and/or brainstem involvement were associated with in-hospital mortality; and overall mortality was high.  相似文献   
76.

Background

Laparoscopy combined with an enhanced recovery pathway (ERP) is widely considered to be the first-choice option for patients with colorectal cancer. However, no previous reports have focused on patients with Crohn’s disease (CD) treated by laparoscopy and ERP.

Methods

Twenty patients with CD underwent laparoscopic ileocecal resection with an ERP at two institutions. The ERP protocol included no bowel preparation nor fasting, no nasogastric tube, no abdominal drains, early removal of urinary catheter, early solid dietary intake and mobilization, opioid-sparing analgesia and restrictive fluid management. This group was compared with a matched historical control group of 70 CD patients who underwent laparoscopic ileocecal resection treated with conventional care.

Results

Compliance with the ERP was high (≥80 %) for all items except no drain placement. A significantly earlier return of bowel function (time to first flatus and stool) was observed in the ERP group. Mean postoperative and total length of stay were significantly shorter in the ERP group. Postoperative complications were similar in both groups.

Conclusions

This is the first reported experience of laparoscopy with ERP in CD patients and suggests that optimized perioperative care combined with minimally invasive techniques may lead to further improvements in surgical outcomes for CD patients.  相似文献   
77.
78.
International Journal of Mental Health and Addiction - The presence of COVID-19 has had psychological consequences among health personnel; these include fear, anxiety, and depression. In the...  相似文献   
79.
Leishmania (Viannia) braziliensis, a protozoan parasite widespread in the New World, is responsible for the infection of different mammal orders, including humans. This species is considered to be a major etiological agent of American cutaneous leishmaniasis. A proteomic study was carried out to identify proteins expressed by L. (V.) braziliensis. One hundred and one spots representing 75 protein entries were identified by MALDI-TOF-TOF. Isoelectric point values estimated by gel electrophoresis matched closely with predicted values, although some discrepancies existed suggesting that post-translational protein modifications may be common in L. braziliensis. Moreover, 20 hypothetical proteins were experimentally identified. Identified proteins were classified into 15 groups according to biological process. Among the proteins identified, approximately 40% have not been previously reported in a proteomic map of Leishmania. In addition, a number of potential virulence factors and drug targets were identified in this protein map, including some proteins associated with the metastatic phenotype. This study describes the first compilation of a proteomic reference map for L. braziliensis (pI 4-7, M(r) 10-130 kDa) and provides a very useful tool for comparative studies of strains isolated from patients presenting different clinical manifestations of leishmaniasis as well as a potential tool to identify markers for clinical diagnosis, therapeutics, and prognosis.  相似文献   
80.
In order to characterize components of the metabolic syndrome (MS) in Venezuelan black Hispanics and compare these metabolic abnormalities with those found in the predominant mixed Hispanic population, 2336 mixed Hispanics (69% women) and 281 black Hispanics (60% women), aged 20-78 years, without prior history of diabetes and/or cardiovascular disease were evaluated in a population-based study in Zulia State, Venezuela. Blood pressure (BP), waist circumference, as well as fasting insulin, fasting blood glucose (FBG), triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C) levels were measured. The criteria proposed by the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) to identify those with metabolic abnormalities were used. We found that black Hispanics showed higher frequency of age-adjusted elevated BP than mixed Hispanics in both men (66.9% vs. 52.3%, p < 0.01) and women (39.3% vs. 30.4%, p < 0.05). In men, elevated FBG was also more frequent in black Hispanics (32.7%) than in mixed Hispanics (22.3%), despite the lack of significant differences in fasting insulin, HOMA-insulin resistance and HOMA-beta cell function values. In women low HDL-C and higher abdominal obesity were more common in black Hispanics (71.8% and 54.1%, respectively) than in mixed Hispanics (56.2% and 44.5%, respectively), despite the greater frequency of high TG in mixed Hispanics (22.6%) when compared to black Hispanics (13.3%). Furthermore, in logistic regression analysis black Hispanic race was independently associated with higher risk for hypertension, fasting hyperglycemia, and low HDL-C. These results suggest that black Hispanics have worse cardiovascular risk profile than mixed Hispanics in Zulia State, with higher BP, higher FBG, more abdominal obesity, and lower HDL-C. Identification and intervention of these high-risk subjects are important strategies for diabetes and cardiovascular disease prevention in Venezuela.  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