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   30029篇
  免费   1619篇
  国内免费   405篇
耳鼻咽喉   53篇
儿科学   1721篇
妇产科学   277篇
基础医学   1983篇
口腔科学   16篇
临床医学   3901篇
内科学   6809篇
皮肤病学   46篇
神经病学   1597篇
特种医学   2187篇
外科学   2262篇
综合类   5233篇
预防医学   2023篇
眼科学   27篇
药学   2488篇
  27篇
中国医学   738篇
肿瘤学   665篇
  2024年   37篇
  2023年   389篇
  2022年   1009篇
  2021年   1156篇
  2020年   994篇
  2019年   823篇
  2018年   842篇
  2017年   819篇
  2016年   952篇
  2015年   967篇
  2014年   2143篇
  2013年   1937篇
  2012年   1956篇
  2011年   2011篇
  2010年   1593篇
  2009年   1575篇
  2008年   1556篇
  2007年   1661篇
  2006年   1474篇
  2005年   1212篇
  2004年   919篇
  2003年   751篇
  2002年   609篇
  2001年   620篇
  2000年   488篇
  1999年   431篇
  1998年   368篇
  1997年   335篇
  1996年   232篇
  1995年   275篇
  1994年   251篇
  1993年   189篇
  1992年   171篇
  1991年   150篇
  1990年   131篇
  1989年   125篇
  1988年   116篇
  1987年   101篇
  1986年   86篇
  1985年   103篇
  1984年   89篇
  1983年   30篇
  1982年   75篇
  1981年   56篇
  1980年   50篇
  1979年   47篇
  1978年   36篇
  1977年   37篇
  1976年   22篇
  1974年   14篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
目的 系统分析痰热清注射液治疗血液肿瘤合并肺部感染的有效性与安全性,为制订临床治疗策略提供依据。 方法 系统检索CBM、CNKI、维普、万方、Pubmed及Embase数据库,采用Cochrane协作网RCT质量评价标准评价纳入研究质量,Meta分析对提取的数据进行分析。 结果 纳入4个随机对照研究,血液肿瘤并肺部感染335例,痰热清注射液治疗组175例,抗生素治疗组160例,纳入研究质量一般; Meta分析合并ORMD值分别为临床总体疗效1.05(0.92~1.20)、临床治愈0.93(0.68~1.26)、临床显效1.33(0.73~2.42)及临床有效1.00(0.74~1.33)、平均退热时间-0.06(-0.38~0.26)、平均肺部啰音消失时间0.21(-0.33~0.75)、肺部阴影缓解时间0.18(-0.19~0.54)、细菌阳性率1.02(0.45~2.33)及细菌清除率0.95(0.77~1.17), 指标差异均无统计学意义(P>0.05)。 结论 单独使用痰热清注射液治疗血液肿瘤并肺部感染的临床疗效、症状体征缓解及细菌清除效果较好,可能与单独使用抗生素效果相当,安全性较好,但尚需高质量证据予以进一步证实。  相似文献   
992.
Antisynthetase syndrome (AS) is a rare disease that affects patients with inflammatory myopathies such as polymyositis (PM) and dermatomyositis (DM). In patients with AS, up to 95% of patients develop antisynthetase syndrome-associated interstitial lung disease (AS-ILD). Although AS-ILD commonly occurs in patients with a well-established diagnosis of AS, it can be the first or only manifestation of an occult AS. The frequency of interstitial lung disease (ILD), myopathy, and skin involvement are often dependent on the type of myositis-specific antibodies present. AS-ILD patients who are positive for both anti-Jo-1 and anti-SSA/RO-52 autoantibodies often present with a severe degree of lung restriction on pulmonary function tests and radiologic imaging with an inadequate response toward immunosuppressive therapies. We describe a 65-year-old woman who presents with chronic dyspnea. She was initially diagnosed with corticosteroid-resistant cryptogenic organizing pneumonia based on the radiological findings on her CT chest. Her symptoms did not improve, and she suffered from intolerable corticosteroid-related side effects. Reviews of systems were positive for arthritis and Raynaud's phenomenon. She was found to have elevated inflammatory markers and autoantibodies such as anti-Jo-1, anti-RO-52, and anti-SSA. A diagnosis of AS-ILD resistant to corticosteroid therapy was made. Her lung function improved with combination therapy of mycophenolate and rituximab. Our case highlights that a detailed history and physical exam, compatible radiologic imaging, and autoantibodies are essential for the diagnosis of AS-ILD.  相似文献   
993.
Aspergillus species are ubiquitous in the environment. Aspergillosis is acquired by inhalation of Aspergillus spores. In normal hosts, spore inhalation rarely causes lung disease. Pulmonary Aspergillosis covers a wide spectrum of clinical syndromes depending on the interaction between Aspergillus and the host (immune-status, prior bronchopulmonary disease). It runs the gamut from invasive Aspergillosis to Aspergillus bronchitis. Invasive Aspergillosis usually occurs in severely immunocompromised patients, typically in neutropenic but also in non-neutropenic patients. Chronic pulmonary Aspergillosis affects patients with chronic structural lung disease such as COPD or previous mycobacterial lung disease, but without other significant immunocompromise. Aspergillus bronchitis affects patients with bronchial disease such as bronchiectasis. Allergic bronchopulmonary Aspergillosis affects patients with bronchial asthma or cystic fibrosis, and is due to an allergic response to Aspergillus.  相似文献   
994.
BackgroundComputed Tomography (CT) Pulmonary Angiography is the most commonly used diagnostic study for acute pulmonary embolism (PE). Echocardiogram (ECHO) is also used for risk stratification in acute PE, however the diagnostic performance of CT versus ECHO for risk stratification remains unclear.MethodsCT and ECHO right ventricle (RV) and left ventricle (LV) diameters were measured in a retrospective cohort of patients with acute PE. RV:LV diameter ratios were calculated and correlation between CT and ECHO RV:LV ratio was assessed. Sensitivity and specificity for the composite adverse events endpoint of mortality, respiratory failure requiring intubation, cardiac arrest, or shock requiring vasopressors within 30 days of admission were assessed for CT or ECHO derived RV:LV ratio alone and in combination with biomarkers (troponin or B-type natriuretic peptide).ResultsA total of 74 subjects met the inclusion criteria and had a mean age of 62±18 years. The proportion of patients with RV:LV >1 was similar when comparing CT (37.8%) versus ECHO (33.8%) (P = 0.61). A statistically significant correlation was found between CT derived and ECHO derived RV:LV diameter ratio (r = 0.832, P < 0.001). The sensitivity and specificity to predict 30-day composite adverse events for CT versus ECHO derived RV:LV diameter ratio >1 together with positive biomarker status was similar with sensitivity and specificity of 87% and 41% versus 87% and 42%, respectively.ConclusionsIn patients with acute PE, CT and ECHO RV:LV diameter ratio correlate well and identify similar proportion of PE patients at risk for early adverse events. These findings may streamline risk stratification of patients with acute PE.  相似文献   
995.
Hydrostatic pulmonary edema is a well-known complication of veinoarterial extracorporeal membrane oxygenation (VA-ECMO) caused by increased left ventricle afterload due to reverse blood flow in the aorta. Several techniques are commonly used for left ventricle venting such as intra-aortic balloon pump, Impella® (Abiomed, Danvers, MA), central surgical cannulation or Rahskind atrial septostomy. We reported two cases of hydrostatic pulmonary edema in patients under VA-ECMO for whom it was decided to perform Rashkind technique. The first is a late anterior myocardial infarction complicated with cardiac arrest and cardiogenic shock. Refractory hypoxemia due to hydrostatic pulmonary edema conducted us to perform atrial septostomy. The second case is a refractory cardiogenic shock due to left main stent thrombosis myocardial infarction. Procedural transesophageal echocardiography revealed a large left atrial thrombus extended to pulmonary veins preventing the procedure. These two cases illustrate the importance and gravity of pulmonary edema induced by VA-ECMO. The first shows that this technique is feasible, allows great left ventricle unloading and improves hypoxemia. The second underlines the interest of performing transesophageal echocardiography to look for pulmonary veins thrombosis that can take part in the elevation of hydrostatic pressure and forbid Rashkind manoeuver.  相似文献   
996.
Background and objectiveChronic Obstructive Pulmonary Disease (COPD) causes substantial morbidity and mortality across the globe. Diagnosis of COPD requires post-bronchodilator FEV1/FVC <0.70 as per GOLD Guidelines. FVC maneuver requires a minimum of 6 seconds of forceful expiration with no flow for 1 second for an accepted effort, which lacks any fixed cut-off point. This leads to discomfort, especially in advanced COPD and old aged population. We conducted this study to find the utility of FEV1/FEV6 as a surrogate for FEV1/FVC, the correlation between the two ratios, and the fixed cut-off value of FEV1/FEV6 for COPD diagnosis.MethodsThis was a prospective, cross-sectional study approved by the institutional ethics committee conducted from January 2017 to November 2018. Consented patients above 18 years suspected of COPD underwent Spirometry as per ATS guidelines. FEV1, FEV6, FEV1/FEV6 and FEV1/FVC ratios were recorded from the best acceptable maneuver.ResultsOut of 560 screened patients, 122 diagnosed as COPD. The correlation coefficient between the post-bronchodilator FEV1/FVC ratio and FEV1/FEV6 ratio was 0.972 (p < 0.01). The relationship between the post-bronchodilator FEV1/FVC ratio and FEV1/FEV6 ratio (linear regression analysis) was found out as: FEV1/FVC = ?1.845 + 1.009(FEV1/FEV6). Using this formula, the post-bronchodilator FEV1/FEV6 value of 71.845 was obtained corresponding to the post-bronchodilator FEV1/FVC value of 70.00.ConclusionWe found a positive correlation coefficient (r = 0.972, p < 0.001) between the FEV1/FEV6 and FEV1/FVC ratios and the cut off value of 71.845 (p < 0.01) for the post-bronchodilator FEV1/FEV6 ratio for the diagnosis of COPD. Thus FEV1/FEV6 should be used as a surrogate for FEV1/FVC for the diagnosis of COPD.  相似文献   
997.
BackgroundNon-paroxysmal atrial fibrillation (AF) has a complex pathophysiological process. The standard catheter ablation approach is pulmonary vein isolation (PVI). The additional value of complex fractionated electrogram (CFAE) ablation is still unclear. We aimed to investigate the additional value of CFAE ablation for non-paroxysmal AF.MethodsWe performed a systematic review and meta-analysis of randomized controlled studies up to May 2020. Articles comparing pulmonary vein isolation (PVI) plus CFAE ablation and PVI alone for AF were obtained from the electronic scientific databases. The pooled mean difference (MD) and pooled risk ratio (RR) were assessed.ResultsA total of 8 randomized controlled trials (RCTs) including 1034 patients were involved. Following a single catheter ablation procedure, the presence of any atrial tachyarrhythmia (ATA) with or without the use of antiarrhythmic drugs (AADs) between both groups were not significantly different (RR = 1.1; 95% confidence interval [CI] = 0.97–1.24; p = 0.13). Similar results were also obtained for the presence of any ATA without the use of AADs (RR = 1.08; 95% CI = 0.96–1.22; p = 0.2). The additional CFAE ablation took longer procedure times (MD = 46.95 min; 95% CI = 38.27–55.63; p = < 0.01) and fluoroscopy times (MD = 11.69 min; 95% CI = 8.54–14.83; p = < 0.01).ConclusionAdditional CFAE ablation failed to improve the outcomes of non-paroxysmal AF patients. It also requires a longer duration of procedure times and fluoroscopy times.  相似文献   
998.
BackgroundPulmonary tuberculosis is a highly prevalent disease in low-income countries; clinical prediction tools allow healthcare personnel to catalog patients with a higher risk of death in order to prioritize medical attention.MethodologyWe conducted a literature search on prognostic models aimed to predict mortality in patients diagnosed with pulmonary tuberculosis. We included prospective and retrospective studies where prognostic models predicting mortality were either developed or validated in patients diagnosed with pulmonary tuberculosis. Three reviewers independently assessed the quality of the included studies using the PROBAST tool (Prediction model study Risk of Bias Assessment Tool). A narrative review of the characteristics of each model was conducted.ResultsSix articles (n = 3553 patients) containing six prediction models were included in the review. Most studies (5 out of 6) were retrospective cohorts, only one study was a prospective case-control study. All the studies had a high risk of bias according to the PROBAST tool in the overall assessment. Regarding the applicability of the prediction models, three studies had a low concern of applicability, two high concern and one unclear concern. Five studies developed new prediction rules. In general, the presented models had a good discriminatory ability, with areas under the curve fluctuating between 0.65 up to 0.91.ConclusionNone of the prognostic models included in the review accurately predict mortality in patients with pulmonary tuberculosis, due to great heterogeneity in the population and a high risk of bias.  相似文献   
999.
Rationale:Reversible posterior leukoencephalopathy syndrome (RPLS) is a clinicoradiological phenomenon first observed 2 decades ago. Reversibility is the hallmark of this rare clinical phenomenon once the triggering pathology is aptly and adequately treated. Tinnitus preceding bilateral hearing loss as a symptomatology of RPLS has not been reported in the literature. Furthermore, chronic obstructive ureteric calculus with superimposed infections as a cause of RPLS has not been reported in the literature.Patient concerns:A 57-year-old female was admitted at our facility because of 2 days history of hearing loss in both ears. She experienced tinnitus in both ears 2 weeks prior to the hearing loss. She is a known hypertensive. She has also undergone multiple surgical treatments for urinary calculi.Diagnosis:Computed tomography (CT) scan of the urinary system revealed a calculus at the right ureter. Magnetic resonance imaging (MRI) showed abnormal signals at both temporo-parieto-occipital (TPO) cortices, the subcortical area, as well as the left hippocampus which was consistent with the diagnosis of RPLS.Interventions:While on antibiotics for treatment of infections, the patient went into hypertensive encephalopathy and pneumonia was also established necessitating intensive care.Outcomes:We observed a resolution of the patient''s temperature and hypertension when the right ureteric stone finally descended into the bladder. Also, we observed disappearance of the abnormal signals at both TPO cortices, the subcortical area, as well as the left hippocampus. Two years follow-up revealed no recurrence of her symptomatology.Lesions:Patients who present with hypertensive encephalopathy maybe more prone to developing RPLS. Renal insufficiency alone or hypertension alone may not be single predisposing entities to RPLS but rather multiple predisposing factors.  相似文献   
1000.
In recent years, personalized or precision medicine has made effective inroads into the management of diseases, including respiratory diseases. The route to implementing this approach must invariably start with the identification and validation of biological biomarkers that are closely related to the diagnosis, treatment, and prognosis of respiratory patients. In this respect, biological biomarkers of greater or lesser reliability have been identified for most respiratory diseases and disease classes, and a large number of studies are being conducted in the search for new indicators. The aim of this review is to update the reader and to analyze the existing scientific literature on the existence and diagnostic, therapeutic, and prognostic validity of the most important biological biomarkers in the main respiratory diseases, and to identify future challenges in this area.  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