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   163458篇
  免费   12328篇
  国内免费   4058篇
耳鼻咽喉   1504篇
儿科学   8405篇
妇产科学   4005篇
基础医学   15114篇
口腔科学   1662篇
临床医学   19809篇
内科学   27910篇
皮肤病学   2604篇
神经病学   12560篇
特种医学   4260篇
外国民族医学   3篇
外科学   16174篇
综合类   26154篇
现状与发展   15篇
预防医学   9507篇
眼科学   2368篇
药学   11312篇
  102篇
中国医学   13091篇
肿瘤学   3285篇
  2024年   158篇
  2023年   2612篇
  2022年   4376篇
  2021年   7273篇
  2020年   7043篇
  2019年   5607篇
  2018年   5660篇
  2017年   5931篇
  2016年   6252篇
  2015年   5904篇
  2014年   12264篇
  2013年   12321篇
  2012年   10089篇
  2011年   11326篇
  2010年   8776篇
  2009年   8295篇
  2008年   8004篇
  2007年   8102篇
  2006年   7278篇
  2005年   6014篇
  2004年   5033篇
  2003年   4387篇
  2002年   3101篇
  2001年   2818篇
  2000年   2357篇
  1999年   2119篇
  1998年   1601篇
  1997年   1447篇
  1996年   1347篇
  1995年   1521篇
  1994年   1332篇
  1993年   1141篇
  1992年   1015篇
  1991年   836篇
  1990年   767篇
  1989年   641篇
  1988年   626篇
  1987年   534篇
  1986年   472篇
  1985年   626篇
  1984年   520篇
  1983年   308篇
  1982年   412篇
  1981年   371篇
  1980年   310篇
  1979年   256篇
  1978年   167篇
  1977年   138篇
  1976年   107篇
  1975年   58篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Background and purposeThe optimal management of patients with tandem lesions (TL), or cervical internal carotid artery (c-ICA) steno-occlusive pathology and ipsilateral intracranial occlusion, who are undergoing endovascular thrombectomy (EVT) remains unknown. We sought to establish the feasibility of a trial designed to address this question.Materials and methodsThe Endovascular Acute Stroke Intervention (EASI) study was a single-centre randomized trial comparing EVT to medical therapy for large-vessel occlusion stroke. Patients with TL receiving EVT were randomly allocated to acute c-ICA stenting or no stenting. The primary outcome was the proportion of patients with a modified Rankin Scale (mRS) score of 0–2 at 90 days. Safety outcomes were symptomatic intracranial hemorrhage (sICH) at 24 hours and mortality at 90 days.ResultsOf 301 patients included in EASI between 2013 and 2018, 24 (8.0%) with TL were randomly allocated to acute stenting (n = 13) or no stenting (n = 11). Baseline characteristics were balanced. Eight (61.5%; 95% CI 35.5%–82.3%) and 7 (63.6%; 95% CI 35.4%–84.9%) patients, respectively, had a favorable outcome (mRS 0–2; P = 1.0). One non-stented patient had a symptomatic intracerebral hemorrhage.ConclusionsThis pilot trial of patients with TL undergoing EVT suggests that a sufficiently powered larger TL trial comparing acute c-ICA stenting to no stenting is feasible.Clinical Trial RegistrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT02157532.  相似文献   
992.
Livedo is a net‐like violaceous skin pattern. It can be classified as physiological or pathological. The physiological livedo reticularis usually appears in cold conditions, whereas the pathological and irregular livedo, which persists in warm temperatures, is often labeled as ‘livedo racemosa’. Some neurological pathologies are associated with livedo, most commonly those with an inflammatory component or those derived from systemic disorders. The present review summarizes the most important central and peripheral neurological diseases in pediatric and adult age groups associated with livedo, providing physicians with an overview of the clinical presentation, etiology, diagnosis and management of these conditions.  相似文献   
993.
《Brain & development》2022,44(9):635-639
BackgroundOrgan transplantation after brain death (BD) of the donor has been promoted in many countries as an established medical treatment. However, some problems with brain-dead organ transplantation have been reported. For example, there is no evidence as to the optimal observation period for a diagnosis and no evidence to support the interpretation of the various body movements observed after the determination of BD.Case reportA previously healthy 17-month-old girl with severe febrile convulsive status was transferred to our intensive care unit. The convulsions were refractory and the patient required respiratory management due to whole brain edema on head CT. Later she was diagnosed with acute encephalopathy. The patient showed a flat EEG, no responses on auditory brainstem responses (ABR), and loss of brainstem reflexes on repeated daily examinations. No apnea test was performed. Based on the diagnosis of clinical BD, coordinator of Japan Organ Transplant Network explained about organ donation on the 17th day of the disease. Subsequently, the family responded that they could not consent to organ donation, and the patient did not proceed to the legal BD determination. Around five weeks after the onset, spontaneous body movements began to appear, as not only the spinal reflexes but also the brainstem involvement.ConclusionThe pathophysiology of acute encephalopathy is largely unknown, and it is difficult to determine the observation period necessary for BD determination. What we have learned from this case is that clinical BD remains ambiguous and cannot be confirmed even with a thorough neurological examination, EEG, and ABR.  相似文献   
994.
995.
目的:评价结核特异性抗原(TBAg)与CD4+T淋巴细胞(简称“CD4”)计数的比值(TBAg/CD4)对AIDS合并活动性肺结核(PTB)的辅助诊断价值。方法:采用前瞻性研究的方法,参照入组标准纳入2018年1月至2020年12月苏州市第五人民医院收治的262例疑似活动性PTB的AIDS患者,并将患者分为AIDS+PTB组(152例)和AIDS组(110例)。采集患者入院次日清晨静脉血进行干扰素体外释放酶联免疫法(TB-IGRA)、血常规、CD4检测,比较两组间TBAg水平和TBAg/CD4比值的差异。以临床诊断为参考标准,评价TB-IGRA检测AIDS合并PTB的效能,并以受试者工作特征曲线(ROC曲线)下面积(AUC)确定诊断效能最佳的检测指标。结果:以临床诊断为参考标准,TB-IGRA检测AIDS合并活动性PTB的敏感度和特异度分别为53.95%(82/152)和75.45%(83/110)。TB-IGRA检测AIDS+PTB组的TBAg、TBAg/CD4水平[分别为92.51(-68.20,906.10)pg/ml和1.01(0.00,10.12)]均明显高于AIDS组[分别为85.20(-33.80,801.30)pg/ml和0.11(0.00,2.07)],对照培养管抗原浓度[529.50(12.50,1160.50)pg/ml]明显低于AIDS组[694.50(29.90,990.00)pg/ml],差异均有统计学意义(Z=-3.481、-9.557、3.289,P值均<0.001)。ROC曲线分析显示,对照培养管抗原浓度、TBAg、TBAg/CD4对诊断AIDS合并活动性PTB的AUC值分别为0.718、0.637和0.842;当TBAg/CD4的临界值为0.592时,约登指数最大,其敏感度为88.10%,特异度为77.10%。结论:相较于AIDS患者,AIDS合并PTB患者的TBAg和TBAg/CD4水平均明显升高,尤以TBAg/CD4诊断价值高,结合患者免疫状态的影响,认为TBAg/CD4对AIDS合并PTB患者具有一定辅助诊断价值。  相似文献   
996.
997.
Background and aimsGastric antral vascular ectasia (GAVE) is characterized by angliodysplastic lesions that can cause upper gastrointestinal bleeding (UGIB). The mechanism behind GAVE and its association with other diseases remains unknown. We investigated the association of metabolic syndrome in cirrhotic GAVE patients when compared to esophageal variceal hemorrhage (EVH) patients.MethodsWe performed a retrospective review of 941 consecutive esophagogastroduodenoscopies (EGDs) for UGIB at a medical center between 2017 and 2019. The GAVE group consisted of EGD or biopsy diagnosed cirrhotic GAVE patients, and the EVH group consisted of EVH patients with active bleeding or stigmata of recent hemorrhage on EGD. Baseline variables including co-morbidities and cirrhotic etiology were recorded. Continuous variables were compared using Wilcoxon test and categorical variables were compared using Chi-square or Fisher's exact test. Multiple logistic regression analysis evaluated the association between GAVE and covariates.ResultsThe final cohort had 96 GAVE and 104 EVH patients. Mean BMI was significantly higher in the GAVE cohort (32.6 vs 27.9, p < 0.0001) in addition to diabetes, hypertension, and hyperlipidemia (53.1% vs 37.5%; 76% vs 47.1%; 38.5% vs 14.4%; respectively, all p < 0.05). Non-alcoholic steatohepatitis (NASH) cirrhosis was more prevalent in GAVE than EVH patients (50% vs 24%, p = 0.0001). Multiple logistics regression revealed female sex, increased BMI, hypertension, and hyperlipidemia all having significantly higher risk of GAVE (all p < 0.05).ConclusionOur data indicates that when compared to cirrhotics patients with EVH, cirrhotics with GAVE have increased risk of metabolic syndrome. This may play a role in the underlying pathophysiology of GAVE.  相似文献   
998.
999.
From 2015 to 2019, 9 patients underwent ultrasound-guided intranodal lymphangiography for the treatment of a chyle leak following thoracic outlet decompression surgery. Chyle leaks were identified by Lipiodol (Guerbet, Roissy, France) extravasation near the left supraclavicular surgical bed in all patients. The technical success rate of thoracic duct embolization was 67% (6 of 9), including fluoroscopic transabdominal antegrade access (n = 4) and ultrasound-guided retrograde access in the left neck (n = 2). Clinical success was achieved in 89% of patients (8 of 9). The mean interval from lymphangiography to drain removal was 6.6 days (range, 4–18 d). No patients had a chyle leak recurrence during clinical follow-up (mean, 304 d).  相似文献   
1000.
ObjectivesCompare anterior pericapsular muscle activity between individuals with and without femoroacetabular impingement syndrome (FAIS) during dynamic tasks, to investigate whether muscle activity is consistent with a role in retracting the capsule to prevent impingement and active restraint of the femoral head in walking.DesignCross-sectional.SettingUniversity-laboratory.ParticipantsThirteen athletes with FAIS and 13 pain-free controls.Main outcome measuresMuscle activity was recorded using fine-wire (Iliocapsularis, iliacus and anterior gluteus minimus) and surface (rectus femoris) electromyography (EMG), during three hip flexion tasks (active and assisted hip flexion; squatting) and four walking trials.ResultsIliocapsularis EMG amplitude was no different between active and assisted hip flexion tasks around 90° of hip flexion in FAIS. There was no difference in EMG between groups in squatting. The pattern of burst activity preceding peak hip extension in iliacus, iliocapsularis, and anterior gluteus minimus was similar in both groups during walking.ConclusionIn FAIS, similar activation of iliocapsularis during active and assisted hip flexion, despite reduced flexion torque demand in the latter, suggests a role in capsular retraction or enhanced hip joint protection. Pericapsular muscle activity in advance of peak hip extension during walking is consistent with a proposed contribution to femoral head control.  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