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   8781篇
  免费   545篇
  国内免费   57篇
耳鼻咽喉   61篇
儿科学   198篇
妇产科学   126篇
基础医学   819篇
口腔科学   173篇
临床医学   776篇
内科学   2279篇
皮肤病学   80篇
神经病学   1184篇
特种医学   282篇
外科学   1579篇
综合类   21篇
一般理论   1篇
预防医学   361篇
眼科学   208篇
药学   459篇
中国医学   13篇
肿瘤学   763篇
  2024年   9篇
  2023年   124篇
  2022年   207篇
  2021年   391篇
  2020年   230篇
  2019年   300篇
  2018年   308篇
  2017年   236篇
  2016年   271篇
  2015年   285篇
  2014年   412篇
  2013年   494篇
  2012年   761篇
  2011年   709篇
  2010年   362篇
  2009年   363篇
  2008年   542篇
  2007年   531篇
  2006年   546篇
  2005年   450篇
  2004年   407篇
  2003年   357篇
  2002年   308篇
  2001年   66篇
  2000年   53篇
  1999年   65篇
  1998年   41篇
  1997年   40篇
  1996年   47篇
  1995年   28篇
  1994年   34篇
  1993年   28篇
  1992年   43篇
  1991年   40篇
  1990年   22篇
  1989年   37篇
  1988年   19篇
  1987年   17篇
  1986年   25篇
  1985年   23篇
  1984年   27篇
  1983年   18篇
  1982年   15篇
  1981年   17篇
  1980年   8篇
  1979年   13篇
  1978年   6篇
  1975年   5篇
  1974年   10篇
  1973年   5篇
排序方式: 共有9383条查询结果,搜索用时 15 毫秒
51.
52.
We report our experience with percutaneous transluminal angioplasty of renal arteries (PTRA) in solitary kidney patients. Our series includes 31 patients (mean age: 52 years). 7 with solitary kidney following surgical nephrectomy and 24 with functioning solitary kidney. PTR indicated in presence of stenoses ranging from 60–95 % of vessel lumen. Procedure, with 29 patients were technically successful and mean values for stenosis dropped from 77 % to 33 %. In order to assess the results technically, changes in arterial blood pressure (according to Martin's classification) and creatinine levels were considered. Of 25 followed-up patients, 13 were cured (52%), 8 improved (32%),and 4 were unchanged (16%%). Complications were observed during procedures in five patients (16. 1 % ), superimposing that of nonsolitary kidney patients. Good revasculariiation, reduction of blood pressure, preservation or even improvement of renal function and low complications, make PTRA the best procedure with solitary kidney patients.  相似文献   
53.
The role of magnetic resonance angiography (MRA) in the evaluation of vascular involvement was studied in 55 patients with abdominal neoplasms. A 2-D time-of-flight (TOF) technique was used in 18 patients. All patients underwent CT and MR examinations before MRA. Also, MR angiograms were compared with digital subtraction angiography in 22 cases, with Doppler US in 13 cases, and with surgical findings in 20 cases. In all patients with liver neoplasms (n = 29) MRA demonstrated the absence of flow in the infiltrated segments. Pericapsular neovascularization was observed in 12 patients. Portal vein involvement was correctly detected in 27 patients. In all cases MRA demonstrated the relationship between the tumor and venous structures. Portosystemic shunts were visualized in 20 of 21 patients with portal hypertension. Vena cava thrombosis (3 cases), compression (5 cases), and displacement (2 cases) were correctly demonstrated. In renal (n = 6) and adrenal gland (n = 3) tumors renal vein compression was correctly detected in 2 cases, displacement in 1 case, and thrombosis in 3 cases, with only 1 false-positive finding. In 7 patients with pancreatic tumors MRA demonstrated splenic vein thrombosis in 2 cases and compression in 2 cases, with one false-positive finding. Our results indicate that MRA provides precise information regarding venous vascular involvement in abdominal neoplasms, but preoperative arterial mapping is still problematic. Correspondence to: E. Squillaci  相似文献   
54.
PURPOSETo describe the CT and MR findings in the brain and spinal cord of patients with cerebrotendinous xanthomatosis and to seek possible correlations between clinical, biochemical (cholestanol levels), and neuroimaging findings.METHODSTen patients with well-defined clinical and biochemical diagnoses of cerebrotendinous xanthomatosis were examined. Brain CT was performed in eight cases. In all patients MR was obtained using spin-echo and gradient-echo sequences. In eight patients spine MR was also performed.RESULTSNeuroradiologic findings included diffuse cerebral and cerebellar atrophy. In half the cases, atrophy of the brain stem and corpus callosum was also found. In the majority of patients cerebellar bilateral focal lesions and mild white matter signal alterations were present. Spinal cord MR did not show signal abnormalities or atrophy.CONCLUSIONSWe found cranial alterations in patients with severe neurologic impairment, but there was no correlation with cholestanol plasma levels. No spinal cord abnormalities were present.  相似文献   
55.
Chronic allograft dysfunction (CAD) is a major cause of graft loss in long-term kidney transplant recipients. To identify predictors of successful conversion from calcineurin inhibitor (CNI) to sirolimus (SRL) we investigated 59 renal transplant patients with CAD without histological signs of acute rejection. They received 12-15 mg SRL once, then 4-5 mg/day, target trough level 8-12 ng/mL. CNI dose was reduced by 50% simultaneously, and withdrawn at 1-2 months. Concomitant immunosuppression remained unchanged. After 1 year patient survival was 100% and graft survival 92%. In responders (54%) creatinine improved (2.75 +/- 0.75 to 2.22 +/- 0.64 mg/dL; p < 0.01). In nonresponders (46%) creatinine deteriorated (3.15 +/- 1.02 to 4.44 +/- 1.60 mg/dL; p < 0.01). Baseline renal function did not differ, however, baseline proteinuria (519 +/- 516 vs. 1532 +/- 867 mg/day, p < 0.01), histological grade of chronic allograft nephropathy (CAN) (1.2 +/- 0.5 vs. 1.9 +/- 0.6; p < 0.01), grade of vascular fibrous intimal thickening (1.2 +/- 0.7 vs. 1.7 +/- 0.7; p = 0.048) and number of acute rejections before conversion (0.73 +/- 0.69 vs. 1.27 +/- 0.96; p < 0.05) differed significantly between responders and nonresponders. In a multivariate analysis low proteinuria was the only independent variable. Proteinuria below 800 mg/day has a positive predictive value of 90%. Proteinuria at conversion below 800 mg/day is the only independent predictor for positive outcome in conversion from CNI to SRL in CAD.  相似文献   
56.
Extraaxial cavernous hemangiomas are rare intracranial lesions that can be located in different cranial compartments. Extension across different tissue planes such as the subcutaneous tissue, skull, orbital cavity, intracranial dura mater, and extracranial trigeminal divisions within the same patient has not been previously reported. This 32-year-old woman suffered left exophthalmos, left sixth nerve palsy, and trigeminal neuropathy. Magnetic resonance imaging studies revealed an extensive multicompartmental lesion, with enhancement following Gd administration. A left orbitopterional approach allowed removal of several cavernomatous lesions located in the orbit, frontotemporal dura, and lateral wall of the cavernous sinus. A histologically based diagnosis of extraaxial cavernous hemangioma was made. In the postoperative period the patient experienced a regression of her symptoms. The authors report on a case of cavernous hemangioma with a unique extension to different intracranial/extracranial compartments. Although radical removal of the lesion was not feasible, partial excision allowed for satisfactory clinical control of the patient's symptoms.  相似文献   
57.
58.

Purpose  

This article aims to provide an overview of how spinal deformities can alter normal spine and thoracic cage growth.  相似文献   
59.
Dini M  Quercioli F  Mori A  Romano GF  Lee AQ  Agostini T 《Injury》2012,43(6):957-959
The standard management of degloving injuries involves either immediate grafting with the avulsed skin or full- or split-thickness grafts at a later date. Alternative methods include pedicle and free flaps and revascularisation. The authors present an innovative technique of treating degloving injuries with cryopreserved split-thickness skin grafts harvested from degloved flap, artificial dermal replacement and vacuum-assisted closure (VAC therapy). To the authors' knowledge, this is the first reported case of such bilaminar reconstruction of a degloving injury.  相似文献   
60.
IntroductionIn the scientific literature, contradictory results have been published on the prognostic value of the loss of expression of blood group antigen A (BAA) in lung cancer. The objective of our study was to analyze this fact in our surgical series.Patients and methodsIn a multicenter study, 402 non-small-cell lung cancer (NSCLC) patients were included. All were classified as stage-I according to the last 2009-TNM classification. We analyzed the prognostic influence of the loss of expression of BAA in the 209 patients expressing blood group A or AB.ResultsThe 5-year cumulative survival was 73% for patients expressing BAA vs 53% for patients with loss of expression (P=.03). When patients were grouped into stages IA and IB, statistical significance was only observed in stage I-A (P=.038). When we analyzed the survival according to histologic type, those patients with adenocarcinoma and loss of expression of BAA had a lower survival rate that was statistically very significant (P=.003). The multivariate analysis showed that age, gender and expression of BAA were independent prognostic factors.ConclusionsThe loss of expression of blood group antigen A has a negative prognostic impact in stage I NSCLC, especially in patients with adenocarcinoma.  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