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   1047篇
  免费   42篇
  国内免费   147篇
儿科学   58篇
妇产科学   6篇
基础医学   80篇
口腔科学   18篇
临床医学   160篇
内科学   265篇
皮肤病学   31篇
神经病学   18篇
特种医学   319篇
外科学   47篇
综合类   24篇
预防医学   40篇
眼科学   13篇
药学   109篇
  1篇
肿瘤学   47篇
  2023年   2篇
  2021年   4篇
  2020年   3篇
  2019年   6篇
  2018年   14篇
  2017年   7篇
  2016年   9篇
  2015年   10篇
  2014年   16篇
  2013年   35篇
  2012年   14篇
  2011年   22篇
  2010年   30篇
  2009年   41篇
  2008年   22篇
  2007年   108篇
  2006年   23篇
  2005年   27篇
  2004年   13篇
  2003年   4篇
  2002年   16篇
  2001年   17篇
  2000年   12篇
  1999年   17篇
  1998年   78篇
  1997年   76篇
  1996年   72篇
  1995年   62篇
  1994年   42篇
  1993年   51篇
  1992年   10篇
  1991年   16篇
  1990年   12篇
  1989年   51篇
  1988年   32篇
  1987年   32篇
  1986年   26篇
  1985年   25篇
  1984年   20篇
  1983年   13篇
  1982年   29篇
  1981年   16篇
  1980年   14篇
  1979年   9篇
  1978年   9篇
  1977年   17篇
  1976年   29篇
  1975年   14篇
  1974年   3篇
  1970年   2篇
排序方式: 共有1236条查询结果,搜索用时 0 毫秒
1.
The results of cinefluoroscopic evaluation in 509 patients in whom there was no evidence of prosthetic mitral or aortic valve regurgitation were compared with those in 41 patients who had perivalvular aortic or mitral regurgitation. Rotational motion of the base ring of each prosthesis (base-ring tilt) was measured in at least two views. A base-ring tilt of 7 degrees or more for aortic prostheses or 11 degrees or more for mitral prostheses was associated with an increased incidence of significant perivalvular regurgitation. Likewise, in patients who had multiple studies, a change between studies in base-ring tilt of 4 degrees or more for aortic prostheses or 5 degrees or more for mitral prostheses was associated with significant perivalvular regurgitation. These data suggest that the presence of either an abnormal base-ring tilt or an abnormal increase in base-ring tilt is strong, supportive evidence of partial prosthetic valve dehiscence.  相似文献   
2.
Intestinal schistosomiasis japonica: CT-pathologic correlation   总被引:1,自引:0,他引:1  
  相似文献   
3.
4.
5.
Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities   总被引:4,自引:0,他引:4  
Shellock  FG; Mink  JH; Fox  JM 《Radiology》1988,168(2):551-553
The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.  相似文献   
6.
7.
Marrow regeneration after mechanical depletion   总被引:1,自引:0,他引:1  
Brecher  G; Tjio  JH; Smith  WW; Haley  JE 《Blood》1976,48(5):679-686
The origin of marrow regeneration after mechanical depletion was reinvestigated in mouse chimeras. The results were compatible with the local origin of stem cells from remnants of incompletely removed marrow, but not with their origin from a common precursor of both bone and hemopoietic cell lines. In transplanted femurs depleted by a modified technique of in vivo evacuation of marrow, hemopoietic regeneration failed to occur. The presence of hemopoietic stem cells in the Haversian canals was thus excluded. The demonstration of ample hemopoiesis with minimal bone formation in nondepleted controls in which bone marrow initially became necrotic provided new evidence that osteogenesis was not a prerequisite of hemopoietic regeneration.  相似文献   
8.
A 15 year old boy with autoimmune polyendocrinopathy-candidosis-ectodermal dystrophy syndrome suffered recurrent episodes of severe intractable diarrhoea, steatorrhoea, and hypocalcaemia. The only treatment modality, which controlled the malabsorption syndrome, was immunosuppression with intravenous high dose methylprednisolone and oral methotrexate maintenance therapy.  相似文献   
9.
A 54-year-old man was treated with weekly 24-h infusion of high-dose 5-fluorouracil (2600 mg/m2) and leucovorin (100 mg/m2) for metastatic colon cancer. At first, he tolerated the treatment well and no significant toxicity was identified. After a total of eight courses of treatment, a stable disease was observed, but mild shortness of breath was found on occasion. The patient had no previous history of cardiac disease and the heart performance assessed by left ventricular ejection fraction before treatment was normal. Unfortunately, acute pulmonary edema with lethal cardiogenic shock occurred during the ninth course of treatment, in spite of intensive medical treatment. The chest X-ray showed extreme cardiomegaly. Repeated assessment of his heart function by echocardiogram and ventricular ejection fraction revealed a very poor cardiac performance. Toxic cardiogenic shock during weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin is extremely rare. To the best of our knowledge, no case has been reported in the English literature. We report a case and the relevant literature about the incidence, clinical picture and possible pathophysiology on 5-fluorouracil-related cardioxicity is reviewed.   相似文献   
10.
A protein S deficient family presenting a variant protein S molecule in plasma and platelets is described. The propositus, age 20, and two brothers suffered from venous thrombotic disease. The propositus, the only family member studied while taking oral anticoagulants, had a protein S antigen (ag) level of 17% and undetectable activity. As demonstrated by immunoblotting both the propositus and one clinically affected brother (42% ag, 7% activity) presented variant protein S molecules of 65,000 molecular weight (mol wt) while the other clinically affected brother (64% ag, 11% activity) had only protein S with normal electrophoretic mobility of 70,000 mol wt. The mother had normal protein S levels (93% ag, 100% activity) but had both normal and variant protein S molecules and based on her functional protein S data a normal anticoagulant activity of the variant molecule is suggested. One asymptomatic but protein S deficient sister (68% ag, 9% activity) as well as the asymptomatic protein S deficient father (59% ag, 10% activity) had only protein S molecules of 70,000 mol wt. The variant protein S bound to C4b-binding protein in plasma, and differed from normal protein S in carbohydrate content. Platelets of each family member contained the same immunoblotting pattern of normal and variant protein S forms as found in plasma, consistent with the hypothesis that protein S gene expression involves codominant expression of two alleles that is similar in cells that control the synthesis of both platelet and plasma forms of protein S.  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