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   16361篇
  免费   880篇
  国内免费   124篇
耳鼻咽喉   151篇
儿科学   323篇
妇产科学   358篇
基础医学   1896篇
口腔科学   394篇
临床医学   1241篇
内科学   5112篇
皮肤病学   419篇
神经病学   1304篇
特种医学   298篇
外科学   2273篇
综合类   102篇
一般理论   8篇
预防医学   1084篇
眼科学   302篇
药学   899篇
中国医学   45篇
肿瘤学   1156篇
  2024年   13篇
  2023年   137篇
  2022年   310篇
  2021年   700篇
  2020年   313篇
  2019年   630篇
  2018年   692篇
  2017年   409篇
  2016年   423篇
  2015年   458篇
  2014年   743篇
  2013年   816篇
  2012年   1485篇
  2011年   1488篇
  2010年   775篇
  2009年   697篇
  2008年   1112篇
  2007年   1116篇
  2006年   966篇
  2005年   914篇
  2004年   846篇
  2003年   675篇
  2002年   686篇
  2001年   84篇
  2000年   59篇
  1999年   90篇
  1998年   105篇
  1997年   99篇
  1996年   68篇
  1995年   47篇
  1994年   46篇
  1993年   40篇
  1992年   28篇
  1991年   25篇
  1990年   28篇
  1989年   20篇
  1988年   16篇
  1987年   11篇
  1986年   11篇
  1984年   19篇
  1983年   13篇
  1982年   11篇
  1981年   13篇
  1980年   11篇
  1979年   9篇
  1975年   11篇
  1971年   9篇
  1970年   8篇
  1969年   11篇
  1967年   9篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
43.
44.
Cardiovascular diseases requiring surgical therapy in patients with prior liver transplantation are rare. Little is known about the outcome of patients with liver allograft undergoing cardiac surgery. Herein we report our experience in this patient population with an emphasis on operative outcomes and mid-term survival. Between January 1998 and December 2004, 12 patients (mean +/- standard deviation age 68 +/- 9 years, 7 [58%] male) with previous liver transplantation who underwent cardiac surgery were identified. Main outcome measures were hospital mortality, postoperative complications, allograft function, and long-term survival. There was no in-hospital mortality. Three major complications (25%) occurred, including 1 each (8%) of respiratory failure, renal failure, and biliary leakage. All complications were resolved by the time of discharge. Allograft dysfunction determined by an increase of liver function parameters was noticed in 4 (33%) and recovered before discharge. The average length of stay in intensive care unit was 72 +/- 45 hours, and the mean length of stay in hospital was 22 +/- 17 days. One- and 5-year survival was 91% +/- 8% and 67% +/- 14%, respectively. Cardiac surgery can be performed safely in liver transplant recipients with extremely low mortality and acceptable morbidities. Allograft dysfunction is a common finding, but it is transient, with early functional recovery. Five-year survival of liver recipients undergoing cardiac procedures is similar to that of the general population undergoing cardiac surgery. Our data suggest that these patients should be considered for cardiac surgery in reference centers with expertise in complex cardiac procedures and perioperative management of these highly specific patients.  相似文献   
45.
46.
We have performed restriction fragment length polymorphism (RFLP) analysis at the low density lipoprotein receptor (LDLR) locus in order to investigate the molecular genetics of familial hypercholesterolemia (FH) in Spain. Firstly, a sample of 50 unrelated patients with a clinical diagnosis of FH was screened for the presence of major rearrangements at this locus by Southern blot analysis of Bgt II digested genomic DNA. Four different mutations were detected, accounting for 8% of the mutant alleles in the Spanish FH sample. Then, we determined the relative allele frequency and estimated linkage disequilibrium between seven RFLPs of the LDLR gene in the remaining 46 FH patients and in 61 normolipidemic controls. Hindi, Avail, Pvu II, Msp I, and Nco I are the most polymorphic sites with individual PIC values higher than 0.28, whereas the Taq I and Stu I sites display low levels of polymorphism. The usefulness of the seven RFLPs to confirm a clinical diagnosis of FH was investigated in 15 FH-families, consisting of 118 individuals, in whom the presence of Familial Defective Apolipoprotein B-100 (FDB) due to the apoB3500 mutation was excluded. Independent haplotypes were constructed for 71 chromosomes: 15 FH and 56 control haplotypes. A total of 14 different haplotypes was found. In 12 families, clinical diagnosis of FH was confirmed by cosegregation analysis, which makes these RFLPs useful for studying the inheritance of the LDLR gene in 80% of Spanish families with FH. Comparison of haplotypes found in the Spanish sample with those found in Swiss and Norwegians suggests heterogeneity of haplotypes among European populations.  相似文献   
47.
Older age is not considered a contraindication for liver transplantation, but age-related morbidity may be a cause of mortality. Survival and the incidence of the main post-transplant complications were assessed in 111 adult liver transplant recipients. They were divided in two groups according to their age (patients younger than 60 years, n=54; patients older than 60 years, n=57) and both groups were compared. Older patients were more frequently transplanted for hepatitis C (p= 0.03) and hepatocellular carcinoma (p= 0.05) and their liver disease was less advanced (Child-Pugh and MELD scores were significantly lower; p=0.004 and p=0.05, respectively). After transplantation, older patients had a significantly lower survival (p=0.02). Higher age was independently associated with mortality (hazard ratio for each 10-year increase: 2.1; 95% confidence interval: 1.1- 4.0; p=0.02). The incidence of de novo neoplasia and nonskin neoplasia were higher in older patients (p=0.02 and p =0.007, respectively). Malignancy was the cause of death in one patient younger than 60 years and in 12 patients older than 60 years (p =0.002). In multivariate analysis, a higher age and smoking were independently associated with a higher risk of dying of de novo neoplasia. In conclusion, older liver transplant recipients have a significantly lower survival than younger patients. Malignancy is responsible for this decreased survival.  相似文献   
48.
The minimax linear quadratic problem, where ‘max’ is taken over a finite set of indices (models) and ‘min’ is taken over the set of admissible controls, is considered. The solution is obtained by the robust optimal control application. The control turns out to be a linear combination of the controls optimal for each individual model. This paper develops a numerical method for the optimal weights adjustment. An example shows a quick convergence of the proposed procedure. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
49.
In this paper we will review the results obtained during the last 2 years with the aponeurotic galea and subgalea for vermillion lip augmentation. The survey was carried out on 42 patients who displayed either an absence of or reduction in the vermillion of one or both lips or a senile lip. In all cases the surgical procedure introduced aponeurotic galea and subgalea in the space found between the orbicular lip muscle and the vestibular mucus, just behind the vermillion. All the operations were performed under local anaesthetic. The size of the aponeurotic galea fragment removed varied in length between 10 and 12 cms. and in width between 1 and 2 cms., using the following parameters for its dimensions: the previous volume of the lips, and the distance between the two buccal commissures when in the “smile position.”  相似文献   
50.
Intestinal microvillous disorders are an uncommon cause of severe diarrhea, with very poor prognosis. The authors report the case of a female infant with Down syndrome, aganglionic megacolon, severe diarrhea, and jejunal biopsy with ultrastructural changes consistent with microvillous atrophy. The patient condition improved after a colostomy performed in the setting of the treatment of Hirschprung disease.  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