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   1503篇
  免费   121篇
  国内免费   29篇
耳鼻咽喉   5篇
儿科学   79篇
妇产科学   17篇
基础医学   201篇
口腔科学   57篇
临床医学   203篇
内科学   326篇
皮肤病学   15篇
神经病学   72篇
特种医学   262篇
外科学   144篇
综合类   19篇
预防医学   71篇
眼科学   7篇
药学   91篇
中国医学   1篇
肿瘤学   83篇
  2021年   15篇
  2019年   12篇
  2018年   24篇
  2017年   13篇
  2016年   16篇
  2015年   16篇
  2014年   22篇
  2013年   28篇
  2012年   30篇
  2011年   35篇
  2010年   43篇
  2009年   33篇
  2008年   29篇
  2007年   47篇
  2006年   43篇
  2005年   32篇
  2004年   32篇
  2003年   57篇
  2002年   30篇
  2001年   42篇
  2000年   31篇
  1999年   34篇
  1998年   65篇
  1997年   72篇
  1996年   86篇
  1995年   52篇
  1994年   41篇
  1993年   46篇
  1992年   30篇
  1991年   33篇
  1990年   41篇
  1989年   59篇
  1988年   65篇
  1987年   51篇
  1986年   46篇
  1985年   48篇
  1984年   19篇
  1983年   17篇
  1982年   18篇
  1981年   12篇
  1980年   23篇
  1979年   19篇
  1978年   20篇
  1977年   25篇
  1976年   19篇
  1975年   12篇
  1973年   7篇
  1971年   7篇
  1970年   8篇
  1967年   9篇
排序方式: 共有1653条查询结果,搜索用时 31 毫秒
1.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
2.
3.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
4.
5.
6.
7.
8.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
目的 探索LDH实验检测细胞活力的可行性。方法 原代培养骨髓细胞和软骨细胞,用LDH实验测定上述两组细胞的活力,并与镜下活体观察到细胞的生长状况相比较。与目前比较成熟的测定细胞活力的MTS实验的测得的值相比较。结果 LDH实验对上述两组细胞的活力的测定结果与镜下活体观察到的结果相符合。与MTS实验的测得的结果经统计学处理无显著差异。结论 LDH实验可用于细胞活力的直接测定,而对活细胞的生存、繁殖无影响。  相似文献   
10.
Neonatal alloimmune thrombocytopenia induced by the human platelet alloantigen 1a (HPA1a) is characterized by generation of alloantibodies by a mother who is homozygous for the HPA1b alloantigen and almost always HLA-DRB3*0101. The disease is viewed as B cell mediated but the linkage with HLA is indicative of a role for T cells. The HPA1a and HPA1b allotypes are defined, respectively, by Leu and Pro at amino acid 33 of the beta-chain of the platelet integrin GPIIbIIIa (alpha(IIb)beta3). Under the assumption that the same polymorphism may control both the B cell epitope and constitute the MHC-bound peptide, we restimulated PBMC from a woman with an affected child with a synthetic peptide from this polymorphic region. Molecular analysis of the responding T cell repertoire identified two T cells which predominated in cultures stimulated with the alloantigen peptide and which were absent in cultures with the autoantigen peptide. In spite of the use of different V families, sequence of the CDR3 region of the T cell receptor (TCR) beta-chain revealed the presence of a shared motif, L-P-S/T. Oligonucleotide probes specific for the CDR3 sequence indicated that these T cells were present in the PBMC at the highest levels immediately after delivery of the affected infant and their frequency dropped at later times.  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