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   1512篇
  免费   48篇
  国内免费   3篇
耳鼻咽喉   17篇
儿科学   82篇
妇产科学   28篇
基础医学   151篇
口腔科学   46篇
临床医学   167篇
内科学   287篇
皮肤病学   35篇
神经病学   89篇
特种医学   292篇
外科学   139篇
综合类   17篇
预防医学   70篇
眼科学   16篇
药学   72篇
中国医学   1篇
肿瘤学   54篇
  2023年   7篇
  2022年   14篇
  2021年   23篇
  2020年   10篇
  2018年   27篇
  2017年   19篇
  2016年   16篇
  2015年   18篇
  2014年   35篇
  2013年   40篇
  2012年   43篇
  2011年   34篇
  2010年   52篇
  2009年   55篇
  2008年   51篇
  2007年   37篇
  2006年   41篇
  2005年   35篇
  2004年   34篇
  2003年   31篇
  2002年   34篇
  2001年   24篇
  2000年   21篇
  1999年   26篇
  1998年   53篇
  1997年   71篇
  1996年   55篇
  1995年   42篇
  1994年   55篇
  1993年   56篇
  1992年   19篇
  1991年   22篇
  1990年   23篇
  1989年   39篇
  1988年   45篇
  1987年   37篇
  1986年   34篇
  1985年   31篇
  1984年   14篇
  1983年   25篇
  1982年   21篇
  1981年   21篇
  1980年   25篇
  1979年   10篇
  1978年   12篇
  1977年   23篇
  1976年   24篇
  1975年   23篇
  1973年   14篇
  1972年   6篇
排序方式: 共有1563条查询结果,搜索用时 15 毫秒
81.
The role of genetics in Parkinson disease (PD) continues to be an area of considerable interest and controversy. We collected information involving the nuclear families of 948 consecutively ascertained PD index cases from the University of Virginia (UVA) Health System, the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson (RWJ) School of Medicine, and Boston University (BU) School of Medicine. We performed a segregation analysis to assess evidence for the presence of a Mendelian pattern of familial transmission. The proportion of male (60.4%) and female (39.6%) cases, the mean age of onset (57.7 years), and the proportion of affected fathers (4.7%), mothers (6.6%), brothers (2.9%), and sisters (3.2%) were similar across the three sites. While most of the index cases were male, modestly more of the reported affected relatives were female. These analyses support the presence of a rare major Mendelian gene for PD in both the age-of-onset and susceptibility model. The age-of-onset model provides evidence for a gene that influences age-dependent penetrance of PD, influencing age of onset rather than susceptibility. We also found evidence for a Mendelian gene influencing susceptibility to the disease. It is not evident whether these two analyses are modeling the same gene or different genes with different effects on PD. The finding of significant genes influencing penetrance for PD raises the question of whether these may interact with environmental factors or other genes to increase the risk for PD. Such gene environment interactions, involving reduced penetrance in PD, may explain the low concordance rates among monozygotic twins for this disease.  相似文献   
82.
Nonarteritic anterior ischaemic optic neuropathy usually caused by hypertension, diabetes and hypercholesterolaemia is quite a common disease. Within its symptoms two are the most important: deep and often not reversible visual aquity loss and visual field defects. The decrease of visual aquity may be the first sign of systemic illness, which is noticed by a patient. In many cases the correct diagnosis and anti-oedematous, anti-inflammatory and vascular treatment may improve their visual function and general condition.  相似文献   
83.
Isis 3521 and G3139 are 20- and 18-mer phosphorothioate oligonucleotides, respectively, targeted to the protein kinase C (PKC)-alpha and bcl-2 mRNAs. Treatment of T24 bladder and PC3 prostate carcinoma cells with full-length and 3'-truncation mutants of Isis 3521 causes down-regulation of PKC-alpha protein and mRNA. However, at the level of a 15-mer and shorter, down-regulation of mRNA expression is no longer observed. Further, no diminution in cellular viability, as measured by 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide assay, in response to increasing concentrations of paclitaxel, can be observed for these shorter oligomers. These observations not only indicate that PKC-alpha protein expression can be down-regulated by both RNase H-dependent and -independent mechanisms but also that down-regulation of PKC-alpha is insufficient by itself to "chemosensitize" cells. G3139, which down-regulates bcl-2 protein and mRNA expression, also down-regulates PKC-alpha protein and mRNA expression but not that of PKC-betaI, -epsilon, or -zeta. However, the down-regulation of PKC-alpha and bcl-2 are not linked. When the carrier Eufectin 5 is employed, only bcl-2 is down-regulated in both T24 and PC3 cells at 50 nM oligonucleotide concentration. At 100 nM, both bcl-2 and PKC-alpha expression are down-regulated, and only at this concentration can "chemosensitization" to paclitaxel and carboplatin be observed. In contrast, the down-regulation of bcl-2 seems to be linked with that of RelA (p65). However, this too is also not sufficient for chemosensitization, even though it leads to the loss of expression of genes under the putative control of nuclear factor-kappaB and to detachment of the cells from plastic surfaces. These results underscore the complexity of the intracellular requirements for the initiation of chemosensitization to anti-neoplastic agents.  相似文献   
84.
Three children with azotaemic renal osteodystrophy were treated with 1,25-dihydroxycholecalciferol (1,25(OH)2D3). All showed clinical, biochemical, and radiological improvement within 6 months of starting treatment. There were no complications. The dose of 1,25(OH)2D3 required was 0-5 microgram per day for 2 children aged 22 and 30 months, and 2 microgram per day for a 15-year-old boy. 2 of the patients were receiving phenobarbitone and phenytoin and in one of them prior treatment with dihydrotachysterol 0-5 mg daily and 6 microgram 1alpha-hydroxycholecalciferol (1alphaOHD3) daily had failed to induce improvement. In one patient, in whom serial iliac bone samples were available, 2 microgram 1,25(OH)2D3 resulted in histological improvement in previously severe osteomalacia. 1,25(OH)2D3 appears to be an effective and safe drug in the treatment of uraemic osteodystrophy.  相似文献   
85.
86.
87.
88.
89.
Eight patients with Fanconi's anemia were given cyclophosphamide alone (seven patients) or combined with procarbazine and antithymocyte globulin (one patient) followed by marrow grafts from HLA-identical siblings. All patients had engraftment. Seven developed acute and three chronic graft-versus-host disease (GVHD). Three patients died with GVHD and infectious complications (days 19, 56, and 82) and one with an intracerebral hemorrhage (day 540). Four patients are surviving 647- 3435 days after grafting, two are well, and two have chronic GVHD that is improving. These results show that Fanconi's anemia can be treated successfully by allogeneic marrow transplantation.  相似文献   
90.
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