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   1025篇
  免费   110篇
  国内免费   15篇
耳鼻咽喉   10篇
儿科学   16篇
妇产科学   12篇
基础医学   242篇
口腔科学   43篇
临床医学   47篇
内科学   175篇
皮肤病学   13篇
神经病学   117篇
特种医学   7篇
外科学   197篇
综合类   46篇
现状与发展   1篇
预防医学   21篇
眼科学   20篇
药学   77篇
中国医学   11篇
肿瘤学   95篇
  2024年   2篇
  2023年   20篇
  2022年   22篇
  2021年   74篇
  2020年   42篇
  2019年   57篇
  2018年   51篇
  2017年   55篇
  2016年   37篇
  2015年   46篇
  2014年   74篇
  2013年   93篇
  2012年   56篇
  2011年   66篇
  2010年   39篇
  2009年   50篇
  2008年   63篇
  2007年   47篇
  2006年   41篇
  2005年   37篇
  2004年   35篇
  2003年   26篇
  2002年   18篇
  2001年   11篇
  2000年   10篇
  1999年   6篇
  1998年   12篇
  1997年   15篇
  1996年   13篇
  1995年   9篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   5篇
  1990年   4篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1982年   1篇
  1980年   2篇
  1979年   3篇
排序方式: 共有1150条查询结果,搜索用时 968 毫秒
81.
Background: Our previous experiments with gene chip suggested that basic fibroblastic growth factor (FGF2) levels were lower in mesenchymal stem cell (MSC) from aplastic anemia patients. The purpose of this study was to determine the expression of FGF2 in MSC and in bone marrow of children with aplastic anemia to better understand the role of low FGF2 expression in the pathogenesis of aplastic anemia. Procedure: MSCs from the bone marrow of aplastic anemia children and control group were cultured in vitro. Growth curves of primary and passage MSC were plotted. FGF2 gene expression in MSCs was detected using quantitative real-time polymerase chain reaction (RT-PCR). FGF2 protein expression in mononuclear cells and FGF2 protein level in extracellular fluid of bone marrow were also investigated. Result: Decreased growth of MSCs from aplastic anemia children was observed after passage 8 in serial subcultivation, and FGF2 gene expression was downregulated. Within the patients’ bone marrow, low FGF2 expression was validated both in mononuclear cells and in the extracellular fluid. Conclusion: Low FGF2 gene expression in MSCs and low FGF2 protein level in bone marrow of aplastic anemia may involve to pathogenesis of aplastic anemia.  相似文献   
82.
We present a young boy whose mild ataxia and abnormal eye movements repeatedly deteriorated with fever, making him unable to sit or walk during fever episodes. SNP-array analysis identified a 202 kb deletion in chromosome 13q33.1 containing the fibroblast growth factor (FGF)14 gene, which is associated with spinocerebellar ataxia (SCA) 27. This 13q deletion was also present in the proband's mother and grandmother. The mother was unable to perform tandem gait walking and had abnormal eye movements but had never sought medical attention. The grandmother predominantly had a postural tremor. FGF14 regulates brain sodium channels, especially in the cerebellum. Sodium channels can be fever sensitive. This family demonstrates phenotypic variability of FGF14 deletions (SCA 27), fever sensitivity of ataxia and the added value of SNP-array analysis in making a diagnosis.  相似文献   
83.
The exstrophy–epispadias complex is a rare spectrum of anomalies affecting the genitourinary system, anterior abdominal wall, and pelvis. Recent advances in the repair of classic bladder exstrophy (CBE) and cloacal exstrophy (CE) have resulted in significant changes in outcomes of surgical management (including higher continence rate, fewer surgical complications, and better cosmesis) and health-related quality of life in these patients. These noteworthy changes resulted from advances in the pathophysiological and genetic backgrounds of this disease and better radiologic assessment of the three-dimensional anatomy of the bony pelvis and its musculature. A PubMed search was performed with the keyword exstrophy. The resulting literature pertaining to genetics, stem cells, imaging, tissue engineering, epidemiology, and endocrinology was reviewed. The following represents an overview of the advances in basic science understanding and imaging of the exstrophy–epispadias spectrum and discusses their possible and future effects on the management of CBE and CE.  相似文献   
84.
85.
Lymphangiogenesis is an important event in progression of colorectal cancer (CRC), and the estimated lymphatic vascular density (LVD) probably indicates facilitated lymphatic tumor cell invasion and metastasis. However, at what time point during tumor progression this process is triggered, is unclear. The aim of this study was twofold. Firstly, to examine LVD in paired samples of CRC tissue and normal mucosa with specific emphasis on possible difference in LVD between tumors stages II and III, and secondly, the expression of the lymphangiogenic growth factor fibroblast growth factor‐2 (FGF‐2). Eighteen patients were studied. Immunostaining for podoplanin was performed to highlight lymphatic vessels. FGF‐2 mRNA expression was determined by quantitative real‐time RT‐PCR, whereas protein expression was quantitatively assessed by densitometric analysis of Western blot signal intensity. The immunoblots were further validated by FGF‐2 immunostaining of histological sections. LVD was significantly increased in tumor tissue compared with the normal mucosa but no changes in LVD between stages II and III CRC was observed. FGF‐2 was found to be downregulated both at the mRNA and protein level in tumor tissues compared with normal mucosa. Lymphangiogenesis was triggered early in tumor development. An increased LVD was established before the tumor reached stage II. FGF‐2 was downregulated in tumor tissue. The importance of this finding remains unclear.  相似文献   
86.
Sanfilippo syndrome type B (MPS III B) is a neurodegenerative disorder characterized by profound mental retardation and early death. It is caused by deficiency of a lysosomal enzyme involved in heparan sulfate (HS) degradation. Because HS accumulation can be a major feature of this disease, we have examined crucial molecular systems associated with HS function. Using a knockout mouse with disruption of the gene responsible for HS degradation, we evaluated the effects of possible HS accumulation on neuroplasticity that are within the spectrum of action of fibroblast growth factors (FGFs) and their receptor (FGFR). We found that levels of mRNA for the FGFR-1 were attenuated in the mutant mice by the age of 6 months, whereas the mRNAs for FGF-1 and FGF-2 were reduced or unchanged in the brain regions tested. Neurogenesis, in which FGF-2 is involved, was inhibited in the MPS III B mouse brain at both young and adult ages. We also examined the expression of the glial fibrillary acidic protein (GFAP) gene and GFAP-positive cell density in both normal and injured conditions to study the functional response of astrocytes to insult. We found that, although the mutation alone caused drastic induction of reactive astrocytes, acute injury to the mutant brains failed to induce additional reactive astrocytes. Our results showed important alterations in the expression of several genes involved in the maintenance of neuroplasticity in the MPS III B. This in turn may result in reduction of neuronal health and brain function.  相似文献   
87.
88.
89.
BACKGROUND: Angiogenesis is essential for development, growth and advancement of solid tumors. During angiogenesis, ETS-1 is strongly expressed in vascular endothelial cells and the adjacent interstitial cells, while the inhibition of ETS-1 expression leads to suppression of angiogenesis. This prompted us to study the clinical implications of ETS-1 in relation to angiogenesis in uterine endometrial cancers. PATIENTS AND METHODS: Sixty patients underwent resection for uterine endometrial cancers. From the tissues of 60 uterine endometrial cancers, the levels of ets-1 mRNA, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived endothelial cell growth factor (PD-ECGF) and interleukin (IL)-8 were determined by competitive RT-PCR using recombinant RNA and enzyme immunoassay, and the localization and counts of microvessel were determined by immunohistochemistry. RESULTS: There was a significant correlation between microvessel count and ets-1 gene expression levels in uterine endometrial cancers. Immunohistochemical staining revealed that the localization of ETS-1 was similar to that of vascular endothelial cells. The level of ets-1 mRNA tended to increase with increasing disease stage. Furthermore, the level of ets-1 mRNA correlated with levels of VEGF in well-differentiated adenocarcinomas (G1) and of bFGF in moderately differentiated adenocarcinomas (G2) and poorly differentiated adenocarcinomas (G3). CONCLUSIONS: ETS-1 is a possible angiogenic mediator in uterine endometrial cancers.  相似文献   
90.
Angiogenesis in the human heart: Gene and cell therapy   总被引:3,自引:0,他引:3  
Tirziu D  Simons M 《Angiogenesis》2005,8(3):241-251
The concept of therapeutic angiogenesis – stimulation of new vessels growth to restore blood supply to ischemic tissue has been studied in a number of clinical trials in patients with advanced coronary and peripheral arterial disease. This review discusses the main biological processes underlying new vessel growth and addresses applications of growth factor and cell therapy based on the stimulation of angiogenesis. While still very young and controversial, cell therapy has an enormous potential that is yet to be explored. Multiple questions remain unanswered including the choice of the best cell type, patient selection and the mechanism of action. Nevertheless, much should be expected in this area in the next decade with the likely emergence of new therapies for treatment of ischemic diseases.  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