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   2582篇
  免费   262篇
  国内免费   58篇
耳鼻咽喉   3篇
儿科学   26篇
基础医学   259篇
口腔科学   11篇
临床医学   86篇
内科学   76篇
皮肤病学   125篇
神经病学   367篇
特种医学   76篇
外国民族医学   1篇
外科学   101篇
综合类   126篇
现状与发展   1篇
预防医学   19篇
眼科学   4篇
药学   177篇
中国医学   17篇
肿瘤学   1427篇
  2024年   3篇
  2023年   59篇
  2022年   42篇
  2021年   165篇
  2020年   106篇
  2019年   98篇
  2018年   89篇
  2017年   94篇
  2016年   106篇
  2015年   203篇
  2014年   173篇
  2013年   272篇
  2012年   152篇
  2011年   145篇
  2010年   130篇
  2009年   100篇
  2008年   117篇
  2007年   82篇
  2006年   102篇
  2005年   80篇
  2004年   49篇
  2003年   71篇
  2002年   59篇
  2001年   52篇
  2000年   44篇
  1999年   43篇
  1998年   36篇
  1997年   29篇
  1996年   22篇
  1995年   26篇
  1994年   13篇
  1993年   19篇
  1992年   13篇
  1991年   13篇
  1990年   18篇
  1989年   11篇
  1988年   7篇
  1987年   10篇
  1986年   8篇
  1985年   6篇
  1984年   11篇
  1983年   6篇
  1982年   7篇
  1981年   5篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1973年   1篇
排序方式: 共有2902条查询结果,搜索用时 15 毫秒
1.
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered.  相似文献   
2.
目前最大限度的安全切除联合同步替莫唑胺辅助放化疗虽然已经成为胶质母细胞瘤的标准治疗手段,但是总体预后仍欠理想。特别是复发之后虽然可以考虑挽救性化疗,但是对于大多数复发患者来说往往难以耐受传统最大耐受剂量方案的化疗。以传统药物为基础的持续低剂量的节律化疗方案由于具备治疗耐受性好且不易产生耐药等优势,逐渐被用于胶质母细胞瘤患者的治疗当中,同时大量相关研究及临床试验也已经显示出一定的疗效,为胶质母细胞瘤的综合治疗提供了新的策略。  相似文献   
3.
4.
5.
FGFR–TACC, found in different tumor types, is characterized by the fusion of a member of fibroblast grown factor receptor (FGFR) tyrosine kinase (TK) family to a member of the transforming acidic coiled-coil (TACC) proteins. Because chromosome numerical alterations, hallmarks of FGFR–TACC fusions are present in many hematological disorders and there are no data on the prevalence, we studied a series of patients with acute myeloid leukemia and myelodysplastic syndrome who presented numerical alterations using cytogenetic traditional analysis. None of the analyzed samples showed FGFR3–TACC3 gene fusion, so screening for this mutation at diagnosis is not recommended.  相似文献   
6.
Summary Eight patients with malignant gliomas verified on CT scan, received an intravenous injection of 50 mg of Adriamycin R, 24 hours prior to surgical removal of the tumour. Peroperatively, both tumour and surrounding tissue specimens were obtained for determination of the tissue concentrations of Adriamycin and its reduced metabolite Adriamycinol. It was found that Adriamycin could be detected in tumour tissue from all patients. The concentration varied between 0,9 and 4,6 nmol/g tissue. In contrast, Adriamycin could only be detected in surrounding brain tissue from one patient.In anin vitro study a human malignant glioma cell line (U-251 MG) was exposed to various concentrations of Adriamycin for 24 hours. It was found that an intracellular drug concentration above 30 nmol/g cells caused a concentration dependent inhibition of cell growth. Thus, it is likely that the poor effect of Adriamycin on patients with malignant gliomas is due to an ineffective drug accumulation in the tumour tissue.  相似文献   
7.
The transforming growth factors type beta 1, beta 2, and beta 1.2 suppress multidrug transport in human pat-1 glioblastoma cells and even in cells that strongly over-express mdr genes and are resistant to inhibition of multidrug transport by chemosensitizers. Thus, inhibition of multidrug transport by cytokines might be a new approach to increase cellular accumulation of chemotherapeutic agents in multidrug resistant glial tumor cells. Interestingly, a member of the more distantly related decapentaplegic subgroup of transforming growth factors, the bone morphogenetic protein BMP 2, did not inhibit multidrug transport.  相似文献   
8.
'Gliosarcomas' have long been considered to be mixed gliomas and sarcomas. The present study failed to define criteria which clearly delineate 'gliosarcomas' from glioblastoma multiforme and suggests that 'gliosarcomas' should be considered as spindle cell glioblastomas. A total of six cases originally diagnosed as 'gliosarcomas' were compared with four cases of glioblastoma multiforme. No clinical or prognostic features were defined which would clearly separate 'gliosarcomas' from glioblastoma multiforme. Macroscopically, biopsies from 'gliosarcomas' ranged from firm, apparently well-circumscribed tumours to poorly circumscribed lesions with a soft consistency resembling glioblastoma multiforme. Histology revealed a continuous spectrum in which 'gliosarcomas' with large reticulin-rich areas of spindle cells merged with typical glioblastomas containing only small islands of spindle cells and reticulin staining. Immunocytochemistry for glial fibrillary acidic protein (GFAP); S100 protein and alpha-smooth muscle actin (ASMA) showed that the majority of cells in reticulin-poor areas of 'gliosarcoma' and glioblastomas expressed S100 protein and GFAP; many expressed ASMA and some expressed both GFAP and ASMA. Spindle cells in reticulin-rich areas of 'gliosarcomas' and glioblastomas most frequently expressed ASMA but many cells also expressed S100 protein and GFAP; some cells expressed both GFAP and ASMA. The results of this study and a review of the literature suggests that there is a clinical, radiological and pathological continuum with glioblastoma and 'gliosarcoma' at different ends of the spectrum. It is suggested, therefore, that most, if not all, 'gliosarcomas' be redesignated as spindle cell glioblastomas and not be considered as a mixture of glioma and sarcoma.  相似文献   
9.
本文就加热及同时增加细胞内氧自由基水平对恶性胶质瘤细胞存活、增殖和细胞间隙连结通讯的影响做初步观察。用M.T.T法测定胶质瘤细胞存活率;用Ki-67抗增殖细胞核抗原单克隆抗体,通过免疫组织化学ABC染色分析胶质瘤细胞的增殖活性;用划痕染料示踪技术观察胶质瘤细胞的细胞间隙连结通讯。结果表明,H2O2和3AT能增强加热对胶质瘤细胞存活与增殖的抑制作用,促进胶质瘤细胞间隙连结通讯的改善,存在着明显的剂量和时间效应。实验结果提示,通过内外源性增加胶质瘤细胞内的氧自由基水平,将有助于强化加热治疗胶质瘤效果,并可以减少加热的剂且,降低副作用。  相似文献   
10.
Summary In radiation therapy for malignant brain tumours, the dose of radiation that can be safely delivered to a tumour is limited by the radiation tolerance of the adjacent normal brain tissue. Among various radiation modalities to produce local tumour eradication without unacceptable complications, we chose a large, single irradiation dose during the operation (intra-operative radiation therapy, IORT). In contrast to X-ray or Cobalt-60 gamma ray irradiation, IORT with a high-energy electron beam delivered by the Shimadzu 20 MeV betatron provides acceptable dose homogeneity with rapid fall-off of the radiation dose beyond the treatment volume. Thus, IORT has the advantage of precise demarcation of the target volume, minimum damage to surrounding normal tissues, and a high absorbed target dose (15–25 Gy in 5–10 min).On the basis of our experience with 170 patients treated by IORT, we established the treatment indications and method in patients with malignant brain tumours. IORT with a dose of 15–25 Gy was delivered to widely resected tumours followed by external radiation therapy. No acute or subacute complications were observed. Treatment results of 30 patients with glioblastoma treated by IORT (mean 18.3 Gy) combined with external radiation therapy (mean 58.5 Gy) resulted in a median survival of 119 weeks and a 2-year survival rate of 61%.Supported by a Research Grant for Cancer (3–46, 4–23) from the Ministry of Health and Welfare, and by a Grant-in-Aid for Scientific Research (03454343) from the Ministry of Education, Science and Culture of Japan.  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