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   299篇
  免费   28篇
  国内免费   31篇
儿科学   25篇
妇产科学   2篇
基础医学   15篇
口腔科学   14篇
临床医学   50篇
内科学   56篇
皮肤病学   1篇
神经病学   26篇
特种医学   55篇
外科学   18篇
综合类   19篇
预防医学   12篇
眼科学   4篇
药学   42篇
中国医学   1篇
肿瘤学   18篇
  2024年   1篇
  2023年   1篇
  2022年   3篇
  2021年   6篇
  2020年   1篇
  2019年   4篇
  2018年   7篇
  2017年   5篇
  2016年   2篇
  2015年   5篇
  2014年   10篇
  2013年   15篇
  2012年   7篇
  2011年   8篇
  2010年   10篇
  2009年   16篇
  2008年   11篇
  2007年   21篇
  2006年   11篇
  2005年   7篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2001年   4篇
  2000年   2篇
  1999年   12篇
  1998年   12篇
  1997年   17篇
  1996年   15篇
  1995年   13篇
  1994年   19篇
  1993年   14篇
  1992年   9篇
  1991年   8篇
  1990年   4篇
  1989年   11篇
  1988年   7篇
  1987年   9篇
  1986年   5篇
  1985年   6篇
  1984年   3篇
  1983年   3篇
  1982年   3篇
  1981年   10篇
  1980年   2篇
  1979年   2篇
  1977年   3篇
  1976年   3篇
  1975年   5篇
排序方式: 共有358条查询结果,搜索用时 15 毫秒
1.
Neuroimaging in Pineal Tumors   总被引:4,自引:0,他引:4  
F Reis  MD  AV Faria  MD  PhD  VA Zanardi  MD  PhD  JR Menezes  MD  F Cendes  MD  PhD  LS Queiroz  MD  PhD 《Journal of neuroimaging》2006,16(1):52-58
BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.  相似文献   
2.
中药材龟板和鳖甲中DNA的提取与扩增   总被引:22,自引:0,他引:22  
中药材龟板和鳖甲中DNA的提取与扩增王亚明,周开亚,吴平,徐珞珊(南京师范大学生物系,南京210097;中国药科大学生药学研究室,南京210009)龟鳖类药材在我国使用历史悠久,具补阴益气的功效。《中国药典》(1990年版)规定龟甲(龟板)的原动物为...  相似文献   
3.
4.

Glioblastoma is associated with a poor prognosis. Even though survival statistics are well-described at the population level, it remains challenging to predict the prognosis of an individual patient despite the increasing number of prognostic models. The aim of this study is to systematically review the literature on prognostic modeling in glioblastoma patients. A systematic literature search was performed to identify all relevant studies that developed a prognostic model for predicting overall survival in glioblastoma patients following the PRISMA guidelines. Participants, type of input, algorithm type, validation, and testing procedures were reviewed per prognostic model. Among 595 citations, 27 studies were included for qualitative review. The included studies developed and evaluated a total of 59 models, of which only seven were externally validated in a different patient cohort. The predictive performance among these studies varied widely according to the AUC (0.58–0.98), accuracy (0.69–0.98), and C-index (0.66–0.70). Three studies deployed their model as an online prediction tool, all of which were based on a statistical algorithm. The increasing performance of survival prediction models will aid personalized clinical decision-making in glioblastoma patients. The scientific realm is gravitating towards the use of machine learning models developed on high-dimensional data, often with promising results. However, none of these models has been implemented into clinical care. To facilitate the clinical implementation of high-performing survival prediction models, future efforts should focus on harmonizing data acquisition methods, improving model interpretability, and externally validating these models in multicentered, prospective fashion.

  相似文献   
5.
6.
To express the core protein of HIV-1 of Chinese prevalent strain (HIV-1 (CN)) in Pichia pastoris, the fulllength gag gene was inserted into the secretory expression vector pHILS1. Linearized recombinant plasmid pHILGAG by Sail was electrotransformed into the yeast strain GS115, and the yeast transformants were identified by PCR. To induce the interest protein to be expressed, the PCR positive transformants were inoculated in the medium of BMGY and BMMY, mRNA of the strain was detected by RT-PCR, and the expressed protein was analyzed by SDS-PAGE, Western blotting and thin layer scanning. mRNA (1.3 kb) was amplified by RT-PCR. SDS-PAGE and Western blotting analysis showed that the molecular mass of the expressed protein was 55 kD, which was similar to the expected value, and the expressed protein could react with McAb to HIV-1 p24. Thin layer scanning analysis demonstrated that the whole amount of the expressed protein was approximately 13 % of the soluble protein in the supernatant. The recombinant yeast had good genetic stability. The optimal expression conditions of the engineering yeast were as follows: BMMY medium, 80-90% of dissolved oxygen, 1% methanol, and 3-day-cultivation course. Gag proteins were expressed under the optimal expression condition and purified via gel filtration chromatography. The purity of the interest protein was up to 85 %. After the purified proteins were inoculated into BALB/c mice, the anti-HIV-1 antibodies in the immunized mice could be detected by Western blotting.  相似文献   
7.
The majority of children with Juvenile Idiopathic Arthritis can nowadays be treated adequately. However despite the use of combinations of antirheumatic drugs, corticosteroids and the newer so called biologicals (blocking the TNF, Interleukin 1 or Interleukin 6 pathways) a proportion of children with arthritis remain resistant also to these therapies and suffer from a very severe, debilitating and potentially fatal disease. For such children autologous stem cell transplantation (ASCT) is successfully performed since 1997. Here we describe the long term outcome of the initial cohort of children with resistant Juvenile Idiopathic arthritis, treated with ASCT. The initial cohort of children was treated with a conditioning regimen containing Cyclophosphamide, anti thymocyte globulins and low dose Total Body irradiation. Overall favourable responses were seen, with a drug free remission rate of 50–55 %. In the more recent years late relapses were noted with lower percentages for drug free long term outcome. Special emphasis is given on 2 cases showing very late relapses, occurring after 7 and 9 years. The observed relapses are often less severe compared to the situation before SCT and can be treated successfully with conventional drugs in the majority of cases. More recently, ASCT was performed in 4 JIA children with a fludarabin containing regimen in stead of low dose TBI. With a 4 to 5 year follow up, these 4 patients are all in drug free full remission. Allogeneic transplant with an HLA matched family donor was reported in 2 JIA cases. Follow up of 1 and 3 year is sofar show clinical disease remission and tapering of medition. In conclusion, given the favourable long term outcome, SCT remains a valuable treatment option for children with drug resistant JIA.  相似文献   
8.
9.
Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries.  相似文献   
10.

The effects of smoking on survival in BM patients have yet to be reviewed and meta-analysed. However, previous studies have shown that smokers had a greater risk of dying from lung cancer compared to non-smokers. This meta-analysis, therefore, aimed to analyse the effects of cigarette smoking on overall survival (OS) and progression-free survival (PFS) in lung cancer BM patients. PubMed, Embase, Web of Science, Cochrane and Google Scholar were searched for comparative studies regarding the effects of smoking on incidence and survival in brain metastases patients up to December 2020. Three independent reviewers extracted overall survival (OS) and progression-free survival data (PFS). Random-effects models were used to pool multivariate-adjusted hazard ratios (HR). Out of 1890 studies, fifteen studies with a total of 2915 patients met our inclusion criteria. Amongst lung carcinoma BM patients, those who were smokers (ever or yes) had a worse overall survival (HR: 1.34, 95% CI 1.13, 1.60, I2: 72.1%, p-heterogeneity?<?0.001) than those who were non-smokers (never or no). A subgroup analysis showed the association to remain significant in the ever/never subgroup (HR: 1.34, 95% CI 1.11, 1.63) but not in the yes/no smoking subgroup (HR: 1.30, 95% CI 0.44, 3.88). This difference between the two subgroups was not statistically significant (p?=?0.91). Amongst lung carcinoma BM patients, smoking was associated with a worse OS and PFS. Future studies examining BMs should report survival data stratified by uniform smoking status definitions.

  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