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   2391046篇
  免费   184725篇
  国内免费   4869篇
耳鼻咽喉   33427篇
儿科学   79602篇
妇产科学   69056篇
基础医学   345228篇
口腔科学   66589篇
临床医学   211358篇
内科学   469597篇
皮肤病学   53608篇
神经病学   191935篇
特种医学   92160篇
外国民族医学   793篇
外科学   363198篇
综合类   54056篇
现状与发展   4篇
一般理论   742篇
预防医学   184288篇
眼科学   55026篇
药学   175451篇
  2篇
中国医学   5204篇
肿瘤学   129316篇
  2018年   25224篇
  2017年   19147篇
  2016年   21696篇
  2015年   24594篇
  2014年   34448篇
  2013年   51731篇
  2012年   70435篇
  2011年   75083篇
  2010年   44337篇
  2009年   42037篇
  2008年   70738篇
  2007年   75640篇
  2006年   76639篇
  2005年   74576篇
  2004年   71695篇
  2003年   68771篇
  2002年   67177篇
  2001年   113182篇
  2000年   115913篇
  1999年   97325篇
  1998年   27811篇
  1997年   25053篇
  1996年   25174篇
  1995年   23877篇
  1994年   21980篇
  1993年   20660篇
  1992年   75803篇
  1991年   73477篇
  1990年   71612篇
  1989年   69049篇
  1988年   63749篇
  1987年   62499篇
  1986年   58978篇
  1985年   56296篇
  1984年   42498篇
  1983年   36471篇
  1982年   21952篇
  1981年   19519篇
  1979年   38921篇
  1978年   27562篇
  1977年   23272篇
  1976年   22105篇
  1975年   23593篇
  1974年   28074篇
  1973年   27069篇
  1972年   25575篇
  1971年   23536篇
  1970年   22160篇
  1969年   20979篇
  1968年   19724篇
排序方式: 共有10000条查询结果,搜索用时 875 毫秒
101.
102.
103.
104.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
105.
Background A high Mandard score implies a non-response to chemotherapy in oesophageal adenocarcinoma. However, some patients exhibit tumour volume reduction and a nodal response despite a high score. This study examines survival and recurrence patterns in these patients.Methods Clinicopathological factors were analysed using multivariable Cox regression assessing time to death and recurrence. Computed tomography-estimated tumour volume change was examined in a subgroup of consecutive patients.Results Five hundred and fifty-five patients were included. Median survival was 55 months (Mandard 1–3) and 21 months (Mandard 4 and 5). In the Mandard 4 and 5 group (332 patients), comparison between complete nodal responders and persistent nodal disease showed improved survival (90 vs 18 months), recurrence rates (locoregional 14.75 vs 28.74%, systemic 24.59 vs 48.42%) and circumferential resection margin positivity (22.95 vs 68.11%). Complete nodal response independently predicted improved survival (hazard ratio 0.34 (0.16–0.74). Post-chemotherapy tumour volume reduction was greater in patients with a complete nodal response (−16.3 vs −7.7 cm3, p = 0.033) with no significant difference between Mandard groups.Conclusion Patients with a complete nodal response to chemotherapy have significantly improved outcomes despite a poor Mandard score. High Mandard score does not correspond with a non-response to chemotherapy in all cases and patients with nodal downstaging may still benefit from adjuvant chemotherapy.Subject terms: Oesophageal cancer, Surgical oncology  相似文献   
106.
107.

Background

Refractory acute myeloid leukemia (AML) includes AML includes failure of disease to respond to standard induction chemotherapy, relapse within 6 months after first CR, and 2 or more relapses. The outcome of these patients is usually very poor; only a small proportion can be rescued by allogenic hematopoietic stem-cell transplantation (allo-HSCT). The aim of this study was to evaluate the efficacy and feasibility of allo-HSCT in patients with refractory AML.

Patients and Methods

We retrospectively analyzed the clinical outcome of 91 patients who were diagnosed with treatment-refractory AML at Hacettepe University Hospital between January 2002 and June 2018. Patients' disease status included refractory AML, defined as failure to respond to standard induction chemotherapy and relapse within 6 months after first complete remission.

Results

The median follow-up was 12 months (range, 0.5-184 months) for the entire group. Kaplan-Meier estimates of the 3-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 67% and 12%, respectively. Additionally, the Kaplan-Meier estimates of 5-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 44% and 4%, respectively (P < .001). Complete remission was obtained in 25 patients (83.3%) who underwent allo-HSCT; however, the disease of only 3 patients (3.8%) exhibited complete response after salvage chemotherapy.

Conclusion

Allo-HSCT is still the best-known treatment option with curative potential in patients with treatment-refractory AML. Therefore, all efforts should be made in an attempt to find a suitable matched donor in order to perform allo-HSCT.  相似文献   
108.
109.
110.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  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