全文获取类型
收费全文 | 2408973篇 |
免费 | 183412篇 |
国内免费 | 12679篇 |
专业分类
耳鼻咽喉 | 32190篇 |
儿科学 | 76240篇 |
妇产科学 | 65636篇 |
基础医学 | 342399篇 |
口腔科学 | 65293篇 |
临床医学 | 220035篇 |
内科学 | 462349篇 |
皮肤病学 | 54293篇 |
神经病学 | 188243篇 |
特种医学 | 92899篇 |
外国民族医学 | 730篇 |
外科学 | 355095篇 |
综合类 | 72885篇 |
现状与发展 | 32篇 |
一般理论 | 724篇 |
预防医学 | 180664篇 |
眼科学 | 55138篇 |
药学 | 185086篇 |
128篇 | |
中国医学 | 13226篇 |
肿瘤学 | 141779篇 |
出版年
2021年 | 23748篇 |
2019年 | 22108篇 |
2018年 | 29739篇 |
2017年 | 23750篇 |
2016年 | 26017篇 |
2015年 | 30541篇 |
2014年 | 41694篇 |
2013年 | 57973篇 |
2012年 | 79049篇 |
2011年 | 83770篇 |
2010年 | 50719篇 |
2009年 | 46990篇 |
2008年 | 74928篇 |
2007年 | 79124篇 |
2006年 | 79523篇 |
2005年 | 76131篇 |
2004年 | 71645篇 |
2003年 | 68878篇 |
2002年 | 65950篇 |
2001年 | 120837篇 |
2000年 | 123484篇 |
1999年 | 103081篇 |
1998年 | 28443篇 |
1997年 | 25744篇 |
1996年 | 25329篇 |
1995年 | 23918篇 |
1994年 | 21815篇 |
1993年 | 20265篇 |
1992年 | 76766篇 |
1991年 | 73533篇 |
1990年 | 71312篇 |
1989年 | 68224篇 |
1988年 | 62282篇 |
1987年 | 60540篇 |
1986年 | 56906篇 |
1985年 | 53800篇 |
1984年 | 40160篇 |
1983年 | 33841篇 |
1982年 | 19804篇 |
1979年 | 35416篇 |
1978年 | 24513篇 |
1977年 | 21118篇 |
1976年 | 19176篇 |
1975年 | 20568篇 |
1974年 | 24398篇 |
1973年 | 23503篇 |
1972年 | 22276篇 |
1971年 | 20551篇 |
1970年 | 19257篇 |
1969年 | 18212篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
141.
Xiaoyan Lu Isabelle R. Miousse Sandra V. Pirela Jodene K. Moore Stepan Melnyk 《Nanotoxicology》2016,10(5):629-639
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs. 相似文献
142.
143.
Benyam Kinde Harrison W. Gabel Caitlin S. Gilbert Eric C. Griffith Michael E. Greenberg 《Proceedings of the National Academy of Sciences of the United States of America》2015,112(22):6800-6806
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
144.
William R. C. Knight Cara R. Baker Nyree Griffin Wahyu Wulaningsih Mark Kelly Andrew R. Davies James A. Gossage 《British journal of cancer》2021,124(10):1653
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
145.
146.
147.
Rafiye Ciftciler Haluk Demiroglu Yahya Buyukasık Elifcan Aladag Salih Aksu Ibrahim C. Haznedaroglu Nilgun Sayınalp Osman Ozcebe Umit Yavuz Malkan Hakan Goker 《Clinical Lymphoma, Myeloma & Leukemia》2019,19(3):177-182
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148.
目的通过检查有龋及无龋母亲的口腔卫生状况,并通过随访收集其婴儿1个月(1月龄)及6个月(6月龄)的唾液样本测序分析,观察母亲患龋情况对其婴儿口腔微生物多样性的影响。方法通过筛查收集1月龄婴儿的唾液样本;于首次采样时记录母亲的口腔卫生状况,根据母亲患龋情况将婴儿分为母亲有龋组(简称有龋组)和母亲无龋组(简称无龋组),跟踪随访至婴儿6个月时再次收集唾液样本。通过高通量测序的方法,分析婴儿不同月龄微生物多样性的变化。结果本研究随访受试者10例(男6例,女4例),其中有龋组7例,无龋组3例,各组间的微生物群落多样性Shannon指数均无显著性差异(P>0.05)。无龋组婴儿1月龄至6月龄时微生物群落的物种组成有较大变化;有龋组婴儿在1月龄和6月龄时组内各样本间物种组成均差异较大;1月龄时两组微生物群落较相似,而至6月龄时两组婴儿唾液的物种组成已开始发生变化。结论有龋组婴儿口腔内菌群多样性总体高于无龋组,在1月龄至6月龄间婴儿口腔内微生物物种的多样性及丰度均有了不同程度的提高。 相似文献
149.
Provocation of Atrial Fibrillation Triggers During Ablation: Does the Use of General Anesthesia Affect Inducibility?
下载免费PDF全文
![点击此处可从《Journal of cardiovascular electrophysiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
150.