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   1105篇
  免费   78篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   17篇
妇产科学   19篇
基础医学   229篇
口腔科学   17篇
临床医学   111篇
内科学   148篇
皮肤病学   18篇
神经病学   44篇
特种医学   27篇
外科学   206篇
综合类   13篇
预防医学   103篇
眼科学   2篇
药学   110篇
中国医学   4篇
肿瘤学   104篇
  2023年   7篇
  2022年   6篇
  2021年   15篇
  2020年   14篇
  2019年   28篇
  2018年   32篇
  2017年   24篇
  2016年   24篇
  2015年   22篇
  2014年   32篇
  2013年   56篇
  2012年   62篇
  2011年   48篇
  2010年   47篇
  2009年   23篇
  2008年   54篇
  2007年   60篇
  2006年   68篇
  2005年   68篇
  2004年   53篇
  2003年   49篇
  2002年   51篇
  2001年   33篇
  2000年   33篇
  1999年   23篇
  1998年   17篇
  1997年   11篇
  1996年   13篇
  1995年   8篇
  1994年   8篇
  1993年   6篇
  1992年   22篇
  1991年   14篇
  1990年   14篇
  1989年   12篇
  1988年   17篇
  1987年   21篇
  1986年   19篇
  1985年   16篇
  1984年   11篇
  1983年   4篇
  1982年   7篇
  1981年   4篇
  1980年   3篇
  1979年   4篇
  1975年   2篇
  1972年   2篇
  1970年   3篇
  1968年   4篇
  1964年   2篇
排序方式: 共有1185条查询结果,搜索用时 15 毫秒
41.
42.
The government of Kazakhstan, a middle-income country in Central Asia, is considering the introduction of rotavirus vaccination into its national immunization program. We performed a cost-effectiveness analysis of rotavirus vaccination spanning 20 years by using a synthesis of dynamic transmission models accounting for herd protection. We found that a vaccination program with 90% coverage would prevent ≈880 rotavirus deaths and save an average of 54,784 life-years for children <5 years of age. Indirect protection accounted for 40% and 60% reduction in severe and mild rotavirus gastroenteritis, respectively. Cost per life year gained was US $18,044 from a societal perspective and US $23,892 from a health care perspective. Comparing the 2 key parameters of cost-effectiveness, mortality rates and vaccine cost at <US $2.78 per dose, vaccination program costs would be entirely offset. To further evaluate efficacy of a vaccine program, benefits of indirect protection conferred by vaccination warrant further study.  相似文献   
43.
44.
45.
We conducted a second nationwide severe acute respiratory syndrome coronavirus 2 seroprevalence study in the Faroe Islands during November 2020. We found crude seroprevalence was 0.3% and prevalence was 0.4% after adjusting for test sensitivity and specificity. This low seroprevalence supports the prevention strategies used in the Faroe Islands.  相似文献   
46.
Embryonal carcinomas (ECs) and seminomas are testicular germ cell tumors. ECs display expression of SOX2, while seminomas display expression of SOX17. In somatic differentiation, SOX17 drives endodermal cell fate. However, seminomas lack expression of endoderm markers, but show features of pluripotency. Here, we use chromatin immunoprecipitation sequencing to report and compare the binding pattern of SOX17 in seminoma-like TCam-2 cells to SOX17 in somatic cells and SOX2 in EC-like 2102EP cells. In seminoma-like cells, SOX17 was detected at canonical (SOX2/OCT4), compressed (SOX17/OCT4) and noncomposite SOX motifs. SOX17 regulates TFAP2C, PRDM1 and PRDM14, thereby maintaining latent pluripotency and suppressing somatic differentiation. In contrast, in somatic cells canonical motifs are rarely bound by SOX17. In sum, only 12% of SOX17-binding sites overlap in seminoma-like and somatic cells. This illustrates that binding site choice is highly dynamic and cell type specific. Deletion of SOX17 in seminoma-like cells resulted in loss of pluripotency, marked by a reduction of OCT4 protein level and loss of alkaline phosphatase activity. Furthermore, we found that in EC-like cells SOX2 regulates pluripotency-associated genes, most likely by partnering with OCT4. In conclusion, SOX17 (in seminomas) functionally replaces SOX2 (in ECs) to maintain expression of the pluripotency cluster.  相似文献   
47.
48.
49.
BACKGROUND: Many members of the human kallikrein gene family are differentially expressed in cancer and a few have potential as diagnostic/prognostic markers. KLK14 is a newly discovered human kallikrein gene that is mainly expressed in the central nervous system and endocrine tissues. Since KLK14 was found to be regulated by steroid hormones in prostate cancer cell lines, we hypothesized that it will be differentially expressed in prostate cancer tissues compared to their normal counterparts. METHODS: Matched prostate tissue samples from the cancerous and non-cancerous parts of the same prostates were obtained from 100 patients who underwent radical prostatectomy. Quantitative analysis of KLK14 expression levels were performed by real-time RT-PCR using SYBR Green I dye on the LightCycler trade mark system. Associations with clinico-pathological parameters were analyzed. RESULTS: KLK14 overexpression in the cancerous compared to non-cancerous tissue was found in 74% of patients (P < 0.001). Mean level of expression was 154 arbitrary units (Au) in cancerous tissues and 14.2 Au in the non-cancerous tissues. The ratio of the cancerous to non-cancerous KLK14 expression values was higher in patients with late stage (stage III) compared to stage II (P = 0.002), and in grade 3 compared to grade 1/2 tumors (P = 0.001). A statistically significant increase was also observed in patients with higher in Gleason score (>6) compared to Gleason score = 6 tumors (P = 0.027). No correlation was found between KLK14 tissue expression levels and serum prostate-specific antigen. CONCLUSIONS: KLK14 expression is significantly higher in cancerous compared to non-cancerous prostatic tissue. The up-regulation of the KLK14 gene in advanced and more aggressive tumors may indicate a possible role for the hK14 protein in tumor spread and opens the possibility of hK14 being a candidate new marker for prostate cancer diagnosis and prognosis.  相似文献   
50.
MicroRNAs (miRNAs) are non-coding RNAs that regulate basic cellular processes and are associated with cancer characteristics. The aim of this review is to summarize the principles of miRNA biogenesis and function and to describe their contribution to tumor development, especially in uro-oncology. Therefore a PubMed search was conducted. Up to March 2009 approximately 4,500 miRNA-related articles were cited in this database. Studies of miRNA expression and functional analyses prove their impact in carcinogenesis and their potential as diagnostic or prognostic markers or as novel therapeutic targets. Only a few miRNA-related studies have been published in uro-oncology so far. Although tumor-specific miRNA expression has been shown for urological neoplasms, the contradicting data show that miRNA research is still in its infancy in this field. A systematic elucidation of characteristic miRNA abnormalities could decisively improve diagnostics as well as therapy of urological tumors.  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