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   1387296篇
  免费   105026篇
  国内免费   10895篇
耳鼻咽喉   19115篇
儿科学   43311篇
妇产科学   38934篇
基础医学   200250篇
口腔科学   37263篇
临床医学   123409篇
内科学   267630篇
皮肤病学   27651篇
神经病学   105092篇
特种医学   54171篇
外国民族医学   444篇
外科学   208996篇
综合类   46978篇
现状与发展   41篇
一般理论   305篇
预防医学   100029篇
眼科学   32339篇
药学   109649篇
  95篇
中国医学   9525篇
肿瘤学   77990篇
  2021年   13642篇
  2019年   11972篇
  2018年   15901篇
  2017年   12544篇
  2016年   13541篇
  2015年   16949篇
  2014年   22536篇
  2013年   30047篇
  2012年   41882篇
  2011年   45161篇
  2010年   27020篇
  2009年   24602篇
  2008年   40873篇
  2007年   43763篇
  2006年   44174篇
  2005年   43524篇
  2004年   40075篇
  2003年   38776篇
  2002年   37833篇
  2001年   60526篇
  2000年   62164篇
  1999年   53492篇
  1998年   16150篇
  1997年   14765篇
  1996年   14591篇
  1995年   13793篇
  1994年   13013篇
  1992年   41905篇
  1991年   41090篇
  1990年   40504篇
  1989年   39272篇
  1988年   36576篇
  1987年   35758篇
  1986年   34079篇
  1985年   32403篇
  1984年   24041篇
  1983年   20913篇
  1982年   12428篇
  1979年   22684篇
  1978年   15877篇
  1977年   13729篇
  1976年   12970篇
  1975年   14201篇
  1974年   16683篇
  1973年   16076篇
  1972年   15318篇
  1971年   14229篇
  1970年   13214篇
  1969年   12731篇
  1968年   11978篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
51.
52.
53.
54.
55.
56.
57.
BackgroundIn the field of transplantation, inducing immune tolerance in recipients is of great importance. Blocking co-stimulatory molecule using anti-CD28 antibody could induce tolerance in a rat kidney transplantation model. Myeloid-derived suppressor cells (MDSCs) reveals strong immune suppressive abilities in kidney transplantation. Here we analyzed key genes of MDSCs leading to transplant tolerance in this model.MethodsMicroarray data of rat gene expression profiles under accession number GSE28545 in the Gene Expression Omnibus (GEO) database were analyzed. Running the LIMMA package in R language, the differentially expressed genes (DEGs) were found. Enrichment analysis of the DEGs was conducted in the Database for Annotation, Visualization and Integrated Discovery (DAVID) database to explore gene ontology (GO) annotation and their Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Their protein-protein interactions (PPIs) were provided by STRING database and was visualized in Cytoscape. Hub genes were carried out by CytoHubba.ResultsThree hundred and thirty-eight DEGs were exported, including 27 upregulated and 311 downregulated genes. The functions and KEGG pathways of the DEGs were assessed and the PPI network was constructed based on the string interactions of the DEGs. The network was visualized in Cytoscape; the entire PPI network consisted of 192 nodes and 469 edges. Zap70, Cdc42, Stat1, Stat4, Ccl5 and Cxcr3 were among the hub genes.ConclusionsThese key genes, corresponding proteins and their functions may provide valuable background for both basic and clinical research and could be the direction of future studies in immune tolerance, especially those examining immunocyte-induced tolerance.  相似文献   
58.
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   
59.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
60.
目的本研究立足于项目组前期研究的成果上,积极探索吉林辽宁两省目标设置水平的差异,并进一步探究受目标设置影响下的工作落实结果情况,探讨产生差异的原因。 方法以系统穷尽的方式收集吉林辽宁两省2000至2017年有关目标与工作落实情况的指标,利用Spearman相关和线性回归分析吉林辽宁两省目标设置对于突发应急工作落实情况的影响。 结果吉林辽宁两省突发应急领域的目标设置水平与工作落实情况总体均呈现上升趋势,截至2017年,吉林目标设置水平与工作落实情况分别为46%与60%,辽宁为60%与53.3%,且目标设置水平与工作落实呈正相关。 结论有公众需要为依据且定量可考的目标设置对于工作落实、推进、完善具有积极的正反馈作用,建立科学量化的突发应急目标设置评价体系是适宜可行的。  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