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   115711篇
  免费   11065篇
  国内免费   3872篇
耳鼻咽喉   957篇
儿科学   2387篇
妇产科学   1167篇
基础医学   29447篇
口腔科学   1741篇
临床医学   8255篇
内科学   18551篇
皮肤病学   3070篇
神经病学   6251篇
特种医学   3570篇
外国民族医学   35篇
外科学   8277篇
综合类   14354篇
现状与发展   25篇
预防医学   4265篇
眼科学   1084篇
药学   12975篇
  12篇
中国医学   3782篇
肿瘤学   10443篇
  2024年   196篇
  2023年   1747篇
  2022年   2907篇
  2021年   4379篇
  2020年   3679篇
  2019年   4356篇
  2018年   4500篇
  2017年   4270篇
  2016年   3925篇
  2015年   4602篇
  2014年   6529篇
  2013年   7621篇
  2012年   6354篇
  2011年   7610篇
  2010年   6153篇
  2009年   6202篇
  2008年   5865篇
  2007年   5534篇
  2006年   5055篇
  2005年   4429篇
  2004年   4116篇
  2003年   3623篇
  2002年   2947篇
  2001年   2460篇
  2000年   2231篇
  1999年   1890篇
  1998年   1838篇
  1997年   1693篇
  1996年   1494篇
  1995年   1499篇
  1994年   1314篇
  1993年   1124篇
  1992年   805篇
  1991年   721篇
  1990年   648篇
  1989年   512篇
  1988年   408篇
  1987年   354篇
  1986年   336篇
  1985年   681篇
  1984年   770篇
  1983年   486篇
  1982年   572篇
  1981年   471篇
  1980年   373篇
  1979年   319篇
  1978年   221篇
  1977年   209篇
  1976年   236篇
  1975年   152篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Background/objectiveObstructive sleep apnea (OSA) is independently associated with dyslipidemia, a surrogate marker of atherosclerosis. Low-density lipoprotein (LDL)-cholesterol is accepted as a major independent risk factor for cardiovascular disease. However, non-high-density lipoprotein (HDL)-cholesterol is a better marker of atherogenic dyslipidemia and recommended as a target of lipid lowering therapy. We aimed to assess the prevalence of atherogenic dyslipidemia, and relationship between OSA severity and serum LDL-cholesterol and non-HDL cholesterol levels in OSA patients.MethodsWe retrospectively evaluated treatment naïve 2361 subjects admitted to the sleep laboratory of a university hospital for polysomnography. All subjects’ lipid profile including total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and non-HDL-cholesterol were measured.ResultsOut of 2361 patients (mean age 49.6 ± 11.9 years; 68.9% male, apnea-hypopnea index 36.6 ± 28.4/h), 185 (7.8%) had no OSA and 2176 (92.2%) had OSA. Atherogenic dyslipidemia prevalence was high (57–66%) in OSA patients, and especially increased in severe OSA compared to other groups (p < 0.05). Though total and LDL-cholesterol did not differ between those with and without OSA, non-HDL-cholesterol (p = 0.020), and triglycerides (p = 0.001) were higher and HDL-cholesterol levels (p = 0.018) were lower in OSA patients than non-OSA. Non-HDL-cholesterol was significantly correlated with OSA severity (p < 0.001) and hypoxia parameters (p < 0.01), whereas LDL-cholesterol showed no correlation.ConclusionsAtherogenic dyslipidemia is highly prevalent and non-HDL-cholesterol levels are significantly increased, predominantly in severe OSA patients. Non-HDL-cholesterol but not LDL-cholesterol, is significantly correlated with OSA severity and hypoxia parameters. Therefore, it could be better to use non-HDL-cholesterol, which is a guideline recommended target of lipid therapy, as a marker of atherosclerotic cardiovascular risk in OSA patients.  相似文献   
62.
63.
目的探讨喉癌患者血小板表面血小板膜糖蛋白Ⅱb/Ⅲa纤维蛋白原受体(PAC-1)、血小板P-选择素(CD62P)阳性表达率以及与患者临床病理特征和复发的关系。方法选取2014年1月~2015年12月间在我院耳鼻喉科手术治疗的116例喉癌患者,随访≥2年,并选取同期在我院体检的健康人群60例为对照组,采用流式细胞仪检测法检测外周血PAC-1和CD62P阳性率,并分析与临床病理特征、复发的关系。结果喉癌患者PAC-1和CD62P阳性表达率分别为(17.82±1.76)%和(22.87±3.13)%,明显高于健康人群(P<0.05);而且在喉癌患者PAC-1表达和CD62P表达呈正相关性(r=0.238,P<0.05)。T3-T4分期或N2-N3分期患者PAC-1和CD62P阳性表达率高于T1-T2分期或N0-N1分期患者(P<0.05)。另外远处转移组PAC-1和CD62P阳性表达率高于未发生转移组(P<0.05);随访期间有24例患者复发,复发率为20.69%。复发喉癌患者PAC-1、CD62P阳性表达率分别为(17.02±0.85)%和(21.84±1.17)%,明显高于未复发的喉癌患者(P<0.05)。经Logistics回归分析,PAC-1和CD62P是喉癌患者复发的独立危险因素(P<0.05)。结论PAC-1和CD62P阳性表达率与喉癌患者T分期、淋巴结转移和远处转移密切相关,同时可作为喉癌局部复发、区域淋巴结转移、远处转移的预测指标。  相似文献   
64.
65.
白细胞介素4(IL-4)是T辅助2(Th2)介导的免疫反应的基本免疫调节细胞因子,IL-4具有复杂的信号系统和多效的功能,但在脑组织中,诸多研究发现IL-4可在炎症中保护认知功能。该文总结了关于IL-4保护认知功能的证据及机制,以及在阿尔茨海默病、缺血性脑血管病以及手术后认知功能障碍中IL-4保护认知功能的途径及证据。  相似文献   
66.
《Clinical therapeutics》2019,41(5):836-847
PurposeA role for the immune system in causing myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) is long suspected, but few studies have looked for specific autoantibodies that might contribute to the symptoms. Our aim was to look for evidence of antibodies to neuronal proteins in patients with ME/CSF.MethodsSera samples from 50 patients and 50 healthy individuals were sent coded to the Neuroimmunology Laboratory in Oxford. Screening for antibody binding to neuronal tissue was performed on brain tissue and neuronal cultures. Specific serum antibodies were assessed by antigen-specific cell-based assays and radioimmunoassays. After antibody testing, the associations between seropositive status and clinical data were investigated.FindingsOverall, 8 patients and 11 participants were found to have some serum immunoreactivity toward neuronal or neuromuscular junction proteins, but only 1 patient and 2 participants had specific serum antibodies. Nevertheless, seropositive status in patients with ME was associated with shorter duration since onset and a more severe disease.ImplicationsThe results indicate no overall increased frequency of antibodies to neuronal proteins in ME/CSF and no evidence of a specific antibody that might be causative or contribute to clinical features in patients. However, the association of seropositive status with shorter duration of disease and more severe symptoms suggests a possible role of antibodies at onset in some patients and should be the focus of future studies.  相似文献   
67.
68.
BackgroundBacteremia causes a major worldwide burden, in terms of financial and productivity costs, as well the morbidity and mortality it can ultimately cause. Proper treatment of bacteremia is a challenge because of the species-dependent response to antibiotics. The T2Bacteria Panel is a U.S. Food and Drug Administration–cleared and culture-independent assay for detection of bacteremia, including common ESKAPE pathogens—Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa—and provides species identification in as little as 3.6 h directly from blood.ObjectiveOur aim was to evaluate the T2Bacteria assay performance and potential to affect patient care in the emergency department (ED).MethodsED patients from a Louisiana and Florida center were enrolled as part of the T2Bacteria Panel clinical study, which was prospective and noninterventional. Blood samples for blood culture (BC) and T2Bacteria were matched in time and anatomic location.ResultsData from 137 ED patients were evaluated. Relative to BC, T2Bacteria showed 100% positive percent agreement and 98.4% negative percent agreement. In addition, for species on the T2Bacteria Panel, the T2Bacteria assay detected 25% more positives associated with infection, and on average identified the infectious species 56.6 h faster. The T2Bacteria assay covered 70.5% of all species detected by BC. Finally, relative to actual care, the T2Bacteria assay could have potentially focused therapy in 8 patients, reduced time to a species-directed therapy in 4 patients, and reduced time to effective therapy in 4 patients.ConclusionsIn this ED population, the T2Bacteria assay was a rapid and sensitive detector of bacteremia from common ESKAPE pathogens and showed the theoretical potential to influence subsequent patient therapy, ranging from antibiotic de-escalation to faster time to effective therapy.  相似文献   
69.
《Cancer cell》2021,39(11):1497-1518.e11
  1. Download : Download high-res image (282KB)
  2. Download : Download full-size image
  相似文献   
70.
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