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   59424篇
  免费   5093篇
  国内免费   2006篇
耳鼻咽喉   280篇
儿科学   2662篇
妇产科学   838篇
基础医学   5737篇
口腔科学   1097篇
临床医学   7488篇
内科学   11771篇
皮肤病学   734篇
神经病学   857篇
特种医学   979篇
外国民族医学   1篇
外科学   5910篇
综合类   9306篇
现状与发展   7篇
预防医学   10384篇
眼科学   298篇
药学   5076篇
  46篇
中国医学   1352篇
肿瘤学   1700篇
  2024年   141篇
  2023年   929篇
  2022年   1823篇
  2021年   2620篇
  2020年   2647篇
  2019年   2058篇
  2018年   1999篇
  2017年   2006篇
  2016年   2266篇
  2015年   2475篇
  2014年   4080篇
  2013年   4742篇
  2012年   4026篇
  2011年   4140篇
  2010年   3027篇
  2009年   2809篇
  2008年   2653篇
  2007年   2809篇
  2006年   2763篇
  2005年   2480篇
  2004年   1962篇
  2003年   1811篇
  2002年   1411篇
  2001年   1322篇
  2000年   1098篇
  1999年   937篇
  1998年   770篇
  1997年   693篇
  1996年   569篇
  1995年   516篇
  1994年   471篇
  1993年   374篇
  1992年   332篇
  1991年   314篇
  1990年   215篇
  1989年   211篇
  1988年   163篇
  1987年   127篇
  1986年   100篇
  1985年   137篇
  1984年   84篇
  1983年   66篇
  1982年   76篇
  1981年   63篇
  1980年   40篇
  1979年   40篇
  1978年   24篇
  1977年   25篇
  1976年   33篇
  1975年   15篇
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
31.
32.
33.
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   
34.
张莹莹  王才智 《安徽医药》2016,37(5):550-553
目的 研究胎膜早破孕妇生殖道感染情况及对妊娠结局的影响。方法 选择2014年5月至2015年1月住院分娩的胎膜早破孕妇70例为早破组,同期无胎膜早破70例为对照组,检测两组生殖道病原微生物感染情况,并比较两组的妊娠结局。结果 早破组生殖道感染阳性率高于对照组,且剖宫产率,母体发生产后出血,绒毛膜羊膜炎,胎儿窘迫及新生儿窒息发生率均高于对照组,差异均有统计学意义(P<0.05)。结论 生殖道感染是胎膜早破最常见的诱因,积极筛查及治疗孕妇生殖道感染可以减少相关产科并发症的发生。  相似文献   
35.
Helicobacter pylori (H. pylori) is a main risk factor for gastric cancer (GC). Epithelial-mesenchymal transition (EMT) is involved in the development and progression of H. pylori-associated GC. However, the exact molecular mechanism of this process remains unclear. The AKT/GSK3β signaling pathway has been demonstrated to promote EMT in several types of cancer. The present study investigated whether H. pylori infection induced EMT, and promoted the development and metastasis of cancer in the normal gastric mucosa, and whether this process was dependent on AKT activation. The expression levels of the EMT-associated proteins, including E-cadherin and N-cadherin, were determined in 165 gastric mucosal samples of different disease stages by immunohistochemical analysis. The expression levels of E-cadherin, N-cadherin, AKT, phosphorylated (p-)AKT (Ser473), GSK3β and p-GSK3β (Ser9) were further determined in H. pylori-infected Mongolian gerbil gastric tissues and cells co-cultured with H. pylori by immunohistochemical analysis and western blotting. The results indicated that the expression levels of the epithelial marker E-cadherin were decreased, whereas the expression levels of the mesenchymal marker N-cadherin were increased during gastric carcinogenesis. Their expression levels were associated with H. pylori infection. Furthermore, H. pylori infection resulted in downregulation of E-cadherin expression and upregulation of N-cadherin expression in Mongolian gerbils and GES-1 cells. In addition, an investigation of the associated mechanism of action revealed that p-AKT (Ser473) and p-GSK3β (Ser9) were activated in GES-1 cells following co-culture with H. pylori. Furthermore, following pretreatment of the cells with the AKT inhibitor VIII, the expression levels of E-cadherin, N-cadherin, p-AKT and p-GSK3β did not show significant differences between GES-1 cells that were co-cultured with or without H. pylori. The levels of p-AKT and p-GSK3β were increased in H. pylori-infected Mongolian gerbils. In conclusion, the present study demonstrated that H. pylori infection activated AKT and resulted in the phosphorylation and inactivation of GSK3β, which in turn promoted early stage EMT. These effects were AKT-dependent. This mechanism may serve as a prerequisite for GC development.  相似文献   
36.
37.
新型冠状病毒肺炎(简称新冠肺炎, COVID-19)是近期流行的一种新发传染病,已造成大量人员感染,其中包括医务人员。为预防生殖医学的医院感染,有效降低新冠肺炎在生殖专科机构传播的风险,通过查询相关文献、指南和规范等,并结合生殖医学特点,制定生殖医学有关的临床区、手术室和实验室及相关人员预防新冠肺炎的措施。  相似文献   
38.
BACKGROUND Accurate detection of gastric infection by Helicobacter pylori(H.pylori) and premalignant lesions are important for effective provision of treatment,preventing the development of gastric neoplasia.Optical enhancement systems with optical magnification improved the identification of mucosal superficial and vascular patterns in patients with dyspepsia.AIM To evaluate an optical enhancement system with high-definition magnification,for diagnosis of normal gastric mucosa,H.pylori-associated gastritis,and gastric atrophy.METHODS A cross-sectional,nonrandomized study from November 2015 to April 2016 performed in a single-tertiary academic center from Ecuador.Seventy-two consecutive patients with functional dyspepsia according to the Rome III criteria,were tested for H.pylori using a stool antigen test and were assigned to an Hp+group or an Hp-control group.Esophagogastroduodenoscopy with highdefinition optical magnification and digital chromoendoscopy was performed,and patients were classified into 4 groups,in accordance to the microvasculararchitecture pattern of the mucosa.Interobserver and intraobserver agreement among operators were calculated.RESULTS Of the 72 participants,35 were Hp+ and 37 were Hp-.Among 10 patients with normal mucosal histology in biopsy samples,90% had a Type I pattern of microvascular architecture by endoscopy.Among participants with type IIa and type IIb patterns,significantly more were Hp+ than Hp-(32 vs 8),and most(31 out of 40) had histological diagnoses of chronic active gastritis.Two of the three participants with a histological diagnosis of atrophy had a type III microvascular pattern.The type I pattern predicted normal mucosa,type IIa–IIb predicted H.pylori infection,and type III predicted atrophy with sensitivities of 90.0%,91.4%,and 66.7%,respectively.The intraobserver and interobserver agreements had kappa values of 0.91 and 0.89,respectively.CONCLUSION High-definition optical magnification with digital chromoendoscopy is useful for diagnosis of normal gastric mucosa and H.pylori-associated gastritis with high accuracy,but further studies are needed to determine whether endoscopic diagnosis of gastric atrophy is feasible.  相似文献   
39.
40.
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