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   65723篇
  免费   4394篇
  国内免费   1826篇
耳鼻咽喉   431篇
儿科学   944篇
妇产科学   600篇
基础医学   7571篇
口腔科学   1105篇
临床医学   6169篇
内科学   6610篇
皮肤病学   366篇
神经病学   8852篇
特种医学   2082篇
外国民族医学   2篇
外科学   4552篇
综合类   10413篇
现状与发展   6篇
一般理论   1篇
预防医学   9723篇
眼科学   694篇
药学   7293篇
  96篇
中国医学   2278篇
肿瘤学   2155篇
  2024年   145篇
  2023年   952篇
  2022年   1482篇
  2021年   2562篇
  2020年   2415篇
  2019年   1846篇
  2018年   1809篇
  2017年   1822篇
  2016年   2057篇
  2015年   2036篇
  2014年   4179篇
  2013年   4602篇
  2012年   4064篇
  2011年   4450篇
  2010年   3475篇
  2009年   3346篇
  2008年   3448篇
  2007年   3257篇
  2006年   2946篇
  2005年   2502篇
  2004年   2073篇
  2003年   1841篇
  2002年   1451篇
  2001年   1260篇
  2000年   1059篇
  1999年   898篇
  1998年   886篇
  1997年   859篇
  1996年   724篇
  1995年   684篇
  1994年   668篇
  1993年   576篇
  1992年   545篇
  1991年   529篇
  1990年   439篇
  1989年   387篇
  1988年   402篇
  1987年   378篇
  1986年   350篇
  1985年   470篇
  1984年   400篇
  1983年   244篇
  1982年   267篇
  1981年   246篇
  1980年   230篇
  1979年   149篇
  1978年   137篇
  1977年   122篇
  1976年   89篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
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   
52.
通过探讨DRG支付方式改革下医院财务管理的应对策略,可以有效地降低医疗支付方式改革对医院财务管理的负面影响,促使医院财务管理在"危"与"机"的转换中抢抓机遇,促进医院财务管理提质增效。  相似文献   
53.
54.
以培养创新型人才为目标,大连医科大学制定实施了“5+3”创新人才培养改革方案,以导师制培养为载体,在医学本科教育全过程中,制定分阶段创新能力培养体系,涵盖课程、讲座、实验设计、论文等基本科研能力训练,强化本科生科研能力培养。通过对首届“5+3”学生阶段性培养成果的统计学分析发现,“5+3”学生发表中文期刊、SCI,主持国家级创新项目、省级创新项目的比例均显著高于普通5年制学生,差异具有统计学意义(P<0.05)。虽然实施过程中存在一些问题和不足,但以导师制为核心的科研基础训练对提高学生科研思维和创新能力效果显著,对培养医学创新型人才具有可实施性。  相似文献   
55.
56.
57.
58.
59.
Purpose:It has been reported previously that intravenously administered gadolinium-based contrast agent (GBCA) leaks into the subarachnoid space around the cortical veins at 4 h after injection in all old people over 37 years, but not in younger people up to 37 years of age in 3D-real IR images. The purpose of this study was to investigate whether there was a strict threshold of 37 years of age for the leakage of the GBCA into the subarachnoid space.Methods:The subjects included 190 patients, that were scanned for 3D-real IR images at 4 hours after intravenous injection of GBCA as a diagnostic test for endolymphatic hydrops. The patient’s age ranged from 14 to 81 years. Two experienced neuroradiologists evaluated the images to determine whether the GBCA leakage around the cortical veins was positive or negative. Any discrepancies between the two observers were discussed and a consensus was obtained.A Mann–Whitney U test and receiver operating characteristic (ROC) curve analysis were used to compare the positive and the negative group and to set the age cut-off value for the prediction of GBCA leakage.Results:The GBCA leakage around the cortical veins was negative in 35 patients and positive in 155 patients. The average age was 33 ± 11 years in the negative group, and 55 ± 12 years in the positive group (P < 0.01). In the ROC analysis for the age and leakage of the GBCA, an area under the curve was 0.905 and the cut-off age was 37.317 years (sensitivity of 0.942 and specificity of 0.771).Conclusion:Intravenously administered GBCA leaks into the subarachnoid space around the cortical veins in most patients over 37 years of age. However, it should be noted that it can be found occasionally in patients under 37 years of age.  相似文献   
60.
ABSTRACT

Tryptophan (Trp) is not only a nutrient enhancer but also has systemic effects. Trp metabolites signaling through the well-known aryl hydrocarbon receptor (AhR) constitute the interface of microbiome-gut-brain axis. However, the pathway through which Trp metabolites affect central nervous system (CNS) function have not been fully elucidated. AhR participates in a broad variety of physiological and pathological processes that also highly relevant to intestinal homeostasis and CNS diseases. Via the AhR-dependent mechanism, Trp metabolites connect bidirectional signaling between the gut microbiome and the brain, mediated via immune, metabolic, and neural (vagal) signaling mechanisms, with downstream effects on behavior and CNS function. These findings shed light on the complex Trp regulation of microbiome-gut-brain axis and add another facet to our understanding that dietary Trp is expected to be a promising noninvasive approach for alleviating systemic diseases.  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