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   66766篇
  免费   4498篇
  国内免费   1867篇
耳鼻咽喉   431篇
儿科学   970篇
妇产科学   611篇
基础医学   7802篇
口腔科学   1089篇
临床医学   6155篇
内科学   6804篇
皮肤病学   369篇
神经病学   9279篇
特种医学   2087篇
外国民族医学   2篇
外科学   4576篇
综合类   10570篇
现状与发展   6篇
预防医学   9741篇
眼科学   710篇
药学   7436篇
  97篇
中国医学   2301篇
肿瘤学   2095篇
  2024年   206篇
  2023年   1029篇
  2022年   1863篇
  2021年   2580篇
  2020年   2432篇
  2019年   1857篇
  2018年   1814篇
  2017年   1836篇
  2016年   2070篇
  2015年   2052篇
  2014年   4184篇
  2013年   4578篇
  2012年   4076篇
  2011年   4438篇
  2010年   3483篇
  2009年   3335篇
  2008年   3453篇
  2007年   3280篇
  2006年   2951篇
  2005年   2515篇
  2004年   2084篇
  2003年   1856篇
  2002年   1461篇
  2001年   1282篇
  2000年   1072篇
  1999年   904篇
  1998年   903篇
  1997年   875篇
  1996年   743篇
  1995年   696篇
  1994年   684篇
  1993年   597篇
  1992年   558篇
  1991年   546篇
  1990年   452篇
  1989年   406篇
  1988年   412篇
  1987年   402篇
  1986年   385篇
  1985年   501篇
  1984年   439篇
  1983年   267篇
  1982年   289篇
  1981年   262篇
  1980年   266篇
  1979年   166篇
  1978年   149篇
  1977年   137篇
  1976年   99篇
  1974年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
This study aimed at evaluating how encapsulation in a regular nanocarrier (NC) (providing extended circulation time) or in a brain-targeting NC (providing prolonged circulation time and increased brain uptake) may influence the therapeutic index compared with the unformulated drug and to explore the key parameters affecting therapeutic performance using a model-based approach. Pharmacokinetic (PK) models were built with chosen PK parameters. For a scenario where central effect depends on area under the unbound brain concentration curve and peripheral toxicity relates to peak unbound plasma concentration, dose-effect and drug-side effect curves were constructed, and the therapeutic index was evaluated. Regular NC improved the therapeutic index compared with the unformulated drug due to reduced peripheral toxicity, while brain-targeting NC enhanced the therapeutic index by lowering peripheral toxicity and increasing central effect. Decreasing drug release rate or systemic clearance of NC with drug still encapsulated could increase the therapeutic index. Also, a drug with shorter half-life would therapeutically benefit more from a NC encapsulation. This work provides insights into how a NC for brain delivery should be optimized to maximize the therapeutic performance and is helpful to predict if and to what extent a drug with certain PK properties would obtain therapeutic benefit from nanoencapsulation.  相似文献   
44.
Renal Denervation for Treatment of Cardiac Arrhythmias . It has now been more than a quarter of a century since modulation of the sympathetic nervous system was proposed for the treatment of cardiac arrhythmias of different origins. But it has also been some time since some of the early surgical attempts have been abandoned. With the development of ablation techniques, however, new approaches and targets have been recently introduced that have revolutionized our way of thinking about sympathetic modulation. Renal nerve ablation technology is now being successfully used for the treatment of resistant hypertension, but the indication spectrum might broaden and new therapeutic options might arise in the near future. This review focuses on the possible impact of renal sympathetic system modulation on cardiac arrhythmias, the current evidence supporting this approach, and the ongoing trials of this method in electrophysiological laboratories. We will discuss the potential roles that sympathetic modulation may play in the future.  相似文献   
45.
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   
46.
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   
47.
48.
49.
50.
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