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   2876篇
  免费   127篇
  国内免费   49篇
耳鼻咽喉   19篇
儿科学   59篇
妇产科学   22篇
基础医学   281篇
口腔科学   78篇
临床医学   280篇
内科学   363篇
皮肤病学   15篇
神经病学   166篇
特种医学   133篇
外科学   638篇
综合类   394篇
预防医学   162篇
眼科学   33篇
药学   266篇
  3篇
中国医学   55篇
肿瘤学   85篇
  2024年   12篇
  2023年   49篇
  2022年   80篇
  2021年   122篇
  2020年   76篇
  2019年   77篇
  2018年   77篇
  2017年   84篇
  2016年   73篇
  2015年   95篇
  2014年   217篇
  2013年   176篇
  2012年   151篇
  2011年   183篇
  2010年   142篇
  2009年   141篇
  2008年   137篇
  2007年   160篇
  2006年   118篇
  2005年   105篇
  2004年   76篇
  2003年   77篇
  2002年   69篇
  2001年   59篇
  2000年   57篇
  1999年   53篇
  1998年   56篇
  1997年   35篇
  1996年   27篇
  1995年   32篇
  1994年   20篇
  1993年   23篇
  1992年   25篇
  1991年   25篇
  1990年   18篇
  1989年   13篇
  1988年   17篇
  1987年   17篇
  1986年   10篇
  1985年   11篇
  1984年   7篇
  1983年   6篇
  1982年   7篇
  1981年   8篇
  1980年   6篇
  1979年   5篇
  1978年   4篇
  1977年   3篇
  1976年   4篇
  1974年   2篇
排序方式: 共有3052条查询结果,搜索用时 531 毫秒
81.
目的 探索批质量保证二次抽样法 (DLQAS)在抗疟药对恶性疟疗效监测中应用的可能性。 方法 在现场按WHO推荐的 2 8d体内法氯喹疗效评估方案收集病例 ,给予氯喹治疗 ,判定治疗失败与否 ,比较传统的流行病学方法与DLQAS法对疗效判定的结果 ,评估和比较对样本量的需求。 结果 传统方法调查到治疗失败率为 40 .7% ,DLQAS法第一阶段和第二阶段调查到治疗失败率均大于WHO推荐换用药物治疗失败率上限 2 5 % ;DLQAS法的样本量比传统的流行病学横断面抽样方法少。 结论 DLQAS的现场调查治疗失败判定结果同传统流行病学方法 ,且样本量小、快速 ,适用于对抗疟药治疗恶性疟疗效监测的现场评估。  相似文献   
82.

Background

It is being increasingly reported that some of the youth onset diabetes patients cannot be classified clearly as type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM) based on usual criteria and the term double diabetes (DD) coined for these cases.

Aim

The objective of the study was to find out the prevalence of DD in youth onset diabetes patients from east Delhi and neighboring NCR region.

Methods

A total of 200 patients with youth onset diabetes below 25 years of age were recruited from a tertiary care hospital in East Delhi. Clinical history, family history of diabetes and anthropometry of patients were recorded. Fasting serum C-peptide, Anti-IA2-antibody and Anti-GAD-antibody were measured in all patients. Patients positive for Anti-GAD-antibody (>1.05 U/ml) and C-peptide level >0.3 nmol/l were characterized as DD patients. Patients negative for Anti-GAD-antibody and C-peptide >0.3 nmol/l were kept under the category of T2DM. Patients with low C-peptide level along with one of the following, positive Anti-GAD-antibody, positive Anti-IA2-antibody and diabetic ketoacidosis (DKA) were considered as T1DM. Remaining patients were kept under the unknown category.

Results

Mean age of study subjects was 18.2 ± 7.1 years. Seven percent (7%) of the subjects were classified as DD, 51% as T1DM, 13% as T2DM and 29% were kept under the unknown category. Mean age of subjects with 22.2 ± 9.7, 16.9 ± 6.7, 20.6 ± 7.7 and 19.4 ± 7.4 years in DD, T1DM, T2DM and unknown category respectively. Mean BMI of subjects with DD, T1DM, T2DM and unknown category was 19.8 ± 5.7, 16.6 ± 3.7, 19.3 ± 4.1 and 18.0 ± 4.6 kg/m2 respectively.

Conclusion

Double diabetes is an important occurrence among youth onset diabetes subjects. Only half of the subjects with youth onset of diabetes had T1DM.  相似文献   
83.
ObjectiveThis study aimed to investigate the effects of long-term use on the retention force and wear behavior of double crown systems.MethodsBased on a common double crown design sixty pairs of telescopic crowns were fabricated and divided into six groups, each consisting ten samples: “Gold standard” cast gold alloy primary and secondary crown (GG) and cast non-precious alloy (NN), computer-aided design (CAD)/computer-aided manufacturing (CAM)-milled zirconia primary crown and galvanoformed secondary crown (ZG), CAD/CAM-milled non-precious alloy primary and secondary crown (CC NN), CAD/CAM-milled zirconia primary crown and non-precious alloy secondary crown (CC ZN) and CAD/CAM-milled zirconia primary crown and polyetheretherketone (PEEK) secondary crown (CC ZP). In the constant presence of artificial saliva, all samples were subjected to 10,000 joining-separation cycles at a velocity of 120 mm/min. Wear was analyzed by reflected light microscopy and confocal microscopy before and after artificial aging.ResultsRetention force losses were observed in each group after long-term use, with significant losses in the groups ZG and CC ZP (pZG = 0.01, pCC ZP = 0.049). During artificial aging, no significant differences in pull-off force were recorded for groups GG, NN and CC ZN. Regarding wear, merely the Y-TZP primary crowns of the CC ZP group displayed no surface changes.SignificanceAll tested production methods and material combinations seem to be suitable for clinical practice. CAD/CAM technology allows similarly predictable results to be achieved as the gold standard. Confocal microscopy is recommended for surface examinations of double crowns.  相似文献   
84.
The argument of whether or not Oral and Maxillofacial Surgery (OMFS) should have both dental and medical core education in the training pathway remains an issue of debate and contention to date. The mid-90s witnessed a gradual trend internationally towards a dual qualification which has slowed down or come to a standstill the last 10 years. This has been more evident in rapidly growing nations in the Middle East/North Africa and Asian subcontinent regions. The maxillofacial identity of a dual degree is being questioned in OMFS-pioneering countries, such as the United Kingdom (UK), which has played a role in the domination of the single degree pathway globally. In this mini review, we will attempt to shed light on the aforementioned regions and put forward a more global role the UK can play in standardising education and training while addressing the cost burden of the dual qualification pathway.  相似文献   
85.
针对生物药剂学实验课程教学存在的落后现象,从实验教学课程体系、教学模式、实验教材及大纲、考核标准与方法等方面进行改革,从人才培养体系整体出发,形成“以能力培养为主线,一个中心,三个层次、三个内容”的科学系统的实验课程教学体系,为建设“双一流”大学药学院学科、培养高素质药学人才提供参考。  相似文献   
86.
Granulocyte‐monocyte apheresis (GMA) is an emerging therapeutic option in active course of ulcerative colitis (UC). Appropriate GMA dose, including total number, frequency, and duration of the individual GMA session, is a matter of debate. It was the aim of the present study to evaluate the efficacy of a dose‐intensified GMA regimen in patients with moderately to severely active UC. A prospective open‐label, single‐center study was performed in 10 patients with active UC (Rachmilewitz Clinical Activity Index [CAI] ≥ 8 points; Rachmilewitz Endoscopic Index ≥ 7 points). Patients had failed to improve after treatment with steroids and/or immunomodulators. GMA was performed twice weekly for 2 h to a maximum of 10 sessions. In each GMA session, the adsorber was changed after 1 h of treatment time. Four patients achieved remission with a CAI ≤ 4 points. Three patients had a response with an improvement of CAI of ≥3 points. Three patients showed no benefit from GMA. The quality of life score determined by the inflammatory bowel disease questionnaire‐Deutschland increased by 26 points in median. First and second filters had similar efficiency in granulocyte and monocyte adsorption. No major adverse effects were observed. Dose‐intensified GMA as reported in this study provided an encouraging short‐term response rate of 70% in patients with moderately to severely active UC not responding to standard steroid or immunomodulator therapy. Although all patients relapsed not later than 16 weeks, GMA might be useful to reduce steroid and immunomodulator usage, or to delay surgery in this patient group.  相似文献   
87.
88.
目的 对比单双侧椎体后凸成形术(PKP)治疗骨质疏松性单一胸腰椎压缩骨折的临床疗效.方法 回顾性分析自2010-06-2013-04北京积水潭医院脊柱科诊治的PKP患者451例,分为单侧和双侧入路组.评价指标:手术时间、透视次数、骨水泥量、VAS评分、椎体高度、Cobb角及骨水泥渗漏.结果 所有患者均顺利完成手术.平均手术时间、骨水泥填充量、平均手术时间、骨水泥注射量、X线曝光时间2组比较,差异有统计学意义(P<0.05).2组术后VAS评分、平均椎体高度、Cobb角较术前显著改善,差异有统计学意义(P<0.05).2组骨水泥渗漏率相似,差异无统计学意义(P>0.05).结论 单侧入路行PKP治疗骨质疏松性单椎体骨折比双侧入路具有手术时间更短、X线放射次数更少等优点,能取得经双侧入路穿刺相似的治疗效果.  相似文献   
89.
Double orifice mitral valve; a coincidental finding.   总被引:1,自引:0,他引:1  
A double orifice mitral valve (DOMV) represents a rare congenital malformation characterised by two valve orifices with two separate subvalvular apparatus. This case demonstrates the necessity of careful imaging of the mitral valve apparatus, not only in patients with atrioventricular septal defects, but also in patients with congenital left obstructive heart disease.  相似文献   
90.
PURPOSE: In patients with chronic genotype 1b hepatitis C and a high viral load, the viral load was reduced by double filtration plasmapheresis (DFPP), followed by combined interferon and ribavirin therapy. The safety and virological effects of this treatment method were preliminarily investigated. METHODS: In nine patients with chronic hepatitis C, DFPP was performed three times on days 1, 2, and 4, and the administration of interferon and ribavirin was initiated immediately after DFPP on day 1. RESULT: The HCV RNA was undetectable in all patients after the plasma was passed through a plasma fractionator (second filter) in the DFPP circuit. After 2 weeks, the HCV RNA tended to decrease in the DFPP group more than in the control group (-2.45+/-1.12 versus -1.57+/-0.95, P=0.073). However, this decrease was not attributable to a sustained virological response (SVR) (22.2% versus 18.2%, P=0.822). Most of the adverse events were caused by the interferon and ribavirin combination therapy. CONCLUSION: DFPP can be safely performed concomitantly with interferon and ribavirin combination therapy in chronic hepatitis C patients. The combination may contribute to an early virological response. The effect of DFPP on the SVR and its significance remain to be clarified.  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