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   68903篇
  免费   4525篇
  国内免费   1760篇
耳鼻咽喉   449篇
儿科学   967篇
妇产科学   598篇
基础医学   7918篇
口腔科学   1131篇
临床医学   6481篇
内科学   7006篇
皮肤病学   391篇
神经病学   9021篇
特种医学   2172篇
外国民族医学   2篇
外科学   4735篇
综合类   10971篇
现状与发展   6篇
预防医学   10189篇
眼科学   708篇
药学   7581篇
  108篇
中国医学   2561篇
肿瘤学   2193篇
  2024年   779篇
  2023年   1323篇
  2022年   2073篇
  2021年   2789篇
  2020年   2694篇
  2019年   2073篇
  2018年   1957篇
  2017年   1968篇
  2016年   2171篇
  2015年   2120篇
  2014年   4285篇
  2013年   4638篇
  2012年   4123篇
  2011年   4476篇
  2010年   3511篇
  2009年   3378篇
  2008年   3467篇
  2007年   3272篇
  2006年   2967篇
  2005年   2507篇
  2004年   2085篇
  2003年   1854篇
  2002年   1452篇
  2001年   1259篇
  2000年   1057篇
  1999年   897篇
  1998年   897篇
  1997年   862篇
  1996年   726篇
  1995年   682篇
  1994年   673篇
  1993年   573篇
  1992年   543篇
  1991年   530篇
  1990年   437篇
  1989年   388篇
  1988年   400篇
  1987年   377篇
  1986年   348篇
  1985年   474篇
  1984年   411篇
  1983年   248篇
  1982年   267篇
  1981年   243篇
  1980年   228篇
  1979年   147篇
  1978年   139篇
  1977年   124篇
  1976年   89篇
  1974年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
目的对医院信息系统大型数据库中积累的病人资料进行挖掘和利用,为医院的经营管理服务。方法引入客户关系管理的概念,构建了3类医院客户分析系统。结果对病人的一般信息、就诊信息、消费水平、付费方式等内容的多重分类分析可产生医院不同的客户群体;对病人就诊、治疗情况的分类分析,可发现某种疾病的发病和潜在发病情况;对体检结果、手术情况的单项分析,可对病人提出随诊建议。结论医院客户关系管理拓展了医院信息系统的功能,有助于病人资源的管理,对不同的客户群体针对性地采取差异性服务,有利于保持和增加病人资源,提高医院效益。  相似文献   
72.
An automated assay of plasma prekallikrein is described. Prekallikrein was converted to kallikrein with Pseudomonas aeruginosa elastase, and the hydrolytic activity of kallikrein to H-D-Pro-Phe-Arg-paranitroanilide subsequently measured.

The conversion was complete within 8 minutes and the amidolytic activity remained stable at least another 10 min at 37 ° C. This method worked in plasma deficient in Hageman factor (blood coagulation factor XII). Using anti-prekallikrein antibody and plasma deficient in prekallikrein, the amidolytic activity generated in normal plasma was identified as due to kallikrein. With plasma samples, the coefficients of variation (CV) for multiple measurements within run (n = 10) and between run (n = 10) were as low as 5.0% and 6.6%, respectively, and the minimum measurable concentration of prekallikrein in plasma was 10% of the normal level.  相似文献   

73.
74.
Australia has a large migrant population with variable fluency in English. Interpreting services help ensure that healthcare services are delivered appropriately to these populations. However, the use of professional interpreters in hospitals is expensive. There are also issues with service availability and convenience. Mobile devices containing software with translating abilities have promising potential to improve communication between patients and hospital staff as an adjunct to professional interpreters. It is highly convenient and inexpensive. There are concerns about the accuracy of the interpretation done with such software and more research needs to be carried out to support or allay these concerns. For now, clinically important and medicolegal related interpretation should be undertaken by professional interpreters whereas less crucial tasks may be performed with the help of interpreting software on mobile devices.  相似文献   
75.
Stroke is usually treated by systemic thrombolytic therapy if the patient presents within an appropriate time window. There is also widespread interest in the development of thrombolytic agents that can be used in cases of delayed presentation. Current agents that can be used in cases of delayed presentation of nerve damage by thrombus. Current systemic thrombolytic therapy is associated with adverse effects such as fibrinogenolysis and bleeding. In an attempt to increase the efficacy, safety, and specificity of thrombolytic therapy, a number of targeted thrombolytic agents have been studied in recent years. This review focuses on the concepts underlying targeted thrombolytic therapy and describes recent drug developments in this field.  相似文献   
76.
77.
78.

Purpose

The research questions of the present study were: (1) Is total knee prosthesis wear behaviour influenced by implant size, body weight and their combined effect? (2) Are these findings significant and helpful from a clinical point of view?

Methods

Two very different sizes of the same total knee prosthesis (TKP), previously tested with ISO 14243 parameters, were tested on a knee simulator for a further two million cycles using a modified ISO 14243 load waveform. Roughness examination was performed on the metallic components. Gravimetric and micro-Raman spectroscopic analyses were carried out on the polyethylene inserts.

Results

The average volumetric mass loss was 69 ± 3 mm3 and 88 ± 4 mm3 for smaller and bigger size, respectively. Bigger TKPs are little influenced by an increased load, while the wear trend of the smaller TKP showed a redoubled slope, and more significant morphology changes were observed. However, the two sizes seem to behave similarly when subjected to a load increase of 15 %; the slope of the volumetric mass loss trend was comparable for the two sets of inserts, which did not appear significantly different also at the molecular level. Roughness average parameters of the lateral femoral condyle support this evidence.

Conclusions

It can be asserted that the body weight and implant size are relevant to the understanding of TKP wear behaviour. A post-implantation body weight increase in a patient with smaller knee dimensions could results in more critical effects on prosthesis long-term performance.  相似文献   
79.
Management of osteonecrosis of the jaw associated with antiresorptive agents is challenging, and outcomes are unpredictable. The severity of disease is the main guide to management, and can help to predict prognosis. Most available staging systems for osteonecrosis, including the widely-used American Association of Oral and Maxillofacial Surgeons (AAOMS) system, classify severity on the basis of clinical and radiographic findings. However, clinical inspection and radiography are limited in their ability to identify the extent of necrotic bone disease compared with computed tomography (CT). We have organised a large multicentre retrospective study (known as MISSION) to investigate the agreement between the AAOMS staging system and the extent of osteonecrosis of the jaw (focal compared with diffuse involvement of bone) as detected on CT. We studied 799 patients with detailed clinical phenotyping who had CT images taken. Features of diffuse bone disease were identified on CT within all AAOMS stages (20%, 8%, 48%, and 24% of patients in stages 0, 1, 2, and 3, respectively). Of the patients classified as stage 0, 110/192 (57%) had diffuse disease on CT, and about 1 in 3 with CT evidence of diffuse bone disease was misclassified by the AAOMS system as having stages 0 and 1 osteonecrosis. In addition, more than a third of patients with AAOMS stage 2 (142/405, 35%) had focal bone disease on CT. We conclude that the AAOMS staging system does not correctly identify the extent of bony disease in patients with osteonecrosis of the jaw.  相似文献   
80.

Introduction

The aim of this study was to evaluate the micromorphologic changes that accompany different surface treatments on mineral trioxide aggregate (MTA) and their effect on the bond strength to the composite resin with 4 adhesive systems.

Methods

Three types of MTA cement, ProRoot MTA (WMTA) (Dentsply, Tulsa, OK), MTA Angelus (AMTA) (Angelus, Londrina, PR, Brazil), and Endocem MTA (EMTA) (Maruchi, Wonju, Korea), were prepared and stored for a week to encourage setting. Surface treatment was performed using phosphoric acid or self-etch primer, and an untreated MTA surface was prepared as a control. The surface changes were observed using scanning electron microscopy. MTA surfaces were bonded with 4 adhesive systems, including Scotchbond Multipurpose (3M ESPE, St Paul, MN), Single Bond 2 (3M ESPE), Clearfil SE BOND (Kuraray, Osaka, Japan), and AdheSE One F (Ivoclar Vivadent, Schaan, Liechtenstein), to evaluate the adhesive effectiveness of MTA followed by composite resin restoration. The shear bond strength of the polymerized specimens was tested.

Results

For WMTA and AMTA, untreated surfaces showed an irregular crystalline plate with clusters of globular aggregate particles. For EMTA, the untreated surface presented a reticular matrix with acicular crystals. After surface treatment, superficial crystalline structures were eroded regardless of the MTA cement and adhesive system used. WMTA bonded significantly more strongly than AMTA and EMTA, regardless of the adhesive system used. In the WMTA and AMTA groups, AdheSE One F showed the highest bond strength to the composite. For EMTA, no significant differences were found across adhesive systems.

Conclusions

Acidic treatment of the MTA surface affected the micromorphology and the bond strength to the composite. Within the limitations of this study, using a 1-step self-etch adhesive system might result in a strong bond to WMTA when the composite resin restoration is required over MTA cement.  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