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   368001篇
  免费   23301篇
  国内免费   1683篇
耳鼻咽喉   4953篇
儿科学   12053篇
妇产科学   11324篇
基础医学   53815篇
口腔科学   8511篇
临床医学   31615篇
内科学   71191篇
皮肤病学   7061篇
神经病学   27125篇
特种医学   14459篇
外国民族医学   49篇
外科学   57493篇
综合类   11501篇
现状与发展   4篇
一般理论   225篇
预防医学   25101篇
眼科学   8264篇
药学   26029篇
  18篇
中国医学   1795篇
肿瘤学   20399篇
  2021年   4598篇
  2020年   2979篇
  2019年   4147篇
  2018年   5962篇
  2017年   4424篇
  2016年   4841篇
  2015年   5783篇
  2014年   7764篇
  2013年   10647篇
  2012年   14755篇
  2011年   15147篇
  2010年   9552篇
  2009年   8469篇
  2008年   13401篇
  2007年   14302篇
  2006年   14038篇
  2005年   13479篇
  2004年   12609篇
  2003年   11801篇
  2002年   11032篇
  2001年   14153篇
  2000年   14258篇
  1999年   12089篇
  1998年   3702篇
  1997年   3416篇
  1996年   3129篇
  1995年   2980篇
  1994年   2724篇
  1992年   8645篇
  1991年   8744篇
  1990年   8515篇
  1989年   8303篇
  1988年   7547篇
  1987年   7253篇
  1986年   6914篇
  1985年   6729篇
  1984年   4977篇
  1983年   4281篇
  1982年   2657篇
  1979年   4565篇
  1978年   3343篇
  1977年   2842篇
  1976年   2597篇
  1975年   2919篇
  1974年   3447篇
  1973年   3465篇
  1972年   3188篇
  1971年   3025篇
  1970年   2897篇
  1969年   2630篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
近年来,笔者采用桃红四物汤治疗雷诺氏病44例,疗效满意,现报告如下. 一般资料 44例患者均为门诊病人,其中女性35例,男性9例;年龄16~58岁,平均26.7岁;病程1~6个月13例,7个月~1年22例,1年以上9例.主要症状均表现为手指皮肤苍白,继而青紫,先从手指尖开始,逐渐累及手指或全掌,呈典型的“手套征”,伴有局部冷、麻、针刺样疼痛或其他异常感觉,接触冷水或遇寒冷或情绪变化时发作,一般脉象沉细.本病发作十数分钟至1小时后症状可自行消失,严重者须保暖治疗(如将患指浸于温水中)方可缓解,皮肤转为潮红,然后恢复正常肤色.  相似文献   
105.
To reduce racial and ethnic disparities in health care, managers, policy makers, and researchers need valid and reliable data on the race and ethnicity of individuals and populations. The federal government is one of the most important sources of such data. In this paper we review the strengths and weaknesses of federal data that pertain to racial and ethnic disparities in health care. We describe recent developments that are likely to influence how these data can be used in the future and discuss how local programs could make use of these data.  相似文献   
106.
107.
108.
Toby O. Smith   《Physiotherapy》2006,92(3):135-145
Pretibial lacerations and lower limb wounds are referred to plastic surgery teams for split skin graft surgery. Traditionally, these patients have been immobilised on bedrest following surgery. More recently, patients have commenced ambulation earlier to avoid medical complications and facilitate discharge. The objective of this literature review was to determine when such patients should begin walking. A literature search was undertaken using the electronic databases AMED, Cinahl, Embase, Medline (via Ovid), PEDro and Pubmed. Clinical trials using human subjects, written in English, were included. Seventeen (of 1137) papers met the inclusion criteria and were reviewed. The literature suggested that patients should begin walking immediately or at the earliest possible opportunity after lower limb skin graft surgery. Although the literature advocated early ambulation, the evidence base presented with a number of recurrent methodological limitations, including small sample sizes, lack of a control sample, and limited follow-up. Accordingly, further research employing large, well-designed, randomised controlled trials is recommended. It will then be possible to understand with greater certainty when patients should begin walking after lower extremity split skin graft surgery.  相似文献   
109.
BACKGROUND/AIMS: The purpose of this work was to develop a new sensor for objective in vivo measurement of the cutaneous temperature based on micro-electro-mechanical systems (MEMS), and to compare these performances with those of a classical thermocouple. Research on this new sensor was carried out to allow the quantification of the thermal properties of the made-up skin. METHODS: Sixteen female subjects divided into two different age groups (18-35 and >50 years old) were recruited for this study. Several zones of the face and forearms were made up at random with foundations containing or not a thermoregulator raw material. The quantity of foundation applied on the skin was standardized and measurements were carried out first before make-up, and then 10 s and 5 min after make-up. The new sensor and the thermocouple were used successively on each zone. The cutaneous temperature was expressed in degrees celsius. RESULTS/CONCLUSION: The two systems are similar in terms of repeatability and reproducibility, with some differences in sensibility. The data measured by the MEMS sensor appear lower than those measured by the thermocouple. After make-up, the MEMS sensor detects a progressive increase of the temperature in time whereas the thermocouple detects a decrease. We found the same evolution on the face but in a more attenuated way. These results tend to show that the devices do not measure the same phenomenon. The thermocouple appears more sensitive to the thermal response of the made-up surface whereas the MEMS sensor appears more sensitive to the heat transfers in the interface between the skin and make-up.  相似文献   
110.
OBJECTIVE: To establish reference intervals for the fetal right, left and total lung volumes and heart volume between 12 and 32 weeks of gestation. METHODS: Fetal lung and heart volumes were measured using three-dimensional (3D) ultrasound in 650 normal singleton pregnancies at 12-32 weeks. The VOCAL (Virtual Organ Computer-aided AnaLysis) technique was used to obtain a sequence of six sections of each lung and the heart around a fixed axis, each after a 30 degrees rotation from the previous one. The rotation axis for the lungs extended from the apex to the upper limit of the diaphragm dome, and the rotation axis for the heart extended from its apex to its connection to the great vessels. The contour of each of these organs was drawn manually in the six different rotation planes to obtain the 3D volume measurement. In 60 cases the fetal lungs and heart volumes were measured by the same sonographer twice and also by a second sonographer once in order to compare the measurements and calculate intra- and interobserver agreement. RESULTS: The total lung volume and heart volume increased with gestation, from respective mean values of 1.6 and 0.6 mL at 12 weeks to 10.9 and 4.3 mL at 20 weeks and 49.3 and 26.6 mL at 32 weeks. The right to left lung volume ratio did not change significantly with gestation (median, 0.7), whereas the heart to total lung volume ratio increased with gestation from about 0.3 at 12 weeks to 0.5 at 32 weeks. In the Bland-Altman plot, the difference between paired measurements by two sonographers was, in 95% of the cases, less than 0.05, 0.5 and 1.9 mL for each lung at 12-13, 19-22 and 29-32 weeks, respectively, and the corresponding values for the heart volumes were 0.04, 0.4 and 2.3 mL. CONCLUSIONS: In normal fetuses the lung and heart volumes increase between 12 and 32 weeks of gestation. The extent to which in pathological pregnancies possible deviations in these measurements from normal prove to be useful in the prediction of outcome remains to be determined.  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