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   1124766篇
  免费   77338篇
  国内免费   1501篇
耳鼻咽喉   15493篇
儿科学   36003篇
妇产科学   29682篇
基础医学   160150篇
口腔科学   30687篇
临床医学   100681篇
内科学   213243篇
皮肤病学   25150篇
神经病学   85926篇
特种医学   45003篇
外国民族医学   201篇
外科学   171629篇
综合类   22460篇
现状与发展   1篇
一般理论   318篇
预防医学   79793篇
眼科学   25613篇
药学   89732篇
  8篇
中国医学   2855篇
肿瘤学   68977篇
  2021年   8578篇
  2019年   8721篇
  2018年   12467篇
  2017年   9769篇
  2016年   11025篇
  2015年   12349篇
  2014年   16848篇
  2013年   24505篇
  2012年   34019篇
  2011年   35838篇
  2010年   20883篇
  2009年   19523篇
  2008年   33056篇
  2007年   35382篇
  2006年   36000篇
  2005年   34225篇
  2004年   32638篇
  2003年   31380篇
  2002年   30195篇
  2001年   60833篇
  2000年   62248篇
  1999年   51706篇
  1998年   13053篇
  1997年   11487篇
  1996年   11466篇
  1995年   10821篇
  1994年   9770篇
  1993年   9246篇
  1992年   38324篇
  1991年   36770篇
  1990年   36222篇
  1989年   34754篇
  1988年   31296篇
  1987年   30360篇
  1986年   28593篇
  1985年   26843篇
  1984年   19530篇
  1983年   16422篇
  1982年   9078篇
  1979年   17291篇
  1978年   11640篇
  1977年   10428篇
  1976年   9037篇
  1975年   10243篇
  1974年   11859篇
  1973年   11462篇
  1972年   10936篇
  1971年   10242篇
  1970年   9424篇
  1969年   9098篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Clinical Oral Investigations - The aims of this study are to assess different saliva substitutes for their efficacy to lubricate the oral cavity, and to relate this oral lubrication to the ability...  相似文献   
82.
83.
84.
85.
86.

Background

Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.

Methods

A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.

Results

The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).

Conclusion

Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.

Level of Evidence

Therapeutic Level IV.  相似文献   
87.
At this study a multi-criteria model was developed to examine the available procedures, techniques and methods of handling infectious waste in the large healthcare unit of University Regional General Hospital of Patras, Western Greece. Particularly, this study examined the: a) current legislation and Directives issued for medical waste management at Greece and among the other EU-members, b) contribution of healthcare wastes (HCW) generation rate on social and economic parameters in selected European countries, c) available procedures, techniques, and methods upon the disposal of infectious wastes at the healthcare studied, and, d) propositions for integrated management of such hazardous wastes. Specifically, the Analytic Hierarchy Process (AHP) methodology was applied under pair wise comparison matrices in two stages: 1) the scale factors and the indicators, and 2) the criteria and their sub–criteria. The assessment of these pair wise matrices included the indicators and the sub–criteria. Subsequently, two pair wise comparison matrices, upon a) the “Fulfillment of environmental objectives” indicator and b) the “Energy consumption” sub criterion, were denoted. The AHP methodology yielded good results; however there is still space of improving the environmental performance. The normalized relative weights obtained for the criteria and sub criteria motivated specific actions that have to be handled. Particularly, the results indicated a very good value in environmental management criteria due the values obtained for the commitment towards the environmental policy standards and the waste management procedures. However, further improvements on staff awareness (such as development programs to enhance sensitivity) and more green purchasing suppliers, should be further addressed.  相似文献   
88.
Hillermann  T.  Homburg  K.  Rainer  M.  Budde  U. 《Der Anaesthesist》2022,71(4):299-302
Die Anaesthesiologie - Eine junge Patientin erleidet während der Anlage einer axillären Plexusblockade einen generalisierten Krampfanfall. Die Mechanismen, im Wesentlichen die vermutlich...  相似文献   
89.
90.
The recent death of our colleague and friend Professor Sir Michael Rutter has quite rightly been greeted by an outpouring of gratitude and respect from distinguished commentators across the globe working in diverse fields of the basic, social and clinical sciences as well as from clinicians and policy makers. These have without exception highlighted his seminal role as a pioneer, perhaps The Pioneer, of the application of the scientific method to the study of child and adolescent mental health and disorder – the father of evidence-based Child Psychiatry and the most influential voice in the new field of Developmental Psychopathology (Stevenson, 2022). In this editorial, we will attempt to build on these commentaries. We will parse Mike’s scientific contributions to our field, in order to identify the personal characteristics and intellectual modus operandi that made him such a uniquely important figure, whose influence will resonate through the many fields he influenced for decades to come. We will also attempt something of a reframing of that contribution. Our thesis being that, although he never agitated for it politically or even stated it as a goal explicitly, Mike’s work was motivated by a desire for social reform and created the scientific catalyst for such reform to occur.  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