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   7818篇
  免费   532篇
  国内免费   59篇
耳鼻咽喉   40篇
儿科学   184篇
妇产科学   179篇
基础医学   810篇
口腔科学   127篇
临床医学   978篇
内科学   1423篇
皮肤病学   62篇
神经病学   807篇
特种医学   261篇
外科学   802篇
综合类   171篇
一般理论   11篇
预防医学   1035篇
眼科学   139篇
药学   802篇
中国医学   9篇
肿瘤学   569篇
  2024年   8篇
  2023年   41篇
  2022年   74篇
  2021年   169篇
  2020年   104篇
  2019年   176篇
  2018年   182篇
  2017年   157篇
  2016年   188篇
  2015年   198篇
  2014年   260篇
  2013年   380篇
  2012年   572篇
  2011年   582篇
  2010年   307篇
  2009年   285篇
  2008年   497篇
  2007年   577篇
  2006年   565篇
  2005年   603篇
  2004年   553篇
  2003年   482篇
  2002年   459篇
  2001年   99篇
  2000年   74篇
  1999年   111篇
  1998年   106篇
  1997年   92篇
  1996年   75篇
  1995年   54篇
  1994年   42篇
  1993年   50篇
  1992年   38篇
  1991年   19篇
  1990年   22篇
  1989年   12篇
  1988年   17篇
  1987年   18篇
  1986年   21篇
  1985年   17篇
  1984年   20篇
  1983年   20篇
  1982年   18篇
  1981年   17篇
  1980年   10篇
  1979年   9篇
  1978年   6篇
  1977年   5篇
  1976年   4篇
  1975年   8篇
排序方式: 共有8409条查询结果,搜索用时 31 毫秒
21.
Abstract  Brooke Army Medical Center isolated 25 highly antibiotic‐resistant Acinetobacter ssp . (primarily A. baumannii ) from wounded soldiers returning from Iraq. Concern about effective treatment of these organisms led our institution to begin investigating low‐frequency ultrasound (LFU) as a method of increasing the effectiveness of antibiotics on A.baumannii in wound management. Studies have suggested that LFU applied in conjunction with antibiotics may increase their overall effectiveness. We hypothesize that combining antibiotics with LFU may be an effective method of wound management and that this combination may be synergistic in its overall effect. In this initial work, we wanted to determine if sonocation would have an effect on our organism of interest, A. baumannii . We selected several organisms, both gram positive and gram negative, that have been shown to be killed by sonocation ( E. coli, S. aureus , and S. pyogenes ) and added three highly resistant A. baumannii isolates. Bacterial death was measured by both colony counts after 24 hours of growth and acridine orange staining using a standard protocol.
Colony counts were significantly reduced by sonocation. Furthermore, A.'baumannii colony counts were also greatly reduced by sonocation. Actual cell destruction was also visualized using acridine orange staining. Our data support the assertion that sonocation has an antibacterial effect on some bacteria, including A. baumannii . Our next step is to add antimicrobial agents and determine if their effectiveness can be increased by sonocation.  相似文献   
22.
We present a case of intermittent cessation of blood flow through stent struts during systole, with normal flow during diastole in the previously stented ostial vein graft. After reviewing the initial procedure, we discovered that the operator had difficulty in positioning the stent. After stent deployment, the ostial stent was malpositioned and was protruding more than 50% into the aorta. During systole, the contrast in the stent struts, which are situated in the aorta, was being washed off by systolic blood flow, while in the diastole, the flow of contrast was normal. This is the first case report of this observation with a brief review.  相似文献   
23.
The Great Safety Performance model uses leading indicators to drive injury prevention and provides a process to improve a company's safety outcomes by maximizing the conditions for safety within the workplace. The model asserts that leaders and workers need to jointly create conditions whereby everyone will know what to do, be able to do it, be equipped to do it, want to do it, and experience interactions that support safe performance in their job duties. These factors are referred to as the conditions for great performance. The Great Safety Performance model can serve as a vehicle to quantify, document, and demonstrate the efforts a company invests to create a safe workplace with safe work practices. By using the Great Safety Performance model, organizations can design and implement a variety of high leverage improvement initiatives specific to their business situations.  相似文献   
24.
‘Wandering’ is one of the most troublesome of behavioural problems in dementia. The term ‘wandering’ covers many different types of behaviour. We examined the hypothesis that the different types of wandering behaviour seen in dementia from a scale using data collected on 83 elderly subjects suffering from either Alzheimer's disease or multiinfarct dementia. We reject the scaling hypothesis. Our data suggest that there are three main categories of wandering behaviour, and that one of these categories is usefully divided into four subcategories.  相似文献   
25.
26.
27.
28.
Recurrence of hepatitis C (HCV) following liver transplantation is common. Herpesvirus reactivation following transplant may have an immunomodulatory effect resulting in increased HCV replication. We studied whether cytomegalovirus (CMV) and human herpesvirus-6 (HHV-6) may be associated with HCV recurrence and viral load after transplant. We prospectively followed 66 HCV liver-transplant recipients with serial viral load testing for CMV and HHV-6. Infection and viral load were correlated with the development of biopsy-proven HCV recurrence and HCV viral loads. Histologic recurrence of HCV occurred in 41/66 (62.1%) patients. In the primary analysis, CMV infection and disease, and HHV-6 infection were not associated with HCV recurrence. Peak CMV and HHV-6 viral loads were not significantly different in patients with and without recurrence. No correlation was observed between HCV viral loads at 1 and 3 months post-transplant and peak HHV-6 or CMV viral loads. In a subgroup analysis, HHV-6 infection was associated with the development of more severe recurrence (hepatitis and/or fibrosis score > or = 2) (p = 0.01). Also, fibrosis scores at last follow up were higher in patients with CMV disease (1.67 vs. 0.56; p = 0.016) and in patients with HHV-6 infection (1.18 vs. 0.55; p = 0.031). In conclusion, HHV-6 and CMV infection and viral load were not associated with increased overall rates of HCV recurrence or HCV viral load after liver transplantation but may be associated with more severe forms of recurrence.  相似文献   
29.
30.
We sought to quantify the systematic and random errors associated with-artifacts in the platens compression test for trabecular bone. Our hypothesis was that while errors may depend on anatomic site, they do not depend on apparent density and therefore have substantial random components. Trabecular bone specimens were first tested nondestructively using newly developed accurate protocols and then were tested again using the platens compression test. Percentage differences in modulus between the techniques (bovine) proximal tibia [n = 18] and humerus [n = 17] and human lumbar spine, [n = 9] were in the range of 4-86%. These differences did not depend on anatomic site (p = 0.21) and were only weakly dependent on apparent density and specimen aspect ratio (r2 < 0.10). The mean percentage difference in modulus was 32.6% representing the systematic component of the end-artifact error. Neglecting the minor variations explained by density and specimen size (approximately 10%), an upper bound on the random error from end-artifacts in this experiment was taken as the SD of the modulus difference (±18.2%). Based on a synthesis of data taken from this study and from the literature, we concluded that the systematic underestimation error in the platens compression test can be only approximated and is in the range of 20-40%; the substantial random error (±12.5%) confounds correction, particularly when the sample size is small. These errors should be considered when interpreting results from the platens test, and more accurate testing techniques should be used when such errors are not acceptable.  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