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   1143754篇
  免费   86237篇
  国内免费   3776篇
耳鼻咽喉   15081篇
儿科学   37194篇
妇产科学   31897篇
基础医学   167355篇
口腔科学   30817篇
临床医学   104320篇
内科学   221559篇
皮肤病学   26920篇
神经病学   90165篇
特种医学   45761篇
外国民族医学   305篇
外科学   169257篇
综合类   25668篇
现状与发展   5篇
一般理论   465篇
预防医学   86818篇
眼科学   26573篇
药学   84607篇
  3篇
中国医学   3566篇
肿瘤学   65431篇
  2021年   11474篇
  2019年   10671篇
  2018年   14655篇
  2017年   11251篇
  2016年   13326篇
  2015年   15959篇
  2014年   20931篇
  2013年   29897篇
  2012年   40958篇
  2011年   42397篇
  2010年   25360篇
  2009年   23158篇
  2008年   37485篇
  2007年   39033篇
  2006年   38752篇
  2005年   37086篇
  2004年   35522篇
  2003年   33494篇
  2002年   31802篇
  2001年   50343篇
  2000年   51176篇
  1999年   42855篇
  1998年   12326篇
  1997年   10976篇
  1996年   10991篇
  1995年   10528篇
  1994年   9749篇
  1993年   9061篇
  1992年   33513篇
  1991年   32734篇
  1990年   32084篇
  1989年   30861篇
  1988年   28117篇
  1987年   28155篇
  1986年   26272篇
  1985年   25318篇
  1984年   18932篇
  1983年   15984篇
  1982年   9625篇
  1979年   17287篇
  1978年   12552篇
  1977年   10637篇
  1976年   10046篇
  1975年   10435篇
  1974年   12631篇
  1973年   12119篇
  1972年   11142篇
  1971年   10292篇
  1970年   9563篇
  1969年   8878篇
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
51.
52.
53.
Scrub typhus usually presents as acute undifferentiated fever. This cross-sectional study included adult patients presenting with acute undifferentiated fever defined as any febrile illness for ≤ 14 days without evidence of localized infection. Scrub typhus cases were defined by an antibody titer of a ≥ fourfold increase in paired sera, a ≥ 1:160 in a single serum using indirect immunofluorescence assay, or a positive result of the immunochromatographic test. Multiple regression analysis identified predictors associated with scrub typhus to develop a prediction rule. Of 250 cases with known etiology of acute undifferentiated fever, influenza (28.0%), hepatitis A (25.2%), and scrub typhus (16.4%) were major causes. A prediction rule for identifying suspected cases of scrub typhus consisted of age ≥ 65 years (two points), recent fieldwork/outdoor activities (one point), onset of illness during an outbreak period (two points), myalgia (one point), and eschar (two points). The c statistic was 0.977 (95% confidence interval = 0.960–0.994). At a cutoff value ≥ 4, the sensitivity and specificity were 92.7% (79.0–98.1%) and 90.9% (86.0–94.3%), respectively. Scrub typhus, the third leading cause of acute undifferentiated fever in our region, can be identified early using the prediction rule.  相似文献   
54.
55.
Vaskulitiden     
  相似文献   
56.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
57.
58.
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose embryo-related genetic abnormalities for couples who present a high risk of a specific inherited disorder. Because this technology involves embryo selection, the medical, bioethical, and legal implications of the technique have been debated, particularly when it is used to select features that are not related to serious diseases. Although several initiatives have attempted to achieve regulatory harmonization, the diversity of healthcare services available and the presence of cultural differences have hampered attempts to achieve this goal. Thus, in different countries, the provision of PGD and regulatory frameworks reflect the perceptions of scientific groups, legislators, and society regarding this technology. In Brazil, several texts have been analyzed by the National Congress to regulate the use of assisted reproduction technologies. Legislative debates, however, are not conclusive, and limited information has been published on how PGD is specifically regulated. The country requires the development of new regulatory standards to ensure adequate access to this technology and to guarantee its safe practice. This study examined official documents published on PGD regulation in Brazil and demonstrated how little direct oversight of PGD currently exists. It provides relevant information to encourage reflection on a particular regulation model in a Brazilian context, and should serve as part of the basis to enable further reform of the clinical practice of PGD in the country.  相似文献   
59.
60.
A 42‐year‐old man presented with a viral prodrome and tested positive for influenza A. He rapidly deteriorated developing cardiogenic shock, rhabdomyolysis, and acute kidney injury. Patient improved 1 week later with supportive measures including vasopressors, inotropes, and an intraaortic balloon pump. We report this case as it highlights the discordance between echocardiographic ventricular wall thickening as a result of myocardial edema, and electrocardiographic findings at presentation, with a reversal in findings at time of resolution. Additionally, there was some suggestion of a regional pattern to the reduced longitudinal strain.  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