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   1166篇
  免费   106篇
  国内免费   22篇
耳鼻咽喉   5篇
儿科学   76篇
妇产科学   17篇
基础医学   111篇
口腔科学   43篇
临床医学   103篇
内科学   173篇
皮肤病学   30篇
神经病学   86篇
特种医学   277篇
外科学   144篇
综合类   39篇
一般理论   1篇
预防医学   67篇
眼科学   4篇
药学   61篇
肿瘤学   57篇
  2021年   13篇
  2019年   11篇
  2018年   15篇
  2017年   17篇
  2016年   23篇
  2015年   23篇
  2014年   20篇
  2013年   23篇
  2012年   25篇
  2011年   27篇
  2010年   32篇
  2009年   27篇
  2008年   28篇
  2007年   22篇
  2006年   25篇
  2005年   22篇
  2004年   27篇
  2003年   23篇
  2002年   24篇
  2001年   27篇
  2000年   30篇
  1999年   18篇
  1998年   43篇
  1997年   47篇
  1996年   44篇
  1995年   39篇
  1994年   24篇
  1993年   34篇
  1992年   25篇
  1991年   29篇
  1990年   21篇
  1989年   31篇
  1988年   37篇
  1987年   52篇
  1986年   29篇
  1985年   21篇
  1984年   17篇
  1983年   22篇
  1982年   15篇
  1981年   29篇
  1980年   22篇
  1979年   13篇
  1978年   10篇
  1977年   15篇
  1976年   26篇
  1975年   12篇
  1972年   12篇
  1971年   10篇
  1969年   10篇
  1968年   10篇
排序方式: 共有1294条查询结果,搜索用时 15 毫秒
1.
2.
3.
Four outbreaks of influenza B infection occurred in Houston, Texas in the years 1976-1984. In the Houston Family Study, age-related infection and illness rates in the recent two epidemics resembled those reported previously. A total of 118 persons, including 35 children followed from birth, were followed longitudinally through this entire period and 331 persons were studied through at least two outbreaks. Fifty-nine (88%) of 67 children studied for four outbreaks were infected and 25% had a second infection; about half of the adults had one infection but only one of 51 was reinfected. Infection rates were proportionally lower for those followed through 2-3 outbreaks. Those with documented infection were protected decreasingly over time against reinfection and associated illness in subsequent epidemics. Such protection decreased in efficacy from 65% after 2-3 years, to 46% after 4-5 years, and to no protection after seven years.  相似文献   
4.
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.  相似文献   
5.
6.
7.
Development of a new wound dressing with antimicrobial delivery capability   总被引:1,自引:0,他引:1  
A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved.  相似文献   
8.
9.
PURPOSETo describe the in vivo CT appearance of acute intracerebral blood clots formed from anemic platelet-depleted blood.METHODSThree patients with intracerebral hemorrhage secondary only to thrombocytopenia were examined with CT within 2 1/2 hours after the onset of clinical symptoms.RESULTSThere were no unusual CT features found in the intracerebral hemorrhages of patients with only thrombocytopenia. Specifically, a hyperdense zone(s) surrounded by areas of decreased density was identified.CONCLUSIONClot retraction (which cannot occur in patients with severe thrombocytopenia) is not necessary for the CT appearance of acute intracerebral hemorrhage.  相似文献   
10.
The use of self-expanding prostheses in the management of malignant oesophageal strictures has become well established. The majority of benign peptic oesophageal strictures can be successfully managed using endoscopic or fluoroscopically guided balloon oesophageal dilatation combined with long-term drug therapy, particularly using proton pumper inhibitors. Although endoscopic oesophageal dilatation can be performed on an outpatient basis, it requires repeated hospital visits. There is a small risk of oesophageal perforation whilst cardio-respiratory complications may be encountered during the use of intravenous sedation in an elderly population. The use of a self-expanding Strecker stent in a 98 year old woman with a benign oesophageal stricture is described.  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