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   1027077篇
  免费   66589篇
  国内免费   1342篇
耳鼻咽喉   13647篇
儿科学   27646篇
妇产科学   24697篇
基础医学   144269篇
口腔科学   28779篇
临床医学   86455篇
内科学   202468篇
皮肤病学   19662篇
神经病学   81759篇
特种医学   41085篇
外国民族医学   79篇
外科学   168495篇
综合类   18843篇
现状与发展   1篇
一般理论   234篇
预防医学   70359篇
眼科学   22279篇
药学   77534篇
  3篇
中国医学   2167篇
肿瘤学   64547篇
  2018年   19945篇
  2017年   15955篇
  2016年   18446篇
  2015年   9240篇
  2014年   12282篇
  2013年   17752篇
  2012年   27111篇
  2011年   34793篇
  2010年   22588篇
  2009年   20086篇
  2008年   34748篇
  2007年   38240篇
  2006年   26697篇
  2005年   27418篇
  2004年   27032篇
  2003年   27272篇
  2002年   25585篇
  2001年   55016篇
  2000年   57042篇
  1999年   47133篇
  1998年   10922篇
  1997年   9720篇
  1996年   9745篇
  1995年   9088篇
  1994年   8441篇
  1993年   7726篇
  1992年   35622篇
  1991年   34055篇
  1990年   32872篇
  1989年   31994篇
  1988年   29097篇
  1987年   28367篇
  1986年   26393篇
  1985年   25250篇
  1984年   17907篇
  1983年   15210篇
  1982年   7883篇
  1981年   6784篇
  1979年   15882篇
  1978年   10663篇
  1977年   9071篇
  1976年   7944篇
  1975年   8629篇
  1974年   10499篇
  1973年   9869篇
  1972年   9357篇
  1971年   8852篇
  1970年   8450篇
  1969年   7959篇
  1968年   7224篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
Uniparental isodisomy (iUPD) is a rare genetic condition caused by non-disjunction during meiosis that ultimately leads to a duplication of either the maternal or paternal chromosome in the affected individual. Two types of disorders can result, those due to imprinted genes and those due to homozygosity of recessive disease-causing mutations. Here, we describe the third known case of complete chromosome 4 iUPD of maternal origin. This condition became apparent during whole genome linkage studies of psychiatric disorders in the Portuguese population. The proband is an adult female with normal fertility and no major medical complaints, but a history of major depressive disorder and multiple suicide attempts. The proband's siblings and parents had normal chromosome 4 genotypes and no history of mood disturbance. A brief review of other studies lends support for the possibility that genes on chromosome 4 might confer risk for mood disorders. We conclude that chromosome 4 maternal uniparental disomy (UPD) is a rare disorder that may present with a major depressive phenotype. The lack of a common disease phenotype between this and two other cases of chromosome 4 iUPD [Lindenbaum et al. [1991] Am J Med Genet 49(Suppl 285):1582; Spena et al. [2004] Eur J Hum Genet 12:891-898) would suggest that there is no vital maternal gene imprinting on chromosome 4. However, since there is no reported case of paternal chromosome 4 UPD, paternal gene imprinting on chromosome 4 cannot be excluded.  相似文献   
132.
In order to assess the state and pathology of the woman's pelvis minor, a number of methods are commonly used among practitioners, encompassing clinical exploration, radiology, MRN, urodynamics, endoscopy and echography.

Echography has been poorly used in clinical pelvic exploration and its reliability is actually a matter of controversy 1. However, echographic surveys can provide us with valuable gynecological data on the state and pathologies of the soft pelvis, within the genital regions or even going beyond them, i.e. the rectal channel, bladder, urethra, anus, vascular plexuses, and all of their supporting tissues.

At our research unit, we have been employing Transvaginal Ultrasound echography (TVU) for a long time in conjunction with other pelvis-focused methods in order to study different kinds of pelvic alterations. TVU has proven to be friendly to use, fast, harmless and inexpensive, allowing serial explorations and producing high-quality dynamic images (loop-cinema, video-tape). Furthermore, this method is fairly aseptic in that the occurrence of faeces in the rectal ampolla is not a nuisance but a bonus in tracking the contours of the rectum walls and other topographical features which would be otherwise difficult to survey.

A complete pelvic floor TVU may add no longer than 5-8 minutes to a routine gynecological examination, can be implemented by the general gynecologist and generates data that can be further studied by the appropriate specialist for a more insightful evaluation 2.  相似文献   
133.
Iron overload presenting as exacerbation of hepatic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation has not been previously described. We report 6 patients with established hepatic GVHD in whom iron overload (median serum ferritin, 7231 mug/dL; median transferrin saturation, 77%) resulting from a lifetime median of 20 units of packed red blood cell transfusions was manifested by worsening of liver function. Liver biopsies performed in 4 patients confirmed severe iron overload and also hepatic GVHD. Analysis for the C282Y and H63D hemochromatosis gene mutation was negative for the homozygous state in all 6 patients. Erythropoietin-assisted phlebotomy resulted in normalization of liver function at a median of 7 months and of serum ferritin at a median of 11 months. Immunosuppressive therapy was successfully tapered in all 4 patients who completed the phlebotomy program, and this supported the impression that iron overload, rather than GVHD, was the principal cause of liver dysfunction. At a median follow-up of 50 months (range, 18-76 months) from the transplantation and 25 months (range, 5-36 months) from ferritin normalization, all 4 patients require maintenance phlebotomy. We conclude that iron overload can mimic GVHD exacerbation, thus resulting in unnecessary continuation or intensification of immunosuppressive therapy for GVHD, and that maintenance phlebotomy is necessary after successful iron-reduction therapy.  相似文献   
134.
135.
136.
137.
138.
139.
140.
Pyogenic liver abscess: an improvement in prognosis   总被引:3,自引:0,他引:3  
Forty-six patients with pyogenic liver abscess have been treated at Paul Brousse Hospital between 1966 and 1986. The overall mortality was 24 per cent, all 11 deaths occurring in 24 patients seen prior to 1978 when there was often a considerable delay in the diagnosis of liver abscess (mean 90 +/- 71 days). In seven patients the diagnosis was not made until post-mortem examination. The mainstay of treatment was surgical drainage. Since 1978 high resolution imaging techniques for the liver, and in particular ultrasound, have been available. The diagnostic delay has been significantly reduced (mean 28 +/- 20 days, P less than 0.01). Patients are receiving definitive treatment at an earlier stage in the evolution of the disease process, with fewer established complications prior to treatment (P less than 0.05). Percutaneous drainage under ultrasound control is the preferred initial drainage procedure in high-risk patients. There have been no deaths in 22 patients treated for pyogenic liver abscess since 1978 (P less than 0.001).  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