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   1136083篇
  免费   80346篇
  国内免费   2935篇
耳鼻咽喉   15504篇
儿科学   39473篇
妇产科学   32093篇
基础医学   164863篇
口腔科学   31755篇
临床医学   100668篇
内科学   218131篇
皮肤病学   26890篇
神经病学   92046篇
特种医学   45831篇
外国民族医学   326篇
外科学   171513篇
综合类   24688篇
一般理论   412篇
预防医学   84487篇
眼科学   26534篇
药学   81639篇
  3篇
中国医学   2352篇
肿瘤学   60156篇
  2018年   12946篇
  2017年   10162篇
  2016年   12067篇
  2015年   13639篇
  2014年   17625篇
  2013年   26461篇
  2012年   35983篇
  2011年   37284篇
  2010年   22329篇
  2009年   20495篇
  2008年   35229篇
  2007年   37596篇
  2006年   38103篇
  2005年   37140篇
  2004年   36001篇
  2003年   34828篇
  2002年   33664篇
  2001年   51312篇
  2000年   52530篇
  1999年   44109篇
  1998年   12418篇
  1997年   11105篇
  1996年   10920篇
  1995年   10399篇
  1994年   9659篇
  1993年   9025篇
  1992年   33991篇
  1991年   33182篇
  1990年   32658篇
  1989年   31445篇
  1988年   28565篇
  1987年   28673篇
  1986年   26707篇
  1985年   25844篇
  1984年   19378篇
  1983年   16309篇
  1982年   9857篇
  1981年   8894篇
  1979年   17973篇
  1978年   13019篇
  1977年   11024篇
  1976年   10351篇
  1975年   11057篇
  1974年   13205篇
  1973年   12682篇
  1972年   11736篇
  1971年   10938篇
  1970年   10137篇
  1969年   9425篇
  1968年   8787篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Migraine is considered to be a functional neurological disorder. In classical migraine (headache associated with prodromal visual field disturbances) and migraine accompagnée (headache associated with transient neurological symptoms), disturbances of cerebral blood flow and amine metabolism are thought to be pathogenetic factors. However, conventional methods of neuroimaging (CAT, NMR) usually do not yield any pathological findings in patients. Since 123I-iodoamphetamine (123I-IMP) crosses the intact blood brain barrier, 123I-IMP-SPECT is used for the assessment of cerebral perfusion in various neurological diseases, including functional disorders. 123I-IMP-SPECT was performed on 5 patients with classical migraine and 18 patients with migraine accompagnée. At the time of investigation, all patients were symptom-free. Cerebral blood flow was decreased in all patients with migraine accompagnée, and often corresponded to the site of headache as well as to the topography of transient neurological symptoms. This reduction was most obvious in a patient with persisting neurological symptoms. Most patients with classical migraine, however, did not show any alteration of cerebral perfusion. It appears that migraine--and in particular migraine accompagnée--is characterized by a permanent alteration not only of cerebral blood flow but also of neuronal activity. Migraine attacks may occur in connection with exacerbations of preexisting metabolic alterations.  相似文献   
993.
994.
A 68-year-old patient was scheduled for a thoracotomy. A double-lumen endobronchial tube was requested by the surgeon to facilitate operating conditions. Initial attempts at intubation by conventional methods were unsuccessful. The proximal ends of a 37F double-lumen tube were then shortened and a 4-mm fibreoptic bronchoscope was passed through the bronchial lumen. The patient's larynx was easily visualized and the bronchoscope was passed into the trachea. The double lumen tube was then advanced over the bronchoscope and correctly positioned. Shortening a double-lumen tube allows the use of a fibreoptic bronchoscope to aid in tracheal intubation in a patient whose larynx is difficult to visualize by conventional methods.  相似文献   
995.
996.
997.
Bone-marrow regeneration after chemo- and radiotherapy-induced aplasia can be monitored by serum levels of myeloperoxidase (MPO), lysozyme (LYS) and lactoferrin (LF). In 10 patients with leukemia, serum measurements were performed before and after bone-marrow transplantation. Bone-marrow regeneration was suggested by increments in serum MPO and LYS 5 and 4 days prior to the increase in mononuclear cells (Mono) and 10 and 9 d before the increase in polymorphonuclear leukocytes (PMN) in the peripheral blood. LF started to rise 4.5 d before detectable circulating PMNs. 2 patients with early relapses of leukemia post transplantation are shown to display atypical patterns of serum MPO and LYS. We conclude that serum measurements of MPO, LYS and LF may be used as early and sensitive means to monitor bone-marrow activity during hematological regeneration. However, the findings also strongly support the earlier proposal that MPO alone may be used to reflect myeloid activity in the bone-marrow in general.  相似文献   
998.
999.
1000.
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