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   1093714篇
  免费   79938篇
  国内免费   2746篇
耳鼻咽喉   14517篇
儿科学   38684篇
妇产科学   31767篇
基础医学   158337篇
口腔科学   30066篇
临床医学   97143篇
内科学   211467篇
皮肤病学   25683篇
神经病学   86686篇
特种医学   42622篇
外国民族医学   337篇
外科学   165258篇
综合类   25122篇
一般理论   408篇
预防医学   82725篇
眼科学   25495篇
药学   78675篇
  3篇
中国医学   2304篇
肿瘤学   59099篇
  2018年   11272篇
  2017年   8842篇
  2016年   10267篇
  2015年   11573篇
  2014年   15746篇
  2013年   23964篇
  2012年   31570篇
  2011年   33509篇
  2010年   20144篇
  2009年   19051篇
  2008年   31461篇
  2007年   33391篇
  2006年   33943篇
  2005年   32737篇
  2004年   31983篇
  2003年   30716篇
  2002年   29691篇
  2001年   52440篇
  2000年   53546篇
  1999年   44889篇
  1998年   12509篇
  1997年   11351篇
  1996年   11232篇
  1995年   10757篇
  1994年   9983篇
  1993年   9374篇
  1992年   35290篇
  1991年   34305篇
  1990年   33889篇
  1989年   32632篇
  1988年   29620篇
  1987年   29692篇
  1986年   27742篇
  1985年   26763篇
  1984年   20036篇
  1983年   16834篇
  1982年   10061篇
  1981年   9135篇
  1979年   18448篇
  1978年   13385篇
  1977年   11285篇
  1976年   10576篇
  1975年   11221篇
  1974年   13396篇
  1973年   12882篇
  1972年   11784篇
  1971年   10970篇
  1970年   10147篇
  1969年   9410篇
  1968年   8771篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
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   
992.
993.
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   
994.
995.
996.
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   
997.
998.
Thirty patients with progressive metastatic breast cancer and one prior chemotherapy regimen were treated with iproplatin at a starting dose of 300 mg/m2 iv every 3 weeks. After the first 11 patients, the starting dose was decreased to 270 mg/m2. There were one complete remission, three partial remissions, and two minor responses. Responses were observed in soft tissue and osseous and visceral areas. Grade 3 nausea and vomiting were observed in 38% of patients, and grade 3 diarrhea occurred in 31%. The dose-limiting toxicity was thrombocytopenia, which required dose de-escalation in 15 patients. No nephrotoxicity, neurotoxicity, or ototoxicity was observed. Iproplatin has modest antitumor activity in this group of previously treated patients with metastatic breast cancer.  相似文献   
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