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   459篇
  免费   25篇
  国内免费   9篇
儿科学   23篇
妇产科学   5篇
基础医学   35篇
口腔科学   14篇
临床医学   54篇
内科学   122篇
皮肤病学   9篇
神经病学   31篇
特种医学   99篇
外科学   29篇
综合类   30篇
预防医学   16篇
眼科学   4篇
药学   2篇
肿瘤学   20篇
  2023年   1篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2018年   3篇
  2017年   6篇
  2016年   3篇
  2015年   9篇
  2014年   6篇
  2013年   10篇
  2012年   6篇
  2011年   14篇
  2010年   22篇
  2009年   18篇
  2008年   10篇
  2007年   19篇
  2006年   16篇
  2005年   9篇
  2004年   13篇
  2003年   5篇
  2002年   4篇
  2001年   8篇
  2000年   3篇
  1999年   5篇
  1998年   26篇
  1997年   25篇
  1996年   36篇
  1995年   19篇
  1994年   14篇
  1993年   19篇
  1992年   3篇
  1991年   5篇
  1990年   9篇
  1989年   11篇
  1988年   17篇
  1987年   13篇
  1986年   14篇
  1985年   10篇
  1984年   9篇
  1983年   12篇
  1982年   7篇
  1981年   13篇
  1980年   7篇
  1979年   1篇
  1978年   5篇
  1977年   7篇
  1976年   7篇
  1975年   4篇
  1973年   2篇
  1972年   1篇
排序方式: 共有493条查询结果,搜索用时 0 毫秒
21.
T1‐weighted fluid‐attenuated inversion recovery (FLAIR) sequence is a relatively new pulse sequence for intracranial MR imaging. This study was performed to compare the image quality of T1‐weighted FLAIR with the T1‐weighted FSE sequence. Twenty patients with brain lesions underwent T1‐weighted fast spin‐echo (FSE) and T1‐weighted FLAIR during the same imaging session. Four quantitative and three qualitative criteria were used to compare the two sequences after contrast. Two of four quantitative criteria pertained to lesion characteristics: lesion to white matter (WM) contrast‐to‐noise ratio (CNR) and lesion to cerebrospinal fluid (CSF) CNR, and two related to signals from normal tissue: grey matter to WM CNR and WM to CSF CNR. The three qualitative criteria were conspicuousness of the lesion, the presence of image artefacts and the overall image contrast. Both T1‐weighted FSE and FLAIR images were effective in demonstrating lesions. Image contrast was superior in T1‐weighted FLAIR images with significantly improved grey matter‐WM CNRs and CSF‐WM CNRs. The overall image contrast was judged to be superior on T1‐weighted FLAIR images compared with T1‐weighted FSE images by all neuroradiologists. Two of three reviewers considered that the FLAIR images had slightly increased imaging artefacts that, however, did not interfere with image interpretation. T1‐weighted FLAIR imaging provides improved lesion‐to‐background and grey to WM contrast‐to‐noise ratios. Superior conspicuity of lesions and overall image contrast is obtained in comparable acquisition times. These indicate an important role for T1‐weighted FLAIR in intracranial imaging and highlight its advantage over the more widely practiced T1‐weighted FSE sequence.  相似文献   
22.
23.
24.
High-dose intravenous gammaglobulin (IVIgG) was given to 12 children and adults with chronic idiopathic thrombocytopenic purpura (ITP) to avoid splenectomy or because they either failed to respond to or required maintenance with high doses of steroids and/or immunosuppressives. The average platelet count increase to initial therapy was 239,500/microliters (range 23,000-790,000). A concomitant IgG Fc receptor blockade, measured by IgG-sensitized 51Cr-labeled autologous erythrocytes, was seen in 11 of 11 patients tested, both splenectomized and not splenectomized, lasting 3-4 wk. Six or more months after treatment, 2 children are in remission, 2 children and 2 adults are stable requiring no therapy with platelet counts of approximately 50,000 and 30,000, respectively, 3 children require maintenance IVIgG therapy at 2-10-wk intervals, and 1 child and 2 adults have become refractory to further IVIgG. Splenectomy was not performed in 4 children. Two adults were able to discontinue daily prednisone. The 3 patients who became unresponsive to Swiss Red Cross gamma-globulin (IgSRK) therapy did so in conjunction with a markedly elevated platelet-associated IgG and IgM. Serum IgM increased an average of 103 mg/dl after the IVIgG infusions. No significant side effects were seen.  相似文献   
25.
26.
27.
敏定偶用于35岁以上妇女的疗效、安全性和周期控制   总被引:11,自引:0,他引:11  
<正> 口服避孕药在投放市场之初,应用于各种年龄段的妇女。然而资料显示早期使用的高剂量口服避孕药会增加心肌梗塞的发病率;在1975年,美国食品药物管理局(FDA)不建议40岁以上的妇女服用避孕药,对30岁以上的吸烟妇女建议她们要么停止吸烟要么改换避孕方式。随着研究的进一步深入及低剂量口服避孕药的问市,已证实任何年龄的非吸烟  相似文献   
28.
Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare recessive disorder resulting from mutations in the autoimmune regulator ( AIRE ) gene. There is no information on AIRE mutations in Indians. In a cross-sectional study, nine patients (eight families), from four referral hospitals in India, were studied for AIRE mutations by direct sequencing. We screened for new mutations in 150 controls by allele-specific PCR. The patients had 1–7 known components of APECED. Three patients had unusual manifestations: presentation with type 1 diabetes; chronic sinusitis and otitis media; and facial dysmorphism. All patients carried homozygous, probably recessive, AIRE mutations. Two unrelated patients from a small in-bred community (Vanika Vaisya) in south India carried an unreported missense mutation, p.V80G, in the N-terminal caspase recruitment domain. Another unique mutation, p.C302X, resulting in a truncated protein with deletion of both zinc-finger domains, was detected in a patient from Gujarat. Neither mutation was detected in controls. Other mutations, previously described in Caucasians, were: 13 base pair deletion (p.C322fsX372) in 4 (38%), and Finn-major (p.R257X) and p.R139X (Sardinian) mutation in one subject each. In conclusion, in this first series of APECED in Indians, we detected AIRE mutations previously reported in Caucasians, as well as unique mutations. Of these, p.V80G is possibly an ancestral mutation in an in-bred community.  相似文献   
29.
30.
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